/*
* allocate and initialize a new BTPageState. the returned structure
* is suitable for immediate use by _bt_buildadd.
*/
static BTPageState *
_bt_pagestate(BTWriteState *wstate, uint32 level)
{
BTPageState *state = (BTPageState *) palloc0(sizeof(BTPageState));
/* create initial page for level */
state->btps_page = _bt_blnewpage(level);
/* and assign it a page position */
state->btps_blkno = wstate->btws_pages_alloced++;
state->btps_minkey = NULL;
/* initialize lastoff so first item goes into P_FIRSTKEY */
state->btps_lastoff = P_HIKEY;
state->btps_level = level;
/* set "full" threshold based on level. See notes at head of file. */
if (level > 0)
state->btps_full = (BLCKSZ * (100 - BTREE_NONLEAF_FILLFACTOR) / 100);
else
state->btps_full = RelationGetTargetPageFreeSpace(wstate->index,
BTREE_DEFAULT_FILLFACTOR);
/* no parent level, yet */
state->btps_next = NULL;
return state;
}
/*
* Per-tuple callback from IndexBuildHeapScan
*/
static void
gistbuildCallback(Relation index,
ItemPointer tupleId,
Datum *values,
bool *isnull,
bool tupleIsAlive __attribute__((unused)),
void *state)
{
GISTBuildState *buildstate = (GISTBuildState *) state;
IndexTuple itup;
MemoryContext oldCtx;
oldCtx = MemoryContextSwitchTo(buildstate->tmpCtx);
/* form an index tuple and point it at the heap tuple */
itup = gistFormTuple(&buildstate->giststate, index,
values, isnull, true /* size is currently bogus */ );
itup->t_tid = *tupleId;
/*
* Since we already have the index relation locked, we call gistdoinsert
* directly. Normal access method calls dispatch through gistinsert,
* which locks the relation for write. This is the right thing to do if
* you're inserting single tups, but not when you're initializing the
* whole index at once.
*
* In this path we respect the fillfactor setting, whereas insertions
* after initial build do not.
*/
gistdoinsert(index, itup,
RelationGetTargetPageFreeSpace(index, GIST_DEFAULT_FILLFACTOR),
&buildstate->giststate);
buildstate->indtuples += 1;
MemoryContextSwitchTo(oldCtx);
MemoryContextReset(buildstate->tmpCtx);
}
/*
* Insert a tuple to the new relation. This has to track heap_insert
* and its subsidiary functions!
*
* t_self of the tuple is set to the new TID of the tuple. If t_ctid of the
* tuple is invalid on entry, it's replaced with the new TID as well (in
* the inserted data only, not in the caller's copy).
*/
static void
raw_heap_insert(RewriteState state, HeapTuple tup)
{
Page page = state->rs_buffer;
Size pageFreeSpace,
saveFreeSpace;
Size len;
OffsetNumber newoff;
HeapTuple heaptup;
/*
* If the new tuple is too big for storage or contains already toasted
* out-of-line attributes from some other relation, invoke the toaster.
*
* Note: below this point, heaptup is the data we actually intend to store
* into the relation; tup is the caller's original untoasted data.
*/
if (state->rs_new_rel->rd_rel->relkind == RELKIND_TOASTVALUE)
{
/* toast table entries should never be recursively toasted */
Assert(!HeapTupleHasExternal(tup));
heaptup = tup;
}
else if (HeapTupleHasExternal(tup) || tup->t_len > TOAST_TUPLE_THRESHOLD)
heaptup = toast_insert_or_update(state->rs_new_rel, tup, NULL,
HEAP_INSERT_SKIP_FSM |
(state->rs_use_wal ?
0 : HEAP_INSERT_SKIP_WAL));
else
heaptup = tup;
len = MAXALIGN(heaptup->t_len); /* be conservative */
/*
* If we're gonna fail for oversize tuple, do it right away
*/
if (len > MaxHeapTupleSize)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("row is too big: size %zu, maximum size %zu",
len, MaxHeapTupleSize)));
/* Compute desired extra freespace due to fillfactor option */
saveFreeSpace = RelationGetTargetPageFreeSpace(state->rs_new_rel,
HEAP_DEFAULT_FILLFACTOR);
/* Now we can check to see if there's enough free space already. */
if (state->rs_buffer_valid)
{
pageFreeSpace = PageGetHeapFreeSpace(page);
if (len + saveFreeSpace > pageFreeSpace)
{
/* Doesn't fit, so write out the existing page */
/* XLOG stuff */
if (state->rs_use_wal)
log_newpage(&state->rs_new_rel->rd_node,
MAIN_FORKNUM,
state->rs_blockno,
page,
true);
/*
* Now write the page. We say isTemp = true even if it's not a
* temp table, because there's no need for smgr to schedule an
* fsync for this write; we'll do it ourselves in
* end_heap_rewrite.
