/*
* Delete item(s) from a btree page.
*
* This must only be used for deleting leaf items. Deleting an item on a
* non-leaf page has to be done as part of an atomic action that includes
* deleting the page it points to.
*
* This routine assumes that the caller has pinned and locked the buffer.
* Also, the given itemnos *must* appear in increasing order in the array.
*/
void
_bt_delitems(Relation rel, Buffer buf,
OffsetNumber *itemnos, int nitems,
bool inVacuum)
{
Page page;
BTPageOpaque opaque;
MIRROREDLOCK_BUFMGR_MUST_ALREADY_BE_HELD;
page = BufferGetPage(buf);
// Fetch gp_persistent_relation_node information that will be added to XLOG record.
RelationFetchGpRelationNodeForXLog(rel);
/* No ereport(ERROR) until changes are logged */
START_CRIT_SECTION();
/* Fix the page */
PageIndexMultiDelete(page, itemnos, nitems);
/*
* If this is within VACUUM, we can clear the vacuum cycleID since this
* page has certainly been processed by the current vacuum scan.
*/
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
if (inVacuum)
opaque->btpo_cycleid = 0;
/*
* Mark the page as not containing any LP_DELETE items. This is not
* certainly true (there might be some that have recently been marked, but
* weren't included in our target-item list), but it will almost always be
* true and it doesn't seem worth an additional page scan to check it.
* Remember that BTP_HAS_GARBAGE is only a hint anyway.
*/
opaque->btpo_flags &= ~BTP_HAS_GARBAGE;
MarkBufferDirty(buf);
/* XLOG stuff */
if (!rel->rd_istemp)
{
xl_btree_delete xlrec;
XLogRecPtr recptr;
XLogRecData rdata[2];
xl_btreenode_set(&(xlrec.btreenode), rel);
xlrec.block = BufferGetBlockNumber(buf);
rdata[0].data = (char *) &xlrec;
rdata[0].len = SizeOfBtreeDelete;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
/*
* The target-offsets array is not in the buffer, but pretend that it
* is. When XLogInsert stores the whole buffer, the offsets array
* need not be stored too.
*/
if (nitems > 0)
{
rdata[1].data = (char *) itemnos;
rdata[1].len = nitems * sizeof(OffsetNumber);
}
else
{
rdata[1].data = NULL;
rdata[1].len = 0;
}
rdata[1].buffer = buf;
rdata[1].buffer_std = true;
rdata[1].next = NULL;
recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_DELETE, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
END_CRIT_SECTION();
}
/*
* Shared functionality between saving and creating a replication slot.
*/
static void
SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel)
{
char tmppath[MAXPGPATH];
char path[MAXPGPATH];
int fd;
ReplicationSlotOnDisk cp;
bool was_dirty;
/* first check whether there's something to write out */
{
volatile ReplicationSlot *vslot = slot;
SpinLockAcquire(&vslot->mutex);
was_dirty = vslot->dirty;
vslot->just_dirtied = false;
SpinLockRelease(&vslot->mutex);
}
/* and don't do anything if there's nothing to write */
if (!was_dirty)
return;
LWLockAcquire(slot->io_in_progress_lock, LW_EXCLUSIVE);
/* silence valgrind :( */
memset(&cp, 0, sizeof(ReplicationSlotOnDisk));
sprintf(tmppath, "%s/state.tmp", dir);
sprintf(path, "%s/state", dir);
fd = OpenTransientFile(tmppath,
O_CREAT | O_EXCL | O_WRONLY | PG_BINARY,
S_IRUSR | S_IWUSR);
if (fd < 0)
{
ereport(elevel,
(errcode_for_file_access(),
errmsg("could not create file \"%s\": %m",
tmppath)));
return;
}
cp.magic = SLOT_MAGIC;
INIT_CRC32C(cp.checksum);
cp.version = SLOT_VERSION;
cp.length = ReplicationSlotOnDiskV2Size;
SpinLockAcquire(&slot->mutex);
memcpy(&cp.slotdata, &slot->data, sizeof(ReplicationSlotPersistentData));
SpinLockRelease(&slot->mutex);
COMP_CRC32C(cp.checksum,
(char *) (&cp) + SnapBuildOnDiskNotChecksummedSize,
SnapBuildOnDiskChecksummedSize);
FIN_CRC32C(cp.checksum);
if ((write(fd, &cp, sizeof(cp))) != sizeof(cp))
{
int save_errno = errno;
CloseTransientFile(fd);
errno = save_errno;
ereport(elevel,
(errcode_for_file_access(),
errmsg("could not write to file \"%s\": %m",
tmppath)));
return;
}
/* fsync the temporary file */
if (pg_fsync(fd) != 0)
{
int save_errno = errno;
CloseTransientFile(fd);
errno = save_errno;
ereport(elevel,
(errcode_for_file_access(),
errmsg("could not fsync file \"%s\": %m",
tmppath)));
return;
}
CloseTransientFile(fd);
/* rename to permanent file, fsync file and directory */
if (rename(tmppath, path) != 0)
{
ereport(elevel,
(errcode_for_file_access(),
errmsg("could not rename file \"%s\" to \"%s\": %m",
tmppath, path)));
return;
}
/* Check CreateSlot() for the reasoning of using a crit. section. */
START_CRIT_SECTION();
fsync_fname(path, false);
fsync_fname((char *) dir, true);
fsync_fname("pg_replslot", true);
END_CRIT_SECTION();
/*
* Successfully wrote, unset dirty bit, unless somebody dirtied again
* already.
*/
{
volatile ReplicationSlot *vslot = slot;
SpinLockAcquire(&vslot->mutex);
if (!vslot->just_dirtied)
vslot->dirty = false;
SpinLockRelease(&vslot->mutex);
}
LWLockRelease(slot->io_in_progress_lock);
}
/*
* Physical write of a page from a buffer slot
*
* On failure, we cannot just ereport(ERROR) since caller has put state in
* shared memory that must be undone. So, we return FALSE and save enough
* info in static variables to let SlruReportIOError make the report.
*
* For now, assume it's not worth keeping a file pointer open across
* independent read/write operations. We do batch operations during
* SimpleLruFlush, though.
*
* fdata is NULL for a standalone write, pointer to open-file info during
* SimpleLruFlush.
*/
static bool
SlruPhysicalWritePage(SlruCtl ctl, int pageno, int slotno, SlruFlush fdata)
{
SlruShared shared = ctl->shared;
int segno = pageno / SLRU_PAGES_PER_SEGMENT;
int rpageno = pageno % SLRU_PAGES_PER_SEGMENT;
int offset = rpageno * BLCKSZ;
char path[MAXPGPATH];
int fd = -1;
/*
* Honor the write-WAL-before-data rule, if appropriate, so that we do not
* write out data before associated WAL records. This is the same action
* performed during FlushBuffer() in the main buffer manager.
*/
if (shared->group_lsn != NULL)
{
/*
* We must determine the largest async-commit LSN for the page. This
* is a bit tedious, but since this entire function is a slow path
* anyway, it seems better to do this here than to maintain a per-page
* LSN variable (which'd need an extra comparison in the
* transaction-commit path).
*/
XLogRecPtr max_lsn;
int lsnindex,
lsnoff;
lsnindex = slotno * shared->lsn_groups_per_page;
max_lsn = shared->group_lsn[lsnindex++];
for (lsnoff = 1; lsnoff < shared->lsn_groups_per_page; lsnoff++)
{
XLogRecPtr this_lsn = shared->group_lsn[lsnindex++];
if (max_lsn < this_lsn)
max_lsn = this_lsn;
}
if (!XLogRecPtrIsInvalid(max_lsn))
{
/*
* As noted above, elog(ERROR) is not acceptable here, so if
* XLogFlush were to fail, we must PANIC. This isn't much of a
* restriction because XLogFlush is just about all critical
* section anyway, but let's make sure.
*/
START_CRIT_SECTION();
XLogFlush(max_lsn);
END_CRIT_SECTION();
}
}
/*
* During a Flush, we may already have the desired file open.
*/
if (fdata)
{
int i;
for (i = 0; i < fdata->num_files; i++)
{
if (fdata->segno[i] == segno)
{
fd = fdata->fd[i];
break;
}
}
}
if (fd < 0)
{
/*
* If the file doesn't already exist, we should create it. It is
* possible for this to need to happen when writing a page that's not
* first in its segment; we assume the OS can cope with that. (Note:
* it might seem that it'd be okay to create files only when
* SimpleLruZeroPage is called for the first page of a segment.
* However, if after a crash and restart the REDO logic elects to
* replay the log from a checkpoint before the latest one, then it's
* possible that we will get commands to set transaction status of
* transactions that have already been truncated from the commit log.
* Easiest way to deal with that is to accept references to
* nonexistent files here and in SlruPhysicalReadPage.)
*
* Note: it is possible for more than one backend to be executing this
* code simultaneously for different pages of the same file. Hence,
* don't use O_EXCL or O_TRUNC or anything like that.
*/
SlruFileName(ctl, path, segno);
fd = OpenTransientFile(path, O_RDWR | O_CREAT | PG_BINARY,
S_IRUSR | S_IWUSR);
if (fd < 0)
{
slru_errcause = SLRU_OPEN_FAILED;
slru_errno = errno;
return false;
}
if (fdata)
{
if (fdata->num_files < MAX_FLUSH_BUFFERS)
{
fdata->fd[fdata->num_files] = fd;
fdata->segno[fdata->num_files] = segno;
fdata->num_files++;
}
else
{
/*
* In the unlikely event that we exceed MAX_FLUSH_BUFFERS,
* fall back to treating it as a standalone write.
*/
fdata = NULL;
}
}
}
if (lseek(fd, (off_t) offset, SEEK_SET) < 0)
{
slru_errcause = SLRU_SEEK_FAILED;
slru_errno = errno;
if (!fdata)
CloseTransientFile(fd);
return false;
}
errno = 0;
if (write(fd, shared->page_buffer[slotno], BLCKSZ) != BLCKSZ)
{
/* if write didn't set errno, assume problem is no disk space */
if (errno == 0)
errno = ENOSPC;
slru_errcause = SLRU_WRITE_FAILED;
slru_errno = errno;
if (!fdata)
CloseTransientFile(fd);
return false;
}
/*
* If not part of Flush, need to fsync now. We assume this happens
* infrequently enough that it's not a performance issue.
*/
if (!fdata)
{
if (ctl->do_fsync && pg_fsync(fd))
{
slru_errcause = SLRU_FSYNC_FAILED;
slru_errno = errno;
CloseTransientFile(fd);
return false;
}
if (CloseTransientFile(fd))
{
slru_errcause = SLRU_CLOSE_FAILED;
slru_errno = errno;
return false;
}
}
return true;
}
/*
* Build a pending-list page from the given array of tuples, and write it out.
*
* Returns amount of free space left on the page.
*/
static int32
writeListPage(Relation index, Buffer buffer,
IndexTuple *tuples, int32 ntuples, BlockNumber rightlink)
{
Page page = BufferGetPage(buffer);
int32 i,
freesize,
size = 0;
OffsetNumber l,
off;
char *workspace;
char *ptr;
/* workspace could be a local array; we use palloc for alignment */
workspace = palloc(BLCKSZ);
START_CRIT_SECTION();
GinInitBuffer(buffer, GIN_LIST);
off = FirstOffsetNumber;
ptr = workspace;
for (i = 0; i < ntuples; i++)
{
int this_size = IndexTupleSize(tuples[i]);
memcpy(ptr, tuples[i], this_size);
ptr += this_size;
size += this_size;
l = PageAddItem(page, (Item) tuples[i], this_size, off, false, false);
if (l == InvalidOffsetNumber)
elog(ERROR, "failed to add item to index page in \"%s\"",
RelationGetRelationName(index));
off++;
}
Assert(size <= BLCKSZ); /* else we overran workspace */
GinPageGetOpaque(page)->rightlink = rightlink;
/*
* tail page may contain only whole row(s) or final part of row placed on
* previous pages (a "row" here meaning all the index tuples generated for
* one heap tuple)
*/
if (rightlink == InvalidBlockNumber)
{
GinPageSetFullRow(page);
GinPageGetOpaque(page)->maxoff = 1;
}
else
{
GinPageGetOpaque(page)->maxoff = 0;
}
MarkBufferDirty(buffer);
if (RelationNeedsWAL(index))
{
ginxlogInsertListPage data;
XLogRecPtr recptr;
data.rightlink = rightlink;
data.ntuples = ntuples;
XLogBeginInsert();
XLogRegisterData((char *) &data, sizeof(ginxlogInsertListPage));
XLogRegisterBuffer(0, buffer, REGBUF_WILL_INIT);
XLogRegisterBufData(0, workspace, size);
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_INSERT_LISTPAGE);
PageSetLSN(page, recptr);
}
/* get free space before releasing buffer */
freesize = PageGetExactFreeSpace(page);
UnlockReleaseBuffer(buffer);
END_CRIT_SECTION();
pfree(workspace);
return freesize;
}
/*
* Load a single slot from disk into memory.
*/
static void
RestoreSlotFromDisk(const char *name)
{
ReplicationSlotOnDisk cp;
int i;
char path[MAXPGPATH];
int fd;
bool restored = false;
int readBytes;
pg_crc32c checksum;
/* no need to lock here, no concurrent access allowed yet */
/* delete temp file if it exists */
sprintf(path, "pg_replslot/%s/state.tmp", name);
if (unlink(path) < 0 && errno != ENOENT)
ereport(PANIC,
(errcode_for_file_access(),
errmsg("could not remove file \"%s\": %m", path)));
sprintf(path, "pg_replslot/%s/state", name);
elog(DEBUG1, "restoring replication slot from \"%s\"", path);
fd = OpenTransientFile(path, O_RDWR | PG_BINARY, 0);
/*
* We do not need to handle this as we are rename()ing the directory into
* place only after we fsync()ed the state file.
*/
if (fd < 0)
ereport(PANIC,
(errcode_for_file_access(),
errmsg("could not open file \"%s\": %m", path)));
/*
* Sync state file before we're reading from it. We might have crashed
* while it wasn't synced yet and we shouldn't continue on that basis.
*/
if (pg_fsync(fd) != 0)
{
CloseTransientFile(fd);
ereport(PANIC,
(errcode_for_file_access(),
errmsg("could not fsync file \"%s\": %m",
path)));
}
/* Also sync the parent directory */
START_CRIT_SECTION();
fsync_fname(path, true);
END_CRIT_SECTION();
/* read part of statefile that's guaranteed to be version independent */
readBytes = read(fd, &cp, ReplicationSlotOnDiskConstantSize);
if (readBytes != ReplicationSlotOnDiskConstantSize)
{
int saved_errno = errno;
CloseTransientFile(fd);
errno = saved_errno;
ereport(PANIC,
(errcode_for_file_access(),
errmsg("could not read file \"%s\", read %d of %u: %m",
path, readBytes,
(uint32) ReplicationSlotOnDiskConstantSize)));
}
/* verify magic */
if (cp.magic != SLOT_MAGIC)
ereport(PANIC,
(errcode_for_file_access(),
errmsg("replication slot file \"%s\" has wrong magic %u instead of %u",
path, cp.magic, SLOT_MAGIC)));
/* verify version */
if (cp.version != SLOT_VERSION)
ereport(PANIC,
(errcode_for_file_access(),
errmsg("replication slot file \"%s\" has unsupported version %u",
path, cp.version)));
/* boundary check on length */
if (cp.length != ReplicationSlotOnDiskV2Size)
ereport(PANIC,
(errcode_for_file_access(),
errmsg("replication slot file \"%s\" has corrupted length %u",
path, cp.length)));
/* Now that we know the size, read the entire file */
readBytes = read(fd,
(char *) &cp + ReplicationSlotOnDiskConstantSize,
cp.length);
if (readBytes != cp.length)
{
int saved_errno = errno;
CloseTransientFile(fd);
errno = saved_errno;
ereport(PANIC,
(errcode_for_file_access(),
errmsg("could not read file \"%s\", read %d of %u: %m",
path, readBytes, cp.length)));
}
CloseTransientFile(fd);
/* now verify the CRC */
INIT_CRC32C(checksum);
COMP_CRC32C(checksum,
(char *) &cp + SnapBuildOnDiskNotChecksummedSize,
SnapBuildOnDiskChecksummedSize);
FIN_CRC32C(checksum);
if (!EQ_CRC32C(checksum, cp.checksum))
ereport(PANIC,
(errmsg("replication slot file %s: checksum mismatch, is %u, should be %u",
path, checksum, cp.checksum)));
/*
* If we crashed with an ephemeral slot active, don't restore but delete
* it.
