Re: wip: functions median and percentile
От | Hitoshi Harada |
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Тема | Re: wip: functions median and percentile |
Дата | |
Msg-id | AANLkTikYR9p71=K=6ZktDU0va9StCV2TsuOzS9NDbW45@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: wip: functions median and percentile (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: wip: functions median and percentile
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Список | pgsql-hackers |
2010/10/2 Tom Lane <tgl@sss.pgh.pa.us>: > Hitoshi Harada <umi.tanuki@gmail.com> writes: >> Another suggestion? > > The implementation I would've expected to see is to do the sort and then > have two code paths for retrieving the median, depending on whether the > sort result is all in memory or not. > Hm? The problem we encountered in the middle of the patch is there is no chance to call tuplesort_end if median is called in moving frame window aggregate because final function is called multiple times during moving. The nearest pattern was array_agg() which uses on-memory state and throw its responsibility to clear memory to executor (nodeAgg / nodeWindowAgg). Am I missing something? Regards, -- Hitoshi Harada
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