*/
RelationOpenSmgr(state->rs_new_rel);
PageSetChecksumInplace(page, state->rs_blockno);
smgrextend(state->rs_new_rel->rd_smgr, MAIN_FORKNUM,
state->rs_blockno, (char *) page, true);
state->rs_blockno++;
state->rs_buffer_valid = false;
}
}
if (!state->rs_buffer_valid)
{
/* Initialize a new empty page */
PageInit(page, BLCKSZ, 0);
state->rs_buffer_valid = true;
}
/* And now we can insert the tuple into the page */
newoff = PageAddItem(page, (Item) heaptup->t_data, heaptup->t_len,
InvalidOffsetNumber, false, true);
if (newoff == InvalidOffsetNumber)
elog(ERROR, "failed to add tuple");
/* Update caller's t_self to the actual position where it was stored */
ItemPointerSet(&(tup->t_self), state->rs_blockno, newoff);
/*
* Insert the correct position into CTID of the stored tuple, too, if the
* caller didn't supply a valid CTID.
*/
if (!ItemPointerIsValid(&tup->t_data->t_ctid))
{
ItemId newitemid;
HeapTupleHeader onpage_tup;
newitemid = PageGetItemId(page, newoff);
onpage_tup = (HeapTupleHeader) PageGetItem(page, newitemid);
onpage_tup->t_ctid = tup->t_self;
}
/* If heaptup is a private copy, release it. */
if (heaptup != tup)
heap_freetuple(heaptup);
}
/*
* RelationGetBufferForTuple
*
* Returns pinned and exclusive-locked buffer of a page in given relation
* with free space >= given len.
*
* If otherBuffer is not InvalidBuffer, then it references a previously
* pinned buffer of another page in the same relation; on return, this
* buffer will also be exclusive-locked. (This case is used by heap_update;
* the otherBuffer contains the tuple being updated.)
*
* The reason for passing otherBuffer is that if two backends are doing
* concurrent heap_update operations, a deadlock could occur if they try
* to lock the same two buffers in opposite orders. To ensure that this
* can't happen, we impose the rule that buffers of a relation must be
* locked in increasing page number order. This is most conveniently done
* by having RelationGetBufferForTuple lock them both, with suitable care
* for ordering.
*
* NOTE: it is unlikely, but not quite impossible, for otherBuffer to be the
* same buffer we select for insertion of the new tuple (this could only
* happen if space is freed in that page after heap_update finds there's not
* enough there). In that case, the page will be pinned and locked only once.
*
* For the vmbuffer and vmbuffer_other arguments, we avoid deadlock by
* locking them only after locking the corresponding heap page, and taking
* no further lwlocks while they are locked.
*
* We normally use FSM to help us find free space. However,
* if HEAP_INSERT_SKIP_FSM is specified, we just append a new empty page to
* the end of the relation if the tuple won't fit on the current target page.
* This can save some cycles when we know the relation is new and doesn't
* contain useful amounts of free space.
*
* HEAP_INSERT_SKIP_FSM is also useful for non-WAL-logged additions to a
* relation, if the caller holds exclusive lock and is careful to invalidate
* relation's smgr_targblock before the first insertion --- that ensures that
* all insertions will occur into newly added pages and not be intermixed
* with tuples from other transactions. That way, a crash can't risk losing
* any committed data of other transactions. (See heap_insert's comments
* for additional constraints needed for safe usage of this behavior.)
*
* The caller can also provide a BulkInsertState object to optimize many
* insertions into the same relation. This keeps a pin on the current
* insertion target page (to save pin/unpin cycles) and also passes a
* BULKWRITE buffer selection strategy object to the buffer manager.
* Passing NULL for bistate selects the default behavior.
*
* We always try to avoid filling existing pages further than the fillfactor.
* This is OK since this routine is not consulted when updating a tuple and
* keeping it on the same page, which is the scenario fillfactor is meant
* to reserve space for.
*
* ereport(ERROR) is allowed here, so this routine *must* be called
* before any (unlogged) changes are made in buffer pool.
*/
Buffer
RelationGetBufferForTuple(Relation relation, Size len,
Buffer otherBuffer, int options,
BulkInsertState bistate,
Buffer *vmbuffer, Buffer *vmbuffer_other)
{
bool use_fsm = !(options & HEAP_INSERT_SKIP_FSM);
Buffer buffer = InvalidBuffer;
Page page;
Size pageFreeSpace,
saveFreeSpace;
BlockNumber targetBlock,
otherBlock;
bool needLock;
len = MAXALIGN(len); /* be conservative */
/* Bulk insert is not supported for updates, only inserts. */
Assert(otherBuffer == InvalidBuffer || !bistate);
/*
* If we're gonna fail for oversize tuple, do it right away
*/
if (len > MaxHeapTupleSize)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("row is too big: size %lu, maximum size %lu",
(unsigned long) len,
(unsigned long) MaxHeapTupleSize)));
/* Compute desired extra freespace due to fillfactor option */
saveFreeSpace = RelationGetTargetPageFreeSpace(relation,
HEAP_DEFAULT_FILLFACTOR);
if (otherBuffer != InvalidBuffer)
otherBlock = BufferGetBlockNumber(otherBuffer);
else
otherBlock = InvalidBlockNumber; /* just to keep compiler quiet */
/*
* We first try to put the tuple on the same page we last inserted a tuple
* on, as cached in the BulkInsertState or relcache entry. If that
* doesn't work, we ask the Free Space Map to locate a suitable page.