*/
if (cp.slotdata.persistency != RS_PERSISTENT)
{
sprintf(path, "pg_replslot/%s", name);
if (!rmtree(path, true))
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not remove directory \"%s\"", path)));
}
fsync_fname("pg_replslot", true);
return;
}
/* nothing can be active yet, don't lock anything */
for (i = 0; i < max_replication_slots; i++)
{
ReplicationSlot *slot;
slot = &ReplicationSlotCtl->replication_slots[i];
if (slot->in_use)
continue;
/* restore the entire set of persistent data */
memcpy(&slot->data, &cp.slotdata,
sizeof(ReplicationSlotPersistentData));
/* initialize in memory state */
slot->effective_xmin = cp.slotdata.xmin;
slot->effective_catalog_xmin = cp.slotdata.catalog_xmin;
slot->candidate_catalog_xmin = InvalidTransactionId;
slot->candidate_xmin_lsn = InvalidXLogRecPtr;
slot->candidate_restart_lsn = InvalidXLogRecPtr;
slot->candidate_restart_valid = InvalidXLogRecPtr;
slot->in_use = true;
slot->active_pid = 0;
restored = true;
break;
}
if (!restored)
ereport(PANIC,
(errmsg("too many replication slots active before shutdown"),
errhint("Increase max_replication_slots and try again.")));
}
IndexBuildResult *
ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
{
IndexBuildResult *result;
double reltuples;
GinBuildState buildstate;
Buffer RootBuffer,
MetaBuffer;
ItemPointerData *list;
Datum key;
GinNullCategory category;
uint32 nlist;
MemoryContext oldCtx;
OffsetNumber attnum;
if (RelationGetNumberOfBlocks(index) != 0)
elog(ERROR, "index \"%s\" already contains data",
RelationGetRelationName(index));
initGinState(&buildstate.ginstate, index);
buildstate.indtuples = 0;
memset(&buildstate.buildStats, 0, sizeof(GinStatsData));
/* initialize the meta page */
MetaBuffer = GinNewBuffer(index);
/* initialize the root page */
RootBuffer = GinNewBuffer(index);
START_CRIT_SECTION();
GinInitMetabuffer(MetaBuffer);
MarkBufferDirty(MetaBuffer);
GinInitBuffer(RootBuffer, GIN_LEAF);
MarkBufferDirty(RootBuffer);
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
Page page;
XLogBeginInsert();
XLogRegisterBuffer(0, MetaBuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
XLogRegisterBuffer(1, RootBuffer, REGBUF_WILL_INIT);
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_CREATE_INDEX);
page = BufferGetPage(RootBuffer);
PageSetLSN(page, recptr);
page = BufferGetPage(MetaBuffer);
PageSetLSN(page, recptr);
}
UnlockReleaseBuffer(MetaBuffer);
UnlockReleaseBuffer(RootBuffer);
END_CRIT_SECTION();
/* count the root as first entry page */
buildstate.buildStats.nEntryPages++;
/*
* create a temporary memory context that is used to hold data not yet
* dumped out to the index
*/
buildstate.tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
"Gin build temporary context",
ALLOCSET_DEFAULT_SIZES);
/*
* create a temporary memory context that is used for calling
* ginExtractEntries(), and can be reset after each tuple
*/
buildstate.funcCtx = AllocSetContextCreate(CurrentMemoryContext,
"Gin build temporary context for user-defined function",
ALLOCSET_DEFAULT_SIZES);
buildstate.accum.ginstate = &buildstate.ginstate;
ginInitBA(&buildstate.accum);
/*
* Do the heap scan. We disallow sync scan here because dataPlaceToPage
* prefers to receive tuples in TID order.
*/
reltuples = IndexBuildHeapScan(heap, index, indexInfo, false,
ginBuildCallback, (void *) &buildstate);
/* dump remaining entries to the index */
oldCtx = MemoryContextSwitchTo(buildstate.tmpCtx);
ginBeginBAScan(&buildstate.accum);
while ((list = ginGetBAEntry(&buildstate.accum,
&attnum, &key, &category, &nlist)) != NULL)
{
/* there could be many entries, so be willing to abort here */
CHECK_FOR_INTERRUPTS();
ginEntryInsert(&buildstate.ginstate, attnum, key, category,
list, nlist, &buildstate.buildStats);
}
MemoryContextSwitchTo(oldCtx);
MemoryContextDelete(buildstate.funcCtx);
MemoryContextDelete(buildstate.tmpCtx);
/*
* Update metapage stats
*/
buildstate.buildStats.nTotalPages = RelationGetNumberOfBlocks(index);
ginUpdateStats(index, &buildstate.buildStats);
/*
* Return statistics
*/
result = (IndexBuildResult *) palloc(sizeof(IndexBuildResult));
result->heap_tuples = reltuples;
result->index_tuples = buildstate.indtuples;
return result;
}
/*
* Write the index tuples contained in *collector into the index's
* pending list.
*
* Function guarantees that all these tuples will be inserted consecutively,
* preserving order
*/
void
ginHeapTupleFastInsert(GinState *ginstate, GinTupleCollector *collector)
{
Relation index = ginstate->index;
Buffer metabuffer;
Page metapage;
GinMetaPageData *metadata = NULL;
Buffer buffer = InvalidBuffer;
Page page = NULL;
ginxlogUpdateMeta data;
bool separateList = false;
bool needCleanup = false;
int cleanupSize;
bool needWal;
if (collector->ntuples == 0)
return;
needWal = RelationNeedsWAL(index);
data.node = index->rd_node;
data.ntuples = 0;
data.newRightlink = data.prevTail = InvalidBlockNumber;
metabuffer = ReadBuffer(index, GIN_METAPAGE_BLKNO);
metapage = BufferGetPage(metabuffer);
if (collector->sumsize + collector->ntuples * sizeof(ItemIdData) > GinListPageSize)
{
/*
* Total size is greater than one page => make sublist
*/
separateList = true;
}
else
{
LockBuffer(metabuffer, GIN_EXCLUSIVE);
metadata = GinPageGetMeta(metapage);
if (metadata->head == InvalidBlockNumber ||
collector->sumsize + collector->ntuples * sizeof(ItemIdData) > metadata->tailFreeSize)
{
/*
* Pending list is empty or total size is greater than freespace
* on tail page => make sublist
*
* We unlock metabuffer to keep high concurrency
*/
separateList = true;
LockBuffer(metabuffer, GIN_UNLOCK);
}
}
if (separateList)
{
/*
* We should make sublist separately and append it to the tail
*/
GinMetaPageData sublist;
memset(&sublist, 0, sizeof(GinMetaPageData));
makeSublist(index, collector->tuples, collector->ntuples, &sublist);
if (needWal)
XLogBeginInsert();
/*
* metapage was unlocked, see above
*/
LockBuffer(metabuffer, GIN_EXCLUSIVE);
metadata = GinPageGetMeta(metapage);
if (metadata->head == InvalidBlockNumber)
{
/*
* Main list is empty, so just insert sublist as main list
*/
START_CRIT_SECTION();
metadata->head = sublist.head;
metadata->tail = sublist.tail;
metadata->tailFreeSize = sublist.tailFreeSize;
metadata->nPendingPages = sublist.nPendingPages;
metadata->nPendingHeapTuples = sublist.nPendingHeapTuples;
}
else
{
/*
* Merge lists
*/
data.prevTail = metadata->tail;
data.newRightlink = sublist.head;
buffer = ReadBuffer(index, metadata->tail);
LockBuffer(buffer, GIN_EXCLUSIVE);
page = BufferGetPage(buffer);
Assert(GinPageGetOpaque(page)->rightlink == InvalidBlockNumber);
START_CRIT_SECTION();
GinPageGetOpaque(page)->rightlink = sublist.head;
MarkBufferDirty(buffer);
metadata->tail = sublist.tail;
metadata->tailFreeSize = sublist.tailFreeSize;
metadata->nPendingPages += sublist.nPendingPages;
metadata->nPendingHeapTuples += sublist.nPendingHeapTuples;
if (needWal)
XLogRegisterBuffer(1, buffer, REGBUF_STANDARD);
}
}
else
{
/*
* Insert into tail page. Metapage is already locked
*/
OffsetNumber l,
off;
int i,
tupsize;
char *ptr;
char *collectordata;
buffer = ReadBuffer(index, metadata->tail);
LockBuffer(buffer, GIN_EXCLUSIVE);
page = BufferGetPage(buffer);
off = (PageIsEmpty(page)) ? FirstOffsetNumber :
OffsetNumberNext(PageGetMaxOffsetNumber(page));
collectordata = ptr = (char *) palloc(collector->sumsize);
data.ntuples = collector->ntuples;
if (needWal)
XLogBeginInsert();
START_CRIT_SECTION();
/*
* Increase counter of heap tuples
*/
Assert(GinPageGetOpaque(page)->maxoff <= metadata->nPendingHeapTuples);
GinPageGetOpaque(page)->maxoff++;
metadata->nPendingHeapTuples++;
for (i = 0; i < collector->ntuples; i++)
{
tupsize = IndexTupleSize(collector->tuples[i]);
l = PageAddItem(page, (Item) collector->tuples[i], tupsize, off, false, false);
if (l == InvalidOffsetNumber)
elog(ERROR, "failed to add item to index page in \"%s\"",
RelationGetRelationName(index));
memcpy(ptr, collector->tuples[i], tupsize);
ptr += tupsize;
off++;
}
Assert((ptr - collectordata) <= collector->sumsize);
if (needWal)
{
XLogRegisterBuffer(1, buffer, REGBUF_STANDARD);
XLogRegisterBufData(1, collectordata, collector->sumsize);
}
metadata->tailFreeSize = PageGetExactFreeSpace(page);
MarkBufferDirty(buffer);
}
/*
* Write metabuffer, make xlog entry
*/
MarkBufferDirty(metabuffer);
if (needWal)
{
XLogRecPtr recptr;
memcpy(&data.metadata, metadata, sizeof(GinMetaPageData));
XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT);
XLogRegisterData((char *) &data, sizeof(ginxlogUpdateMeta));
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_UPDATE_META_PAGE);
PageSetLSN(metapage, recptr);
if (buffer != InvalidBuffer)
{
PageSetLSN(page, recptr);
}
}
if (buffer != InvalidBuffer)
UnlockReleaseBuffer(buffer);
/*
* Force pending list cleanup when it becomes too long. And,
* ginInsertCleanup could take significant amount of time, so we prefer to
* call it when it can do all the work in a single collection cycle. In
* non-vacuum mode, it shouldn't require maintenance_work_mem, so fire it
* while pending list is still small enough to fit into
* gin_pending_list_limit.
*
* ginInsertCleanup() should not be called inside our CRIT_SECTION.
*/
cleanupSize = GinGetPendingListCleanupSize(index);
if (metadata->nPendingPages * GIN_PAGE_FREESIZE > cleanupSize * 1024L)
needCleanup = true;
UnlockReleaseBuffer(metabuffer);
END_CRIT_SECTION();
if (needCleanup)
ginInsertCleanup(ginstate, true, NULL);
}
/*
* Initialize a sequence's relation with the specified tuple as content
*/
static void
fill_seq_with_data(Relation rel, HeapTuple tuple)
{
Buffer buf;
Page page;
sequence_magic *sm;
OffsetNumber offnum;
/* Initialize first page of relation with special magic number */
buf = ReadBuffer(rel, P_NEW);
Assert(BufferGetBlockNumber(buf) == 0);
page = BufferGetPage(buf);
PageInit(page, BufferGetPageSize(buf), sizeof(sequence_magic));
sm = (sequence_magic *) PageGetSpecialPointer(page);
sm->magic = SEQ_MAGIC;
/* Now insert sequence tuple */
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
/*
* Since VACUUM does not process sequences, we have to force the tuple to
* have xmin = FrozenTransactionId now. Otherwise it would become
* invisible to SELECTs after 2G transactions. It is okay to do this
* because if the current transaction aborts, no other xact will ever
* examine the sequence tuple anyway.
*/
HeapTupleHeaderSetXmin(tuple->t_data, FrozenTransactionId);
HeapTupleHeaderSetXminFrozen(tuple->t_data);
HeapTupleHeaderSetCmin(tuple->t_data, FirstCommandId);
HeapTupleHeaderSetXmax(tuple->t_data, InvalidTransactionId);
tuple->t_data->t_infomask |= HEAP_XMAX_INVALID;
ItemPointerSet(&tuple->t_data->t_ctid, 0, FirstOffsetNumber);
/* check the comment above nextval_internal()'s equivalent call. */
if (RelationNeedsWAL(rel))
GetTopTransactionId();
START_CRIT_SECTION();
MarkBufferDirty(buf);
offnum = PageAddItem(page, (Item) tuple->t_data, tuple->t_len,
InvalidOffsetNumber, false, false);
if (offnum != FirstOffsetNumber)
elog(ERROR, "failed to add sequence tuple to page");
/* XLOG stuff */
if (RelationNeedsWAL(rel))
{
xl_seq_rec xlrec;
XLogRecPtr recptr;
XLogBeginInsert();
XLogRegisterBuffer(0, buf, REGBUF_WILL_INIT);
xlrec.node = rel->rd_node;
XLogRegisterData((char *) &xlrec, sizeof(xl_seq_rec));
XLogRegisterData((char *) tuple->t_data, tuple->t_len);
recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG);
PageSetLSN(page, recptr);
}
END_CRIT_SECTION();
UnlockReleaseBuffer(buf);
}
/*
* AlterSequence
*
* Modify the definition of a sequence relation
*/
ObjectAddress
AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
{
Oid relid;
SeqTable elm;
Relation seqrel;
Buffer buf;
HeapTupleData seqdatatuple;
Form_pg_sequence seqform;
Form_pg_sequence_data seqdata;
FormData_pg_sequence_data newseqdata;
List *owned_by;
ObjectAddress address;
Relation rel;
HeapTuple tuple;
/* Open and lock sequence. */
relid = RangeVarGetRelid(stmt->sequence, AccessShareLock, stmt->missing_ok);
if (relid == InvalidOid)
{
ereport(NOTICE,
(errmsg("relation \"%s\" does not exist, skipping",
stmt->sequence->relname)));
return InvalidObjectAddress;
}
init_sequence(relid, &elm, &seqrel);
/* allow ALTER to sequence owner only */
if (!pg_class_ownercheck(relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
stmt->sequence->relname);
/* lock page' buffer and read tuple into new sequence structure */
seqdata = read_seq_tuple(seqrel, &buf, &seqdatatuple);
/* Copy old values of options into workspace */
memcpy(&newseqdata, seqdata, sizeof(FormData_pg_sequence_data));
rel = heap_open(SequenceRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy1(SEQRELID,
ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for sequence %u",
relid);
seqform = (Form_pg_sequence) GETSTRUCT(tuple);
/* Check and set new values */
init_params(pstate, stmt->options, false, seqform, &newseqdata, &owned_by);
/* Clear local cache so that we don't think we have cached numbers */
/* Note that we do not change the currval() state */
elm->cached = elm->last;
/* check the comment above nextval_internal()'s equivalent call. */
if (RelationNeedsWAL(seqrel))
GetTopTransactionId();
/* Now okay to update the on-disk tuple */
START_CRIT_SECTION();
memcpy(seqdata, &newseqdata, sizeof(FormData_pg_sequence_data));
MarkBufferDirty(buf);
/* XLOG stuff */
if (RelationNeedsWAL(seqrel))
{
xl_seq_rec xlrec;
XLogRecPtr recptr;
Page page = BufferGetPage(buf);
XLogBeginInsert();
XLogRegisterBuffer(0, buf, REGBUF_WILL_INIT);
xlrec.node = seqrel->rd_node;
XLogRegisterData((char *) &xlrec, sizeof(xl_seq_rec));
XLogRegisterData((char *) seqdatatuple.t_data, seqdatatuple.t_len);
recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG);
PageSetLSN(page, recptr);
}
END_CRIT_SECTION();
UnlockReleaseBuffer(buf);
/* process OWNED BY if given */
if (owned_by)
process_owned_by(seqrel, owned_by);
InvokeObjectPostAlterHook(RelationRelationId, relid, 0);
ObjectAddressSet(address, RelationRelationId, relid);
relation_close(seqrel, NoLock);
simple_heap_update(rel, &tuple->t_self, tuple);
CatalogUpdateIndexes(rel, tuple);
heap_close(rel, RowExclusiveLock);
return address;
}
/*
* _bt_pagedel() -- Delete a page from the b-tree, if legal to do so.
*
* This action unlinks the page from the b-tree structure, removing all
* pointers leading to it --- but not touching its own left and right links.
* The page cannot be physically reclaimed right away, since other processes
* may currently be trying to follow links leading to the page; they have to
* be allowed to use its right-link to recover. See nbtree/README.
*
* On entry, the target buffer must be pinned and locked (either read or write
* lock is OK). This lock and pin will be dropped before exiting.
*
* The "stack" argument can be a search stack leading (approximately) to the
* target page, or NULL --- outside callers typically pass NULL since they
* have not done such a search, but internal recursion cases pass the stack
* to avoid duplicated search effort.
*
* Returns the number of pages successfully deleted (zero if page cannot
* be deleted now; could be more than one if parent pages were deleted too).
*
* NOTE: this leaks memory. Rather than trying to clean up everything
* carefully, it's better to run it in a temp context that can be reset
* frequently.
*/
int
_bt_pagedel(Relation rel, Buffer buf, BTStack stack)
{
int result;
BlockNumber target,
leftsib,
rightsib,
parent;
OffsetNumber poffset,
maxoff;
uint32 targetlevel,
ilevel;
ItemId itemid;
IndexTuple targetkey,
itup;
ScanKey itup_scankey;
Buffer lbuf,
rbuf,
pbuf;
bool parent_half_dead;
bool parent_one_child;
bool rightsib_empty;
Buffer metabuf = InvalidBuffer;
Page metapg = NULL;
BTMetaPageData *metad = NULL;
Page page;
BTPageOpaque opaque;
/*
* We can never delete rightmost pages nor root pages. While at it, check
* that page is not already deleted and is empty.
*/
page = BufferGetPage(buf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
if (P_RIGHTMOST(opaque) || P_ISROOT(opaque) || P_ISDELETED(opaque) ||
P_FIRSTDATAKEY(opaque) <= PageGetMaxOffsetNumber(page))
{
/* Should never fail to delete a half-dead page */
Assert(!P_ISHALFDEAD(opaque));
_bt_relbuf(rel, buf);
return 0;
}
/*
* Save info about page, including a copy of its high key (it must have
* one, being non-rightmost).
*/
target = BufferGetBlockNumber(buf);
targetlevel = opaque->btpo.level;
leftsib = opaque->btpo_prev;
itemid = PageGetItemId(page, P_HIKEY);
targetkey = CopyIndexTuple((IndexTuple) PageGetItem(page, itemid));
/*
* To avoid deadlocks, we'd better drop the target page lock before going
* further.
*/
_bt_relbuf(rel, buf);
/*
* We need an approximate pointer to the page's parent page. We use the
* standard search mechanism to search for the page's high key; this will
* give us a link to either the current parent or someplace to its left
* (if there are multiple equal high keys). In recursion cases, the
* caller already generated a search stack and we can just re-use that
* work.
*/
if (stack == NULL)
{
if (!InRecovery)
{
/* we need an insertion scan key to do our search, so build one */
itup_scankey = _bt_mkscankey(rel, targetkey);
/* find the leftmost leaf page containing this key */
stack = _bt_search(rel, rel->rd_rel->relnatts, itup_scankey, false,
&lbuf, BT_READ);
/* don't need a pin on that either */
_bt_relbuf(rel, lbuf);
/*
* If we are trying to delete an interior page, _bt_search did
* more than we needed. Locate the stack item pointing to our
* parent level.
