void
smgr_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
/* Backup blocks are not used in smgr records */
Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
if (info == XLOG_SMGR_CREATE)
{
xl_smgr_create *xlrec = (xl_smgr_create *) XLogRecGetData(record);
SMgrRelation reln;
reln = smgropen(xlrec->rnode);
smgrcreate(reln, MAIN_FORKNUM, true);
}
else if (info == XLOG_SMGR_TRUNCATE)
{
xl_smgr_truncate *xlrec = (xl_smgr_truncate *) XLogRecGetData(record);
SMgrRelation reln;
Relation rel;
reln = smgropen(xlrec->rnode);
/*
* Forcibly create relation if it doesn't exist (which suggests that
* it was dropped somewhere later in the WAL sequence). As in
* XLogOpenRelation, we prefer to recreate the rel and replay the log
* as best we can until the drop is seen.
*/
smgrcreate(reln, MAIN_FORKNUM, true);
smgrtruncate(reln, MAIN_FORKNUM, xlrec->blkno, false);
/* Also tell xlogutils.c about it */
XLogTruncateRelation(xlrec->rnode, MAIN_FORKNUM, xlrec->blkno);
/* Truncate FSM and VM too */
rel = CreateFakeRelcacheEntry(xlrec->rnode);
if (smgrexists(reln, FSM_FORKNUM))
FreeSpaceMapTruncateRel(rel, xlrec->blkno);
if (smgrexists(reln, VISIBILITYMAP_FORKNUM))
visibilitymap_truncate(rel, xlrec->blkno);
FreeFakeRelcacheEntry(rel);
}
else
elog(PANIC, "smgr_redo: unknown op code %u", info);
}
/*
* Ensure that the visibility map fork is at least vm_nblocks long, extending
* it if necessary with zeroed pages.
*/
static void
vm_extend(Relation rel, BlockNumber vm_nblocks)
{
BlockNumber vm_nblocks_now;
Page pg;
pg = (Page) palloc(BLCKSZ);
PageInit(pg, BLCKSZ, 0);
/*
* We use the relation extension lock to lock out other backends trying to
* extend the visibility map at the same time. It also locks out extension
* of the main fork, unnecessarily, but extending the visibility map
* happens seldom enough that it doesn't seem worthwhile to have a
* separate lock tag type for it.
*
* Note that another backend might have extended or created the relation
* by the time we get the lock.
*/
LockRelationForExtension(rel, ExclusiveLock);
/* Might have to re-open if a cache flush happened */
RelationOpenSmgr(rel);
/*
* Create the file first if it doesn't exist. If smgr_vm_nblocks is
* positive then it must exist, no need for an smgrexists call.
*/
if ((rel->rd_smgr->smgr_vm_nblocks == 0 ||
rel->rd_smgr->smgr_vm_nblocks == InvalidBlockNumber) &&
!smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
smgrcreate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, false);
vm_nblocks_now = smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM);
/* Now extend the file */
while (vm_nblocks_now < vm_nblocks)
{
smgrextend(rel->rd_smgr, VISIBILITYMAP_FORKNUM, vm_nblocks_now,
(char *) pg, false);
vm_nblocks_now++;
}
/*
* Send a shared-inval message to force other backends to close any smgr
* references they may have for this rel, which we are about to change.
* This is a useful optimization because it means that backends don't have
* to keep checking for creation or extension of the file, which happens
* infrequently.
*/
CacheInvalidateSmgr(rel->rd_smgr->smgr_rnode);
/* Update local cache with the up-to-date size */
rel->rd_smgr->smgr_vm_nblocks = vm_nblocks_now;
UnlockRelationForExtension(rel, ExclusiveLock);
pfree(pg);
}
void
smgr_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
if (info == XLOG_SMGR_CREATE)
{
xl_smgr_create *xlrec = (xl_smgr_create *) XLogRecGetData(record);
SMgrRelation reln;
reln = smgropen(xlrec->rnode);
smgrcreate(reln, false, true);
}
else if (info == XLOG_SMGR_TRUNCATE)
{
xl_smgr_truncate *xlrec = (xl_smgr_truncate *) XLogRecGetData(record);
SMgrRelation reln;
BlockNumber newblks;
reln = smgropen(xlrec->rnode);
/* Can't use smgrtruncate because it would try to xlog */
/*
* First, force bufmgr to drop any buffers it has for the to-be-
* truncated blocks. We must do this, else subsequent XLogReadBuffer
* operations will not re-extend the file properly.
