Re: BUG #6629: Creating a gist index fails with "too many LWLocks taken"

On Fri, May 11, 2012 at 10:19 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> writes:
>> On 11.05.2012 16:52, Tom Lane wrote:
>>> IMO, no part of the system should ever get within an order of magnitude
>>> of holding 100 LWLocks concurrently.
>
>> I agree we should never get anywhere near that limit. But if we do -
>> because of another bug like this one - it would be nice if it was just
>> an ERROR, instead of a PANIC.
>
> By the time you hit that limit, you have already got a problem that
> should never have gotten into the field, I think.  Simon's idea of
> logging a warning once we get beyond a sane number of LWLocks seems like
> it might be helpful towards finding such problems earlier; though I'd
> put the "sane" limit at maybe 20 or so.

+1.

> Perhaps it'd be useful to
> measure what the max length of that list is during the regression tests.

Yeah.

And maybe any build with --enable-cassert should also emit WARNINGs
when we go past whatever we determine the same limit to be.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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