*/
ilevel = 0;
for (;;)
{
if (stack == NULL)
elog(ERROR, "not enough stack items");
if (ilevel == targetlevel)
break;
stack = stack->bts_parent;
ilevel++;
}
}
else
{
/*
* During WAL recovery, we can't use _bt_search (for one reason,
* it might invoke user-defined comparison functions that expect
* facilities not available in recovery mode). Instead, just set
* up a dummy stack pointing to the left end of the parent tree
* level, from which _bt_getstackbuf will walk right to the parent
* page. Painful, but we don't care too much about performance in
* this scenario.
*/
pbuf = _bt_get_endpoint(rel, targetlevel + 1, false);
stack = (BTStack) palloc(sizeof(BTStackData));
stack->bts_blkno = BufferGetBlockNumber(pbuf);
stack->bts_offset = InvalidOffsetNumber;
/* bts_btentry will be initialized below */
stack->bts_parent = NULL;
_bt_relbuf(rel, pbuf);
}
}
/*
* We cannot delete a page that is the rightmost child of its immediate
* parent, unless it is the only child --- in which case the parent has to
* be deleted too, and the same condition applies recursively to it. We
* have to check this condition all the way up before trying to delete. We
* don't need to re-test when deleting a non-leaf page, though.
*/
if (targetlevel == 0 &&
!_bt_parent_deletion_safe(rel, target, stack))
return 0;
/*
* We have to lock the pages we need to modify in the standard order:
* moving right, then up. Else we will deadlock against other writers.
*
* So, we need to find and write-lock the current left sibling of the
* target page. The sibling that was current a moment ago could have
* split, so we may have to move right. This search could fail if either
* the sibling or the target page was deleted by someone else meanwhile;
* if so, give up. (Right now, that should never happen, since page
* deletion is only done in VACUUM and there shouldn't be multiple VACUUMs
* concurrently on the same table.)
*/
if (leftsib != P_NONE)
{
lbuf = _bt_getbuf(rel, leftsib, BT_WRITE);
page = BufferGetPage(lbuf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
while (P_ISDELETED(opaque) || opaque->btpo_next != target)
{
/* step right one page */
leftsib = opaque->btpo_next;
_bt_relbuf(rel, lbuf);
if (leftsib == P_NONE)
{
elog(LOG, "no left sibling (concurrent deletion?) in \"%s\"",
RelationGetRelationName(rel));
return 0;
}
lbuf = _bt_getbuf(rel, leftsib, BT_WRITE);
page = BufferGetPage(lbuf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
}
}
else
lbuf = InvalidBuffer;
/*
* Next write-lock the target page itself. It should be okay to take just
* a write lock not a superexclusive lock, since no scans would stop on an
* empty page.
*/
buf = _bt_getbuf(rel, target, BT_WRITE);
page = BufferGetPage(buf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
/*
* Check page is still empty etc, else abandon deletion. The empty check
* is necessary since someone else might have inserted into it while we
* didn't have it locked; the others are just for paranoia's sake.
*/
if (P_RIGHTMOST(opaque) || P_ISROOT(opaque) || P_ISDELETED(opaque) ||
P_FIRSTDATAKEY(opaque) <= PageGetMaxOffsetNumber(page))
{
_bt_relbuf(rel, buf);
if (BufferIsValid(lbuf))
_bt_relbuf(rel, lbuf);
return 0;
}
if (opaque->btpo_prev != leftsib)
elog(ERROR, "left link changed unexpectedly in block %u of index \"%s\"",
target, RelationGetRelationName(rel));
/*
* And next write-lock the (current) right sibling.
*/
rightsib = opaque->btpo_next;
rbuf = _bt_getbuf(rel, rightsib, BT_WRITE);
page = BufferGetPage(rbuf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
if (opaque->btpo_prev != target)
elog(ERROR, "right sibling's left-link doesn't match: "
"block %u links to %u instead of expected %u in index \"%s\"",
rightsib, opaque->btpo_prev, target,
RelationGetRelationName(rel));
/*
* Next find and write-lock the current parent of the target page. This is
* essentially the same as the corresponding step of splitting.
*/
ItemPointerSet(&(stack->bts_btentry.t_tid), target, P_HIKEY);
pbuf = _bt_getstackbuf(rel, stack, BT_WRITE);
if (pbuf == InvalidBuffer)
elog(ERROR, "failed to re-find parent key in index \"%s\" for deletion target page %u",
RelationGetRelationName(rel), target);
parent = stack->bts_blkno;
poffset = stack->bts_offset;
/*
* If the target is the rightmost child of its parent, then we can't
* delete, unless it's also the only child --- in which case the parent
* changes to half-dead status. The "can't delete" case should have been
* detected by _bt_parent_deletion_safe, so complain if we see it now.
*/
page = BufferGetPage(pbuf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
maxoff = PageGetMaxOffsetNumber(page);
parent_half_dead = false;
parent_one_child = false;
if (poffset >= maxoff)
{
if (poffset == P_FIRSTDATAKEY(opaque))
parent_half_dead = true;
else
elog(ERROR, "failed to delete rightmost child %u of block %u in index \"%s\"",
target, parent, RelationGetRelationName(rel));
}
else
{
/* Will there be exactly one child left in this parent? */
if (OffsetNumberNext(P_FIRSTDATAKEY(opaque)) == maxoff)
parent_one_child = true;
}
/*
* If we are deleting the next-to-last page on the target's level, then
* the rightsib is a candidate to become the new fast root. (In theory, it
* might be possible to push the fast root even further down, but the odds
* of doing so are slim, and the locking considerations daunting.)
*
* We don't support handling this in the case where the parent is becoming
* half-dead, even though it theoretically could occur.
*
* We can safely acquire a lock on the metapage here --- see comments for
* _bt_newroot().
*/
if (leftsib == P_NONE && !parent_half_dead)
{
page = BufferGetPage(rbuf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
Assert(opaque->btpo.level == targetlevel);
if (P_RIGHTMOST(opaque))
{
/* rightsib will be the only one left on the level */
metabuf = _bt_getbuf(rel, BTREE_METAPAGE, BT_WRITE);
metapg = BufferGetPage(metabuf);
metad = BTPageGetMeta(metapg);
/*
* The expected case here is btm_fastlevel == targetlevel+1; if
* the fastlevel is <= targetlevel, something is wrong, and we
* choose to overwrite it to fix it.
*/
if (metad->btm_fastlevel > targetlevel + 1)
{
/* no update wanted */
_bt_relbuf(rel, metabuf);
metabuf = InvalidBuffer;
}
}
}
/*
* Check that the parent-page index items we're about to delete/overwrite
* contain what we expect. This can fail if the index has become
* corrupt for some reason. We want to throw any error before entering
* the critical section --- otherwise it'd be a PANIC.
*
* The test on the target item is just an Assert because _bt_getstackbuf
* should have guaranteed it has the expected contents. The test on the
* next-child downlink is known to sometimes fail in the field, though.
*/
page = BufferGetPage(pbuf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
#ifdef USE_ASSERT_CHECKING
itemid = PageGetItemId(page, poffset);
itup = (IndexTuple) PageGetItem(page, itemid);
Assert(ItemPointerGetBlockNumber(&(itup->t_tid)) == target);
#endif
if (!parent_half_dead)
{
OffsetNumber nextoffset;
nextoffset = OffsetNumberNext(poffset);
itemid = PageGetItemId(page, nextoffset);
itup = (IndexTuple) PageGetItem(page, itemid);
if (ItemPointerGetBlockNumber(&(itup->t_tid)) != rightsib)
elog(ERROR, "right sibling %u of block %u is not next child %u of block %u in index \"%s\"",
rightsib, target, ItemPointerGetBlockNumber(&(itup->t_tid)),
parent, RelationGetRelationName(rel));
}
/*
* Here we begin doing the deletion.
*/
/* No ereport(ERROR) until changes are logged */
START_CRIT_SECTION();
/*
* Update parent. The normal case is a tad tricky because we want to
* delete the target's downlink and the *following* key. Easiest way is
* to copy the right sibling's downlink over the target downlink, and then
* delete the following item.
*/
if (parent_half_dead)
{
PageIndexTupleDelete(page, poffset);
opaque->btpo_flags |= BTP_HALF_DEAD;
}
else
{
OffsetNumber nextoffset;
itemid = PageGetItemId(page, poffset);
itup = (IndexTuple) PageGetItem(page, itemid);
ItemPointerSet(&(itup->t_tid), rightsib, P_HIKEY);
nextoffset = OffsetNumberNext(poffset);
PageIndexTupleDelete(page, nextoffset);
}
/*
* Update siblings' side-links. Note the target page's side-links will
* continue to point to the siblings. Asserts here are just rechecking
* things we already verified above.
*/
if (BufferIsValid(lbuf))
{
page = BufferGetPage(lbuf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
Assert(opaque->btpo_next == target);
opaque->btpo_next = rightsib;
}
page = BufferGetPage(rbuf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
Assert(opaque->btpo_prev == target);
opaque->btpo_prev = leftsib;
rightsib_empty = (P_FIRSTDATAKEY(opaque) > PageGetMaxOffsetNumber(page));
/*
* Mark the page itself deleted. It can be recycled when all current
* transactions are gone.
*/
page = BufferGetPage(buf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
opaque->btpo_flags &= ~BTP_HALF_DEAD;
opaque->btpo_flags |= BTP_DELETED;
opaque->btpo.xact = ReadNewTransactionId();
/* And update the metapage, if needed */
if (BufferIsValid(metabuf))
{
metad->btm_fastroot = rightsib;
metad->btm_fastlevel = targetlevel;
MarkBufferDirty(metabuf);
}
/* Must mark buffers dirty before XLogInsert */
MarkBufferDirty(pbuf);
MarkBufferDirty(rbuf);
MarkBufferDirty(buf);
if (BufferIsValid(lbuf))
MarkBufferDirty(lbuf);
/* XLOG stuff */
if (!rel->rd_istemp)
{
xl_btree_delete_page xlrec;
xl_btree_metadata xlmeta;
uint8 xlinfo;
XLogRecPtr recptr;
XLogRecData rdata[5];
XLogRecData *nextrdata;
xlrec.target.node = rel->rd_node;
ItemPointerSet(&(xlrec.target.tid), parent, poffset);
xlrec.deadblk = target;
xlrec.leftblk = leftsib;
xlrec.rightblk = rightsib;
xlrec.btpo_xact = opaque->btpo.xact;
rdata[0].data = (char *) &xlrec;
rdata[0].len = SizeOfBtreeDeletePage;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = nextrdata = &(rdata[1]);
if (BufferIsValid(metabuf))
{
xlmeta.root = metad->btm_root;
xlmeta.level = metad->btm_level;
xlmeta.fastroot = metad->btm_fastroot;
xlmeta.fastlevel = metad->btm_fastlevel;
nextrdata->data = (char *) &xlmeta;
nextrdata->len = sizeof(xl_btree_metadata);
nextrdata->buffer = InvalidBuffer;
nextrdata->next = nextrdata + 1;
nextrdata++;
xlinfo = XLOG_BTREE_DELETE_PAGE_META;
}
else if (parent_half_dead)
xlinfo = XLOG_BTREE_DELETE_PAGE_HALF;
else
xlinfo = XLOG_BTREE_DELETE_PAGE;
nextrdata->data = NULL;
nextrdata->len = 0;
nextrdata->next = nextrdata + 1;
nextrdata->buffer = pbuf;
nextrdata->buffer_std = true;
nextrdata++;
nextrdata->data = NULL;
nextrdata->len = 0;
nextrdata->buffer = rbuf;
nextrdata->buffer_std = true;
nextrdata->next = NULL;
if (BufferIsValid(lbuf))
{
nextrdata->next = nextrdata + 1;
nextrdata++;
nextrdata->data = NULL;
nextrdata->len = 0;
nextrdata->buffer = lbuf;
nextrdata->buffer_std = true;
nextrdata->next = NULL;
}
recptr = XLogInsert(RM_BTREE_ID, xlinfo, rdata);
if (BufferIsValid(metabuf))
{
PageSetLSN(metapg, recptr);
PageSetTLI(metapg, ThisTimeLineID);
}
page = BufferGetPage(pbuf);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
page = BufferGetPage(rbuf);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
page = BufferGetPage(buf);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
if (BufferIsValid(lbuf))
{
page = BufferGetPage(lbuf);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
}
END_CRIT_SECTION();
/* release metapage; send out relcache inval if metapage changed */
if (BufferIsValid(metabuf))
{
CacheInvalidateRelcache(rel);
_bt_relbuf(rel, metabuf);
}
/* can always release leftsib immediately */
if (BufferIsValid(lbuf))
_bt_relbuf(rel, lbuf);
/*
* If parent became half dead, recurse to delete it. Otherwise, if right
* sibling is empty and is now the last child of the parent, recurse to
* try to delete it. (These cases cannot apply at the same time, though
* the second case might itself recurse to the first.)
*
* When recursing to parent, we hold the lock on the target page until
* done. This delays any insertions into the keyspace that was just
* effectively reassigned to the parent's right sibling. If we allowed
* that, and there were enough such insertions before we finish deleting
* the parent, page splits within that keyspace could lead to inserting
* out-of-order keys into the grandparent level. It is thought that that
* wouldn't have any serious consequences, but it still seems like a
* pretty bad idea.
*/
if (parent_half_dead)
{
/* recursive call will release pbuf */
_bt_relbuf(rel, rbuf);
result = _bt_pagedel(rel, pbuf, stack->bts_parent) + 1;
_bt_relbuf(rel, buf);
}
else if (parent_one_child && rightsib_empty)
{
_bt_relbuf(rel, pbuf);
_bt_relbuf(rel, buf);
/* recursive call will release rbuf */
result = _bt_pagedel(rel, rbuf, stack) + 1;
}
else
{
_bt_relbuf(rel, pbuf);
_bt_relbuf(rel, buf);
_bt_relbuf(rel, rbuf);
result = 1;
}
return result;
}
/*
* Creates new posting tree containing the given TIDs. Returns the page
* number of the root of the new posting tree.
*
* items[] must be in sorted order with no duplicates.
*/
BlockNumber
createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
GinStatsData *buildStats)
{
BlockNumber blkno;
Buffer buffer;
Page page;
int nrootitems;
/* Calculate how many TIDs will fit on first page. */
nrootitems = Min(nitems, GinMaxLeafDataItems);
/*
* Create the root page.
*/
buffer = GinNewBuffer(index);
page = BufferGetPage(buffer);
blkno = BufferGetBlockNumber(buffer);
START_CRIT_SECTION();
GinInitBuffer(buffer, GIN_DATA | GIN_LEAF);
memcpy(GinDataPageGetData(page), items, sizeof(ItemPointerData) * nrootitems);
GinPageGetOpaque(page)->maxoff = nrootitems;
MarkBufferDirty(buffer);
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
XLogRecData rdata[2];
ginxlogCreatePostingTree data;
data.node = index->rd_node;
data.blkno = blkno;
data.nitem = nrootitems;
rdata[0].buffer = InvalidBuffer;
rdata[0].data = (char *) &data;
rdata[0].len = sizeof(ginxlogCreatePostingTree);
rdata[0].next = &rdata[1];
rdata[1].buffer = InvalidBuffer;
rdata[1].data = (char *) items;
rdata[1].len = sizeof(ItemPointerData) * nrootitems;
rdata[1].next = NULL;
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_CREATE_PTREE, rdata);
PageSetLSN(page, recptr);
}
UnlockReleaseBuffer(buffer);
END_CRIT_SECTION();
/* During index build, count the newly-added data page */
if (buildStats)
buildStats->nDataPages++;
/*
* Add any remaining TIDs to the newly-created posting tree.
*/
if (nitems > nrootitems)
{
ginInsertItemPointers(index, blkno,
items + nrootitems,
nitems - nrootitems,
buildStats);
}
return blkno;
}
/*
* _bt_getroot() -- Get the root page of the btree.
*
* Since the root page can move around the btree file, we have to read
* its location from the metadata page, and then read the root page
* itself. If no root page exists yet, we have to create one. The
* standard class of race conditions exists here; I think I covered
* them all in the Hopi Indian rain dance of lock requests below.
*
* The access type parameter (BT_READ or BT_WRITE) controls whether
* a new root page will be created or not. If access = BT_READ,
* and no root page exists, we just return InvalidBuffer. For
* BT_WRITE, we try to create the root page if it doesn't exist.
* NOTE that the returned root page will have only a read lock set
* on it even if access = BT_WRITE!
*
* The returned page is not necessarily the true root --- it could be
* a "fast root" (a page that is alone in its level due to deletions).
* Also, if the root page is split while we are "in flight" to it,
* what we will return is the old root, which is now just the leftmost
* page on a probably-not-very-wide level. For most purposes this is
* as good as or better than the true root, so we do not bother to
* insist on finding the true root. We do, however, guarantee to
* return a live (not deleted or half-dead) page.
*
* On successful return, the root page is pinned and read-locked.
* The metadata page is not locked or pinned on exit.
*/
Buffer
_bt_getroot(Relation rel, int access)
{
Buffer metabuf;
Page metapg;
BTPageOpaque metaopaque;
Buffer rootbuf;
Page rootpage;
BTPageOpaque rootopaque;
BlockNumber rootblkno;
uint32 rootlevel;
BTMetaPageData *metad;
/*
* Try to use previously-cached metapage data to find the root. This
* normally saves one buffer access per index search, which is a very
* helpful savings in bufmgr traffic and hence contention.
*/
if (rel->rd_amcache != NULL)
{
metad = (BTMetaPageData *) rel->rd_amcache;
/* We shouldn't have cached it if any of these fail */
Assert(metad->btm_magic == BTREE_MAGIC);
Assert(metad->btm_version == BTREE_VERSION);
Assert(metad->btm_root != P_NONE);
rootblkno = metad->btm_fastroot;
Assert(rootblkno != P_NONE);
rootlevel = metad->btm_fastlevel;
rootbuf = _bt_getbuf(rel, rootblkno, BT_READ);
rootpage = BufferGetPage(rootbuf);
rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);
/*
* Since the cache might be stale, we check the page more carefully
* here than normal. We *must* check that it's not deleted. If it's
* not alone on its level, then we reject too --- this may be overly
* paranoid but better safe than sorry. Note we don't check P_ISROOT,
* because that's not set in a "fast root".
