Re: wip: functions median and percentile

Hitoshi Harada <umi.tanuki@gmail.com> writes:
> 2010/10/1 Tom Lane <tgl@sss.pgh.pa.us>:
>> If this patch tries to force the entire sort to happen in memory,
>> it is not committable.

> What about array_agg()? Doesn't it exceed memory even if the huge data come in?

Yeah, but for array_agg the user should be expecting a result of
approximately the size of the whole input, so if he overruns memory he
hasn't got a lot of room to complain.  There is no reason for a user to
expect that median or percentile will fall over on large input, and
every reason to expect them to be more robust than that.

			regards, tom lane