*/
DropRelFileNodeBuffers(xlrec->rnode, false, xlrec->blkno);
/*
* Tell the free space map to forget anything it may have stored for
* the about-to-be-deleted blocks. We want to be sure it won't return
* bogus block numbers later on.
*/
FreeSpaceMapTruncateRel(&reln->smgr_rnode, xlrec->blkno);
/* Do the truncation */
newblks = (*(smgrsw[reln->smgr_which].smgr_truncate)) (reln,
xlrec->blkno,
false);
if (newblks == InvalidBlockNumber)
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not truncate relation %u/%u/%u to %u blocks: %m",
reln->smgr_rnode.spcNode,
reln->smgr_rnode.dbNode,
reln->smgr_rnode.relNode,
xlrec->blkno)));
/* Also tell xlogutils.c about it */
XLogTruncateRelation(xlrec->rnode, xlrec->blkno);
}
else
elog(PANIC, "smgr_redo: unknown op code %u", info);
}
/*
* Ensure that the FSM fork is at least fsm_nblocks long, extending
* it if necessary with empty pages. And by empty, I mean pages filled
* with zeros, meaning there's no free space.
*/
static void
fsm_extend(Relation rel, BlockNumber fsm_nblocks)
{
BlockNumber fsm_nblocks_now;
Page pg;
pg = (Page) palloc(BLCKSZ);
PageInit(pg, BLCKSZ, 0);
/*
* We use the relation extension lock to lock out other backends trying to
* extend the FSM at the same time. It also locks out extension of the
* main fork, unnecessarily, but extending the FSM happens seldom enough
* that it doesn't seem worthwhile to have a separate lock tag type for
* it.
*
* Note that another backend might have extended or created the relation
* by the time we get the lock.
*/
LockRelationForExtension(rel, ExclusiveLock);
/* Might have to re-open if a cache flush happened */
RelationOpenSmgr(rel);
/*
* Create the FSM file first if it doesn't exist. If smgr_fsm_nblocks is
* positive then it must exist, no need for an smgrexists call.
*/
if ((rel->rd_smgr->smgr_fsm_nblocks == 0 ||
rel->rd_smgr->smgr_fsm_nblocks == InvalidBlockNumber) &&
!smgrexists(rel->rd_smgr, FSM_FORKNUM))
smgrcreate(rel->rd_smgr, FSM_FORKNUM, false);
fsm_nblocks_now = smgrnblocks(rel->rd_smgr, FSM_FORKNUM);
while (fsm_nblocks_now < fsm_nblocks)
{
PageSetChecksumInplace(pg, fsm_nblocks_now);
smgrextend(rel->rd_smgr, FSM_FORKNUM, fsm_nblocks_now,
(char *) pg, false);
fsm_nblocks_now++;
}
/* Update local cache with the up-to-date size */
rel->rd_smgr->smgr_fsm_nblocks = fsm_nblocks_now;
UnlockRelationForExtension(rel, ExclusiveLock);
pfree(pg);
}
/*
* Ensure that the visibility map fork is at least vm_nblocks long, extending
* it if necessary with zeroed pages.
*/
static void
vm_extend(Relation rel, BlockNumber vm_nblocks)
{
BlockNumber vm_nblocks_now;
Page pg;
pg = (Page) palloc(BLCKSZ);
PageInit(pg, BLCKSZ, 0);
/*
* We use the relation extension lock to lock out other backends trying to
* extend the visibility map at the same time. It also locks out extension
* of the main fork, unnecessarily, but extending the visibility map
* happens seldom enough that it doesn't seem worthwhile to have a
* separate lock tag type for it.
*
* Note that another backend might have extended or created the relation
* before we get the lock.
