On Sun, 15 Aug 2004, Tom Lane wrote:
> Ole Tange <[EMAIL PROTECTED]> writes:
> > As I read it the output tells me what was done during the milliseconds:
>
> No, you have a fundamental misconception here. The notation means that
> the first output row from a plan step was delivered after X
> milliseconds, and the last row after Y milliseconds.
Thanks. For a novice tuner like me it would be nice if you could see more
easily where the time was spent. However, the output is _far_ more
intuitive that MySQL's.
> It is gonna take a while to sort 175000 rows ... but possibly increasing
> sort_mem would help.
It didn't. However, I could reformulate the DISTINCT query as a GROUP BY
on all the selected fields and this uses Hash aggregate which is far
faster.
Now I am curious: Why isn't DISTINCT implemented using a Hash aggregate?
/Ole
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TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
