Re: Select hangs and there are lots of files in table and index directories.

Tom,

You are correct. The was an infinate loop created because of the
differences in the date math between Oracle and Postgres.

Thank again for your help.
On Mon, Jan 27, 2014 at 7:43 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Peter Blair <petertblair(at)gmail(dot)com> writes:
> > Have a problem where a stored procedure is taking a week to run. The
> > stored procedure should take less than a second to run.
>
> Is that "it's known to terminate if you give it a week", or "we've let
> it run for a week and it shows no sign of ever terminating"?
>
> > In researching a
> > select hanging problem, three things are suggested; an autovacuum
> problem,
> > a resource is locked, or there is something wrong with the stored
> procedure.
>
> I'd bet on the last, given that you're apparently working with an immature
> port from Oracle. The error recovery semantics, in particular, are enough
> different in PL/SQL and PL/pgSQL that it's not too hard to credit having
> accidentally written an infinite loop via careless translation.
>
> > Lastly, in the directories used to store the tables and indexes, there
> are
> > 918896 files in the tables directory and 921291 files in the indexes
> > directory. All of the file names are just numbers (no extensions).
> About
> > 60 files are added to each directory every second. On our test systems
> and
> > at our other customer site, there are only about 50 files in each
> directory.
> > Why are there so many files?
>
> If the filenames are just numbers, then they must be actual tables or
> indexes, not temp files. (You could cross-check that theory by noting
> whether the system catalogs, such as pg_class, are bloating at a
> proportional rate.) I'm guessing that there's some loop in your procedure
> that's creating new temp tables, or maybe even non-temp tables. You would
> not be able to see them via "select * from pg_class" in another session
> because they're not committed yet, but they'd be taking up filesystem
> entries. The loop might or might not be dropping the tables again; IIRC
> the filesystem entries wouldn't get cleaned up till end of transaction
> even if the tables are nominally dropped.
>
> Not much to go on, but I'd look for a loop that includes a CREATE TABLE
> and a BEGIN ... EXCEPT block, and take a close look at the conditions
> under which the EXCEPT allows the loop to continue.
>
> regards, tom lane
>