* Since the FSM's info might be out of date, we have to be prepared to
* loop around and retry multiple times. (To insure this isn't an infinite
* loop, we must update the FSM with the correct amount of free space on
* each page that proves not to be suitable.) If the FSM has no record of
* a page with enough free space, we give up and extend the relation.
*
* When use_fsm is false, we either put the tuple onto the existing target
* page or extend the relation.
*/
if (len + saveFreeSpace > MaxHeapTupleSize)
{
/* can't fit, don't bother asking FSM */
targetBlock = InvalidBlockNumber;
use_fsm = false;
}
else if (bistate && bistate->current_buf != InvalidBuffer)
targetBlock = BufferGetBlockNumber(bistate->current_buf);
else
targetBlock = RelationGetTargetBlock(relation);
if (targetBlock == InvalidBlockNumber && use_fsm)
{
/*
* We have no cached target page, so ask the FSM for an initial
* target.
*/
targetBlock = GetPageWithFreeSpace(relation, len + saveFreeSpace);
/*
* If the FSM knows nothing of the rel, try the last page before we
* give up and extend. This avoids one-tuple-per-page syndrome during
* bootstrapping or in a recently-started system.
*/
if (targetBlock == InvalidBlockNumber)
{
BlockNumber nblocks = RelationGetNumberOfBlocks(relation);
if (nblocks > 0)
targetBlock = nblocks - 1;
}
}
while (targetBlock != InvalidBlockNumber)
{
/*
* Read and exclusive-lock the target block, as well as the other
* block if one was given, taking suitable care with lock ordering and
* the possibility they are the same block.
*
* If the page-level all-visible flag is set, caller will need to
* clear both that and the corresponding visibility map bit. However,
* by the time we return, we'll have x-locked the buffer, and we don't
* want to do any I/O while in that state. So we check the bit here
* before taking the lock, and pin the page if it appears necessary.
* Checking without the lock creates a risk of getting the wrong
* answer, so we'll have to recheck after acquiring the lock.
*/
if (otherBuffer == InvalidBuffer)
{
/* easy case */
buffer = ReadBufferBI(relation, targetBlock, bistate);
if (PageIsAllVisible(BufferGetPage(buffer)))
visibilitymap_pin(relation, targetBlock, vmbuffer);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
}
else if (otherBlock == targetBlock)
{
/* also easy case */
buffer = otherBuffer;
if (PageIsAllVisible(BufferGetPage(buffer)))
visibilitymap_pin(relation, targetBlock, vmbuffer);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
}
else if (otherBlock < targetBlock)
{
/* lock other buffer first */
buffer = ReadBuffer(relation, targetBlock);
if (PageIsAllVisible(BufferGetPage(buffer)))
visibilitymap_pin(relation, targetBlock, vmbuffer);
LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
}
else
{
/* lock target buffer first */
buffer = ReadBuffer(relation, targetBlock);
if (PageIsAllVisible(BufferGetPage(buffer)))
visibilitymap_pin(relation, targetBlock, vmbuffer);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
}
/*
* We now have the target page (and the other buffer, if any) pinned
* and locked. However, since our initial PageIsAllVisible checks
* were performed before acquiring the lock, the results might now be
* out of date, either for the selected victim buffer, or for the
* other buffer passed by the caller. In that case, we'll need to
* give up our locks, go get the pin(s) we failed to get earlier, and
* re-lock. That's pretty painful, but hopefully shouldn't happen
* often.
*
* Note that there's a small possibility that we didn't pin the page
* above but still have the correct page pinned anyway, either because
* we've already made a previous pass through this loop, or because
* caller passed us the right page anyway.
*
* Note also that it's possible that by the time we get the pin and
* retake the buffer locks, the visibility map bit will have been
* cleared by some other backend anyway. In that case, we'll have
* done a bit of extra work for no gain, but there's no real harm
* done.
*/
if (otherBuffer == InvalidBuffer || buffer <= otherBuffer)
GetVisibilityMapPins(relation, buffer, otherBuffer,
targetBlock, otherBlock, vmbuffer,
vmbuffer_other);
else
GetVisibilityMapPins(relation, otherBuffer, buffer,
otherBlock, targetBlock, vmbuffer_other,
vmbuffer);
/*
* Now we can check to see if there's enough free space here. If so,
* we're done.
*/
page = BufferGetPage(buffer);
pageFreeSpace = PageGetHeapFreeSpace(page);
if (len + saveFreeSpace <= pageFreeSpace)
{
/* use this page as future insert target, too */
RelationSetTargetBlock(relation, targetBlock);
return buffer;
}
/*
* Not enough space, so we must give up our page locks and pin (if
* any) and prepare to look elsewhere. We don't care which order we
* unlock the two buffers in, so this can be slightly simpler than the
* code above.
*/
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
if (otherBuffer == InvalidBuffer)
ReleaseBuffer(buffer);
else if (otherBlock != targetBlock)
{
LockBuffer(otherBuffer, BUFFER_LOCK_UNLOCK);
ReleaseBuffer(buffer);
}
/* Without FSM, always fall out of the loop and extend */
if (!use_fsm)
break;
/*
* Update FSM as to condition of this page, and ask for another page
* to try.