*/
LockRelationForExtension(rel, ExclusiveLock);
/* Create the file first if it doesn't exist */
if ((rel->rd_vm_nblocks == 0 || rel->rd_vm_nblocks == InvalidBlockNumber)
&& !smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
{
smgrcreate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, false);
vm_nblocks_now = 0;
}
else
vm_nblocks_now = smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM);
while (vm_nblocks_now < vm_nblocks)
{
smgrextend(rel->rd_smgr, VISIBILITYMAP_FORKNUM, vm_nblocks_now,
(char *) pg, rel->rd_istemp);
vm_nblocks_now++;
}
UnlockRelationForExtension(rel, ExclusiveLock);
pfree(pg);
/* Update the relcache with the up-to-date size */
if (!InRecovery)
CacheInvalidateRelcache(rel);
rel->rd_vm_nblocks = vm_nblocks_now;
}
/*
* RelationCreateStorage
* Create physical storage for a relation.
*
* Create the underlying disk file storage for the relation. This only
* creates the main fork; additional forks are created lazily by the
* modules that need them.
*
* This function is transactional. The creation is WAL-logged, and if the
* transaction aborts later on, the storage will be destroyed.
*/
void
RelationCreateStorage(RelFileNode rnode, char relpersistence)
{
PendingRelDelete *pending;
SMgrRelation srel;
BackendId backend;
bool needs_wal;
switch (relpersistence)
{
case RELPERSISTENCE_TEMP:
backend = MyBackendId;
needs_wal = false;
break;
case RELPERSISTENCE_UNLOGGED:
backend = InvalidBackendId;
needs_wal = false;
break;
case RELPERSISTENCE_PERMANENT:
backend = InvalidBackendId;
needs_wal = true;
break;
default:
elog(ERROR, "invalid relpersistence: %c", relpersistence);
return; /* placate compiler */
}
srel = smgropen(rnode, backend);
smgrcreate(srel, MAIN_FORKNUM, false);
if (needs_wal)
log_smgrcreate(&srel->smgr_rnode.node, MAIN_FORKNUM);
/* Add the relation to the list of stuff to delete at abort */
pending = (PendingRelDelete *)
MemoryContextAlloc(TopMemoryContext, sizeof(PendingRelDelete));
pending->relnode = rnode;
pending->backend = backend;
pending->atCommit = false; /* delete if abort */
pending->nestLevel = GetCurrentTransactionNestLevel();
pending->next = pendingDeletes;
pendingDeletes = pending;
}
/*
* RelationCreateStorage
* Create physical storage for a relation.
*
* Create the underlying disk file storage for the relation. This only
* creates the main fork; additional forks are created lazily by the
* modules that need them.
*
* This function is transactional. The creation is WAL-logged, and if the
* transaction aborts later on, the storage will be destroyed.
*/
void
RelationCreateStorage(RelFileNode rnode, bool istemp)
{
PendingRelDelete *pending;
XLogRecPtr lsn;
XLogRecData rdata;
xl_smgr_create xlrec;
SMgrRelation srel;
srel = smgropen(rnode);
smgrcreate(srel, MAIN_FORKNUM, false);
if (!istemp)
{
/*
* Make an XLOG entry showing the file creation. If we abort, the
* file will be dropped at abort time.
*/
xlrec.rnode = rnode;
rdata.data = (char *) &xlrec;
rdata.len = sizeof(xlrec);
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
lsn = XLogInsert(RM_SMGR_ID, XLOG_SMGR_CREATE, &rdata);
}
/* Add the relation to the list of stuff to delete at abort */
pending = (PendingRelDelete *)
MemoryContextAlloc(TopMemoryContext, sizeof(PendingRelDelete));
pending->relnode = rnode;
pending->isTemp = istemp;
pending->atCommit = false; /* delete if abort */
pending->nestLevel = GetCurrentTransactionNestLevel();
pending->next = pendingDeletes;
pendingDeletes = pending;
}
/*
* Open a relation during XLOG replay
*
* Note: this once had an API that allowed NULL return on failure, but it
* no longer does; any failure results in elog().
*/
Relation
XLogOpenRelation(RelFileNode rnode)
{
XLogRelDesc *res;
XLogRelCacheEntry *hentry;
bool found;
hentry = (XLogRelCacheEntry *)
hash_search(_xlrelcache, (void *) &rnode, HASH_FIND, NULL);
if (hentry)
{
res = hentry->rdesc;
res->lessRecently->moreRecently = res->moreRecently;
res->moreRecently->lessRecently = res->lessRecently;
}
else
{
/*
* We need to fault in the database directory on the standby.
