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Improved concurrent inserts with empty entry point, part 2

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This commit is contained in:
Andrew Kane
2023-08-10 18:31:58 -07:00
parent ed513e62c1
commit 9b967d592f
3 changed files with 100 additions and 48 deletions
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84
src/hnswinsert.c
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@@ -110,7 +110,7 @@ HnswInsertAppendPage(Relation index, Buffer *nbuf, Page *npage, GenericXLogState
* Add to element and neighbor pages
*/
static void
WriteNewElementPages(Relation index, HnswElement e, int m)
WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPage, BlockNumber *newInsertPage)
{
Buffer buf;
Page page;
@@ -119,7 +119,6 @@ WriteNewElementPages(Relation index, HnswElement e, int m)
Size ntupSize;
Size combinedSize;
HnswElementTuple etup;
BlockNumber insertPage = GetInsertPage(index);
BlockNumber originalInsertPage = insertPage;
int dimensions = e->vec->dim;
HnswNeighborTuple ntup;
@@ -266,7 +265,7 @@ WriteNewElementPages(Relation index, HnswElement e, int m)
/* Update the insert page */
if (insertPage != originalInsertPage && (!OffsetNumberIsValid(freeOffno) || firstFreePage == insertPage))
HnswUpdateMetaPage(index, false, NULL, insertPage, MAIN_FORKNUM);
*newInsertPage = insertPage;
}
/*
@@ -350,6 +349,50 @@ UpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswEleme
}
}
/*
* Add the entry point
*/
static bool
HnswAddEntryPoint(Relation index, HnswElement element, int m, HnswElement * entryPoint)
{
Buffer buf;
Page page;
GenericXLogState *state;
HnswMetaPage metap;
BlockNumber newInsertPage = InvalidBlockNumber;
/* Lock the metapage to prevent concurrent inserts */
buf = ReadBuffer(index, HNSW_METAPAGE_BLKNO);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
page = BufferGetPage(buf);
metap = HnswPageGetMeta(page);
/* Check for new entry point after lock is acquired */
if (BlockNumberIsValid(metap->entryBlkno))
{
*entryPoint = HnswInitElementFromBlock(metap->entryBlkno, metap->entryOffno);
UnlockReleaseBuffer(buf);
return false;
}
/* Write element and neighbor tuples */
WriteNewElementPages(index, element, m, metap->insertPage, &newInsertPage);
/* Start WAL */
state = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(state, buf, 0);
/* Update the metapage info */
HnswUpdateMetaPageInfo(page, true, element, newInsertPage);
/* Commit and unlock */
HnswCommitBuffer(buf, state);
return true;
}
/*
* Add a heap TID to an existing element
*/
@@ -406,6 +449,8 @@ HnswAddDuplicate(Relation index, HnswElement element, HnswElement dup)
static void
WriteElement(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement element, int m, int efConstruction, HnswElement dup, HnswElement entryPoint)
{
BlockNumber newInsertPage = InvalidBlockNumber;
/* Try to add to existing page */
if (dup != NULL)
{
@@ -413,25 +458,19 @@ WriteElement(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement elem
return;
}
/* If fails, take this path */
WriteNewElementPages(index, element, m);
/* Write element and neighbor tuples */
WriteNewElementPages(index, element, m, GetInsertPage(index), &newInsertPage);
/* Update insert page if needed */
if (BlockNumberIsValid(newInsertPage))
HnswUpdateMetaPage(index, false, NULL, newInsertPage, MAIN_FORKNUM);
/* Update neighbors */
UpdateNeighborPages(index, procinfo, collation, element, m);
/* Update metapage if needed */
if (entryPoint == NULL || element->level > entryPoint->level)
{
/* TODO Lock metapage for entire block */
HnswElement newEntryPoint = HnswGetEntryPoint(index);
if (entryPoint == NULL && newEntryPoint != NULL)
{
/* Try again with new entry point */
HnswInsertElement(element, newEntryPoint, index, procinfo, collation, m, efConstruction, true);
UpdateNeighborPages(index, procinfo, collation, element, m);
}
else
HnswUpdateMetaPage(index, true, element, InvalidBlockNumber, MAIN_FORKNUM);
}
if (element->level > entryPoint->level)
HnswUpdateMetaPage(index, true, element, InvalidBlockNumber, MAIN_FORKNUM);
}
/*
@@ -469,6 +508,13 @@ HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_ti
/* Get entry point */
entryPoint = HnswGetEntryPoint(index);
/* Special case for no entry point */
if (entryPoint == NULL)
{
if (HnswAddEntryPoint(index, element, m, &entryPoint))
return true;
}
/* Insert element in graph */
HnswInsertElement(element, entryPoint, index, procinfo, collation, m, efConstruction, false);