*/
targetBlock = RecordAndGetPageWithFreeSpace(relation,
targetBlock,
pageFreeSpace,
len + saveFreeSpace);
}
/*
* Have to extend the relation.
*
* We have to use a lock to ensure no one else is extending the rel at the
* same time, else we will both try to initialize the same new page. We
* can skip locking for new or temp relations, however, since no one else
* could be accessing them.
*/
needLock = !RELATION_IS_LOCAL(relation);
if (needLock)
LockRelationForExtension(relation, ExclusiveLock);
/*
* XXX This does an lseek - rather expensive - but at the moment it is the
* only way to accurately determine how many blocks are in a relation. Is
* it worth keeping an accurate file length in shared memory someplace,
* rather than relying on the kernel to do it for us?
*/
buffer = ReadBufferBI(relation, P_NEW, bistate);
/*
* We can be certain that locking the otherBuffer first is OK, since it
* must have a lower page number.
*/
if (otherBuffer != InvalidBuffer)
LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
/*
* Now acquire lock on the new page.
*/
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* Release the file-extension lock; it's now OK for someone else to extend
* the relation some more. Note that we cannot release this lock before
* we have buffer lock on the new page, or we risk a race condition
* against vacuumlazy.c --- see comments therein.
*/
if (needLock)
UnlockRelationForExtension(relation, ExclusiveLock);
/*
* We need to initialize the empty new page. Double-check that it really
* is empty (this should never happen, but if it does we don't want to
* risk wiping out valid data).
*/
page = BufferGetPage(buffer);
if (!PageIsNew(page))
elog(ERROR, "page %u of relation \"%s\" should be empty but is not",
BufferGetBlockNumber(buffer),
RelationGetRelationName(relation));
PageInit(page, BufferGetPageSize(buffer), 0);
if (len > PageGetHeapFreeSpace(page))
{
/* We should not get here given the test at the top */
elog(PANIC, "tuple is too big: size %lu", (unsigned long) len);
}
/*
* Remember the new page as our target for future insertions.
*
* XXX should we enter the new page into the free space map immediately,
* or just keep it for this backend's exclusive use in the short run
* (until VACUUM sees it)? Seems to depend on whether you expect the
* current backend to make more insertions or not, which is probably a
* good bet most of the time. So for now, don't add it to FSM yet.
*/
RelationSetTargetBlock(relation, BufferGetBlockNumber(buffer));
return buffer;
}
/*
* Optionally prune and repair fragmentation in the specified page.
*
* This is an opportunistic function. It will perform housekeeping
* only if the page heuristically looks like a candidate for pruning and we
* can acquire buffer cleanup lock without blocking.
*
* Note: this is called quite often. It's important that it fall out quickly
* if there's not any use in pruning.
*
* Caller must have pin on the buffer, and must *not* have a lock on it.
*
* OldestXmin is the cutoff XID used to distinguish whether tuples are DEAD
* or RECENTLY_DEAD (see HeapTupleSatisfiesVacuum).
*/
void
heap_page_prune_opt(Relation relation, Buffer buffer, TransactionId OldestXmin)
{
Page page = BufferGetPage(buffer);
Size minfree;
/*
* In GPDB we may call into here without having a local snapshot and thus
* no valid OldestXmin transaction id. Exit early if so.
*/
if (!TransactionIdIsValid(OldestXmin))
return;
/*
* Let's see if we really need pruning.
*
* Forget it if page is not hinted to contain something prunable that's
* older than OldestXmin.
*/
if (!PageIsPrunable(page, OldestXmin))
return;
/*
* We prune when a previous UPDATE failed to find enough space on the page
* for a new tuple version, or when free space falls below the relation's
* fill-factor target (but not less than 10%).
*
* Checking free space here is questionable since we aren't holding any
* lock on the buffer; in the worst case we could get a bogus answer. It's
* unlikely to be *seriously* wrong, though, since reading either pd_lower
* or pd_upper is probably atomic. Avoiding taking a lock seems more
* important than sometimes getting a wrong answer in what is after all
* just a heuristic estimate.
*/
minfree = RelationGetTargetPageFreeSpace(relation,
HEAP_DEFAULT_FILLFACTOR);
minfree = Max(minfree, BLCKSZ / 10);
if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
{
/*
* Check if we have gp_persistent_relation_node information, to be
* added to the XLOG record. As in some cases it maybe too late to
* fetch the same and hence for such cases just give-up.
*/
if (!RelationAllowedToGenerateXLogRecord(relation))
return;
/* OK, try to get exclusive buffer lock */
if (!ConditionalLockBufferForCleanup(buffer))
return;
/*
* Now that we have buffer lock, get accurate information about the
* page's free space, and recheck the heuristic about whether to
* prune. (We needn't recheck PageIsPrunable, since no one else could
* have pruned while we hold pin.)
*/
if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
{
/* OK to prune (though not to remove redirects) */
(void) heap_page_prune(relation, buffer, OldestXmin, false, true);
}
/* And release buffer lock */
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
}
}
/*
* Get a buffer of the type and parity specified by flags, having at least
* as much free space as indicated by needSpace. We use the lastUsedPages
* cache to assign the same buffer previously requested when possible.