*/
if (!P_IGNORE(rootopaque) &&
rootopaque->btpo.level == rootlevel &&
P_LEFTMOST(rootopaque) &&
P_RIGHTMOST(rootopaque))
{
/* OK, accept cached page as the root */
return rootbuf;
}
_bt_relbuf(rel, rootbuf);
/* Cache is stale, throw it away */
if (rel->rd_amcache)
pfree(rel->rd_amcache);
rel->rd_amcache = NULL;
}
metabuf = _bt_getbuf(rel, BTREE_METAPAGE, BT_READ);
metapg = BufferGetPage(metabuf);
metaopaque = (BTPageOpaque) PageGetSpecialPointer(metapg);
metad = BTPageGetMeta(metapg);
/* sanity-check the metapage */
if (!(metaopaque->btpo_flags & BTP_META) ||
metad->btm_magic != BTREE_MAGIC)
ereport(ERROR,
(errcode(ERRCODE_INDEX_CORRUPTED),
errmsg("index \"%s\" is not a btree",
RelationGetRelationName(rel))));
if (metad->btm_version != BTREE_VERSION)
ereport(ERROR,
(errcode(ERRCODE_INDEX_CORRUPTED),
errmsg("version mismatch in index \"%s\": file version %d, code version %d",
RelationGetRelationName(rel),
metad->btm_version, BTREE_VERSION)));
/* if no root page initialized yet, do it */
if (metad->btm_root == P_NONE)
{
/* If access = BT_READ, caller doesn't want us to create root yet */
if (access == BT_READ)
{
_bt_relbuf(rel, metabuf);
return InvalidBuffer;
}
/* trade in our read lock for a write lock */
LockBuffer(metabuf, BUFFER_LOCK_UNLOCK);
LockBuffer(metabuf, BT_WRITE);
/*
* Race condition: if someone else initialized the metadata between
* the time we released the read lock and acquired the write lock, we
* must avoid doing it again.
*/
if (metad->btm_root != P_NONE)
{
/*
* Metadata initialized by someone else. In order to guarantee no
* deadlocks, we have to release the metadata page and start all
* over again. (Is that really true? But it's hardly worth trying
* to optimize this case.)
*/
_bt_relbuf(rel, metabuf);
return _bt_getroot(rel, access);
}
/*
* Get, initialize, write, and leave a lock of the appropriate type on
* the new root page. Since this is the first page in the tree, it's
* a leaf as well as the root.
*/
rootbuf = _bt_getbuf(rel, P_NEW, BT_WRITE);
rootblkno = BufferGetBlockNumber(rootbuf);
rootpage = BufferGetPage(rootbuf);
rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);
rootopaque->btpo_prev = rootopaque->btpo_next = P_NONE;
rootopaque->btpo_flags = (BTP_LEAF | BTP_ROOT);
rootopaque->btpo.level = 0;
rootopaque->btpo_cycleid = 0;
/* NO ELOG(ERROR) till meta is updated */
START_CRIT_SECTION();
metad->btm_root = rootblkno;
metad->btm_level = 0;
metad->btm_fastroot = rootblkno;
metad->btm_fastlevel = 0;
MarkBufferDirty(rootbuf);
MarkBufferDirty(metabuf);
/* XLOG stuff */
if (!rel->rd_istemp)
{
xl_btree_newroot xlrec;
XLogRecPtr recptr;
XLogRecData rdata;
xlrec.node = rel->rd_node;
xlrec.rootblk = rootblkno;
xlrec.level = 0;
rdata.data = (char *) &xlrec;
rdata.len = SizeOfBtreeNewroot;
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_NEWROOT, &rdata);
PageSetLSN(rootpage, recptr);
PageSetTLI(rootpage, ThisTimeLineID);
PageSetLSN(metapg, recptr);
PageSetTLI(metapg, ThisTimeLineID);
}
END_CRIT_SECTION();
/*
* Send out relcache inval for metapage change (probably unnecessary
* here, but let's be safe).
*/
CacheInvalidateRelcache(rel);
/*
* swap root write lock for read lock. There is no danger of anyone
* else accessing the new root page while it's unlocked, since no one
* else knows where it is yet.
*/
LockBuffer(rootbuf, BUFFER_LOCK_UNLOCK);
LockBuffer(rootbuf, BT_READ);
/* okay, metadata is correct, release lock on it */
_bt_relbuf(rel, metabuf);
}
else
{
rootblkno = metad->btm_fastroot;
Assert(rootblkno != P_NONE);
rootlevel = metad->btm_fastlevel;
/*
* Cache the metapage data for next time
*/
rel->rd_amcache = MemoryContextAlloc(rel->rd_indexcxt,
sizeof(BTMetaPageData));
memcpy(rel->rd_amcache, metad, sizeof(BTMetaPageData));
/*
* We are done with the metapage; arrange to release it via first
* _bt_relandgetbuf call
*/
rootbuf = metabuf;
for (;;)
{
rootbuf = _bt_relandgetbuf(rel, rootbuf, rootblkno, BT_READ);
rootpage = BufferGetPage(rootbuf);
rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);
if (!P_IGNORE(rootopaque))
break;
/* it's dead, Jim. step right one page */
if (P_RIGHTMOST(rootopaque))
elog(ERROR, "no live root page found in index \"%s\"",
RelationGetRelationName(rel));
rootblkno = rootopaque->btpo_next;
}
/* Note: can't check btpo.level on deleted pages */
if (rootopaque->btpo.level != rootlevel)
elog(ERROR, "root page %u of index \"%s\" has level %u, expected %u",
rootblkno, RelationGetRelationName(rel),
rootopaque->btpo.level, rootlevel);
}
/*
* By here, we have a pin and read lock on the root page, and no lock set
* on the metadata page. Return the root page's buffer.
*/
return rootbuf;
}
void
_bt_delitems_delete(Relation rel, Buffer buf,
OffsetNumber *itemnos, int nitems, Relation heapRel)
{
Page page = BufferGetPage(buf);
BTPageOpaque opaque;
Assert(nitems > 0);
/* No ereport(ERROR) until changes are logged */
START_CRIT_SECTION();
/* Fix the page */
PageIndexMultiDelete(page, itemnos, nitems);
/*
* We can clear the vacuum cycle ID since this page has certainly been
* processed by the current vacuum scan.
*/
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
opaque->btpo_cycleid = 0;
/*
* Mark the page as not containing any LP_DEAD items. This is not
* certainly true (there might be some that have recently been marked, but
* weren't included in our target-item list), but it will almost always be
* true and it doesn't seem worth an additional page scan to check it.
* Remember that BTP_HAS_GARBAGE is only a hint anyway.
*/
opaque->btpo_flags &= ~BTP_HAS_GARBAGE;
MarkBufferDirty(buf);
/* XLOG stuff */
if (!rel->rd_istemp)
{
XLogRecPtr recptr;
XLogRecData rdata[3];
xl_btree_delete xlrec_delete;
xlrec_delete.node = rel->rd_node;
xlrec_delete.hnode = heapRel->rd_node;
xlrec_delete.block = BufferGetBlockNumber(buf);
xlrec_delete.nitems = nitems;
rdata[0].data = (char *) &xlrec_delete;
rdata[0].len = SizeOfBtreeDelete;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
/*
* We need the target-offsets array whether or not we store the to
* allow us to find the latestRemovedXid on a standby server.
*/
rdata[1].data = (char *) itemnos;
rdata[1].len = nitems * sizeof(OffsetNumber);
rdata[1].buffer = InvalidBuffer;
rdata[1].next = &(rdata[2]);
rdata[2].data = NULL;
rdata[2].len = 0;
rdata[2].buffer = buf;
rdata[2].buffer_std = true;
rdata[2].next = NULL;
recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_DELETE, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
END_CRIT_SECTION();
}
/*
* Delete item(s) from a btree page.
*
* This must only be used for deleting leaf items. Deleting an item on a
* non-leaf page has to be done as part of an atomic action that includes
* deleting the page it points to.
*
* This routine assumes that the caller has pinned and locked the buffer.
* Also, the given itemnos *must* appear in increasing order in the array.
*
* We record VACUUMs and b-tree deletes differently in WAL. InHotStandby
* we need to be able to pin all of the blocks in the btree in physical
* order when replaying the effects of a VACUUM, just as we do for the
* original VACUUM itself. lastBlockVacuumed allows us to tell whether an
* intermediate range of blocks has had no changes at all by VACUUM,
* and so must be scanned anyway during replay. We always write a WAL record
* for the last block in the index, whether or not it contained any items
* to be removed. This allows us to scan right up to end of index to
* ensure correct locking.
*/
void
_bt_delitems_vacuum(Relation rel, Buffer buf,
OffsetNumber *itemnos, int nitems, BlockNumber lastBlockVacuumed)
{
Page page = BufferGetPage(buf);
BTPageOpaque opaque;
/* No ereport(ERROR) until changes are logged */
START_CRIT_SECTION();
/* Fix the page */
if (nitems > 0)
PageIndexMultiDelete(page, itemnos, nitems);
/*
* We can clear the vacuum cycle ID since this page has certainly been
* processed by the current vacuum scan.
*/
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
opaque->btpo_cycleid = 0;
/*
* Mark the page as not containing any LP_DEAD items. This is not
* certainly true (there might be some that have recently been marked, but
* weren't included in our target-item list), but it will almost always be
* true and it doesn't seem worth an additional page scan to check it.
* Remember that BTP_HAS_GARBAGE is only a hint anyway.
*/
opaque->btpo_flags &= ~BTP_HAS_GARBAGE;
MarkBufferDirty(buf);
/* XLOG stuff */
if (!rel->rd_istemp)
{
XLogRecPtr recptr;
XLogRecData rdata[2];
xl_btree_vacuum xlrec_vacuum;
xlrec_vacuum.node = rel->rd_node;
xlrec_vacuum.block = BufferGetBlockNumber(buf);
xlrec_vacuum.lastBlockVacuumed = lastBlockVacuumed;
rdata[0].data = (char *) &xlrec_vacuum;
rdata[0].len = SizeOfBtreeVacuum;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
/*
* The target-offsets array is not in the buffer, but pretend that it
* is. When XLogInsert stores the whole buffer, the offsets array
* need not be stored too.
*/
if (nitems > 0)
{
rdata[1].data = (char *) itemnos;
rdata[1].len = nitems * sizeof(OffsetNumber);
}
else
{
rdata[1].data = NULL;
rdata[1].len = 0;
}
rdata[1].buffer = buf;
rdata[1].buffer_std = true;
rdata[1].next = NULL;
recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_VACUUM, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
END_CRIT_SECTION();
}
/*
* Delete a posting tree page.
*/
static void
ginDeletePage(GinVacuumState *gvs, BlockNumber deleteBlkno, BlockNumber leftBlkno,
BlockNumber parentBlkno, OffsetNumber myoff, bool isParentRoot)
{
Buffer dBuffer;
Buffer lBuffer;
Buffer pBuffer;
Page page,
parentPage;
BlockNumber rightlink;
/*
* Lock the pages in the same order as an insertion would, to avoid
* deadlocks: left, then right, then parent.
*/
lBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, leftBlkno,
RBM_NORMAL, gvs->strategy);
dBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, deleteBlkno,
RBM_NORMAL, gvs->strategy);
pBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, parentBlkno,
RBM_NORMAL, gvs->strategy);
LockBuffer(lBuffer, GIN_EXCLUSIVE);
LockBuffer(dBuffer, GIN_EXCLUSIVE);
if (!isParentRoot) /* parent is already locked by
* LockBufferForCleanup() */
LockBuffer(pBuffer, GIN_EXCLUSIVE);
START_CRIT_SECTION();
/* Unlink the page by changing left sibling's rightlink */
page = BufferGetPage(dBuffer);
rightlink = GinPageGetOpaque(page)->rightlink;
page = BufferGetPage(lBuffer);
GinPageGetOpaque(page)->rightlink = rightlink;
/* Delete downlink from parent */
parentPage = BufferGetPage(pBuffer);
#ifdef USE_ASSERT_CHECKING
do
{
PostingItem *tod = GinDataPageGetPostingItem(parentPage, myoff);
Assert(PostingItemGetBlockNumber(tod) == deleteBlkno);
} while (0);
#endif
GinPageDeletePostingItem(parentPage, myoff);
page = BufferGetPage(dBuffer);
/*
* we shouldn't change rightlink field to save workability of running
* search scan
*/
GinPageGetOpaque(page)->flags = GIN_DELETED;
MarkBufferDirty(pBuffer);
MarkBufferDirty(lBuffer);
MarkBufferDirty(dBuffer);
if (RelationNeedsWAL(gvs->index))
{
XLogRecPtr recptr;
ginxlogDeletePage data;
/*
* We can't pass REGBUF_STANDARD for the deleted page, because we
* didn't set pd_lower on pre-9.4 versions. The page might've been
* binary-upgraded from an older version, and hence not have pd_lower
* set correctly. Ditto for the left page, but removing the item from
* the parent updated its pd_lower, so we know that's OK at this
* point.
*/
XLogBeginInsert();
XLogRegisterBuffer(0, dBuffer, 0);
XLogRegisterBuffer(1, pBuffer, REGBUF_STANDARD);
XLogRegisterBuffer(2, lBuffer, 0);
data.parentOffset = myoff;
data.rightLink = GinPageGetOpaque(page)->rightlink;
XLogRegisterData((char *) &data, sizeof(ginxlogDeletePage));
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_DELETE_PAGE);
PageSetLSN(page, recptr);
PageSetLSN(parentPage, recptr);
PageSetLSN(BufferGetPage(lBuffer), recptr);
}
if (!isParentRoot)
LockBuffer(pBuffer, GIN_UNLOCK);
ReleaseBuffer(pBuffer);
UnlockReleaseBuffer(lBuffer);
UnlockReleaseBuffer(dBuffer);
END_CRIT_SECTION();
gvs->result->pages_deleted++;
}
static int64
nextval_internal(Oid relid)
{
SeqTable elm;
Relation seqrel;
Buffer buf;
Page page;
HeapTuple pgstuple;
Form_pg_sequence pgsform;
HeapTupleData seqdatatuple;
Form_pg_sequence_data seq;
int64 incby,
maxv,
minv,
cache,
log,
fetch,
last;
int64 result,
next,
rescnt = 0;
bool cycle;
bool logit = false;
/* open and AccessShareLock sequence */
init_sequence(relid, &elm, &seqrel);
if (pg_class_aclcheck(elm->relid, GetUserId(),
ACL_USAGE | ACL_UPDATE) != ACLCHECK_OK)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied for sequence %s",
RelationGetRelationName(seqrel))));
/* read-only transactions may only modify temp sequences */
if (!seqrel->rd_islocaltemp)
PreventCommandIfReadOnly("nextval()");
/*
* Forbid this during parallel operation because, to make it work, the
* cooperating backends would need to share the backend-local cached
* sequence information. Currently, we don't support that.
*/
PreventCommandIfParallelMode("nextval()");
if (elm->last != elm->cached) /* some numbers were cached */
{
Assert(elm->last_valid);
Assert(elm->increment != 0);
elm->last += elm->increment;
relation_close(seqrel, NoLock);
last_used_seq = elm;
return elm->last;
}
pgstuple = SearchSysCache1(SEQRELID, ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(pgstuple))
elog(ERROR, "cache lookup failed for sequence %u", relid);
pgsform = (Form_pg_sequence) GETSTRUCT(pgstuple);
cycle = pgsform->seqcycle;
incby = pgsform->seqincrement;
maxv = pgsform->seqmax;
minv = pgsform->seqmin;
cache = pgsform->seqcache;
ReleaseSysCache(pgstuple);
/* lock page' buffer and read tuple */
seq = read_seq_tuple(seqrel, &buf, &seqdatatuple);
page = BufferGetPage(buf);
elm->increment = incby;
last = next = result = seq->last_value;
fetch = cache;
log = seq->log_cnt;
if (!seq->is_called)
{
rescnt++; /* return last_value if not is_called */
fetch--;
}
/*
* Decide whether we should emit a WAL log record. If so, force up the
* fetch count to grab SEQ_LOG_VALS more values than we actually need to
* cache. (These will then be usable without logging.)
*
* If this is the first nextval after a checkpoint, we must force a new
* WAL record to be written anyway, else replay starting from the
* checkpoint would fail to advance the sequence past the logged values.
* In this case we may as well fetch extra values.
*/
if (log < fetch || !seq->is_called)
{
/* forced log to satisfy local demand for values */
fetch = log = fetch + SEQ_LOG_VALS;
logit = true;
}
else
{
XLogRecPtr redoptr = GetRedoRecPtr();
if (PageGetLSN(page) <= redoptr)
{
/* last update of seq was before checkpoint */
fetch = log = fetch + SEQ_LOG_VALS;
logit = true;
}
}
while (fetch) /* try to fetch cache [+ log ] numbers */
{
/*
* Check MAXVALUE for ascending sequences and MINVALUE for descending
* sequences
*/
if (incby > 0)
{
/* ascending sequence */
if ((maxv >= 0 && next > maxv - incby) ||
(maxv < 0 && next + incby > maxv))
{
if (rescnt > 0)
break; /* stop fetching */
if (!cycle)
{
char buf[100];
snprintf(buf, sizeof(buf), INT64_FORMAT, maxv);
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("nextval: reached maximum value of sequence \"%s\" (%s)",
RelationGetRelationName(seqrel), buf)));
}
next = minv;
}
else
next += incby;
}
else
{
/* descending sequence */
if ((minv < 0 && next < minv - incby) ||
(minv >= 0 && next + incby < minv))
{
if (rescnt > 0)
break; /* stop fetching */
if (!cycle)
{
char buf[100];
snprintf(buf, sizeof(buf), INT64_FORMAT, minv);
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("nextval: reached minimum value of sequence \"%s\" (%s)",
RelationGetRelationName(seqrel), buf)));
}
next = maxv;
}
else
next += incby;
}
fetch--;
if (rescnt < cache)
{
log--;
rescnt++;
last = next;
if (rescnt == 1) /* if it's first result - */
result = next; /* it's what to return */
}
}
log -= fetch; /* adjust for any unfetched numbers */
Assert(log >= 0);
/* save info in local cache */
elm->last = result; /* last returned number */
elm->cached = last; /* last fetched number */
elm->last_valid = true;
last_used_seq = elm;
/*
* If something needs to be WAL logged, acquire an xid, so this
* transaction's commit will trigger a WAL flush and wait for syncrep.
