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Improved locking for HNSW vacuum

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This commit is contained in:
Andrew Kane
2023-08-21 16:12:29 -07:00
parent 782a1051e3
commit 641ddf5413
1 changed files with 21 additions and 0 deletions
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21
src/hnswvacuum.c
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@@ -374,14 +374,32 @@ RepairGraph(HnswVacuumState * vacuumstate)
{ {
HnswElement element = (HnswElement) lfirst(lc2); HnswElement element = (HnswElement) lfirst(lc2);
HnswElement entryPoint; HnswElement entryPoint;
LOCKMODE lockmode = ShareLock;
/* Check if any neighbors point to deleted values */ /* Check if any neighbors point to deleted values */
if (!NeedsUpdated(vacuumstate, element)) if (!NeedsUpdated(vacuumstate, element))
continue; continue;
/* Get a shared lock */
LockPage(index, HNSW_UPDATE_LOCK, lockmode);
/* Refresh entry point for each element */ /* Refresh entry point for each element */
entryPoint = HnswGetEntryPoint(index); entryPoint = HnswGetEntryPoint(index);
/* Prevent concurrent inserts when likely updating entry point */
if (entryPoint == NULL || element->level > entryPoint->level)
{
/* Release shared lock */
UnlockPage(index, HNSW_UPDATE_LOCK, lockmode);
/* Get exclusive lock */
lockmode = ExclusiveLock;
LockPage(index, HNSW_UPDATE_LOCK, lockmode);
/* Get latest entry point after lock is acquired */
entryPoint = HnswGetEntryPoint(index);
}
/* Repair connections */ /* Repair connections */
RepairGraphElement(vacuumstate, element, entryPoint); RepairGraphElement(vacuumstate, element, entryPoint);
@@ -391,6 +409,9 @@ RepairGraph(HnswVacuumState * vacuumstate)
*/ */
if (entryPoint == NULL || element->level > entryPoint->level) if (entryPoint == NULL || element->level > entryPoint->level)
HnswUpdateMetaPage(index, HNSW_UPDATE_ENTRY_GREATER, element, InvalidBlockNumber, MAIN_FORKNUM); HnswUpdateMetaPage(index, HNSW_UPDATE_ENTRY_GREATER, element, InvalidBlockNumber, MAIN_FORKNUM);
/* Release lock */
UnlockPage(index, HNSW_UPDATE_LOCK, lockmode);
} }
/* Reset memory context */ /* Reset memory context */