Re: Slow query with a lot of data

From: Moritz Onken <onken(at)houseofdesign(dot)de>
To:
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Slow query with a lot of data
Date: 2008-08-19 11:39:15
Message-ID: 24E3FBFF-E0B8-435E-ACE1-652E93FE2213@houseofdesign.de
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>>
> As far as I can tell, it should. If it is clustered on an index on
> domain, and then analysed, it should no longer have to sort on domain.
>
> Could you post here the results of running:
>
> select * from pg_stats where attname = 'domain';
>

schemaname | tablename | attname | null_frac |
avg_width | n_distinct |
most_common_vals
|
most_common_freqs
|
histogram_bounds
|
correlation

public | result | domain | 0 |
4 | 1642 |
{3491378,3213829,3316634,3013831,3062500,3242775,3290846,3171997,3412018,3454092
} |
{0.352333,0.021,0.01,0.00766667,0.00566667,0.00533333,0.00533333,0.005,0.00266667,0.00266667
} |
{3001780,3031753,3075043,3129688,3176566,3230067,3286784,3341445,3386233,3444374,3491203
} |
1

No idea what that means :)
>>
>
> Sounds like an awfully long time to me. Also, I think restricting it
> to 280 users is probably not making it any faster.

If I hadn't restricted it to 280 users it would have run ~350days...

Thanks for your help!

moritz

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