Re: Database corruption using 7.4.1

"Florian G. Pflug" <fgp@phlo.org> writes:
> ... I upgraded to 7.4.2, and fixed the system-tables
> according to the 7.4.2 release-note. But this didn't really help - the
> "analyze table" issued after fixing the system-tables exited with an
> error about an invalid page header in one of our tables. Dumping the
> database was also impossible at that stage - some tables would cause pg_dump
> to either abort, or to silently block (we had it running for about 10
> minutes, and it didn't output a single line in that time).

> Since that 7.4.2 release-note only talked about crashing queries due to the
> 7.4.1 bug, but not about data-corruption occuring, I wondered if the
> symptoms I have seen are related to the alignment bug in 7.4.1 or not.

No, I don't think so.  The alignment bug could cause the planner to
crash while retrieving statistics about a table, but it would not have
any effect on fetching the data in a table.  In particular I don't
believe it could have any effect at all on a COPY command, which is what
I think you are saying was failing?

> I finally fixed the problem by dumping all relevant tables "by hand", and
> restoring them into a clean install of 7.4.2.

How exactly did you do the "by hand" dump?

            regards, tom lane