* The returned buffer is already pinned and exclusive-locked.
*
* *isNew is set true if the page was initialized here, false if it was
* already valid.
*/
Buffer
SpGistGetBuffer(Relation index, int flags, int needSpace, bool *isNew)
{
SpGistCache *cache = spgGetCache(index);
SpGistLastUsedPage *lup;
/* Bail out if even an empty page wouldn't meet the demand */
if (needSpace > SPGIST_PAGE_CAPACITY)
elog(ERROR, "desired SPGiST tuple size is too big");
/*
* If possible, increase the space request to include relation's
* fillfactor. This ensures that when we add unrelated tuples to a page,
* we try to keep 100-fillfactor% available for adding tuples that are
* related to the ones already on it. But fillfactor mustn't cause an
* error for requests that would otherwise be legal.
*/
needSpace += RelationGetTargetPageFreeSpace(index,
SPGIST_DEFAULT_FILLFACTOR);
needSpace = Min(needSpace, SPGIST_PAGE_CAPACITY);
/* Get the cache entry for this flags setting */
lup = GET_LUP(cache, flags);
/* If we have nothing cached, just turn it over to allocNewBuffer */
if (lup->blkno == InvalidBlockNumber)
{
*isNew = true;
return allocNewBuffer(index, flags);
}
/* fixed pages should never be in cache */
Assert(!SpGistBlockIsFixed(lup->blkno));
/* If cached freeSpace isn't enough, don't bother looking at the page */
if (lup->freeSpace >= needSpace)
{
Buffer buffer;
Page page;
buffer = ReadBuffer(index, lup->blkno);
if (!ConditionalLockBuffer(buffer))
{
/*
* buffer is locked by another process, so return a new buffer
*/
ReleaseBuffer(buffer);
*isNew = true;
return allocNewBuffer(index, flags);
}
page = BufferGetPage(buffer);
if (PageIsNew(page) || SpGistPageIsDeleted(page) || PageIsEmpty(page))
{
/* OK to initialize the page */
uint16 pageflags = 0;
if (GBUF_REQ_LEAF(flags))
pageflags |= SPGIST_LEAF;
if (GBUF_REQ_NULLS(flags))
pageflags |= SPGIST_NULLS;
SpGistInitBuffer(buffer, pageflags);
lup->freeSpace = PageGetExactFreeSpace(page) - needSpace;
*isNew = true;
return buffer;
}
/*
* Check that page is of right type and has enough space. We must
* recheck this since our cache isn't necessarily up to date.
*/
if ((GBUF_REQ_LEAF(flags) ? SpGistPageIsLeaf(page) : !SpGistPageIsLeaf(page)) &&
(GBUF_REQ_NULLS(flags) ? SpGistPageStoresNulls(page) : !SpGistPageStoresNulls(page)))
{
int freeSpace = PageGetExactFreeSpace(page);
if (freeSpace >= needSpace)
{
/* Success, update freespace info and return the buffer */
lup->freeSpace = freeSpace - needSpace;
*isNew = false;
return buffer;
}
}
/*
* fallback to allocation of new buffer
*/
UnlockReleaseBuffer(buffer);
}
/* No success with cache, so return a new buffer */
*isNew = true;
return allocNewBuffer(index, flags);
}
/*
* Optionally prune and repair fragmentation in the specified page.
*
* This is an opportunistic function. It will perform housekeeping
* only if the page heuristically looks like a candidate for pruning and we
* can acquire buffer cleanup lock without blocking.
*
* Note: this is called quite often. It's important that it fall out quickly
* if there's not any use in pruning.
*
* Caller must have pin on the buffer, and must *not* have a lock on it.
*
* OldestXmin is the cutoff XID used to distinguish whether tuples are DEAD
* or RECENTLY_DEAD (see HeapTupleSatisfiesVacuum).
*/
void
heap_page_prune_opt(Relation relation, Buffer buffer, TransactionId OldestXmin)
{
Page page = BufferGetPage(buffer);
Size minfree;
/*
* Let's see if we really need pruning.
*
* Forget it if page is not hinted to contain something prunable that's
* older than OldestXmin.
*/
if (!PageIsPrunable(page, OldestXmin))
return;
/*
* We can't write WAL in recovery mode, so there's no point trying to
* clean the page. The master will likely issue a cleaning WAL record soon
* anyway, so this is no particular loss.
*/
if (RecoveryInProgress())
return;
/*
* We prune when a previous UPDATE failed to find enough space on the page
* for a new tuple version, or when free space falls below the relation's
* fill-factor target (but not less than 10%).
*
* Checking free space here is questionable since we aren't holding any
* lock on the buffer; in the worst case we could get a bogus answer. It's
* unlikely to be *seriously* wrong, though, since reading either pd_lower
* or pd_upper is probably atomic. Avoiding taking a lock seems more
* important than sometimes getting a wrong answer in what is after all
* just a heuristic estimate.
