diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/nbtree/nbtsearch.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c index d6023732c9b..1608dd49d57 100644 --- a/src/backend/access/nbtree/nbtsearch.c +++ b/src/backend/access/nbtree/nbtsearch.c @@ -862,14 +862,15 @@ _bt_compare(Relation rel, * We need to be clever about the direction of scan, the search * conditions, and the tree ordering. We find the first item (or, * if backwards scan, the last item) in the tree that satisfies the - * qualifications in the scan key. On success exit, the page containing - * the current index tuple is pinned but not locked, and data about - * the matching tuple(s) on the page has been loaded into so->currPos. + * qualifications in the scan key. On success exit, data about the + * matching tuple(s) on the page has been loaded into so->currPos. We'll + * drop all locks and hold onto a pin on page's buffer, except when + * _bt_drop_lock_and_maybe_pin dropped the pin to avoid blocking VACUUM. * scan->xs_heaptid is set to the heap TID of the current tuple, and if * requested, scan->xs_itup points to a copy of the index tuple. * * If there are no matching items in the index, we return false, with no - * pins or locks held. + * pins or locks held. so->currPos will remain invalid. * * Note that scan->keyData[], and the so->keyData[] scankey built from it, * are both search-type scankeys (see nbtree/README for more about this). @@ -1470,6 +1471,8 @@ _bt_next(IndexScanDesc scan, ScanDirection dir) BTScanOpaque so = (BTScanOpaque) scan->opaque; BTScanPosItem *currItem; + Assert(BTScanPosIsValid(so->currPos)); + /* * Advance to next tuple on current page; or if there's no more, try to * step to the next page with data. |