diff options
Diffstat (limited to 'src/backend/access/heap/heapam.c')
| -rw-r--r-- | src/backend/access/heap/heapam.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 9cbc161d7a9..03d4abc938b 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -635,8 +635,15 @@ heapgettup(HeapScanDesc scan, } else { + /* + * The previous returned tuple may have been vacuumed since the + * previous scan when we use a non-MVCC snapshot, so we must + * re-establish the lineoff <= PageGetMaxOffsetNumber(dp) + * invariant + */ lineoff = /* previous offnum */ - OffsetNumberPrev(ItemPointerGetOffsetNumber(&(tuple->t_self))); + Min(lines, + OffsetNumberPrev(ItemPointerGetOffsetNumber(&(tuple->t_self)))); } /* page and lineoff now reference the physically previous tid */ @@ -678,6 +685,13 @@ heapgettup(HeapScanDesc scan, lpp = PageGetItemId(dp, lineoff); for (;;) { + /* + * Only continue scanning the page while we have lines left. + * + * Note that this protects us from accessing line pointers past + * PageGetMaxOffsetNumber(); both for forward scans when we resume the + * table scan, and for when we start scanning a new page. + */ while (linesleft > 0) { if (ItemIdIsNormal(lpp)) @@ -8556,10 +8570,8 @@ heap_xlog_vacuum(XLogReaderState *record) ItemIdSetUnused(lp); } - /* - * Update the page's hint bit about whether it has free pointers - */ - PageSetHasFreeLinePointers(page); + /* Attempt to truncate line pointer array now */ + PageTruncateLinePointerArray(page); PageSetLSN(page, lsn); MarkBufferDirty(buffer); |