*/
minfree = RelationGetTargetPageFreeSpace(relation,
HEAP_DEFAULT_FILLFACTOR);
minfree = Max(minfree, BLCKSZ / 10);
if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
{
/* OK, try to get exclusive buffer lock */
if (!ConditionalLockBufferForCleanup(buffer))
return;
/*
* Now that we have buffer lock, get accurate information about the
* page's free space, and recheck the heuristic about whether to
* prune. (We needn't recheck PageIsPrunable, since no one else could
* have pruned while we hold pin.)
*/
if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
{
TransactionId ignore = InvalidTransactionId; /* return value not
* needed */
/* OK to prune */
(void) heap_page_prune(relation, buffer, OldestXmin, true, &ignore);
}
/* And release buffer lock */
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
}
}
/*
* Optionally prune and repair fragmentation in the specified page.
*
* This is an opportunistic function. It will perform housekeeping
* only if the page heuristically looks like a candidate for pruning and we
* can acquire buffer cleanup lock without blocking.
*
* Note: this is called quite often. It's important that it fall out quickly
* if there's not any use in pruning.
*
* Caller must have pin on the buffer, and must *not* have a lock on it.
*
* OldestXmin is the cutoff XID used to distinguish whether tuples are DEAD
* or RECENTLY_DEAD (see HeapTupleSatisfiesVacuum).
*/
void
heap_page_prune_opt(Relation relation, Buffer buffer)
{
Page page = BufferGetPage(buffer);
Size minfree;
TransactionId OldestXmin;
/*
* We can't write WAL in recovery mode, so there's no point trying to
* clean the page. The master will likely issue a cleaning WAL record soon
* anyway, so this is no particular loss.
*/
if (RecoveryInProgress())
return;
/*
* Use the appropriate xmin horizon for this relation. If it's a proper
* catalog relation or a user defined, additional, catalog relation, we
* need to use the horizon that includes slots, otherwise the data-only
* horizon can be used. Note that the toast relation of user defined
* relations are *not* considered catalog relations.
*
* It is OK to apply the old snapshot limit before acquiring the cleanup
* lock because the worst that can happen is that we are not quite as
* aggressive about the cleanup (by however many transaction IDs are
* consumed between this point and acquiring the lock). This allows us to
* save significant overhead in the case where the page is found not to be
* prunable.
*/
if (IsCatalogRelation(relation) ||
RelationIsAccessibleInLogicalDecoding(relation))
OldestXmin = RecentGlobalXmin;
else
OldestXmin =
TransactionIdLimitedForOldSnapshots(RecentGlobalDataXmin,
relation);
Assert(TransactionIdIsValid(OldestXmin));
/*
* Let's see if we really need pruning.
*
* Forget it if page is not hinted to contain something prunable that's
* older than OldestXmin.
*/
if (!PageIsPrunable(page, OldestXmin))
return;
/*
* We prune when a previous UPDATE failed to find enough space on the page
* for a new tuple version, or when free space falls below the relation's
* fill-factor target (but not less than 10%).
*
* Checking free space here is questionable since we aren't holding any
* lock on the buffer; in the worst case we could get a bogus answer. It's
* unlikely to be *seriously* wrong, though, since reading either pd_lower
* or pd_upper is probably atomic. Avoiding taking a lock seems more
* important than sometimes getting a wrong answer in what is after all
* just a heuristic estimate.
*/
minfree = RelationGetTargetPageFreeSpace(relation,
HEAP_DEFAULT_FILLFACTOR);
minfree = Max(minfree, BLCKSZ / 10);
if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
{
/* OK, try to get exclusive buffer lock */
if (!ConditionalLockBufferForCleanup(buffer))
return;
/*
* Now that we have buffer lock, get accurate information about the
* page's free space, and recheck the heuristic about whether to
* prune. (We needn't recheck PageIsPrunable, since no one else could
* have pruned while we hold pin.)
*/
if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
{
TransactionId ignore = InvalidTransactionId; /* return value not
* needed */
/* OK to prune */
(void) heap_page_prune(relation, buffer, OldestXmin, true, &ignore);
}
/* And release buffer lock */
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
}
}
/*
* RelationGetBufferForTuple
*
* Returns pinned and exclusive-locked buffer of a page in given relation
* with free space >= given len.
*
* If otherBuffer is not InvalidBuffer, then it references a previously
* pinned buffer of another page in the same relation; on return, this
* buffer will also be exclusive-locked. (This case is used by heap_update;
* the otherBuffer contains the tuple being updated.)
*
* The reason for passing otherBuffer is that if two backends are doing
* concurrent heap_update operations, a deadlock could occur if they try
* to lock the same two buffers in opposite orders. To ensure that this
* can't happen, we impose the rule that buffers of a relation must be
* locked in increasing page number order. This is most conveniently done
* by having RelationGetBufferForTuple lock them both, with suitable care
* for ordering.
*
* NOTE: it is unlikely, but not quite impossible, for otherBuffer to be the
* same buffer we select for insertion of the new tuple (this could only
* happen if space is freed in that page after heap_update finds there's not
* enough there). In that case, the page will be pinned and locked only once.
*
* If use_fsm is true (the normal case), we use FSM to help us find free
* space. If use_fsm is false, we always append a new empty page to the
* end of the relation if the tuple won't fit on the current target page.
