/*
* 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;
XLogRecData rdata[3];
xlrec.node = index->rd_node;
xlrec.blkno = BufferGetBlockNumber(buffer);
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;
ACCEPT_RDATA_DATA(&xlrec, SizeOfSpgxlogVacuumRedirect, 0);
ACCEPT_RDATA_DATA(itemToPlaceholder, sizeof(OffsetNumber) * xlrec.nToPlaceholder, 1);
ACCEPT_RDATA_BUFFER(buffer, 2);
recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_VACUUM_REDIRECT, rdata);
PageSetLSN(page, recptr);
}
END_CRIT_SECTION();
}
static void
spgRedoVacuumRedirect(XLogReaderState *record)
{
XLogRecPtr lsn = record->EndRecPtr;
char *ptr = XLogRecGetData(record);
spgxlogVacuumRedirect *xldata = (spgxlogVacuumRedirect *) ptr;
OffsetNumber *itemToPlaceholder;
Buffer buffer;
itemToPlaceholder = xldata->offsets;
/*
* If any redirection tuples are being removed, make sure there are no
* live Hot Standby transactions that might need to see them.
*/
if (InHotStandby)
{
if (TransactionIdIsValid(xldata->newestRedirectXid))
{
RelFileNode node;
XLogRecGetBlockTag(record, 0, &node, NULL, NULL);
ResolveRecoveryConflictWithSnapshot(xldata->newestRedirectXid,
node);
}
}
if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
{
Page page = BufferGetPage(buffer);
SpGistPageOpaque opaque = SpGistPageGetOpaque(page);
int i;
/* Convert redirect pointers to plain placeholders */
for (i = 0; i < xldata->nToPlaceholder; i++)
{
SpGistDeadTuple dt;
dt = (SpGistDeadTuple) PageGetItem(page,
PageGetItemId(page, itemToPlaceholder[i]));
Assert(dt->tupstate == SPGIST_REDIRECT);
dt->tupstate = SPGIST_PLACEHOLDER;
ItemPointerSetInvalid(&dt->pointer);
}
Assert(opaque->nRedirection >= xldata->nToPlaceholder);
opaque->nRedirection -= xldata->nToPlaceholder;
opaque->nPlaceholder += xldata->nToPlaceholder;
/* Remove placeholder tuples at end of page */
if (xldata->firstPlaceholder != InvalidOffsetNumber)
{
int max = PageGetMaxOffsetNumber(page);
OffsetNumber *toDelete;
toDelete = palloc(sizeof(OffsetNumber) * max);
for (i = xldata->firstPlaceholder; i <= max; i++)
toDelete[i - xldata->firstPlaceholder] = i;
i = max - xldata->firstPlaceholder + 1;
Assert(opaque->nPlaceholder >= i);
opaque->nPlaceholder -= i;
/* The array is sorted, so can use PageIndexMultiDelete */
PageIndexMultiDelete(page, toDelete, i);
pfree(toDelete);
}
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
}
/*
* Add a new item to the page, replacing a PLACEHOLDER item if possible.
* Return the location it's inserted at, or InvalidOffsetNumber on failure.
*
* If startOffset isn't NULL, we start searching for placeholders at
* *startOffset, and update that to the next place to search. This is just
* an optimization for repeated insertions.
*
* If errorOK is false, we throw error when there's not enough room,
* rather than returning InvalidOffsetNumber.
*/
OffsetNumber
SpGistPageAddNewItem(SpGistState *state, Page page, Item item, Size size,
OffsetNumber *startOffset, bool errorOK)
{
SpGistPageOpaque opaque = SpGistPageGetOpaque(page);
OffsetNumber i,
maxoff,
offnum;
if (opaque->nPlaceholder > 0 &&
PageGetExactFreeSpace(page) + SGDTSIZE >= MAXALIGN(size))
{
/* Try to replace a placeholder */
maxoff = PageGetMaxOffsetNumber(page);
offnum = InvalidOffsetNumber;
for (;;)
{
if (startOffset && *startOffset != InvalidOffsetNumber)
i = *startOffset;
else
i = FirstOffsetNumber;
for (; i <= maxoff; i++)
{
SpGistDeadTuple it = (SpGistDeadTuple) PageGetItem(page,
PageGetItemId(page, i));
if (it->tupstate == SPGIST_PLACEHOLDER)
{
offnum = i;
break;
}
}
/* Done if we found a placeholder */
if (offnum != InvalidOffsetNumber)
break;
if (startOffset && *startOffset != InvalidOffsetNumber)
{
/* Hint was no good, re-search from beginning */
*startOffset = InvalidOffsetNumber;
continue;
}
/* Hmm, no placeholder found? */
opaque->nPlaceholder = 0;
break;
}
if (offnum != InvalidOffsetNumber)
{
/* Replace the placeholder tuple */
PageIndexTupleDelete(page, offnum);
offnum = PageAddItem(page, item, size, offnum, false, false);
/*
* We should not have failed given the size check at the top of
* the function, but test anyway. If we did fail, we must PANIC
* because we've already deleted the placeholder tuple, and
* there's no other way to keep the damage from getting to disk.