*/
if (rnode.spcNode != GLOBALTABLESPACE_OID && IsStandbyMode())
{
char *primaryFilespaceLocation = NULL;
char *dbPath;
if (IsBuiltinTablespace(rnode.spcNode))
{
/*
* No filespace to fetch.
*/
}
else
{
char *mirrorFilespaceLocation = NULL;
/*
* Investigate whether the containing directories exist to give more detail.
*/
PersistentTablespace_GetPrimaryAndMirrorFilespaces(
rnode.spcNode,
&primaryFilespaceLocation,
&mirrorFilespaceLocation);
if (primaryFilespaceLocation == NULL ||
strlen(primaryFilespaceLocation) == 0)
{
elog(ERROR, "Empty primary filespace directory location");
}
if (mirrorFilespaceLocation != NULL)
{
pfree(mirrorFilespaceLocation);
mirrorFilespaceLocation = NULL;
}
}
dbPath = (char*)palloc(MAXPGPATH + 1);
FormDatabasePath(
dbPath,
primaryFilespaceLocation,
rnode.spcNode,
rnode.dbNode);
if (primaryFilespaceLocation != NULL)
{
pfree(primaryFilespaceLocation);
primaryFilespaceLocation = NULL;
}
if (mkdir(dbPath, 0700) == 0)
{
if (Debug_persistent_recovery_print)
{
elog(PersistentRecovery_DebugPrintLevel(),
"XLogOpenRelation: Re-created database directory \"%s\"",
dbPath);
}
}
else
{
/*
* Allowed to already exist.
*/
if (errno != EEXIST)
{
elog(ERROR, "could not create database directory \"%s\": %m",
dbPath);
}
else
{
if (Debug_persistent_recovery_print)
{
elog(PersistentRecovery_DebugPrintLevel(),
"XLogOpenRelation: Database directory \"%s\" already exists",
dbPath);
}
}
}
pfree(dbPath);
}
res = _xl_new_reldesc();
sprintf(RelationGetRelationName(&(res->reldata)), "%u", rnode.relNode);
res->reldata.rd_node = rnode;
/*
* We set up the lockRelId in case anything tries to lock the dummy
* relation. Note that this is fairly bogus since relNode may be
* different from the relation's OID. It shouldn't really matter
* though, since we are presumably running by ourselves and can't have
* any lock conflicts ...
*/
res->reldata.rd_lockInfo.lockRelId.dbId = rnode.dbNode;
res->reldata.rd_lockInfo.lockRelId.relId = rnode.relNode;
hentry = (XLogRelCacheEntry *)
hash_search(_xlrelcache, (void *) &rnode, HASH_ENTER, &found);
if (found)
elog(PANIC, "xlog relation already present on insert into cache");
hentry->rdesc = res;
res->reldata.rd_targblock = InvalidBlockNumber;
res->reldata.rd_smgr = NULL;
RelationOpenSmgr(&(res->reldata));
/*
* Create the target file if it doesn't already exist. This lets us
* cope if the replay sequence contains writes to a relation that is
* later deleted. (The original coding of this routine would instead
* return NULL, causing the writes to be suppressed. But that seems
* like it risks losing valuable data if the filesystem loses an inode
* during a crash. Better to write the data until we are actually
* told to delete the file.)
*/
// NOTE: We no longer re-create files automatically because
// new FileRep persistent objects will ensure files exist.
// UNDONE: Can't remove this block of code yet until boot time calls to this routine are analyzed...
{
MirrorDataLossTrackingState mirrorDataLossTrackingState;
int64 mirrorDataLossTrackingSessionNum;
bool mirrorDataLossOccurred;
// UNDONE: What about the persistent rel files table???
// UNDONE: This condition should not occur anymore.