* This can save some cycles when we know the relation is new and doesn't
* contain useful amounts of free space.
*
* The use_fsm = false case is also useful for non-WAL-logged additions to a
* relation, if the caller holds exclusive lock and is careful to invalidate
* relation->rd_targblock before the first insertion --- that ensures that
* all insertions will occur into newly added pages and not be intermixed
* with tuples from other transactions. That way, a crash can't risk losing
* any committed data of other transactions. (See heap_insert's comments
* for additional constraints needed for safe usage of this behavior.)
*
* We always try to avoid filling existing pages further than the fillfactor.
* This is OK since this routine is not consulted when updating a tuple and
* keeping it on the same page, which is the scenario fillfactor is meant
* to reserve space for.
*
* ereport(ERROR) is allowed here, so this routine *must* be called
* before any (unlogged) changes are made in buffer pool.
*/
Buffer
RelationGetBufferForTuple(Relation relation, Size len,
Buffer otherBuffer, bool use_fsm)
{
Buffer buffer = InvalidBuffer;
Page pageHeader;
Size pageFreeSpace,
saveFreeSpace;
BlockNumber targetBlock,
otherBlock;
bool needLock;
MIRROREDLOCK_BUFMGR_MUST_ALREADY_BE_HELD;
len = MAXALIGN(len); /* be conservative */
/*
* If we're gonna fail for oversize tuple, do it right away
*/
if (len > MaxHeapTupleSize)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("row is too big: size %lu, maximum size %lu",
(unsigned long) len,
(unsigned long) MaxHeapTupleSize)));
/* Compute desired extra freespace due to fillfactor option */
saveFreeSpace = RelationGetTargetPageFreeSpace(relation,
HEAP_DEFAULT_FILLFACTOR);
if (otherBuffer != InvalidBuffer)
otherBlock = BufferGetBlockNumber(otherBuffer);
else
otherBlock = InvalidBlockNumber; /* just to keep compiler quiet */
/*
* We first try to put the tuple on the same page we last inserted a tuple
* on, as cached in the relcache entry. If that doesn't work, we ask the
* shared Free Space Map to locate a suitable page. Since the FSM's info
* might be out of date, we have to be prepared to loop around and retry
* multiple times. (To insure this isn't an infinite loop, we must update
* the FSM with the correct amount of free space on each page that proves
* not to be suitable.) If the FSM has no record of a page with enough
* free space, we give up and extend the relation.
*
* When use_fsm is false, we either put the tuple onto the existing target
* page or extend the relation.
*/
if (len + saveFreeSpace <= MaxHeapTupleSize)
targetBlock = relation->rd_targblock;
else
{
/* can't fit, don't screw up FSM request tracking by trying */
targetBlock = InvalidBlockNumber;
use_fsm = false;
}
if (targetBlock == InvalidBlockNumber && use_fsm)
{
/*
* We have no cached target page, so ask the FSM for an initial
* target.
*/
targetBlock = GetPageWithFreeSpace(&relation->rd_node,
len + saveFreeSpace);
/*
* If the FSM knows nothing of the rel, try the last page before we
* give up and extend. This avoids one-tuple-per-page syndrome during
* bootstrapping or in a recently-started system.
*/
if (targetBlock == InvalidBlockNumber)
{
BlockNumber nblocks = RelationGetNumberOfBlocks(relation);
if (nblocks > 0)
targetBlock = nblocks - 1;
}
}
while (targetBlock != InvalidBlockNumber)
{
/*
* Read and exclusive-lock the target block, as well as the other
* block if one was given, taking suitable care with lock ordering and
* the possibility they are the same block.
*/
if (otherBuffer == InvalidBuffer)
{
/* easy case */
buffer = ReadBuffer(relation, targetBlock);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
}
else if (otherBlock == targetBlock)
{
/* also easy case */
buffer = otherBuffer;
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
}
else if (otherBlock < targetBlock)
{
/* lock other buffer first */
buffer = ReadBuffer(relation, targetBlock);
LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
}
else
{
/* lock target buffer first */
buffer = ReadBuffer(relation, targetBlock);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
}
/*
* Now we can check to see if there's enough free space here. If so,
* we're done.
*/
pageHeader = (Page) BufferGetPage(buffer);
pageFreeSpace = PageGetFreeSpace(pageHeader);
if (len + saveFreeSpace <= pageFreeSpace)
{
/* use this page as future insert target, too */
relation->rd_targblock = targetBlock;
return buffer;
}
/*
* Not enough space, so we must give up our page locks and pin (if
* any) and prepare to look elsewhere. We don't care which order we
* unlock the two buffers in, so this can be slightly simpler than the
* code above.
*/
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
if (otherBuffer == InvalidBuffer)
ReleaseBuffer(buffer);
else if (otherBlock != targetBlock)
{
LockBuffer(otherBuffer, BUFFER_LOCK_UNLOCK);
ReleaseBuffer(buffer);
}
/* Without FSM, always fall out of the loop and extend */
if (!use_fsm)
break;
/*
* Update FSM as to condition of this page, and ask for another page
* to try.
