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Reduced WAL generation for HNSW index builds

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This commit is contained in:
Andrew Kane
2023-12-19 11:49:40 -05:00
parent 921427ee03
commit 5d7bf9509d
5 changed files with 80 additions and 49 deletions
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1
CHANGELOG.md
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@@ -2,6 +2,7 @@
- Improved performance of HNSW
- Added support for on-disk parallel index builds for HNSW
- Reduced WAL generation for HNSW index builds
- Fixed `invalid memory alloc request size` error with HNSW index build
## 0.5.1 (2023-10-10)

4
src/hnsw.h
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@@ -336,8 +336,8 @@ void HnswUpdateMetaPage(Relation index, int updateEntry, HnswElement entryPoint
void HnswSetNeighborTuple(HnswNeighborTuple ntup, HnswElement e, int m);
void HnswAddHeapTid(HnswElement element, ItemPointer heaptid);
void HnswInitNeighbors(HnswElement element, int m);
bool HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_tid, Relation heapRel);
void HnswUpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement e, int m, bool checkExisting);
bool HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_tid, Relation heapRel, bool building);
void HnswUpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement e, int m, bool checkExisting, bool building);
void HnswLoadElementFromTuple(HnswElement element, HnswElementTuple etup, bool loadHeaptids, bool loadVec);
void HnswLoadElement(HnswElement element, float *distance, Datum *q, Relation index, FmgrInfo *procinfo, Oid collation, bool loadVec);
void HnswSetElementTuple(HnswElementTuple etup, HnswElement element);

