Re: 7.1.2: Backend message type 0x44 when selecting from a table

Lincoln Yeoh <lyeoh(at)pop(dot)jaring(dot)my> writes:
> Trying to pg_dump the table gives me this:
> <snipped>
> ERROR: MemoryContextAlloc: invalid request size 1163153238
> PQendcopy: resetting connection

This looks like a corrupted-data problem ...

> I've truncated the table and it runs ok now.

... but the evidence is now gone, so we can't really probe into it
further :-(. You might be well advised to run some hardware diagnostics
to see if you have any RAM problems, flaky disk controllers, that sort
of thing. Not that Postgres has no bugs, of course, but we've seen
quite a number of data-corruption reports that ultimately traced to
hardware problems.

The behavior during a SELECT seems odd also:

> SELECT * from arch_ranks_arch4 ;
> Backend message type 0x44 arrived while idle
> pqReadData() -- backend closed the channel unexpectedly.

This suggests that libpq and the backend got out of sync somehow,
but I thought we'd fixed that class of problems years ago. If you
can reproduce this it'd be worth looking into.

regards, tom lane