*/
targetBlock = RecordAndGetPageWithFreeSpace(&relation->rd_node,
targetBlock,
pageFreeSpace,
len + saveFreeSpace);
}
/*
* Have to extend the relation.
*
* We have to use a lock to ensure no one else is extending the rel at the
* same time, else we will both try to initialize the same new page. We
* can skip locking for new or temp relations, however, since no one else
* could be accessing them.
*/
needLock = !RELATION_IS_LOCAL(relation);
if (needLock)
LockRelationForExtension(relation, ExclusiveLock);
/*
* XXX This does an lseek - rather expensive - but at the moment it is the
* only way to accurately determine how many blocks are in a relation. Is
* it worth keeping an accurate file length in shared memory someplace,
* rather than relying on the kernel to do it for us?
*/
buffer = ReadBuffer(relation, P_NEW);
/*
* We can be certain that locking the otherBuffer first is OK, since it
* must have a lower page number.
*/
if (otherBuffer != InvalidBuffer)
LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
/*
* Now acquire lock on the new page.
*/
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* Release the file-extension lock; it's now OK for someone else to extend
* the relation some more. Note that we cannot release this lock before
* we have buffer lock on the new page, or we risk a race condition
* against vacuumlazy.c --- see comments therein.
*/
if (needLock)
UnlockRelationForExtension(relation, ExclusiveLock);
/*
* We need to initialize the empty new page. Double-check that it really
* is empty (this should never happen, but if it does we don't want to
* risk wiping out valid data).
*/
pageHeader = (Page) BufferGetPage(buffer);
if (!PageIsNew((PageHeader) pageHeader))
elog(ERROR, "page %u of relation \"%s\" should be empty but is not",
BufferGetBlockNumber(buffer),
RelationGetRelationName(relation));
PageInit(pageHeader, BufferGetPageSize(buffer), 0);
if (len > PageGetFreeSpace(pageHeader))
{
/* We should not get here given the test at the top */
elog(PANIC, "tuple is too big: size %lu", (unsigned long) len);
}
/*
* Remember the new page as our target for future insertions.
*
* XXX should we enter the new page into the free space map immediately,
* or just keep it for this backend's exclusive use in the short run
* (until VACUUM sees it)? Seems to depend on whether you expect the
* current backend to make more insertions or not, which is probably a
* good bet most of the time. So for now, don't add it to FSM yet.
*/
relation->rd_targblock = BufferGetBlockNumber(buffer);
return buffer;
}
/**
* @brief Create LoadStatus file and load heap tuples directly.
* @return void
*/
static void
DirectWriterInsert(DirectWriter *self, HeapTuple tuple)
{
Page page;
OffsetNumber offnum;
ItemId itemId;
Item item;
LoadStatus *ls = &self->ls;
/* Compress the tuple data if needed. */
if (tuple->t_len > TOAST_TUPLE_THRESHOLD)
tuple = toast_insert_or_update(self->base.rel, tuple, NULL, 0);
BULKLOAD_PROFILE(&prof_writer_toast);
/* Assign oids if needed. */
if (self->base.rel->rd_rel->relhasoids)
{
Assert(!OidIsValid(HeapTupleGetOid(tuple)));
HeapTupleSetOid(tuple, GetNewOid(self->base.rel));
}
/* Assume the tuple has been toasted already. */
if (MAXALIGN(tuple->t_len) > MaxHeapTupleSize)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("row is too big: size %lu, maximum size %lu",
(unsigned long) tuple->t_len,
(unsigned long) MaxHeapTupleSize)));
/* Fill current page, or go to next page if the page is full. */
page = GetCurrentPage(self);
if (PageGetFreeSpace(page) < MAXALIGN(tuple->t_len) +
RelationGetTargetPageFreeSpace(self->base.rel, HEAP_DEFAULT_FILLFACTOR))
{
if (self->curblk < BLOCK_BUF_NUM - 1)
self->curblk++;
else
{
flush_pages(self);
self->curblk = 0; /* recycle from first block */
}
page = GetCurrentPage(self);
/* Initialize current block */
PageInit(page, BLCKSZ, 0);
PageSetTLI(page, ThisTimeLineID);
}
tuple->t_data->t_infomask &= ~(HEAP_XACT_MASK);
tuple->t_data->t_infomask2 &= ~(HEAP2_XACT_MASK);
tuple->t_data->t_infomask |= HEAP_XMAX_INVALID;
HeapTupleHeaderSetXmin(tuple->t_data, self->xid);
HeapTupleHeaderSetCmin(tuple->t_data, self->cid);
HeapTupleHeaderSetXmax(tuple->t_data, 0);
/* put the tuple on local page. */
offnum = PageAddItem(page, (Item) tuple->t_data,
tuple->t_len, InvalidOffsetNumber, false, true);
ItemPointerSet(&(tuple->t_self), LS_TOTAL_CNT(ls) + self->curblk, offnum);
itemId = PageGetItemId(page, offnum);
item = PageGetItem(page, itemId);
((HeapTupleHeader) item)->t_ctid = tuple->t_self;
BULKLOAD_PROFILE(&prof_writer_table);
SpoolerInsert(&self->spooler, tuple);
BULKLOAD_PROFILE(&prof_writer_index);
}