* It's sufficient to ensure the toplevel transaction has an xid, no need
* to assign xids subxacts, that'll already trigger an appropriate wait.
* (Have to do that here, so we're outside the critical section)
*/
if (logit && RelationNeedsWAL(seqrel))
GetTopTransactionId();
/* ready to change the on-disk (or really, in-buffer) tuple */
START_CRIT_SECTION();
/*
* We must mark the buffer dirty before doing XLogInsert(); see notes in
* SyncOneBuffer(). However, we don't apply the desired changes just yet.
* This looks like a violation of the buffer update protocol, but it is in
* fact safe because we hold exclusive lock on the buffer. Any other
* process, including a checkpoint, that tries to examine the buffer
* contents will block until we release the lock, and then will see the
* final state that we install below.
*/
MarkBufferDirty(buf);
/* XLOG stuff */
if (logit && RelationNeedsWAL(seqrel))
{
xl_seq_rec xlrec;
XLogRecPtr recptr;
/*
* We don't log the current state of the tuple, but rather the state
* as it would appear after "log" more fetches. This lets us skip
* that many future WAL records, at the cost that we lose those
* sequence values if we crash.
*/
XLogBeginInsert();
XLogRegisterBuffer(0, buf, REGBUF_WILL_INIT);
/* set values that will be saved in xlog */
seq->last_value = next;
seq->is_called = true;
seq->log_cnt = 0;
xlrec.node = seqrel->rd_node;
XLogRegisterData((char *) &xlrec, sizeof(xl_seq_rec));
XLogRegisterData((char *) seqdatatuple.t_data, seqdatatuple.t_len);
recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG);
PageSetLSN(page, recptr);
}
/* Now update sequence tuple to the intended final state */
seq->last_value = last; /* last fetched number */
seq->is_called = true;
seq->log_cnt = log; /* how much is logged */
END_CRIT_SECTION();
UnlockReleaseBuffer(buf);
relation_close(seqrel, NoLock);
return result;
}
IndexBulkDeleteResult *
ginbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback, void *callback_state)
{
Relation index = info->index;
BlockNumber blkno = GIN_ROOT_BLKNO;
GinVacuumState gvs;
Buffer buffer;
BlockNumber rootOfPostingTree[BLCKSZ / (sizeof(IndexTupleData) + sizeof(ItemId))];
uint32 nRoot;
gvs.tmpCxt = AllocSetContextCreate(CurrentMemoryContext,
"Gin vacuum temporary context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
gvs.index = index;
gvs.callback = callback;
gvs.callback_state = callback_state;
gvs.strategy = info->strategy;
initGinState(&gvs.ginstate, index);
/* first time through? */
if (stats == NULL)
{
/* Yes, so initialize stats to zeroes */
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
/*
* and cleanup any pending inserts */
ginInsertCleanup(&gvs.ginstate, !IsAutoVacuumWorkerProcess(),
false, stats);
}
/* we'll re-count the tuples each time */
stats->num_index_tuples = 0;
gvs.result = stats;
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
/* find leaf page */
for (;;)
{
Page page = BufferGetPage(buffer);
IndexTuple itup;
LockBuffer(buffer, GIN_SHARE);
Assert(!GinPageIsData(page));
if (GinPageIsLeaf(page))
{
LockBuffer(buffer, GIN_UNLOCK);
LockBuffer(buffer, GIN_EXCLUSIVE);
if (blkno == GIN_ROOT_BLKNO && !GinPageIsLeaf(page))
{
LockBuffer(buffer, GIN_UNLOCK);
continue; /* check it one more */
}
break;
}
Assert(PageGetMaxOffsetNumber(page) >= FirstOffsetNumber);
itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, FirstOffsetNumber));
blkno = GinGetDownlink(itup);
Assert(blkno != InvalidBlockNumber);
UnlockReleaseBuffer(buffer);
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
}
/* right now we found leftmost page in entry's BTree */
for (;;)
{
Page page = BufferGetPage(buffer);
Page resPage;
uint32 i;
Assert(!GinPageIsData(page));
resPage = ginVacuumEntryPage(&gvs, buffer, rootOfPostingTree, &nRoot);
blkno = GinPageGetOpaque(page)->rightlink;
if (resPage)
{
START_CRIT_SECTION();
PageRestoreTempPage(resPage, page);
MarkBufferDirty(buffer);
xlogVacuumPage(gvs.index, buffer);
UnlockReleaseBuffer(buffer);
END_CRIT_SECTION();
}
else
{
UnlockReleaseBuffer(buffer);
}
vacuum_delay_point();
for (i = 0; i < nRoot; i++)
{
ginVacuumPostingTree(&gvs, rootOfPostingTree[i]);
vacuum_delay_point();
}
if (blkno == InvalidBlockNumber) /* rightmost page */
break;
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
LockBuffer(buffer, GIN_EXCLUSIVE);
}
MemoryContextDelete(gvs.tmpCxt);
return gvs.result;
}
/*
* Main internal procedure that handles 2 & 3 arg forms of SETVAL.
*
* Note that the 3 arg version (which sets the is_called flag) is
* only for use in pg_dump, and setting the is_called flag may not
* work if multiple users are attached to the database and referencing
* the sequence (unlikely if pg_dump is restoring it).
*
* It is necessary to have the 3 arg version so that pg_dump can
* restore the state of a sequence exactly during data-only restores -
* it is the only way to clear the is_called flag in an existing
* sequence.
*/
static void
do_setval(Oid relid, int64 next, bool iscalled)
{
SeqTable elm;
Relation seqrel;
Buffer buf;
HeapTupleData seqdatatuple;
Form_pg_sequence_data seq;
HeapTuple pgstuple;
Form_pg_sequence pgsform;
int64 maxv,
minv;
/* open and AccessShareLock sequence */
init_sequence(relid, &elm, &seqrel);
if (pg_class_aclcheck(elm->relid, GetUserId(), ACL_UPDATE) != ACLCHECK_OK)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied for sequence %s",
RelationGetRelationName(seqrel))));
pgstuple = SearchSysCache1(SEQRELID, ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(pgstuple))
elog(ERROR, "cache lookup failed for sequence %u", relid);
pgsform = (Form_pg_sequence) GETSTRUCT(pgstuple);
maxv = pgsform->seqmax;
minv = pgsform->seqmin;
ReleaseSysCache(pgstuple);
/* read-only transactions may only modify temp sequences */
if (!seqrel->rd_islocaltemp)
PreventCommandIfReadOnly("setval()");
/*
* Forbid this during parallel operation because, to make it work, the
* cooperating backends would need to share the backend-local cached
* sequence information. Currently, we don't support that.
*/
PreventCommandIfParallelMode("setval()");
/* lock page' buffer and read tuple */
seq = read_seq_tuple(seqrel, &buf, &seqdatatuple);
if ((next < minv) || (next > maxv))
{
char bufv[100],
bufm[100],
bufx[100];
snprintf(bufv, sizeof(bufv), INT64_FORMAT, next);
snprintf(bufm, sizeof(bufm), INT64_FORMAT, minv);
snprintf(bufx, sizeof(bufx), INT64_FORMAT, maxv);
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("setval: value %s is out of bounds for sequence \"%s\" (%s..%s)",
bufv, RelationGetRelationName(seqrel),
bufm, bufx)));
}
/* Set the currval() state only if iscalled = true */
if (iscalled)
{
elm->last = next; /* last returned number */
elm->last_valid = true;
}
/* In any case, forget any future cached numbers */
elm->cached = elm->last;
/* check the comment above nextval_internal()'s equivalent call. */
if (RelationNeedsWAL(seqrel))
GetTopTransactionId();
/* ready to change the on-disk (or really, in-buffer) tuple */
START_CRIT_SECTION();
seq->last_value = next; /* last fetched number */
seq->is_called = iscalled;
seq->log_cnt = 0;
MarkBufferDirty(buf);
/* XLOG stuff */
if (RelationNeedsWAL(seqrel))
{
xl_seq_rec xlrec;
XLogRecPtr recptr;
Page page = BufferGetPage(buf);
XLogBeginInsert();
XLogRegisterBuffer(0, buf, REGBUF_WILL_INIT);
xlrec.node = seqrel->rd_node;
XLogRegisterData((char *) &xlrec, sizeof(xl_seq_rec));
XLogRegisterData((char *) seqdatatuple.t_data, seqdatatuple.t_len);
recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG);
PageSetLSN(page, recptr);
}
END_CRIT_SECTION();
UnlockReleaseBuffer(buf);
relation_close(seqrel, NoLock);
}
/*
* Deletes pending list pages up to (not including) newHead page.
* If newHead == InvalidBlockNumber then function drops the whole list.
*
* metapage is pinned and exclusive-locked throughout this function.
*
* Returns true if another cleanup process is running concurrently
* (if so, we can just abandon our own efforts)
*/
static bool
shiftList(Relation index, Buffer metabuffer, BlockNumber newHead,
IndexBulkDeleteResult *stats)
{
Page metapage;
GinMetaPageData *metadata;
BlockNumber blknoToDelete;
metapage = BufferGetPage(metabuffer);
metadata = GinPageGetMeta(metapage);
blknoToDelete = metadata->head;
do
{
Page page;
int i;
int64 nDeletedHeapTuples = 0;
ginxlogDeleteListPages data;
XLogRecData rdata[1];
Buffer buffers[GIN_NDELETE_AT_ONCE];
data.node = index->rd_node;
rdata[0].buffer = InvalidBuffer;
rdata[0].data = (char *) &data;
rdata[0].len = sizeof(ginxlogDeleteListPages);
rdata[0].next = NULL;
data.ndeleted = 0;
while (data.ndeleted < GIN_NDELETE_AT_ONCE && blknoToDelete != newHead)
{
data.toDelete[data.ndeleted] = blknoToDelete;
buffers[data.ndeleted] = ReadBuffer(index, blknoToDelete);
LockBuffer(buffers[data.ndeleted], GIN_EXCLUSIVE);
page = BufferGetPage(buffers[data.ndeleted]);
data.ndeleted++;
if (GinPageIsDeleted(page))
{
/* concurrent cleanup process is detected */
for (i = 0; i < data.ndeleted; i++)
UnlockReleaseBuffer(buffers[i]);
return true;
}
nDeletedHeapTuples += GinPageGetOpaque(page)->maxoff;
blknoToDelete = GinPageGetOpaque(page)->rightlink;
}
if (stats)
stats->pages_deleted += data.ndeleted;
START_CRIT_SECTION();
metadata->head = blknoToDelete;
Assert(metadata->nPendingPages >= data.ndeleted);
metadata->nPendingPages -= data.ndeleted;
Assert(metadata->nPendingHeapTuples >= nDeletedHeapTuples);
metadata->nPendingHeapTuples -= nDeletedHeapTuples;
if (blknoToDelete == InvalidBlockNumber)
{
metadata->tail = InvalidBlockNumber;
metadata->tailFreeSize = 0;
metadata->nPendingPages = 0;
metadata->nPendingHeapTuples = 0;
}
MarkBufferDirty(metabuffer);
for (i = 0; i < data.ndeleted; i++)
{
page = BufferGetPage(buffers[i]);
GinPageGetOpaque(page)->flags = GIN_DELETED;
MarkBufferDirty(buffers[i]);
}
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
memcpy(&data.metadata, metadata, sizeof(GinMetaPageData));
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_DELETE_LISTPAGE, rdata);
PageSetLSN(metapage, recptr);
for (i = 0; i < data.ndeleted; i++)
{
page = BufferGetPage(buffers[i]);
PageSetLSN(page, recptr);
}
}
for (i = 0; i < data.ndeleted; i++)
UnlockReleaseBuffer(buffers[i]);
END_CRIT_SECTION();
} while (blknoToDelete != newHead);
return false;
}
/*
* visibilitymap_set - set a bit on a previously pinned page
*
* recptr is the LSN of the XLOG record we're replaying, if we're in recovery,
* or InvalidXLogRecPtr in normal running. The page LSN is advanced to the
* one provided; in normal running, we generate a new XLOG record and set the
* page LSN to that value. cutoff_xid is the largest xmin on the page being
* marked all-visible; it is needed for Hot Standby, and can be
* InvalidTransactionId if the page contains no tuples.
*
* Caller is expected to set the heap page's PD_ALL_VISIBLE bit before calling
* this function. Except in recovery, caller should also pass the heap
* buffer. When checksums are enabled and we're not in recovery, we must add
* the heap buffer to the WAL chain to protect it from being torn.
*
* You must pass a buffer containing the correct map page to this function.
* Call visibilitymap_pin first to pin the right one. This function doesn't do
* any I/O.
*/
void
visibilitymap_set(Relation rel, BlockNumber heapBlk, Buffer heapBuf,
XLogRecPtr recptr, Buffer vmBuf, TransactionId cutoff_xid)
{
BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
uint32 mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
uint8 mapBit = HEAPBLK_TO_MAPBIT(heapBlk);
Page page;
char *map;
#ifdef TRACE_VISIBILITYMAP
elog(DEBUG1, "vm_set %s %d", RelationGetRelationName(rel), heapBlk);
#endif
Assert(InRecovery || XLogRecPtrIsInvalid(recptr));
Assert(InRecovery || BufferIsValid(heapBuf));
/* Check that we have the right heap page pinned, if present */
if (BufferIsValid(heapBuf) && BufferGetBlockNumber(heapBuf) != heapBlk)
elog(ERROR, "wrong heap buffer passed to visibilitymap_set");
/* Check that we have the right VM page pinned */
if (!BufferIsValid(vmBuf) || BufferGetBlockNumber(vmBuf) != mapBlock)
elog(ERROR, "wrong VM buffer passed to visibilitymap_set");
page = BufferGetPage(vmBuf);
map = PageGetContents(page);
LockBuffer(vmBuf, BUFFER_LOCK_EXCLUSIVE);
if (!(map[mapByte] & (1 << mapBit)))
{
START_CRIT_SECTION();
map[mapByte] |= (1 << mapBit);
MarkBufferDirty(vmBuf);
if (RelationNeedsWAL(rel))
{
if (XLogRecPtrIsInvalid(recptr))
{
Assert(!InRecovery);
recptr = log_heap_visible(rel->rd_node, heapBuf, vmBuf,
cutoff_xid);
/*
* If data checksums are enabled, we need to protect the heap
* page from being torn.
*/
if (DataChecksumsEnabled())
{
Page heapPage = BufferGetPage(heapBuf);
/* caller is expected to set PD_ALL_VISIBLE first */
Assert(PageIsAllVisible(heapPage));
PageSetLSN(heapPage, recptr);
}
}
PageSetLSN(page, recptr);
}
END_CRIT_SECTION();
}
LockBuffer(vmBuf, BUFFER_LOCK_UNLOCK);
}
/*
* Deletes pending list pages up to (not including) newHead page.
* If newHead == InvalidBlockNumber then function drops the whole list.
*
* metapage is pinned and exclusive-locked throughout this function.
*
* Returns true if another cleanup process is running concurrently
* (if so, we can just abandon our own efforts)
*/
static bool
shiftList(Relation index, Buffer metabuffer, BlockNumber newHead,
bool fill_fsm, IndexBulkDeleteResult *stats)
{
Page metapage;
GinMetaPageData *metadata;
BlockNumber blknoToDelete;
metapage = BufferGetPage(metabuffer);
metadata = GinPageGetMeta(metapage);
blknoToDelete = metadata->head;
do
{
Page page;
int i;
int64 nDeletedHeapTuples = 0;
ginxlogDeleteListPages data;
Buffer buffers[GIN_NDELETE_AT_ONCE];
BlockNumber freespace[GIN_NDELETE_AT_ONCE];
data.ndeleted = 0;
while (data.ndeleted < GIN_NDELETE_AT_ONCE && blknoToDelete != newHead)
{
freespace[data.ndeleted] = blknoToDelete;
buffers[data.ndeleted] = ReadBuffer(index, blknoToDelete);
LockBuffer(buffers[data.ndeleted], GIN_EXCLUSIVE);
page = BufferGetPage(buffers[data.ndeleted]);
data.ndeleted++;
if (GinPageIsDeleted(page))
{
/* concurrent cleanup process is detected */
for (i = 0; i < data.ndeleted; i++)
UnlockReleaseBuffer(buffers[i]);
return true;
}
nDeletedHeapTuples += GinPageGetOpaque(page)->maxoff;
blknoToDelete = GinPageGetOpaque(page)->rightlink;
}
if (stats)
stats->pages_deleted += data.ndeleted;
/*
* This operation touches an unusually large number of pages, so
* prepare the XLogInsert machinery for that before entering the
* critical section.
