Hi, On Wed, Oct 27, 2021 at 2:12 PM Jayadevan M <maymala.jayade...@gmail.com> wrote: > > We moved our PostgreSQL database from one hosting provider to another using > pgbackrest. In the new environment, some comparison operations were > failing. The issue was fixed by running an update. But I am trying to find > out what would have happened. > > select * from accounts where email = 'someem...@gmail.com'; -- failed for > some email ids even though there were records. > > select * from accounts where lower(trim(email)) <> email; -- fetched no > records. > > select * from accounts where email::bytea = 'someem...@gmail.com'::bytea; - > worked for those records where comparison was failing. > > update accounts set email = trim(lower(email)); -- fixed the issue. > > Source database was PG 13.2, target 13.3. > > Any suggestions will be appreciated - not sure if other tables/columns are > affected.
Most likely you had a different version of the glibc or ICU libraries on the new system, which lead to your indexes on collatable datatypes partially corrupted. See https://wiki.postgresql.org/wiki/Collations for more details. You can issue a REINDEX for each impacted index, or a database-wide REINDEX.
