"Todd A. Cook" <tcook@blackducksoftware.com> writes:
> Todd A. Cook wrote:
>> Tom Lane wrote:
>>> If you have time to repeat the experiments, it would be interesting to
>>> see what happens with consistent default_statistics_target across 8.3
>>> and 8.4.
>>
>> That would seem to be it:
>> 8.4b2 183 min 84,028,897,040 on (defaults, default_statistics_target=10)
>>
>> I'll run the test on 8.3.7 with default_statistics_target=100 over the weekend.
> The results for this are also consistent with Tom's theory:
> 8.3.7 205 min 84,048,866,924 on (defaults, default_statistics_target=100)
OK, thanks for following up. So this is a different effect from the
COPY ring buffer size issue being argued about over on pgsql-hackers.
I think we can just say that this one is a price being paid
intentionally for better statistics, and if you don't need better
statistics you can back off the target setting ...
regards, tom lane