*/
if (RelationNeedsWAL(index))
XLogEnsureRecordSpace(data.ndeleted, 0);
START_CRIT_SECTION();
metadata->head = blknoToDelete;
Assert(metadata->nPendingPages >= data.ndeleted);
metadata->nPendingPages -= data.ndeleted;
Assert(metadata->nPendingHeapTuples >= nDeletedHeapTuples);
metadata->nPendingHeapTuples -= nDeletedHeapTuples;
if (blknoToDelete == InvalidBlockNumber)
{
metadata->tail = InvalidBlockNumber;
metadata->tailFreeSize = 0;
metadata->nPendingPages = 0;
metadata->nPendingHeapTuples = 0;
}
MarkBufferDirty(metabuffer);
for (i = 0; i < data.ndeleted; i++)
{
page = BufferGetPage(buffers[i]);
GinPageGetOpaque(page)->flags = GIN_DELETED;
MarkBufferDirty(buffers[i]);
}
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
XLogBeginInsert();
XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT);
for (i = 0; i < data.ndeleted; i++)
XLogRegisterBuffer(i + 1, buffers[i], REGBUF_WILL_INIT);
memcpy(&data.metadata, metadata, sizeof(GinMetaPageData));
XLogRegisterData((char *) &data,
sizeof(ginxlogDeleteListPages));
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_DELETE_LISTPAGE);
PageSetLSN(metapage, recptr);
for (i = 0; i < data.ndeleted; i++)
{
page = BufferGetPage(buffers[i]);
PageSetLSN(page, recptr);
}
}
for (i = 0; i < data.ndeleted; i++)
UnlockReleaseBuffer(buffers[i]);
END_CRIT_SECTION();
for (i = 0; fill_fsm && i < data.ndeleted; i++)
RecordFreeIndexPage(index, freespace[i]);
} while (blknoToDelete != newHead);
return false;
}
/*
* Attempt to expand the hash table by creating one new bucket.
*
* This will silently do nothing if it cannot get the needed locks.
*
* The caller should hold no locks on the hash index.
*
* The caller must hold a pin, but no lock, on the metapage buffer.
* The buffer is returned in the same state.
*/
void
_hash_expandtable(Relation rel, Buffer metabuf)
{
HashMetaPage metap;
Bucket old_bucket;
Bucket new_bucket;
uint32 spare_ndx;
BlockNumber start_oblkno;
BlockNumber start_nblkno;
uint32 maxbucket;
uint32 highmask;
uint32 lowmask;
/*
* Write-lock the meta page. It used to be necessary to acquire a
* heavyweight lock to begin a split, but that is no longer required.
*/
_hash_chgbufaccess(rel, metabuf, HASH_NOLOCK, HASH_WRITE);
_hash_checkpage(rel, metabuf, LH_META_PAGE);
metap = HashPageGetMeta(BufferGetPage(metabuf));
/*
* Check to see if split is still needed; someone else might have already
* done one while we waited for the lock.
*
* Make sure this stays in sync with _hash_doinsert()
*/
if (metap->hashm_ntuples <=
(double) metap->hashm_ffactor * (metap->hashm_maxbucket + 1))
goto fail;
/*
* Can't split anymore if maxbucket has reached its maximum possible
* value.
*
* Ideally we'd allow bucket numbers up to UINT_MAX-1 (no higher because
* the calculation maxbucket+1 mustn't overflow). Currently we restrict
* to half that because of overflow looping in _hash_log2() and
* insufficient space in hashm_spares[]. It's moot anyway because an
* index with 2^32 buckets would certainly overflow BlockNumber and hence
* _hash_alloc_buckets() would fail, but if we supported buckets smaller
* than a disk block then this would be an independent constraint.
*
* If you change this, see also the maximum initial number of buckets in
* _hash_metapinit().
*/
if (metap->hashm_maxbucket >= (uint32) 0x7FFFFFFE)
goto fail;
/*
* Determine which bucket is to be split, and attempt to lock the old
* bucket. If we can't get the lock, give up.
*
* The lock protects us against other backends, but not against our own
* backend. Must check for active scans separately.
*/
new_bucket = metap->hashm_maxbucket + 1;
old_bucket = (new_bucket & metap->hashm_lowmask);
start_oblkno = BUCKET_TO_BLKNO(metap, old_bucket);
if (_hash_has_active_scan(rel, old_bucket))
goto fail;
if (!_hash_try_getlock(rel, start_oblkno, HASH_EXCLUSIVE))
goto fail;
/*
* Likewise lock the new bucket (should never fail).
*
* Note: it is safe to compute the new bucket's blkno here, even though we
* may still need to update the BUCKET_TO_BLKNO mapping. This is because
* the current value of hashm_spares[hashm_ovflpoint] correctly shows
* where we are going to put a new splitpoint's worth of buckets.
*/
start_nblkno = BUCKET_TO_BLKNO(metap, new_bucket);
if (_hash_has_active_scan(rel, new_bucket))
elog(ERROR, "scan in progress on supposedly new bucket");
if (!_hash_try_getlock(rel, start_nblkno, HASH_EXCLUSIVE))
elog(ERROR, "could not get lock on supposedly new bucket");
/*
* If the split point is increasing (hashm_maxbucket's log base 2
* increases), we need to allocate a new batch of bucket pages.
*/
spare_ndx = _hash_log2(new_bucket + 1);
if (spare_ndx > metap->hashm_ovflpoint)
{
Assert(spare_ndx == metap->hashm_ovflpoint + 1);
/*
* The number of buckets in the new splitpoint is equal to the total
* number already in existence, i.e. new_bucket. Currently this maps
* one-to-one to blocks required, but someday we may need a more
* complicated calculation here.
*/
if (!_hash_alloc_buckets(rel, start_nblkno, new_bucket))
{
/* can't split due to BlockNumber overflow */
_hash_droplock(rel, start_oblkno, HASH_EXCLUSIVE);
_hash_droplock(rel, start_nblkno, HASH_EXCLUSIVE);
goto fail;
}
}
/*
* Okay to proceed with split. Update the metapage bucket mapping info.
*
* Since we are scribbling on the metapage data right in the shared
* buffer, any failure in this next little bit leaves us with a big
* problem: the metapage is effectively corrupt but could get written back
* to disk. We don't really expect any failure, but just to be sure,
* establish a critical section.
*/
START_CRIT_SECTION();
metap->hashm_maxbucket = new_bucket;
if (new_bucket > metap->hashm_highmask)
{
/* Starting a new doubling */
metap->hashm_lowmask = metap->hashm_highmask;
metap->hashm_highmask = new_bucket | metap->hashm_lowmask;
}
/*
* If the split point is increasing (hashm_maxbucket's log base 2
* increases), we need to adjust the hashm_spares[] array and
* hashm_ovflpoint so that future overflow pages will be created beyond
* this new batch of bucket pages.
*/
if (spare_ndx > metap->hashm_ovflpoint)
{
metap->hashm_spares[spare_ndx] = metap->hashm_spares[metap->hashm_ovflpoint];
metap->hashm_ovflpoint = spare_ndx;
}
/* Done mucking with metapage */
END_CRIT_SECTION();
/*
* Copy bucket mapping info now; this saves re-accessing the meta page
* inside _hash_splitbucket's inner loop. Note that once we drop the
* split lock, other splits could begin, so these values might be out of
* date before _hash_splitbucket finishes. That's okay, since all it
* needs is to tell which of these two buckets to map hashkeys into.
*/
maxbucket = metap->hashm_maxbucket;
highmask = metap->hashm_highmask;
lowmask = metap->hashm_lowmask;
/* Write out the metapage and drop lock, but keep pin */
_hash_chgbufaccess(rel, metabuf, HASH_WRITE, HASH_NOLOCK);
/* Relocate records to the new bucket */
_hash_splitbucket(rel, metabuf, old_bucket, new_bucket,
start_oblkno, start_nblkno,
maxbucket, highmask, lowmask);
/* Release bucket locks, allowing others to access them */
_hash_droplock(rel, start_oblkno, HASH_EXCLUSIVE);
_hash_droplock(rel, start_nblkno, HASH_EXCLUSIVE);
return;
/* Here if decide not to split or fail to acquire old bucket lock */
fail:
/* We didn't write the metapage, so just drop lock */
_hash_chgbufaccess(rel, metabuf, HASH_READ, HASH_NOLOCK);
}
/*
* Main entry point to GiST index build. Initially calls insert over and over,
* but switches to more efficient buffering build algorithm after a certain
* number of tuples (unless buffering mode is disabled).
*/
Datum
gistbuild(PG_FUNCTION_ARGS)
{
Relation heap = (Relation) PG_GETARG_POINTER(0);
Relation index = (Relation) PG_GETARG_POINTER(1);
IndexInfo *indexInfo = (IndexInfo *) PG_GETARG_POINTER(2);
IndexBuildResult *result;
double reltuples;
GISTBuildState buildstate;
Buffer buffer;
Page page;
MemoryContext oldcxt = CurrentMemoryContext;
int fillfactor;
buildstate.indexrel = index;
if (index->rd_options)
{
/* Get buffering mode from the options string */
GiSTOptions *options = (GiSTOptions *) index->rd_options;
char *bufferingMode = (char *) options + options->bufferingModeOffset;
if (strcmp(bufferingMode, "on") == 0)
buildstate.bufferingMode = GIST_BUFFERING_STATS;
else if (strcmp(bufferingMode, "off") == 0)
buildstate.bufferingMode = GIST_BUFFERING_DISABLED;
else
buildstate.bufferingMode = GIST_BUFFERING_AUTO;
fillfactor = options->fillfactor;
}
else
{
/*
* By default, switch to buffering mode when the index grows too large
* to fit in cache.
*/
buildstate.bufferingMode = GIST_BUFFERING_AUTO;
fillfactor = GIST_DEFAULT_FILLFACTOR;
}
/* Calculate target amount of free space to leave on pages */
buildstate.freespace = BLCKSZ * (100 - fillfactor) / 100;
/*
* We expect to be called exactly once for any index relation. If that's
* not the case, big trouble's what we have.
*/
if (RelationGetNumberOfBlocks(index) != 0)
elog(ERROR, "index \"%s\" already contains data",
RelationGetRelationName(index));
/* no locking is needed */
buildstate.giststate = initGISTstate(index);
/*
* Create a temporary memory context that is reset once for each tuple
* processed. (Note: we don't bother to make this a child of the
* giststate's scanCxt, so we have to delete it separately at the end.)
*/
buildstate.giststate->tempCxt = createTempGistContext();
/* initialize the root page */
buffer = gistNewBuffer(index);
Assert(BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO);
page = BufferGetPage(buffer);
START_CRIT_SECTION();
GISTInitBuffer(buffer, F_LEAF);
MarkBufferDirty(buffer);
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
XLogRecData rdata;
rdata.data = (char *) &(index->rd_node);
rdata.len = sizeof(RelFileNode);
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_CREATE_INDEX, &rdata);
PageSetLSN(page, recptr);
}
else
PageSetLSN(page, gistGetFakeLSN(heap));
UnlockReleaseBuffer(buffer);
END_CRIT_SECTION();
/* build the index */
buildstate.indtuples = 0;
buildstate.indtuplesSize = 0;
/*
* Do the heap scan.
*/
reltuples = IndexBuildHeapScan(heap, index, indexInfo, true,
gistBuildCallback, (void *) &buildstate);
/*
* If buffering was used, flush out all the tuples that are still in the
* buffers.
*/
if (buildstate.bufferingMode == GIST_BUFFERING_ACTIVE)
{
elog(DEBUG1, "all tuples processed, emptying buffers");
gistEmptyAllBuffers(&buildstate);
gistFreeBuildBuffers(buildstate.gfbb);
}
/* okay, all heap tuples are indexed */
MemoryContextSwitchTo(oldcxt);
MemoryContextDelete(buildstate.giststate->tempCxt);
freeGISTstate(buildstate.giststate);
/*
* Return statistics
*/
result = (IndexBuildResult *) palloc(sizeof(IndexBuildResult));
result->heap_tuples = reltuples;
result->index_tuples = (double) buildstate.indtuples;
PG_RETURN_POINTER(result);
}
/*
* Vacuum a regular (non-root) leaf page
*
* We must delete tuples that are targeted for deletion by the VACUUM,
* but not move any tuples that are referenced by outside links; we assume
* those are the ones that are heads of chains.
*
* If we find a REDIRECT that was made by a concurrently-running transaction,
* we must add its target TID to pendingList. (We don't try to visit the
* target immediately, first because we don't want VACUUM locking more than
* one buffer at a time, and second because the duplicate-filtering logic
* in spgAddPendingTID is useful to ensure we can't get caught in an infinite
* loop in the face of continuous concurrent insertions.)
*
* If forPending is true, we are examining the page as a consequence of
* chasing a redirect link, not as part of the normal sequential scan.
* We still vacuum the page normally, but we don't increment the stats
* about live tuples; else we'd double-count those tuples, since the page
* has been or will be visited in the sequential scan as well.
*/
static void
vacuumLeafPage(spgBulkDeleteState *bds, Relation index, Buffer buffer,
bool forPending)
{
Page page = BufferGetPage(buffer);
spgxlogVacuumLeaf xlrec;
OffsetNumber toDead[MaxIndexTuplesPerPage];
OffsetNumber toPlaceholder[MaxIndexTuplesPerPage];
OffsetNumber moveSrc[MaxIndexTuplesPerPage];
OffsetNumber moveDest[MaxIndexTuplesPerPage];
OffsetNumber chainSrc[MaxIndexTuplesPerPage];
OffsetNumber chainDest[MaxIndexTuplesPerPage];
OffsetNumber predecessor[MaxIndexTuplesPerPage + 1];
bool deletable[MaxIndexTuplesPerPage + 1];
int nDeletable;
OffsetNumber i,
max = PageGetMaxOffsetNumber(page);
memset(predecessor, 0, sizeof(predecessor));
memset(deletable, 0, sizeof(deletable));
nDeletable = 0;
/* Scan page, identify tuples to delete, accumulate stats */
for (i = FirstOffsetNumber; i <= max; i++)
{
SpGistLeafTuple lt;
lt = (SpGistLeafTuple) PageGetItem(page,
PageGetItemId(page, i));
if (lt->tupstate == SPGIST_LIVE)
{
Assert(ItemPointerIsValid(<->heapPtr));
if (bds->callback(<->heapPtr, bds->callback_state))
{
bds->stats->tuples_removed += 1;
deletable[i] = true;
nDeletable++;
}
else
{
if (!forPending)
bds->stats->num_index_tuples += 1;
}
/* Form predecessor map, too */
if (lt->nextOffset != InvalidOffsetNumber)
{
/* paranoia about corrupted chain links */
if (lt->nextOffset < FirstOffsetNumber ||
lt->nextOffset > max ||
predecessor[lt->nextOffset] != InvalidOffsetNumber)
elog(ERROR, "inconsistent tuple chain links in page %u of index \"%s\"",
BufferGetBlockNumber(buffer),
RelationGetRelationName(index));
predecessor[lt->nextOffset] = i;
}
}
else if (lt->tupstate == SPGIST_REDIRECT)
{
SpGistDeadTuple dt = (SpGistDeadTuple) lt;
Assert(dt->nextOffset == InvalidOffsetNumber);
Assert(ItemPointerIsValid(&dt->pointer));
/*
* Add target TID to pending list if the redirection could have
* happened since VACUUM started.
*
* Note: we could make a tighter test by seeing if the xid is
* "running" according to the active snapshot; but tqual.c doesn't
* currently export a suitable API, and it's not entirely clear
* that a tighter test is worth the cycles anyway.
*/
if (TransactionIdFollowsOrEquals(dt->xid, bds->myXmin))
spgAddPendingTID(bds, &dt->pointer);
}
else
{
Assert(lt->nextOffset == InvalidOffsetNumber);
}
}
if (nDeletable == 0)
return; /* nothing more to do */
/*----------
* Figure out exactly what we have to do. We do this separately from
* actually modifying the page, mainly so that we have a representation
* that can be dumped into WAL and then the replay code can do exactly
* the same thing. The output of this step consists of six arrays
* describing four kinds of operations, to be performed in this order:
*
* toDead[]: tuple numbers to be replaced with DEAD tuples
* toPlaceholder[]: tuple numbers to be replaced with PLACEHOLDER tuples
* moveSrc[]: tuple numbers that need to be relocated to another offset
* (replacing the tuple there) and then replaced with PLACEHOLDER tuples
* moveDest[]: new locations for moveSrc tuples
* chainSrc[]: tuple numbers whose chain links (nextOffset) need updates
* chainDest[]: new values of nextOffset for chainSrc members
*
* It's easiest to figure out what we have to do by processing tuple
* chains, so we iterate over all the tuples (not just the deletable
* ones!) to identify chain heads, then chase down each chain and make
* work item entries for deletable tuples within the chain.
*----------
*/
xlrec.nDead = xlrec.nPlaceholder = xlrec.nMove = xlrec.nChain = 0;
for (i = FirstOffsetNumber; i <= max; i++)
{
SpGistLeafTuple head;
bool interveningDeletable;
OffsetNumber prevLive;
OffsetNumber j;
head = (SpGistLeafTuple) PageGetItem(page,
PageGetItemId(page, i));
if (head->tupstate != SPGIST_LIVE)
continue; /* can't be a chain member */
if (predecessor[i] != 0)
continue; /* not a chain head */
/* initialize ... */
interveningDeletable = false;
prevLive = deletable[i] ? InvalidOffsetNumber : i;
/* scan down the chain ... */
j = head->nextOffset;
while (j != InvalidOffsetNumber)
{
SpGistLeafTuple lt;
lt = (SpGistLeafTuple) PageGetItem(page,
PageGetItemId(page, j));
if (lt->tupstate != SPGIST_LIVE)
{
/* all tuples in chain should be live */
elog(ERROR, "unexpected SPGiST tuple state: %d",
lt->tupstate);
}
if (deletable[j])
{
/* This tuple should be replaced by a placeholder */
toPlaceholder[xlrec.nPlaceholder] = j;
xlrec.nPlaceholder++;
/* previous live tuple's chain link will need an update */
interveningDeletable = true;
}
else if (prevLive == InvalidOffsetNumber)
{
/*
* This is the first live tuple in the chain. It has to move
* to the head position.
*/
moveSrc[xlrec.nMove] = j;
moveDest[xlrec.nMove] = i;
xlrec.nMove++;
/* Chain updates will be applied after the move */
prevLive = i;
interveningDeletable = false;
}
else
{
/*
* Second or later live tuple. Arrange to re-chain it to the
* previous live one, if there was a gap.
