Re: BUG #16849: index and table data inconsistency

PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> I have data in a varchar field like '092', '00000000169', '0000001' and so
> on. There is a btree index on this field. my searches are similar to below
> ones.
> select searched_field from searched_table where searched_field = '092';

> When I search data, it uses the given index and returns no value. But when I
> disable index scan, it does a sequential scan and return data.

> We have witnessed this case in one index in our production(11.7) and
> staging(12.2) environments on same index. Then we dropped the index and
> recreate it. The problem is solved. But, to me, index and data must be
> consistent.

Most likely you got bit by an operating-system locale change causing
a change in sort order and thereby making the index self-inconsistent.
See

https://wiki.postgresql.org/wiki/Locale_data_changes

There's work afoot to have Postgres automatically notice when the
OS changes underneath it, but that's not done yet.

regards, tom lane