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Improved logic for updating HNSW insert page

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This commit is contained in:
Andrew Kane
2023-08-11 13:24:56 -07:00
parent daef83a112
commit ae5de26893
2 changed files with 20 additions and 12 deletions
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28
src/hnswinsert.c
View File

@@ -34,7 +34,7 @@ GetInsertPage(Relation index)
* Check for a free offset * Check for a free offset
*/ */
static bool static bool
HnswFreeOffset(Relation index, Buffer buf, Page page, HnswElement element, Size ntupSize, Buffer *nbuf, Page *npage, OffsetNumber *freeOffno, OffsetNumber *freeNeighborOffno, BlockNumber *firstFreePage) HnswFreeOffset(Relation index, Buffer buf, Page page, HnswElement element, Size ntupSize, Buffer *nbuf, Page *npage, OffsetNumber *freeOffno, OffsetNumber *freeNeighborOffno, BlockNumber *newInsertPage)
{ {
OffsetNumber offno; OffsetNumber offno;
OffsetNumber maxoffno = PageGetMaxOffsetNumber(page); OffsetNumber maxoffno = PageGetMaxOffsetNumber(page);
@@ -49,14 +49,15 @@ HnswFreeOffset(Relation index, Buffer buf, Page page, HnswElement element, Size
if (etup->deleted) if (etup->deleted)
{ {
BlockNumber elementPage = BufferGetBlockNumber(buf);
BlockNumber neighborPage = ItemPointerGetBlockNumber(&etup->neighbortid); BlockNumber neighborPage = ItemPointerGetBlockNumber(&etup->neighbortid);
OffsetNumber neighborOffno = ItemPointerGetOffsetNumber(&etup->neighbortid); OffsetNumber neighborOffno = ItemPointerGetOffsetNumber(&etup->neighbortid);
ItemId itemid; ItemId itemid;
if (!BlockNumberIsValid(*firstFreePage)) if (!BlockNumberIsValid(*newInsertPage))
*firstFreePage = neighborPage; *newInsertPage = elementPage;
if (neighborPage == BufferGetBlockNumber(buf)) if (neighborPage == elementPage)
{ {
*nbuf = buf; *nbuf = buf;
*npage = page; *npage = page;
@@ -110,7 +111,7 @@ HnswInsertAppendPage(Relation index, Buffer *nbuf, Page *npage, GenericXLogState
* Add to element and neighbor pages * Add to element and neighbor pages
*/ */
static void static void
WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPage, BlockNumber *newInsertPage) WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPage, BlockNumber *updatedInsertPage)
{ {
Buffer buf; Buffer buf;
Page page; Page page;
@@ -119,6 +120,7 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
Size ntupSize; Size ntupSize;
Size combinedSize; Size combinedSize;
Size maxSize; Size maxSize;
Size minCombinedSize;
HnswElementTuple etup; HnswElementTuple etup;
BlockNumber originalInsertPage = insertPage; BlockNumber originalInsertPage = insertPage;
int dimensions = e->vec->dim; int dimensions = e->vec->dim;
@@ -127,13 +129,14 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
Page npage; Page npage;
OffsetNumber freeOffno = InvalidOffsetNumber; OffsetNumber freeOffno = InvalidOffsetNumber;
OffsetNumber freeNeighborOffno = InvalidOffsetNumber; OffsetNumber freeNeighborOffno = InvalidOffsetNumber;
BlockNumber firstFreePage = InvalidBlockNumber; BlockNumber newInsertPage = InvalidBlockNumber;
/* Calculate sizes */ /* Calculate sizes */
etupSize = HNSW_ELEMENT_TUPLE_SIZE(dimensions); etupSize = HNSW_ELEMENT_TUPLE_SIZE(dimensions);
ntupSize = HNSW_NEIGHBOR_TUPLE_SIZE(e->level, m); ntupSize = HNSW_NEIGHBOR_TUPLE_SIZE(e->level, m);
combinedSize = etupSize + ntupSize + sizeof(ItemIdData); combinedSize = etupSize + ntupSize + sizeof(ItemIdData);
maxSize = BLCKSZ - MAXALIGN(SizeOfPageHeaderData) - MAXALIGN(sizeof(HnswPageOpaqueData)); maxSize = BLCKSZ - MAXALIGN(SizeOfPageHeaderData) - MAXALIGN(sizeof(HnswPageOpaqueData));
minCombinedSize = etupSize + HNSW_NEIGHBOR_TUPLE_SIZE(0, m) + sizeof(ItemIdData);
/* Prepare element tuple */ /* Prepare element tuple */
etup = palloc0(etupSize); etup = palloc0(etupSize);
@@ -152,6 +155,10 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
state = GenericXLogStart(index); state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0); page = GenericXLogRegisterBuffer(state, buf, 0);
/* Check for size for element at level 0 */
if (!BlockNumberIsValid(newInsertPage) && PageGetFreeSpace(page) >= minCombinedSize)
newInsertPage = insertPage;
/* First, try the fastest path */ /* First, try the fastest path */
/* Space for both tuples on the current page */ /* Space for both tuples on the current page */
/* This can split existing tuples in rare cases */ /* This can split existing tuples in rare cases */
@@ -163,7 +170,7 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
} }
/* Next, try space from a deleted element */ /* Next, try space from a deleted element */
if (HnswFreeOffset(index, buf, page, e, ntupSize, &nbuf, &npage, &freeOffno, &freeNeighborOffno, &firstFreePage)) if (HnswFreeOffset(index, buf, page, e, ntupSize, &nbuf, &npage, &freeOffno, &freeNeighborOffno, &newInsertPage))
{ {
if (nbuf != buf) if (nbuf != buf)
npage = GenericXLogRegisterBuffer(state, nbuf, 0); npage = GenericXLogRegisterBuffer(state, nbuf, 0);
@@ -223,7 +230,8 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
e->blkno = BufferGetBlockNumber(buf); e->blkno = BufferGetBlockNumber(buf);
e->neighborPage = BufferGetBlockNumber(nbuf); e->neighborPage = BufferGetBlockNumber(nbuf);
insertPage = e->neighborPage; if (!BlockNumberIsValid(newInsertPage))
newInsertPage = e->neighborPage;
if (OffsetNumberIsValid(freeOffno)) if (OffsetNumberIsValid(freeOffno))
{ {
@@ -269,8 +277,8 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
UnlockReleaseBuffer(nbuf); UnlockReleaseBuffer(nbuf);
/* Update the insert page */ /* Update the insert page */
if (insertPage != originalInsertPage && (!OffsetNumberIsValid(freeOffno) || firstFreePage == insertPage)) if (BlockNumberIsValid(newInsertPage) && newInsertPage != originalInsertPage)
*newInsertPage = insertPage; *updatedInsertPage = newInsertPage;
} }
/* /*

4
src/hnswvacuum.c
View File

@@ -416,7 +416,7 @@ MarkDeleted(HnswVacuumState * vacuumstate)
{ {
/* Set to first free page */ /* Set to first free page */
if (!BlockNumberIsValid(insertPage)) if (!BlockNumberIsValid(insertPage))
insertPage = ItemPointerGetBlockNumber(&etup->neighbortid); insertPage = blkno;
continue; continue;
} }
@@ -479,7 +479,7 @@ MarkDeleted(HnswVacuumState * vacuumstate)
/* Set to first free page */ /* Set to first free page */
if (!BlockNumberIsValid(insertPage)) if (!BlockNumberIsValid(insertPage))
insertPage = neighborPage; insertPage = blkno;
/* Prepare new xlog */ /* Prepare new xlog */
state = GenericXLogStart(index); state = GenericXLogStart(index);