diff options
| author | Peter Geoghegan | 2020-06-25 17:55:28 +0000 |
|---|---|---|
| committer | Peter Geoghegan | 2020-06-25 17:55:28 +0000 |
| commit | 10f1ab2cb8bea3c6741a78f6dc19a5c91c0a34e1 (patch) | |
| tree | 37a1a8de2bd0d98a2a76341fb5d8a6426d757f0f /src/include | |
| parent | 463b808e757928f053490dd397af77a80b4e7baa (diff) | |
Fix misuse of table_index_fetch_tuple_check().
Commit 0d861bbb, which added deduplication to nbtree, had
_bt_check_unique() pass a TID to table_index_fetch_tuple_check() that
isn't safe to mutate. table_index_fetch_tuple_check()'s tid argument is
modified when the TID in question is not the latest visible tuple in a
hot chain, though this wasn't documented.
To fix, go back to using a local copy of the TID in _bt_check_unique(),
and update comments above table_index_fetch_tuple_check().
Backpatch: 13-, where B-Tree deduplication was introduced.
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/access/tableam.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h index eb18739c365..b3d2a6dd315 100644 --- a/src/include/access/tableam.h +++ b/src/include/access/tableam.h @@ -989,7 +989,9 @@ table_index_fetch_end(struct IndexFetchTableData *scan) /* * Fetches, as part of an index scan, tuple at `tid` into `slot`, after doing * a visibility test according to `snapshot`. If a tuple was found and passed - * the visibility test, returns true, false otherwise. + * the visibility test, returns true, false otherwise. Note that *tid may be + * modified when we return true (see later remarks on multiple row versions + * reachable via a single index entry). * * *call_again needs to be false on the first call to table_index_fetch_tuple() for * a tid. If there potentially is another tuple matching the tid, *call_again |