| From: | Nikita Glukhov <n(dot)gluhov(at)postgrespro(dot)ru> |
|---|---|
| To: | PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | [BUGFIX] amcanbackward is not checked before building backward index paths |
| Date: | 2018-05-15 14:59:56 |
| Message-ID: | 20c684f7-8160-f669-5adc-3f60ef12230f@postgrespro.ru |
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| Lists: | pgsql-hackers |
Hi hackers!
Experimenting with the new pluggable storage API, I found that amcanbackward
flag is not checked in build_index_paths() before
build_index_pathkeys(... BackwardScanDirection) call when we are building
paths for ORDER BY. And this flag is even not copied into IndexOptInfo struct.
Obviously, this can lead to misuse of Backward Index [Only] Scan plans.
Attached patch with the corresponding fix.
There are no test cases because now only btree supports ordered scans but it
supports backward scans too.
--
Nikita Glukhov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
| Attachment | Content-Type | Size |
|---|---|---|
| 0001-Disable-backward-scans-on-indices-that-do-not-support-it.patch | text/x-patch | 2.3 KB |
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