25
src/hnswbuild.c
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@@ -95,7 +95,7 @@ CreateMetaPage(HnswBuildState * buildstate)
* Add a new page
*/
static void
HnswBuildAppendPage(Relation index, Buffer *buf, Page *page, GenericXLogState **state, ForkNumber forkNum)
HnswBuildAppendPage(Relation index, Buffer *buf, Page *page, ForkNumber forkNum)
{
/* Add a new page */
Buffer newbuf = HnswNewBuffer(index, forkNum);
@@ -104,7 +104,6 @@ HnswBuildAppendPage(Relation index, Buffer *buf, Page *page, GenericXLogState **
HnswPageGetOpaque(*page)->nextblkno = BufferGetBlockNumber(newbuf);
/* Commit */
GenericXLogFinish(*state);
UnlockReleaseBuffer(*buf);
/* Can take a while, so ensure we can interrupt */
@@ -115,8 +114,7 @@ HnswBuildAppendPage(Relation index, Buffer *buf, Page *page, GenericXLogState **
/* Prepare new page */
*buf = newbuf;
*state = GenericXLogStart(index);
*page = GenericXLogRegisterBuffer(*state, *buf, GENERIC_XLOG_FULL_IMAGE);
*page = BufferGetPage(*buf);
HnswInitPage(*buf, *page);
}
@@ -135,7 +133,6 @@ CreateElementPages(HnswBuildState * buildstate)
BlockNumber insertPage;
Buffer buf;
Page page;
GenericXLogState *state;
ListCell *lc;
/* Calculate sizes */
@@ -148,8 +145,7 @@ CreateElementPages(HnswBuildState * buildstate)
/* Prepare first page */
buf = HnswNewBuffer(index, forkNum);
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, GENERIC_XLOG_FULL_IMAGE);
page = BufferGetPage(buf);
HnswInitPage(buf, page);
foreach(lc, buildstate->elements)
@@ -175,7 +171,7 @@ CreateElementPages(HnswBuildState * buildstate)
/* Keep element and neighbors on the same page if possible */
if (PageGetFreeSpace(page) < etupSize || (combinedSize <= maxSize && PageGetFreeSpace(page) < combinedSize))
HnswBuildAppendPage(index, &buf, &page, &state, forkNum);
HnswBuildAppendPage(index, &buf, &page, forkNum);
/* Calculate offsets */
element->blkno = BufferGetBlockNumber(buf);
@@ -199,7 +195,7 @@ CreateElementPages(HnswBuildState * buildstate)
/* Add new page if needed */
if (PageGetFreeSpace(page) < ntupSize)
HnswBuildAppendPage(index, &buf, &page, &state, forkNum);
HnswBuildAppendPage(index, &buf, &page, forkNum);
/* Add placeholder for neighbors */
if (PageAddItem(page, (Item) ntup, ntupSize, InvalidOffsetNumber, false, false) != element->neighborOffno)
@@ -209,7 +205,6 @@ CreateElementPages(HnswBuildState * buildstate)
insertPage = BufferGetBlockNumber(buf);
/* Commit */
GenericXLogFinish(state);
UnlockReleaseBuffer(buf);
HnswUpdateMetaPage(index, HNSW_UPDATE_ENTRY_ALWAYS, buildstate->entryPoint, insertPage, forkNum);
@@ -238,7 +233,6 @@ CreateNeighborPages(HnswBuildState * buildstate)
HnswElement e = lfirst(lc);
Buffer buf;
Page page;
GenericXLogState *state;
Size ntupSize = HNSW_NEIGHBOR_TUPLE_SIZE(e->level, m);
/* Can take a while, so ensure we can interrupt */
@@ -247,8 +241,7 @@ CreateNeighborPages(HnswBuildState * buildstate)
buf = ReadBufferExtended(index, forkNum, e->neighborPage, RBM_NORMAL, NULL);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0);
page = BufferGetPage(buf);
HnswSetNeighborTuple(ntup, e, m);
@@ -256,7 +249,6 @@ CreateNeighborPages(HnswBuildState * buildstate)
elog(ERROR, "failed to add index item to \"%s\"", RelationGetRelationName(index));
/* Commit */
GenericXLogFinish(state);
UnlockReleaseBuffer(buf);
}
@@ -398,7 +390,7 @@ BuildCallback(Relation index, CALLBACK_ITEM_POINTER, Datum *values,
oldCtx = MemoryContextSwitchTo(buildstate->tmpCtx);
if (HnswInsertTuple(buildstate->index, values, isnull, tid, buildstate->heap))
if (HnswInsertTuple(buildstate->index, values, isnull, tid, buildstate->heap, true))
{
if (buildstate->hnswshared)
{
@@ -895,6 +887,9 @@ BuildIndex(Relation heap, Relation index, IndexInfo *indexInfo,
if (!buildstate->flushed)
FlushPages(buildstate);
if (RelationNeedsWAL(index))
log_newpage_range(index, MAIN_FORKNUM, 0, RelationGetNumberOfBlocks(index), true);
FreeBuildState(buildstate);
}