*/
if (interveningDeletable)
{
chainSrc[xlrec.nChain] = prevLive;
chainDest[xlrec.nChain] = j;
xlrec.nChain++;
}
prevLive = j;
interveningDeletable = false;
}
j = lt->nextOffset;
}
if (prevLive == InvalidOffsetNumber)
{
/* The chain is entirely removable, so we need a DEAD tuple */
toDead[xlrec.nDead] = i;
xlrec.nDead++;
}
else if (interveningDeletable)
{
/* One or more deletions at end of chain, so close it off */
chainSrc[xlrec.nChain] = prevLive;
chainDest[xlrec.nChain] = InvalidOffsetNumber;
xlrec.nChain++;
}
}
/* sanity check ... */
if (nDeletable != xlrec.nDead + xlrec.nPlaceholder + xlrec.nMove)
elog(ERROR, "inconsistent counts of deletable tuples");
/* Do the updates */
START_CRIT_SECTION();
spgPageIndexMultiDelete(&bds->spgstate, page,
toDead, xlrec.nDead,
SPGIST_DEAD, SPGIST_DEAD,
InvalidBlockNumber, InvalidOffsetNumber);
spgPageIndexMultiDelete(&bds->spgstate, page,
toPlaceholder, xlrec.nPlaceholder,
SPGIST_PLACEHOLDER, SPGIST_PLACEHOLDER,
InvalidBlockNumber, InvalidOffsetNumber);
/*
* We implement the move step by swapping the item pointers of the source
* and target tuples, then replacing the newly-source tuples with
* placeholders. This is perhaps unduly friendly with the page data
* representation, but it's fast and doesn't risk page overflow when a
* tuple to be relocated is large.
*/
for (i = 0; i < xlrec.nMove; i++)
{
ItemId idSrc = PageGetItemId(page, moveSrc[i]);
ItemId idDest = PageGetItemId(page, moveDest[i]);
ItemIdData tmp;
tmp = *idSrc;
*idSrc = *idDest;
*idDest = tmp;
}
spgPageIndexMultiDelete(&bds->spgstate, page,
moveSrc, xlrec.nMove,
SPGIST_PLACEHOLDER, SPGIST_PLACEHOLDER,
InvalidBlockNumber, InvalidOffsetNumber);
for (i = 0; i < xlrec.nChain; i++)
{
SpGistLeafTuple lt;
lt = (SpGistLeafTuple) PageGetItem(page,
PageGetItemId(page, chainSrc[i]));
Assert(lt->tupstate == SPGIST_LIVE);
lt->nextOffset = chainDest[i];
}
MarkBufferDirty(buffer);
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
XLogBeginInsert();
STORE_STATE(&bds->spgstate, xlrec.stateSrc);
XLogRegisterData((char *) &xlrec, SizeOfSpgxlogVacuumLeaf);
/* sizeof(xlrec) should be a multiple of sizeof(OffsetNumber) */
XLogRegisterData((char *) toDead, sizeof(OffsetNumber) * xlrec.nDead);
XLogRegisterData((char *) toPlaceholder, sizeof(OffsetNumber) * xlrec.nPlaceholder);
XLogRegisterData((char *) moveSrc, sizeof(OffsetNumber) * xlrec.nMove);
XLogRegisterData((char *) moveDest, sizeof(OffsetNumber) * xlrec.nMove);
XLogRegisterData((char *) chainSrc, sizeof(OffsetNumber) * xlrec.nChain);
XLogRegisterData((char *) chainDest, sizeof(OffsetNumber) * xlrec.nChain);
XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_VACUUM_LEAF);
PageSetLSN(page, recptr);
}
END_CRIT_SECTION();
}
/*
* Permanently drop the currently acquired replication slot which will be
* released by the point this function returns.
*/
static void
ReplicationSlotDropAcquired(void)
{
char path[MAXPGPATH];
char tmppath[MAXPGPATH];
ReplicationSlot *slot = MyReplicationSlot;
Assert(MyReplicationSlot != NULL);
/* slot isn't acquired anymore */
MyReplicationSlot = NULL;
/*
* If some other backend ran this code concurrently with us, we might try
* to delete a slot with a certain name while someone else was trying to
* create a slot with the same name.
*/
LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE);
/* Generate pathnames. */
sprintf(path, "pg_replslot/%s", NameStr(slot->data.name));
sprintf(tmppath, "pg_replslot/%s.tmp", NameStr(slot->data.name));
/*
* Rename the slot directory on disk, so that we'll no longer recognize
* this as a valid slot. Note that if this fails, we've got to mark the
* slot inactive before bailing out. If we're dropping an ephemeral slot,
* we better never fail hard as the caller won't expect the slot to
* survive and this might get called during error handling.
*/
if (rename(path, tmppath) == 0)
{
/*
* We need to fsync() the directory we just renamed and its parent to
* make sure that our changes are on disk in a crash-safe fashion. If
* fsync() fails, we can't be sure whether the changes are on disk or
* not. For now, we handle that by panicking;
* StartupReplicationSlots() will try to straighten it out after
* restart.
*/
START_CRIT_SECTION();
fsync_fname(tmppath, true);
fsync_fname("pg_replslot", true);
END_CRIT_SECTION();
}
else
{
volatile ReplicationSlot *vslot = slot;
bool fail_softly = slot->data.persistency == RS_EPHEMERAL;
SpinLockAcquire(&slot->mutex);
vslot->active_pid = 0;
SpinLockRelease(&slot->mutex);
ereport(fail_softly ? WARNING : ERROR,
(errcode_for_file_access(),
errmsg("could not rename file \"%s\" to \"%s\": %m",
path, tmppath)));
}
/*
* The slot is definitely gone. Lock out concurrent scans of the array
* long enough to kill it. It's OK to clear the active flag here without
* grabbing the mutex because nobody else can be scanning the array here,
* and nobody can be attached to this slot and thus access it without
* scanning the array.
*/
LWLockAcquire(ReplicationSlotControlLock, LW_EXCLUSIVE);
slot->active_pid = 0;
slot->in_use = false;
LWLockRelease(ReplicationSlotControlLock);
/*
* Slot is dead and doesn't prevent resource removal anymore, recompute
* limits.
*/
ReplicationSlotsComputeRequiredXmin(false);
ReplicationSlotsComputeRequiredLSN();
/*
* If removing the directory fails, the worst thing that will happen is
* that the user won't be able to create a new___ slot with the same name
* until the next server restart. We warn about it, but that's all.
*/
if (!rmtree(tmppath, true))
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not remove directory \"%s\"", tmppath)));
/*
* We release this at the very end, so that nobody starts trying to create
* a slot while we're still cleaning up the detritus of the old one.
*/
LWLockRelease(ReplicationSlotAllocationLock);
}
/*
* Vacuum a root page when it is also a leaf
*
* On the root, we just delete any dead leaf tuples; no fancy business
*/
static void
vacuumLeafRoot(spgBulkDeleteState *bds, Relation index, Buffer buffer)
{
Page page = BufferGetPage(buffer);
spgxlogVacuumRoot xlrec;
OffsetNumber toDelete[MaxIndexTuplesPerPage];
OffsetNumber i,
max = PageGetMaxOffsetNumber(page);
xlrec.nDelete = 0;
/* Scan page, identify tuples to delete, accumulate stats */
for (i = FirstOffsetNumber; i <= max; i++)
{
SpGistLeafTuple lt;
lt = (SpGistLeafTuple) PageGetItem(page,
PageGetItemId(page, i));
if (lt->tupstate == SPGIST_LIVE)
{
Assert(ItemPointerIsValid(<->heapPtr));
if (bds->callback(<->heapPtr, bds->callback_state))
{
bds->stats->tuples_removed += 1;
toDelete[xlrec.nDelete] = i;
xlrec.nDelete++;
}
else
{
bds->stats->num_index_tuples += 1;
}
}
else
{
/* all tuples on root should be live */
elog(ERROR, "unexpected SPGiST tuple state: %d",
lt->tupstate);
}
}
if (xlrec.nDelete == 0)
return; /* nothing more to do */
/* Do the update */
START_CRIT_SECTION();
/* The tuple numbers are in order, so we can use PageIndexMultiDelete */
PageIndexMultiDelete(page, toDelete, xlrec.nDelete);
MarkBufferDirty(buffer);
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
XLogBeginInsert();
/* Prepare WAL record */
STORE_STATE(&bds->spgstate, xlrec.stateSrc);
XLogRegisterData((char *) &xlrec, SizeOfSpgxlogVacuumRoot);
/* sizeof(xlrec) should be a multiple of sizeof(OffsetNumber) */
XLogRegisterData((char *) toDelete,
sizeof(OffsetNumber) * xlrec.nDelete);
XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_VACUUM_ROOT);
PageSetLSN(page, recptr);
}
END_CRIT_SECTION();
}
/*
* Insert value (stored in GinBtree) to tree described by stack
*
* During an index build, buildStats is non-null and the counters
* it contains should be incremented as needed.
*
* NB: the passed-in stack is freed, as though by freeGinBtreeStack.
*/
void
ginInsertValue(GinBtree btree, GinBtreeStack *stack, GinStatsData *buildStats)
{
GinBtreeStack *parent;
BlockNumber rootBlkno;
Page page,
rpage,
lpage;
/* extract root BlockNumber from stack */
Assert(stack != NULL);
parent = stack;
while (parent->parent)
parent = parent->parent;
rootBlkno = parent->blkno;
Assert(BlockNumberIsValid(rootBlkno));
/* this loop crawls up the stack until the insertion is complete */
for (;;)
{
XLogRecData *rdata;
BlockNumber savedRightLink;
page = BufferGetPage(stack->buffer);
savedRightLink = GinPageGetOpaque(page)->rightlink;
if (btree->isEnoughSpace(btree, stack->buffer, stack->off))
{
START_CRIT_SECTION();
btree->placeToPage(btree, stack->buffer, stack->off, &rdata);
MarkBufferDirty(stack->buffer);
if (RelationNeedsWAL(btree->index))
{
XLogRecPtr recptr;
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_INSERT, rdata);
PageSetLSN(page, recptr);
}
LockBuffer(stack->buffer, GIN_UNLOCK);
END_CRIT_SECTION();
freeGinBtreeStack(stack);
return;
}
else
{
Buffer rbuffer = GinNewBuffer(btree->index);
Page newlpage;
/*
* newlpage is a pointer to memory page, it doesn't associate with
* buffer, stack->buffer should be untouched
*/
newlpage = btree->splitPage(btree, stack->buffer, rbuffer, stack->off, &rdata);
((ginxlogSplit *) (rdata->data))->rootBlkno = rootBlkno;
/* During index build, count the newly-split page */
if (buildStats)
{
if (btree->isData)
buildStats->nDataPages++;
else
buildStats->nEntryPages++;
}
parent = stack->parent;
if (parent == NULL)
{
/*
* split root, so we need to allocate new left page and place
* pointer on root to left and right page
*/
Buffer lbuffer = GinNewBuffer(btree->index);
((ginxlogSplit *) (rdata->data))->isRootSplit = TRUE;
((ginxlogSplit *) (rdata->data))->rrlink = InvalidBlockNumber;
page = BufferGetPage(stack->buffer);
lpage = BufferGetPage(lbuffer);
rpage = BufferGetPage(rbuffer);
GinPageGetOpaque(rpage)->rightlink = InvalidBlockNumber;
GinPageGetOpaque(newlpage)->rightlink = BufferGetBlockNumber(rbuffer);
((ginxlogSplit *) (rdata->data))->lblkno = BufferGetBlockNumber(lbuffer);
START_CRIT_SECTION();
GinInitBuffer(stack->buffer, GinPageGetOpaque(newlpage)->flags & ~GIN_LEAF);
PageRestoreTempPage(newlpage, lpage);
btree->fillRoot(btree, stack->buffer, lbuffer, rbuffer);
MarkBufferDirty(rbuffer);
MarkBufferDirty(lbuffer);
MarkBufferDirty(stack->buffer);
if (RelationNeedsWAL(btree->index))
{
XLogRecPtr recptr;
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_SPLIT, rdata);
PageSetLSN(page, recptr);
PageSetLSN(lpage, recptr);
PageSetLSN(rpage, recptr);
}
UnlockReleaseBuffer(rbuffer);
UnlockReleaseBuffer(lbuffer);
LockBuffer(stack->buffer, GIN_UNLOCK);
END_CRIT_SECTION();
freeGinBtreeStack(stack);
/* During index build, count the newly-added root page */
if (buildStats)
{
if (btree->isData)
buildStats->nDataPages++;
else
buildStats->nEntryPages++;
}
return;
}
else
{
/* split non-root page */
((ginxlogSplit *) (rdata->data))->isRootSplit = FALSE;
((ginxlogSplit *) (rdata->data))->rrlink = savedRightLink;
lpage = BufferGetPage(stack->buffer);
rpage = BufferGetPage(rbuffer);
GinPageGetOpaque(rpage)->rightlink = savedRightLink;
GinPageGetOpaque(newlpage)->rightlink = BufferGetBlockNumber(rbuffer);
START_CRIT_SECTION();
PageRestoreTempPage(newlpage, lpage);
MarkBufferDirty(rbuffer);
MarkBufferDirty(stack->buffer);
if (RelationNeedsWAL(btree->index))
{
XLogRecPtr recptr;
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_SPLIT, rdata);
PageSetLSN(lpage, recptr);
PageSetLSN(rpage, recptr);
}
UnlockReleaseBuffer(rbuffer);
END_CRIT_SECTION();
}
}
btree->isDelete = FALSE;
/* search parent to lock */
LockBuffer(parent->buffer, GIN_EXCLUSIVE);
/* move right if it's needed */
page = BufferGetPage(parent->buffer);
while ((parent->off = btree->findChildPtr(btree, page, stack->blkno, parent->off)) == InvalidOffsetNumber)
{
BlockNumber rightlink = GinPageGetOpaque(page)->rightlink;
LockBuffer(parent->buffer, GIN_UNLOCK);
if (rightlink == InvalidBlockNumber)
{
/*
* rightmost page, but we don't find parent, we should use
* plain search...
*/
ginFindParents(btree, stack, rootBlkno);
parent = stack->parent;
Assert(parent != NULL);
break;
}
parent->blkno = rightlink;
parent->buffer = ReleaseAndReadBuffer(parent->buffer, btree->index, parent->blkno);
LockBuffer(parent->buffer, GIN_EXCLUSIVE);
page = BufferGetPage(parent->buffer);
}
UnlockReleaseBuffer(stack->buffer);
pfree(stack);
stack = parent;
}
}
/*
* Clean up redirect and placeholder tuples on the given page
*
* Redirect tuples can be marked placeholder once they're old enough.
* Placeholder tuples can be removed if it won't change the offsets of
* non-placeholder ones.
*
* Unlike the routines above, this works on both leaf and inner pages.
*/
static void
vacuumRedirectAndPlaceholder(Relation index, Buffer buffer)
{
Page page = BufferGetPage(buffer);
SpGistPageOpaque opaque = SpGistPageGetOpaque(page);
OffsetNumber i,
max = PageGetMaxOffsetNumber(page),
firstPlaceholder = InvalidOffsetNumber;
bool hasNonPlaceholder = false;
bool hasUpdate = false;
OffsetNumber itemToPlaceholder[MaxIndexTuplesPerPage];
OffsetNumber itemnos[MaxIndexTuplesPerPage];
spgxlogVacuumRedirect xlrec;
xlrec.nToPlaceholder = 0;
xlrec.newestRedirectXid = InvalidTransactionId;
START_CRIT_SECTION();
/*
* Scan backwards to convert old redirection tuples to placeholder tuples,
* and identify location of last non-placeholder tuple while at it.
*/
for (i = max;
i >= FirstOffsetNumber &&
(opaque->nRedirection > 0 || !hasNonPlaceholder);
i--)
{
SpGistDeadTuple dt;
dt = (SpGistDeadTuple) PageGetItem(page, PageGetItemId(page, i));
if (dt->tupstate == SPGIST_REDIRECT &&
TransactionIdPrecedes(dt->xid, RecentGlobalXmin))
{
dt->tupstate = SPGIST_PLACEHOLDER;
Assert(opaque->nRedirection > 0);
opaque->nRedirection--;
opaque->nPlaceholder++;
/* remember newest XID among the removed redirects */
if (!TransactionIdIsValid(xlrec.newestRedirectXid) ||
TransactionIdPrecedes(xlrec.newestRedirectXid, dt->xid))
xlrec.newestRedirectXid = dt->xid;
ItemPointerSetInvalid(&dt->pointer);
itemToPlaceholder[xlrec.nToPlaceholder] = i;
xlrec.nToPlaceholder++;
hasUpdate = true;
}
if (dt->tupstate == SPGIST_PLACEHOLDER)
{
if (!hasNonPlaceholder)
firstPlaceholder = i;
}
else
{
hasNonPlaceholder = true;
}
}
/*
* Any placeholder tuples at the end of page can safely be removed. We
* can't remove ones before the last non-placeholder, though, because we
* can't alter the offset numbers of non-placeholder tuples.
*/
if (firstPlaceholder != InvalidOffsetNumber)
{
/*
* We do not store this array to rdata because it's easy to recreate.
*/
for (i = firstPlaceholder; i <= max; i++)
itemnos[i - firstPlaceholder] = i;
i = max - firstPlaceholder + 1;
Assert(opaque->nPlaceholder >= i);
opaque->nPlaceholder -= i;
/* The array is surely sorted, so can use PageIndexMultiDelete */
PageIndexMultiDelete(page, itemnos, i);
hasUpdate = true;
}
xlrec.firstPlaceholder = firstPlaceholder;
if (hasUpdate)
MarkBufferDirty(buffer);
if (hasUpdate && RelationNeedsWAL(index))
{
XLogRecPtr recptr;
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, SizeOfSpgxlogVacuumRedirect);
XLogRegisterData((char *) itemToPlaceholder,
sizeof(OffsetNumber) * xlrec.nToPlaceholder);
XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_VACUUM_REDIRECT);
PageSetLSN(page, recptr);
}
END_CRIT_SECTION();
}
/*
* Prune and repair fragmentation in the specified page.
*
* Caller must have pin and buffer cleanup lock on the page.
*
* OldestXmin is the cutoff XID used to distinguish whether tuples are DEAD
* or RECENTLY_DEAD (see HeapTupleSatisfiesVacuum).
*
* If report_stats is true then we send the number of reclaimed heap-only
* tuples to pgstats. (This must be FALSE during vacuum, since vacuum will
* send its own new total to pgstats, and we don't want this delta applied
* on top of that.)
