On Thu, Oct 27, 2022 at 10:26 AM Allan Kamau <kamauallan@xxxxxxxxx> wrote:
On Thu, Oct 27, 2022 at 10:20 AM Kristjan Mustkivi <sonicmonkey@xxxxxxxxx> wrote:Dear community,
Right after upgrading our postgres servers from 11.15 to 11.17 we
started to encounter problems with data. Namely, when the query hit
the index, it returned a single row; when the query hit a relation
directly, it returned more than one row. Attempt to REINDEX revealed
the underlying data had duplicates (unique index reindexing failed).
Version facts:
we started out with 11.12
jan 2022 upgraded to 11.14
mar 2022 to 11.15
oct 2022 to 11.17
We are not sure when this corruption actually happened. Could it be
related to the indexing bugs reported in
https://www.postgresql.org/docs/release/11.14/? And the condition only
became known to us after 11.17 rollout which can perhaps be explained
by the following: while 11.17 does not have any outstanding index
related fixes, then https://www.postgresql.org/docs/release/11.15/
mentions fix for index-only scans and so does
https://www.postgresql.org/docs/release/11.16/.
The bottom line is we would like to understand if the index corruption
and its manifestation is explained by the above release fixes or is
there something else that should be investigated further here with the
help from the community.
With best regards,
--
Kristjan Mustkivi
Email: kristjan.mustkivi@xxxxxxxxx
Hi Kristjan,What if you construct a select statement containing the row id and the column which has the problematic index into a new table. Then perform queries on this table to test for uniqueness of the column on which the problematic index was reported.Allan.
How was the data "transfer" between upgrades done? Was it by dump and restore?
If you have the 11.15 instance running having the data, you may do the selection of the row id and the specific column which the index is based into a new table and perform queries on this too to determine uniqueness of the values therein. Likewise do the same for the 11.17 version.
Is it possible to build and install PG 15 from source on a different directory (using --prefix ) then perform pg_dump using the binaries of this installation into a directory. Then configure PG 15 installation to listen on a different TCP/IP port to the one you are currently using with 11.17 instance. Once started, test to see if the index anomaly is present in the PG 15 instance. Alternatively you may use the PG 15 docker image and docker to start a PG 15 docker container for your tests instead of having to build and install PG 15 for this test.
-Allan