97
src/hnswinsert.c
View File

@@ -92,7 +92,7 @@ HnswFreeOffset(Relation index, Buffer buf, Page page, HnswElement element, Size
* Add a new page
*/
static void
HnswInsertAppendPage(Relation index, Buffer *nbuf, Page *npage, GenericXLogState *state, Page page)
HnswInsertAppendPage(Relation index, Buffer *nbuf, Page *npage, GenericXLogState *state, Page page, bool building)
{
/* Add a new page */
LockRelationForExtension(index, ExclusiveLock);
@@ -100,7 +100,11 @@ HnswInsertAppendPage(Relation index, Buffer *nbuf, Page *npage, GenericXLogState
UnlockRelationForExtension(index, ExclusiveLock);
/* Init new page */
*npage = GenericXLogRegisterBuffer(state, *nbuf, GENERIC_XLOG_FULL_IMAGE);
if (building)
*npage = BufferGetPage(*nbuf);
else
*npage = GenericXLogRegisterBuffer(state, *nbuf, GENERIC_XLOG_FULL_IMAGE);
HnswInitPage(*nbuf, *npage);
/* Update previous buffer */
@@ -111,7 +115,7 @@ HnswInsertAppendPage(Relation index, Buffer *nbuf, Page *npage, GenericXLogState
* Add to element and neighbor pages
*/
static void
WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPage, BlockNumber *updatedInsertPage)
WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPage, BlockNumber *updatedInsertPage, bool building)
{
Buffer buf;
Page page;
@@ -151,8 +155,13 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
buf = ReadBuffer(index, currentPage);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0);
if (building)
page = BufferGetPage(buf);
else
{
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0);
}
/* Keep track of first page where element at level 0 can fit */
if (!BlockNumberIsValid(newInsertPage) && PageGetFreeSpace(page) >= minCombinedSize)
@@ -172,7 +181,12 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
if (HnswFreeOffset(index, buf, page, e, ntupSize, &nbuf, &npage, &freeOffno, &freeNeighborOffno, &newInsertPage))
{
if (nbuf != buf)
npage = GenericXLogRegisterBuffer(state, nbuf, 0);
{
if (building)
npage = BufferGetPage(nbuf);
else
npage = GenericXLogRegisterBuffer(state, nbuf, 0);
}
break;
}
@@ -181,7 +195,7 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
/* Skip if both tuples can fit on the same page */
if (combinedSize > maxSize && PageGetFreeSpace(page) >= etupSize && !BlockNumberIsValid(HnswPageGetOpaque(page)->nextblkno))
{
HnswInsertAppendPage(index, &nbuf, &npage, state, page);
HnswInsertAppendPage(index, &nbuf, &npage, state, page, building);
break;
}
@@ -190,7 +204,8 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
if (BlockNumberIsValid(currentPage))
{
/* Move to next page */
GenericXLogAbort(state);
if (!building)
GenericXLogAbort(state);
UnlockReleaseBuffer(buf);
}
else
@@ -198,22 +213,28 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
Buffer newbuf;
Page newpage;
HnswInsertAppendPage(index, &newbuf, &newpage, state, page);
HnswInsertAppendPage(index, &newbuf, &newpage, state, page, building);
/* Commit */
GenericXLogFinish(state);
if (!building)
GenericXLogFinish(state);
/* Unlock previous buffer */
UnlockReleaseBuffer(buf);
/* Prepare new buffer */
state = GenericXLogStart(index);
buf = newbuf;
page = GenericXLogRegisterBuffer(state, buf, 0);
if (building)
page = BufferGetPage(buf);
else
{
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0);
}
/* Create new page for neighbors if needed */
if (PageGetFreeSpace(page) < combinedSize)
HnswInsertAppendPage(index, &nbuf, &npage, state, page);
HnswInsertAppendPage(index, &nbuf, &npage, state, page, building);
else
{
nbuf = buf;
@@ -267,7 +288,8 @@ WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPag
}
/* Commit */
GenericXLogFinish(state);
if (!building)
GenericXLogFinish(state);
UnlockReleaseBuffer(buf);
if (nbuf != buf)
UnlockReleaseBuffer(nbuf);
@@ -301,7 +323,7 @@ ConnectionExists(HnswElement e, HnswNeighborTuple ntup, int startIdx, int lm)
* Update neighbors
*/
void
HnswUpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement e, int m, bool checkExisting)
HnswUpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement e, int m, bool checkExisting, bool building)
{
for (int lc = e->level; lc >= 0; lc--)
{
@@ -342,8 +364,13 @@ HnswUpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswE
/* Register page */
buf = ReadBuffer(index, hc->element->neighborPage);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0);
if (building)
page = BufferGetPage(buf);
else
{
