Re: Some queries starting to hang

Explain analyze could at least put an asterisk around actual time that
deviated by some factor from the estimated time.

On Tue, June 6, 2006 10:39 am, Simon Riggs wrote:

>
> This is a good example of a case where the inefficiency of EXPLAIN
> ANALYZE would be a contributory factor to it not actually being
> available for diagnosing a problem.
>
> Maybe we need something even more drastic than recent proposed changes
> to EXPLAIN ANALYZE?
>
> Perhaps we could annotate the query tree with individual limits. That
> way a node that was expecting to deal with 1 row would simply stop
> executing the EXPLAIN ANALYZE when it hit N times as many rows (default=no
> limit). That way, we would still be able to see a bad plan even without
> waiting for the whole query to execute - just stop at a point where the
> plan is far enough off track. That would give us what we need: pinpoint
> exactly which part of the plan is off-track and see how far off track it
> is. If the limits were configurable, we'd be able to opt for
> faster-but-less-accurate or slower-yet-100% accuracy behaviour. We
> wouldn't need to worry about timing overhead either then.
>
> e.g. EXPLAIN ANALYZE ERRLIMIT 10 SELECT ...
>
> --
> Simon Riggs
> EnterpriseDB http://www.enterprisedb.com
>
>
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