*/
if (offnum != InvalidOffsetNumber)
{
Assert(opaque->nPlaceholder > 0);
opaque->nPlaceholder--;
if (startOffset)
*startOffset = offnum + 1;
}
else
elog(PANIC, "failed to add item of size %u to SPGiST index page",
(int) size);
return offnum;
}
}
/* No luck in replacing a placeholder, so just add it to the page */
offnum = PageAddItem(page, item, size,
InvalidOffsetNumber, false, false);
if (offnum == InvalidOffsetNumber && !errorOK)
elog(ERROR, "failed to add item of size %u to SPGiST index page",
(int) size);
return offnum;
}
static void
spgRedoAddNode(XLogReaderState *record)
{
XLogRecPtr lsn = record->EndRecPtr;
char *ptr = XLogRecGetData(record);
spgxlogAddNode *xldata = (spgxlogAddNode *) ptr;
char *innerTuple;
SpGistInnerTupleData innerTupleHdr;
SpGistState state;
Buffer buffer;
Page page;
XLogRedoAction action;
ptr += sizeof(spgxlogAddNode);
innerTuple = ptr;
/* the tuple is unaligned, so make a copy to access its header */
memcpy(&innerTupleHdr, innerTuple, sizeof(SpGistInnerTupleData));
fillFakeState(&state, xldata->stateSrc);
if (!XLogRecHasBlockRef(record, 1))
{
/* update in place */
Assert(xldata->parentBlk == -1);
if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
{
page = BufferGetPage(buffer);
PageIndexTupleDelete(page, xldata->offnum);
if (PageAddItem(page, (Item) innerTuple, innerTupleHdr.size,
xldata->offnum,
false, false) != xldata->offnum)
elog(ERROR, "failed to add item of size %u to SPGiST index page",
innerTupleHdr.size);
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
}
else
{
BlockNumber blkno;
BlockNumber blknoNew;
XLogRecGetBlockTag(record, 0, NULL, NULL, &blkno);
XLogRecGetBlockTag(record, 1, NULL, NULL, &blknoNew);
/*
* In normal operation we would have all three pages (source, dest,
* and parent) locked simultaneously; but in WAL replay it should be
* safe to update them one at a time, as long as we do it in the right
* order. We must insert the new tuple before replacing the old tuple
* with the redirect tuple.
*/
/* Install new tuple first so redirect is valid */
if (xldata->newPage)
{
/* AddNode is not used for nulls pages */
buffer = XLogInitBufferForRedo(record, 1);
SpGistInitBuffer(buffer, 0);
action = BLK_NEEDS_REDO;
}
else
action = XLogReadBufferForRedo(record, 1, &buffer);
if (action == BLK_NEEDS_REDO)
{
page = BufferGetPage(buffer);
addOrReplaceTuple(page, (Item) innerTuple,
innerTupleHdr.size, xldata->offnumNew);
/*
* If parent is in this same page, update it now.
*/
if (xldata->parentBlk == 1)
{
SpGistInnerTuple parentTuple;
parentTuple = (SpGistInnerTuple) PageGetItem(page,
PageGetItemId(page, xldata->offnumParent));
spgUpdateNodeLink(parentTuple, xldata->nodeI,
blknoNew, xldata->offnumNew);
}
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
/* Delete old tuple, replacing it with redirect or placeholder tuple */
if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
{
SpGistDeadTuple dt;
page = BufferGetPage(buffer);
if (state.isBuild)
dt = spgFormDeadTuple(&state, SPGIST_PLACEHOLDER,
InvalidBlockNumber,
InvalidOffsetNumber);
else
dt = spgFormDeadTuple(&state, SPGIST_REDIRECT,
blknoNew,
xldata->offnumNew);
PageIndexTupleDelete(page, xldata->offnum);
if (PageAddItem(page, (Item) dt, dt->size,
xldata->offnum,
false, false) != xldata->offnum)
elog(ERROR, "failed to add item of size %u to SPGiST index page",
dt->size);
if (state.isBuild)
SpGistPageGetOpaque(page)->nPlaceholder++;
else
SpGistPageGetOpaque(page)->nRedirection++;
/*
* If parent is in this same page, update it now.
*/
if (xldata->parentBlk == 0)
{
SpGistInnerTuple parentTuple;
parentTuple = (SpGistInnerTuple) PageGetItem(page,
PageGetItemId(page, xldata->offnumParent));
spgUpdateNodeLink(parentTuple, xldata->nodeI,
blknoNew, xldata->offnumNew);
}
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
/*
* Update parent downlink (if we didn't do it as part of the source or
* destination page update already).
*/
if (xldata->parentBlk == 2)
{
if (XLogReadBufferForRedo(record, 2, &buffer) == BLK_NEEDS_REDO)
{
SpGistInnerTuple parentTuple;
page = BufferGetPage(buffer);
parentTuple = (SpGistInnerTuple) PageGetItem(page,
PageGetItemId(page, xldata->offnumParent));
spgUpdateNodeLink(parentTuple, xldata->nodeI,
blknoNew, xldata->offnumNew);
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
}
if (BufferIsValid(buffer))
UnlockReleaseBuffer(buffer);
}
}
}
