Luke Lonergan wrote:
> Mark,
>
>
>>>Time: 197870.105 ms
>>
>>So 198 seconds is the uncached read time with count (Just for clarity,
>>did you clear the Pg and filesystem caches or unmount / remount the
>>filesystem?)
>
>
> Nope - the longer time is due to the "second write" known issue with
> Postgres - it writes the data to the table, but all of the pages are marked
> dirty? So, always on the first scan after loading they are written again.
> This is clear as you watch vmstat - the pattern on the first seq scan is
> half read / half write.
>
Ah - indeed - first access after a COPY no? I should have thought of
that, sorry!