Re: weird empty return from select problem; periodically get no data returned - could it be a network issue?

Please reply to the list, not just to me. "reply all" or (in smarter
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I've cc'd the list.

On 10/07/10 00:15, Susan Cassidy wrote:
> I didn't set up the cluster (just started working here a few months ago), so I don't know for sure. A comment in one of the scripts in the bin directory for the pg_* cluster commands says something about the postgresql-common package. This is Debian 4.0 (etch). dpkg -l has a line with:
> postgresql-common 91 PostgreSQL database-cluster manager

Oh, you're probably not using clustering at all, then, just being thrown
by the terminology.

PostgreSQL uses the term "cluster" to refer to a group of databases
managed by a postmaster. The chosen terminology is becoming increasingly
confusing as real clustering increases in prevalence.

It'd still be helpful to confirm that it's just a vanilla install of
PostgreSQL from debian packages on etch, as it sounds like.

As for the empty row sets ... in your position, I'd be increasing my
tracing/logging levels both on the database backend and in the dbi
driver, then trying to match up empty row return incidents with those
trace logs. When you can't reproduce a problem on demand tracing is
often the only option unless you can figure it out with the information
at hand.

I'd also want to verify that my indexes were in good condition, as a
damaged index can cause all sorts of wacky results. They shouldn't
happen, but in reality have been known to whether due to
hardware/filesystem issues or the occasional PostgreSQL bug. The easiest
way to make sure your indexes are good - if you can schedule some
downtime - is to REINDEX. If you can't, there are other alternatives.

--
Craig Ringer