// UNDONE: segmentFileNum and AO?
mirrorDataLossTrackingState =
FileRepPrimary_GetMirrorDataLossTrackingSessionNum(
&mirrorDataLossTrackingSessionNum);
smgrcreate(
res->reldata.rd_smgr,
res->reldata.rd_isLocalBuf,
/* relationName */ NULL, // Ok to be NULL -- we don't know the name here.
mirrorDataLossTrackingState,
mirrorDataLossTrackingSessionNum,
/* ignoreAlreadyExists */ true,
&mirrorDataLossOccurred);
}
}
res->moreRecently = &(_xlrelarr[0]);
res->lessRecently = _xlrelarr[0].lessRecently;
_xlrelarr[0].lessRecently = res;
res->lessRecently->moreRecently = res;
Assert(&(res->reldata) != NULL); // Assert what it says in the interface -- we don't return NULL anymore.
return &(res->reldata);
}
/*
* XLogReadBufferExtended
* Read a page during XLOG replay
*
* This is functionally comparable to ReadBufferExtended. There's some
* differences in the behavior wrt. the "mode" argument:
*
* In RBM_NORMAL mode, if the page doesn't exist, or contains all-zeroes, we
* return InvalidBuffer. In this case the caller should silently skip the
* update on this page. (In this situation, we expect that the page was later
* dropped or truncated. If we don't see evidence of that later in the WAL
* sequence, we'll complain at the end of WAL replay.)
*
* In RBM_ZERO_* modes, if the page doesn't exist, the relation is extended
* with all-zeroes pages up to the given block number.
*
* In RBM_NORMAL_NO_LOG mode, we return InvalidBuffer if the page doesn't
* exist, and we don't check for all-zeroes. Thus, no log entry is made
* to imply that the page should be dropped or truncated later.
*
* NB: A redo function should normally not call this directly. To get a page
* to modify, use XLogReplayBuffer instead. It is important that all pages
* modified by a WAL record are registered in the WAL records, or they will be
* invisible to tools that that need to know which pages are modified.
*/
Buffer
XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
BlockNumber blkno, ReadBufferMode mode)
{
BlockNumber lastblock;
Buffer buffer;
SMgrRelation smgr;
Assert(blkno != P_NEW);
/* Open the relation at smgr level */
smgr = smgropen(rnode, InvalidBackendId);
/*
* Create the target file if it doesn't already exist. This lets us cope
* if the replay sequence contains writes to a relation that is later
* deleted. (The original coding of this routine would instead suppress
* the writes, but that seems like it risks losing valuable data if the
* filesystem loses an inode during a crash. Better to write the data
* until we are actually told to delete the file.)
*/
smgrcreate(smgr, forknum, true);
lastblock = smgrnblocks(smgr, forknum);
if (blkno < lastblock)
{
/* page exists in file */
buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
mode, NULL);
}
else
{
/* hm, page doesn't exist in file */
if (mode == RBM_NORMAL)
{
log_invalid_page(rnode, forknum, blkno, false);
return InvalidBuffer;
}
if (mode == RBM_NORMAL_NO_LOG)
return InvalidBuffer;
/* OK to extend the file */
/* we do this in recovery only - no rel-extension lock needed */
Assert(InRecovery);
buffer = InvalidBuffer;
do
{
if (buffer != InvalidBuffer)
{
if (mode == RBM_ZERO_AND_LOCK || mode == RBM_ZERO_AND_CLEANUP_LOCK)
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
ReleaseBuffer(buffer);
}
buffer = ReadBufferWithoutRelcache(rnode, forknum,
P_NEW, mode, NULL);
}
while (BufferGetBlockNumber(buffer) < blkno);
/* Handle the corner case that P_NEW returns non-consecutive pages */
if (BufferGetBlockNumber(buffer) != blkno)
{
if (mode == RBM_ZERO_AND_LOCK || mode == RBM_ZERO_AND_CLEANUP_LOCK)
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
ReleaseBuffer(buffer);
buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
mode, NULL);
}
}
if (mode == RBM_NORMAL)
{
/* check that page has been initialized */
Page page = (Page) BufferGetPage(buffer);
/*
* We assume that PageIsNew is safe without a lock. During recovery,
* there should be no other backends that could modify the buffer at
* the same time.
*/
if (PageIsNew(page))
{
ReleaseBuffer(buffer);
log_invalid_page(rnode, forknum, blkno, true);
return InvalidBuffer;
}
}
return buffer;
}
void
smgr_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
/* Backup blocks are not used in smgr records */
Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
if (info == XLOG_SMGR_CREATE)
{
xl_smgr_create *xlrec = (xl_smgr_create *) XLogRecGetData(record);
SMgrRelation reln;
reln = smgropen(xlrec->rnode, InvalidBackendId);
smgrcreate(reln, xlrec->forkNum, true);
}
else if (info == XLOG_SMGR_TRUNCATE)
{
xl_smgr_truncate *xlrec = (xl_smgr_truncate *) XLogRecGetData(record);
SMgrRelation reln;
Relation rel;
reln = smgropen(xlrec->rnode, InvalidBackendId);
/*
* Forcibly create relation if it doesn't exist (which suggests that
* it was dropped somewhere later in the WAL sequence). As in
* XLogReadBuffer, we prefer to recreate the rel and replay the log as
* best we can until the drop is seen.
