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Commit846cfe0

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Fix obsolete _bt_first comments.
_bt_first doesn't necessarily hold onto a buffer pin on success exit.Fix header comments that claimed that we'll always hold onto a pin.Oversight in commit2ed5b87.
1 parent0d82970 commit846cfe0

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‎src/backend/access/nbtree/nbtsearch.c

Lines changed: 7 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -862,14 +862,15 @@ _bt_compare(Relation rel,
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*We need to be clever about the direction of scan, the search
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*conditions, and the tree ordering. We find the first item (or,
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*if backwards scan, the last item) in the tree that satisfies the
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*qualifications in the scan key. On success exit, the page containing
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*the current index tuple is pinned but not locked, and data about
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*the matching tuple(s) on the page has been loaded into so->currPos.
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*qualifications in the scan key. On success exit, data about the
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*matching tuple(s) on the page has been loaded into so->currPos. We'll
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*drop all locks and hold onto a pin on page's buffer, except when
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*_bt_drop_lock_and_maybe_pin dropped the pin to avoid blocking VACUUM.
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*scan->xs_heaptid is set to the heap TID of the current tuple, and if
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*requested, scan->xs_itup points to a copy of the index tuple.
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*
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* If there are no matching items in the index, we return false, with no
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* pins or locks held.
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* pins or locks held. so->currPos will remain invalid.
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*
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* Note that scan->keyData[], and the so->keyData[] scankey built from it,
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* are both search-type scankeys (see nbtree/README for more about this).
@@ -1470,6 +1471,8 @@ _bt_next(IndexScanDesc scan, ScanDirection dir)
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BTScanOpaqueso= (BTScanOpaque)scan->opaque;
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BTScanPosItem*currItem;
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Assert(BTScanPosIsValid(so->currPos));
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/*
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* Advance to next tuple on current page; or if there's no more, try to
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* step to the next page with data.

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