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0);
}
/* Get tuple */
itemid = PageGetItemId(page, offno);
@@ -385,9 +412,10 @@ HnswUpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswE
elog(ERROR, "failed to add index item to \"%s\"", RelationGetRelationName(index));
/* Commit */
GenericXLogFinish(state);
if (!building)
GenericXLogFinish(state);
}
else
else if (!building)
GenericXLogAbort(state);
UnlockReleaseBuffer(buf);
@@ -399,7 +427,7 @@ HnswUpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswE
* Add a heap TID to an existing element
*/
static bool
HnswAddDuplicate(Relation index, HnswElement element, HnswElement dup)
HnswAddDuplicate(Relation index, HnswElement element, HnswElement dup, bool building)
{
Buffer buf;
Page page;
@@ -412,8 +440,13 @@ HnswAddDuplicate(Relation index, HnswElement element, HnswElement dup)
/* Read page */
buf = ReadBuffer(index, dup->blkno);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0);
if (building)
page = BufferGetPage(buf);
else
{
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0);
}
/* Find space */
itemid = PageGetItemId(page, dup->offno);
@@ -428,7 +461,8 @@ HnswAddDuplicate(Relation index, HnswElement element, HnswElement dup)
/* Either being deleted or we lost our chance to another backend */
if (i == 0 || i == HNSW_HEAPTIDS)
{
GenericXLogAbort(state);
if (!building)
GenericXLogAbort(state);
UnlockReleaseBuffer(buf);
return false;
}
@@ -441,7 +475,8 @@ HnswAddDuplicate(Relation index, HnswElement element, HnswElement dup)
elog(ERROR, "failed to add index item to \"%s\"", RelationGetRelationName(index));
/* Commit */
GenericXLogFinish(state);
if (!building)
GenericXLogFinish(state);
UnlockReleaseBuffer(buf);
return true;
@@ -451,26 +486,26 @@ HnswAddDuplicate(Relation index, HnswElement element, HnswElement dup)
* Write changes to disk
*/
static void
WriteElement(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement element, int m, int efConstruction, HnswElement dup, HnswElement entryPoint)
WriteElement(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement element, int m, int efConstruction, HnswElement dup, HnswElement entryPoint, bool building)
{
BlockNumber newInsertPage = InvalidBlockNumber;
/* Try to add to existing page */
if (dup != NULL)
{
if (HnswAddDuplicate(index, element, dup))
if (HnswAddDuplicate(index, element, dup, building))
return;
}
/* Write element and neighbor tuples */
WriteNewElementPages(index, element, m, GetInsertPage(index), &newInsertPage);
WriteNewElementPages(index, element, m, GetInsertPage(index), &newInsertPage, building);
/* Update insert page if needed */
if (BlockNumberIsValid(newInsertPage))
HnswUpdateMetaPage(index, 0, NULL, newInsertPage, MAIN_FORKNUM);
/* Update neighbors */
HnswUpdateNeighborPages(index, procinfo, collation, element, m, false);
HnswUpdateNeighborPages(index, procinfo, collation, element, m, false, building);
/* Update metapage if needed */
if (entryPoint == NULL || element->level > entryPoint->level)
@@ -481,7 +516,7 @@ WriteElement(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement elem
* Insert a tuple into the index
*/
bool
HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_tid, Relation heapRel)
HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_tid, Relation heapRel, bool building)
{
Datum value;
FmgrInfo *normprocinfo;
@@ -540,7 +575,7 @@ HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_ti
dup = HnswFindDuplicate(element);
/* Write to disk */
WriteElement(index, procinfo, collation, element, m, efConstruction, dup, entryPoint);
WriteElement(index, procinfo, collation, element, m, efConstruction, dup, entryPoint, building);
/* Release lock */
UnlockPage(index, HNSW_UPDATE_LOCK, lockmode);
@@ -574,7 +609,7 @@ hnswinsert(Relation index, Datum *values, bool *isnull, ItemPointer heap_tid,
oldCtx = MemoryContextSwitchTo(insertCtx);
/* Insert tuple */
HnswInsertTuple(index, values, isnull, heap_tid, heap);
HnswInsertTuple(index, values, isnull, heap_tid, heap, false);
/* Delete memory context */
MemoryContextSwitchTo(oldCtx);

2
src/hnswvacuum.c
View File

@@ -230,7 +230,7 @@ RepairGraphElement(HnswVacuumState * vacuumstate, HnswElement element, HnswEleme
UnlockReleaseBuffer(buf);
/* Update neighbors */
HnswUpdateNeighborPages(index, procinfo, collation, element, m, true);
HnswUpdateNeighborPages(index, procinfo, collation, element, m, true, false);
}
/*