*/
smgrcreate(reln, MAIN_FORKNUM, true);
/*
* Before we perform the truncation, update minimum recovery point
* to cover this WAL record. Once the relation is truncated, there's
* no going back. The buffer manager enforces the WAL-first rule
* for normal updates to relation files, so that the minimum recovery
* point is always updated before the corresponding change in the
* data file is flushed to disk. We have to do the same manually
* here.
*
* Doing this before the truncation means that if the truncation fails
* for some reason, you cannot start up the system even after restart,
* until you fix the underlying situation so that the truncation will
* succeed. Alternatively, we could update the minimum recovery point
* after truncation, but that would leave a small window where the
* WAL-first rule could be violated.
*/
XLogFlush(lsn);
smgrtruncate(reln, MAIN_FORKNUM, xlrec->blkno);
/* Also tell xlogutils.c about it */
XLogTruncateRelation(xlrec->rnode, MAIN_FORKNUM, xlrec->blkno);
/* Truncate FSM and VM too */
rel = CreateFakeRelcacheEntry(xlrec->rnode);
if (smgrexists(reln, FSM_FORKNUM))
FreeSpaceMapTruncateRel(rel, xlrec->blkno);
if (smgrexists(reln, VISIBILITYMAP_FORKNUM))
visibilitymap_truncate(rel, xlrec->blkno);
FreeFakeRelcacheEntry(rel);
}
else
elog(PANIC, "smgr_redo: unknown op code %u", info);
}
/*
* Open a relation during XLOG replay
*
* Note: this once had an API that allowed NULL return on failure, but it
* no longer does; any failure results in elog().
*/
Relation
XLogOpenRelation(RelFileNode rnode)
{
XLogRelDesc *res;
XLogRelCacheEntry *hentry;
bool found;
hentry = (XLogRelCacheEntry *)
hash_search(_xlrelcache, (void *) &rnode, HASH_FIND, NULL);
if (hentry)
{
res = hentry->rdesc;
res->lessRecently->moreRecently = res->moreRecently;
res->moreRecently->lessRecently = res->lessRecently;
}
else
{
res = _xl_new_reldesc();
sprintf(RelationGetRelationName(&(res->reldata)), "%u", rnode.relNode);
res->reldata.rd_node = rnode;
/*
* We set up the lockRelId in case anything tries to lock the dummy
* relation. Note that this is fairly bogus since relNode may be
* different from the relation's OID. It shouldn't really matter
* though, since we are presumably running by ourselves and can't have
* any lock conflicts ...
*/
res->reldata.rd_lockInfo.lockRelId.dbId = rnode.dbNode;
res->reldata.rd_lockInfo.lockRelId.relId = rnode.relNode;
hentry = (XLogRelCacheEntry *)
hash_search(_xlrelcache, (void *) &rnode, HASH_ENTER, &found);
if (found)
elog(PANIC, "xlog relation already present on insert into cache");
hentry->rdesc = res;
res->reldata.rd_targblock = InvalidBlockNumber;
res->reldata.rd_smgr = NULL;
RelationOpenSmgr(&(res->reldata));
/*
* Create the target file if it doesn't already exist. This lets us
* cope if the replay sequence contains writes to a relation that is
* later deleted. (The original coding of this routine would instead
* return NULL, causing the writes to be suppressed. But that seems
* like it risks losing valuable data if the filesystem loses an inode
* during a crash. Better to write the data until we are actually
* told to delete the file.)
*/
smgrcreate(res->reldata.rd_smgr, res->reldata.rd_istemp, true);
}
res->moreRecently = &(_xlrelarr[0]);
res->lessRecently = _xlrelarr[0].lessRecently;
_xlrelarr[0].lessRecently = res;
res->lessRecently->moreRecently = res;
return &(res->reldata);
}