*
* Returns the number of tuples deleted from the page and sets
* latestRemovedXid.
*/
int
heap_page_prune(Relation relation, Buffer buffer, TransactionId OldestXmin,
bool report_stats, TransactionId *latestRemovedXid)
{
int ndeleted = 0;
Page page = BufferGetPage(buffer);
OffsetNumber offnum,
maxoff;
PruneState prstate;
/*
* Our strategy is to scan the page and make lists of items to change,
* then apply the changes within a critical section. This keeps as much
* logic as possible out of the critical section, and also ensures that
* WAL replay will work the same as the normal case.
*
* First, initialize the new pd_prune_xid value to zero (indicating no
* prunable tuples). If we find any tuples which may soon become
* prunable, we will save the lowest relevant XID in new_prune_xid. Also
* initialize the rest of our working state.
*/
prstate.new_prune_xid = InvalidTransactionId;
prstate.latestRemovedXid = *latestRemovedXid;
prstate.nredirected = prstate.ndead = prstate.nunused = 0;
memset(prstate.marked, 0, sizeof(prstate.marked));
/* Scan the page */
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
ItemId itemid;
/* Ignore items already processed as part of an earlier chain */
if (prstate.marked[offnum])
continue;
/* Nothing to do if slot is empty or already dead */
itemid = PageGetItemId(page, offnum);
if (!ItemIdIsUsed(itemid) || ItemIdIsDead(itemid))
continue;
/* Process this item or chain of items */
ndeleted += heap_prune_chain(relation, buffer, offnum,
OldestXmin,
&prstate);
}
/* Any error while applying the changes is critical */
START_CRIT_SECTION();
/* Have we found any prunable items? */
if (prstate.nredirected > 0 || prstate.ndead > 0 || prstate.nunused > 0)
{
/*
* Apply the planned item changes, then repair page fragmentation, and
* update the page's hint bit about whether it has free line pointers.
*/
heap_page_prune_execute(buffer,
prstate.redirected, prstate.nredirected,
prstate.nowdead, prstate.ndead,
prstate.nowunused, prstate.nunused);
/*
* Update the page's pd_prune_xid field to either zero, or the lowest
* XID of any soon-prunable tuple.
*/
((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
/*
* Also clear the "page is full" flag, since there's no point in
* repeating the prune/defrag process until something else happens to
* the page.
*/
PageClearFull(page);
MarkBufferDirty(buffer);
/*
* Emit a WAL HEAP_CLEAN record showing what we did
*/
if (RelationNeedsWAL(relation))
{
XLogRecPtr recptr;
recptr = log_heap_clean(relation, buffer,
prstate.redirected, prstate.nredirected,
prstate.nowdead, prstate.ndead,
prstate.nowunused, prstate.nunused,
prstate.latestRemovedXid);
PageSetLSN(BufferGetPage(buffer), recptr);
PageSetTLI(BufferGetPage(buffer), ThisTimeLineID);
}
}
else
{
/*
* If we didn't prune anything, but have found a new value for the
* pd_prune_xid field, update it and mark the buffer dirty. This is
* treated as a non-WAL-logged hint.
*
* Also clear the "page is full" flag if it is set, since there's no
* point in repeating the prune/defrag process until something else
* happens to the page.
*/
if (((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
PageIsFull(page))
{
((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
PageClearFull(page);
SetBufferCommitInfoNeedsSave(buffer);
}
}
END_CRIT_SECTION();
/*
* If requested, report the number of tuples reclaimed to pgstats. This is
* ndeleted minus ndead, because we don't want to count a now-DEAD root
* item as a deletion for this purpose.
*/
if (report_stats && ndeleted > prstate.ndead)
pgstat_update_heap_dead_tuples(relation, ndeleted - prstate.ndead);
*latestRemovedXid = prstate.latestRemovedXid;
/*
* XXX Should we update the FSM information of this page ?
*
* There are two schools of thought here. We may not want to update FSM
* information so that the page is not used for unrelated UPDATEs/INSERTs
* and any free space in this page will remain available for further
* UPDATEs in *this* page, thus improving chances for doing HOT updates.
*
* But for a large table and where a page does not receive further UPDATEs
* for a long time, we might waste this space by not updating the FSM
* information. The relation may get extended and fragmented further.
*
* One possibility is to leave "fillfactor" worth of space in this page
* and update FSM with the remaining space.
*
* In any case, the current FSM implementation doesn't accept
* one-page-at-a-time updates, so this is all academic for now.
*/
return ndeleted;
}
/*
* Place tuples from 'itup' to 'buffer'. If 'oldoffnum' is valid, the tuple
* at that offset is atomically removed along with inserting the new tuples.
* This is used to replace a tuple with a new one.
*
* If 'leftchildbuf' is valid, we're inserting the downlink for the page
* to the right of 'leftchildbuf', or updating the downlink for 'leftchildbuf'.
* F_FOLLOW_RIGHT flag on 'leftchildbuf' is cleared and NSN is set.
*
* If 'markfollowright' is true and the page is split, the left child is
* marked with F_FOLLOW_RIGHT flag. That is the normal case. During buffered
* index build, however, there is no concurrent access and the page splitting
* is done in a slightly simpler fashion, and false is passed.
*
* If there is not enough room on the page, it is split. All the split
* pages are kept pinned and locked and returned in *splitinfo, the caller
* is responsible for inserting the downlinks for them. However, if
* 'buffer' is the root page and it needs to be split, gistplacetopage()
* performs the split as one atomic operation, and *splitinfo is set to NIL.
* In that case, we continue to hold the root page locked, and the child
* pages are released; note that new tuple(s) are *not* on the root page
* but in one of the new child pages.
*
* If 'newblkno' is not NULL, returns the block number of page the first
* new/updated tuple was inserted to. Usually it's the given page, but could
* be its right sibling if the page was split.
*
* Returns 'true' if the page was split, 'false' otherwise.
*/
bool
gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
Buffer buffer,
IndexTuple *itup, int ntup, OffsetNumber oldoffnum,
BlockNumber *newblkno,
Buffer leftchildbuf,
List **splitinfo,
bool markfollowright,
Relation heapRel,
bool is_build)
{
BlockNumber blkno = BufferGetBlockNumber(buffer);
Page page = BufferGetPage(buffer);
bool is_leaf = (GistPageIsLeaf(page)) ? true : false;
XLogRecPtr recptr;
int i;
bool is_split;
/*
* Refuse to modify a page that's incompletely split. This should not
* happen because we finish any incomplete splits while we walk down the
* tree. However, it's remotely possible that another concurrent inserter
* splits a parent page, and errors out before completing the split. We
* will just throw an error in that case, and leave any split we had in
* progress unfinished too. The next insert that comes along will clean up
* the mess.
*/
if (GistFollowRight(page))
elog(ERROR, "concurrent GiST page split was incomplete");
*splitinfo = NIL;
/*
* if isupdate, remove old key: This node's key has been modified, either
* because a child split occurred or because we needed to adjust our key
* for an insert in a child node. Therefore, remove the old version of
* this node's key.
*
* for WAL replay, in the non-split case we handle this by setting up a
* one-element todelete array; in the split case, it's handled implicitly
* because the tuple vector passed to gistSplit won't include this tuple.
*/
is_split = gistnospace(page, itup, ntup, oldoffnum, freespace);
/*
* If leaf page is full, try at first to delete dead tuples. And then
* check again.
*/
if (is_split && GistPageIsLeaf(page) && GistPageHasGarbage(page))
{
gistprunepage(rel, page, buffer, heapRel);
is_split = gistnospace(page, itup, ntup, oldoffnum, freespace);
}
if (is_split)
{
/* no space for insertion */
IndexTuple *itvec;
int tlen;
SplitedPageLayout *dist = NULL,
*ptr;
BlockNumber oldrlink = InvalidBlockNumber;
GistNSN oldnsn = 0;
SplitedPageLayout rootpg;
bool is_rootsplit;
int npage;
is_rootsplit = (blkno == GIST_ROOT_BLKNO);
/*
* Form index tuples vector to split. If we're replacing an old tuple,
* remove the old version from the vector.
*/
itvec = gistextractpage(page, &tlen);
if (OffsetNumberIsValid(oldoffnum))
{
/* on inner page we should remove old tuple */
int pos = oldoffnum - FirstOffsetNumber;
tlen--;
if (pos != tlen)
memmove(itvec + pos, itvec + pos + 1, sizeof(IndexTuple) * (tlen - pos));
}
itvec = gistjoinvector(itvec, &tlen, itup, ntup);
dist = gistSplit(rel, page, itvec, tlen, giststate);
/*
* Check that split didn't produce too many pages.
*/
npage = 0;
for (ptr = dist; ptr; ptr = ptr->next)
npage++;
/* in a root split, we'll add one more page to the list below */
if (is_rootsplit)
npage++;
if (npage > GIST_MAX_SPLIT_PAGES)
elog(ERROR, "GiST page split into too many halves (%d, maximum %d)",
npage, GIST_MAX_SPLIT_PAGES);
/*
* Set up pages to work with. Allocate new buffers for all but the
* leftmost page. The original page becomes the new leftmost page, and
* is just replaced with the new contents.
*
* For a root-split, allocate new buffers for all child pages, the
* original page is overwritten with new root page containing
* downlinks to the new child pages.
*/
ptr = dist;
if (!is_rootsplit)
{
/* save old rightlink and NSN */
oldrlink = GistPageGetOpaque(page)->rightlink;
oldnsn = GistPageGetNSN(page);
dist->buffer = buffer;
dist->block.blkno = BufferGetBlockNumber(buffer);
dist->page = PageGetTempPageCopySpecial(BufferGetPage(buffer));
/* clean all flags except F_LEAF */
GistPageGetOpaque(dist->page)->flags = (is_leaf) ? F_LEAF : 0;
ptr = ptr->next;
}
for (; ptr; ptr = ptr->next)
{
/* Allocate new page */
ptr->buffer = gistNewBuffer(rel);
GISTInitBuffer(ptr->buffer, (is_leaf) ? F_LEAF : 0);
ptr->page = BufferGetPage(ptr->buffer);
ptr->block.blkno = BufferGetBlockNumber(ptr->buffer);
PredicateLockPageSplit(rel,
BufferGetBlockNumber(buffer),
BufferGetBlockNumber(ptr->buffer));
}
/*
* Now that we know which blocks the new pages go to, set up downlink
* tuples to point to them.
*/
for (ptr = dist; ptr; ptr = ptr->next)
{
ItemPointerSetBlockNumber(&(ptr->itup->t_tid), ptr->block.blkno);
GistTupleSetValid(ptr->itup);
}
/*
* If this is a root split, we construct the new root page with the
* downlinks here directly, instead of requiring the caller to insert
* them. Add the new root page to the list along with the child pages.
*/
if (is_rootsplit)
{
IndexTuple *downlinks;
int ndownlinks = 0;
int i;
rootpg.buffer = buffer;
rootpg.page = PageGetTempPageCopySpecial(BufferGetPage(rootpg.buffer));
GistPageGetOpaque(rootpg.page)->flags = 0;
/* Prepare a vector of all the downlinks */
for (ptr = dist; ptr; ptr = ptr->next)
ndownlinks++;
downlinks = palloc(sizeof(IndexTuple) * ndownlinks);
for (i = 0, ptr = dist; ptr; ptr = ptr->next)
downlinks[i++] = ptr->itup;
rootpg.block.blkno = GIST_ROOT_BLKNO;
rootpg.block.num = ndownlinks;
rootpg.list = gistfillitupvec(downlinks, ndownlinks,
&(rootpg.lenlist));
rootpg.itup = NULL;
rootpg.next = dist;
dist = &rootpg;
}
else
{
/* Prepare split-info to be returned to caller */
for (ptr = dist; ptr; ptr = ptr->next)
{
GISTPageSplitInfo *si = palloc(sizeof(GISTPageSplitInfo));
si->buf = ptr->buffer;
si->downlink = ptr->itup;
*splitinfo = lappend(*splitinfo, si);
}
}
/*
* Fill all pages. All the pages are new, ie. freshly allocated empty
* pages, or a temporary copy of the old page.
*/
for (ptr = dist; ptr; ptr = ptr->next)
{
char *data = (char *) (ptr->list);
for (i = 0; i < ptr->block.num; i++)
{
IndexTuple thistup = (IndexTuple) data;
if (PageAddItem(ptr->page, (Item) data, IndexTupleSize(thistup), i + FirstOffsetNumber, false, false) == InvalidOffsetNumber)
elog(ERROR, "failed to add item to index page in \"%s\"", RelationGetRelationName(rel));
/*
* If this is the first inserted/updated tuple, let the caller
* know which page it landed on.
*/
if (newblkno && ItemPointerEquals(&thistup->t_tid, &(*itup)->t_tid))
*newblkno = ptr->block.blkno;
data += IndexTupleSize(thistup);
}
/* Set up rightlinks */
if (ptr->next && ptr->block.blkno != GIST_ROOT_BLKNO)
GistPageGetOpaque(ptr->page)->rightlink =
ptr->next->block.blkno;
else
GistPageGetOpaque(ptr->page)->rightlink = oldrlink;
/*
* Mark the all but the right-most page with the follow-right
* flag. It will be cleared as soon as the downlink is inserted
* into the parent, but this ensures that if we error out before
* that, the index is still consistent. (in buffering build mode,
* any error will abort the index build anyway, so this is not
* needed.)
*/
if (ptr->next && !is_rootsplit && markfollowright)
GistMarkFollowRight(ptr->page);
else
GistClearFollowRight(ptr->page);
/*
* Copy the NSN of the original page to all pages. The
* F_FOLLOW_RIGHT flags ensure that scans will follow the
* rightlinks until the downlinks are inserted.
*/
GistPageSetNSN(ptr->page, oldnsn);
}
/*
* gistXLogSplit() needs to WAL log a lot of pages, prepare WAL
* insertion for that. NB: The number of pages and data segments
* specified here must match the calculations in gistXLogSplit()!
*/
if (!is_build && RelationNeedsWAL(rel))
XLogEnsureRecordSpace(npage, 1 + npage * 2);
START_CRIT_SECTION();
/*
* Must mark buffers dirty before XLogInsert, even though we'll still
* be changing their opaque fields below.
*/
for (ptr = dist; ptr; ptr = ptr->next)
MarkBufferDirty(ptr->buffer);
if (BufferIsValid(leftchildbuf))
MarkBufferDirty(leftchildbuf);
/*
* The first page in the chain was a temporary working copy meant to
* replace the old page. Copy it over the old page.
*/
PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
dist->page = BufferGetPage(dist->buffer);
/*
* Write the WAL record.
*
* If we're building a new index, however, we don't WAL-log changes
* yet. The LSN-NSN interlock between parent and child requires that
* LSNs never move backwards, so set the LSNs to a value that's
* smaller than any real or fake unlogged LSN that might be generated
* later. (There can't be any concurrent scans during index build, so
* we don't need to be able to detect concurrent splits yet.)
*/
if (is_build)
recptr = GistBuildLSN;
else
{
if (RelationNeedsWAL(rel))
recptr = gistXLogSplit(is_leaf,
dist, oldrlink, oldnsn, leftchildbuf,
markfollowright);
else
recptr = gistGetFakeLSN(rel);
}
for (ptr = dist; ptr; ptr = ptr->next)
PageSetLSN(ptr->page, recptr);
/*
* Return the new child buffers to the caller.
*
* If this was a root split, we've already inserted the downlink
* pointers, in the form of a new root page. Therefore we can release
* all the new buffers, and keep just the root page locked.
*/
if (is_rootsplit)
{
for (ptr = dist->next; ptr; ptr = ptr->next)
UnlockReleaseBuffer(ptr->buffer);
}
}
else
{
/*
* Enough space. We always get here if ntup==0.
*/
START_CRIT_SECTION();
/*
* Delete old tuple if any, then insert new tuple(s) if any. If
* possible, use the fast path of PageIndexTupleOverwrite.
*/
if (OffsetNumberIsValid(oldoffnum))
{
if (ntup == 1)
{
/* One-for-one replacement, so use PageIndexTupleOverwrite */
if (!PageIndexTupleOverwrite(page, oldoffnum, (Item) *itup,
IndexTupleSize(*itup)))
elog(ERROR, "failed to add item to index page in \"%s\"",
RelationGetRelationName(rel));
}
else
{
/* Delete old, then append new tuple(s) to page */
PageIndexTupleDelete(page, oldoffnum);
gistfillbuffer(page, itup, ntup, InvalidOffsetNumber);
}
}
else
{
/* Just append new tuples at the end of the page */
gistfillbuffer(page, itup, ntup, InvalidOffsetNumber);
}
MarkBufferDirty(buffer);
if (BufferIsValid(leftchildbuf))
MarkBufferDirty(leftchildbuf);
if (is_build)
recptr = GistBuildLSN;
else
{
if (RelationNeedsWAL(rel))
{
OffsetNumber ndeloffs = 0,
deloffs[1];
if (OffsetNumberIsValid(oldoffnum))
{
deloffs[0] = oldoffnum;
ndeloffs = 1;
}
recptr = gistXLogUpdate(buffer,
deloffs, ndeloffs, itup, ntup,
leftchildbuf);
}
else
recptr = gistGetFakeLSN(rel);
}
PageSetLSN(page, recptr);
if (newblkno)
*newblkno = blkno;
}
/*
* If we inserted the downlink for a child page, set NSN and clear
* F_FOLLOW_RIGHT flag on the left child, so that concurrent scans know to
* follow the rightlink if and only if they looked at the parent page
* before we inserted the downlink.
*
* Note that we do this *after* writing the WAL record. That means that
* the possible full page image in the WAL record does not include these
* changes, and they must be replayed even if the page is restored from
* the full page image. There's a chicken-and-egg problem: if we updated
* the child pages first, we wouldn't know the recptr of the WAL record
* we're about to write.
*/
if (BufferIsValid(leftchildbuf))
{
Page leftpg = BufferGetPage(leftchildbuf);
GistPageSetNSN(leftpg, recptr);
GistClearFollowRight(leftpg);
PageSetLSN(leftpg, recptr);
}
END_CRIT_SECTION();
return is_split;
}
