diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/nbtree/nbtpage.c | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c index 6e65db91eb5..e581ab1cccf 100644 --- a/src/backend/access/nbtree/nbtpage.c +++ b/src/backend/access/nbtree/nbtpage.c @@ -1284,7 +1284,7 @@ _bt_pagedel(Relation rel, Buffer buf) { if (!_bt_unlink_halfdead_page(rel, buf, &rightsib_empty)) { - _bt_relbuf(rel, buf); + /* _bt_unlink_halfdead_page already released buffer */ return ndeleted; } ndeleted++; @@ -1501,6 +1501,11 @@ _bt_mark_page_halfdead(Relation rel, Buffer leafbuf, BTStack stack) * Returns 'false' if the page could not be unlinked (shouldn't happen). * If the (new) right sibling of the page is empty, *rightsib_empty is set * to true. + * + * Must hold pin and lock on leafbuf at entry (read or write doesn't matter). + * On success exit, we'll be holding pin and write lock. On failure exit, + * we'll release both pin and lock before returning (we define it that way + * to avoid having to reacquire a lock we already released). */ static bool _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty) @@ -1543,11 +1548,13 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty) /* * If the leaf page still has a parent pointing to it (or a chain of * parents), we don't unlink the leaf page yet, but the topmost remaining - * parent in the branch. + * parent in the branch. Set 'target' and 'buf' to reference the page + * actually being unlinked. */ if (ItemPointerIsValid(leafhikey)) { target = ItemPointerGetBlockNumber(leafhikey); + Assert(target != leafblkno); /* fetch the block number of the topmost parent's left sibling */ buf = _bt_getbuf(rel, target, BT_READ); @@ -1567,7 +1574,7 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty) target = leafblkno; buf = leafbuf; - leftsib = opaque->btpo_prev; + leftsib = leafleftsib; targetlevel = 0; } @@ -1598,8 +1605,20 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty) _bt_relbuf(rel, lbuf); if (leftsib == P_NONE) { - elog(LOG, "no left sibling (concurrent deletion?) in \"%s\"", + elog(LOG, "no left sibling (concurrent deletion?) of block %u in \"%s\"", + target, RelationGetRelationName(rel)); + if (target != leafblkno) + { + /* we have only a pin on target, but pin+lock on leafbuf */ + ReleaseBuffer(buf); + _bt_relbuf(rel, leafbuf); + } + else + { + /* we have only a pin on leafbuf */ + ReleaseBuffer(leafbuf); + } return false; } lbuf = _bt_getbuf(rel, leftsib, BT_WRITE); |