| From: | Mark Kirkwood <mark(dot)kirkwood(at)catalyst(dot)net(dot)nz> |
|---|---|
| To: | Gary Warner <gar(at)cis(dot)uab(dot)edu> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Seq Scan used instead of Index Scan |
| Date: | 2011-11-24 01:30:01 |
| Message-ID: | 4ECD9E19.8080303@catalyst.net.nz |
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| Lists: | pgsql-performance |
Can you post your non-default postgresql.conf settings? (I'd hazard a
guess that you have effective_cache_size set to the default 128MB).
Best wishes
Mark
On 24/11/11 11:24, Gary Warner wrote:
> Very Fast Version:
>
> Recently my database stopped respecting one of my indexes, which took a query that should run in "subsecond response time" and turning it into something that with small data sets runs in the 7-10 minute range and with large data sets runs in the 30 minute - eternity range.
>
> Explain Analyze tells me that what used to be an Index Scan has become a Seq Scan, doing a full table scan through 140 million records.
>
> Any thoughts on why that happens?
>
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