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!
