Re: [HACKERS] optimizer and type question
От | Taral |
---|---|
Тема | Re: [HACKERS] optimizer and type question |
Дата | |
Msg-id | 99032217565000.10257@taral.dobiecenter.com обсуждение исходный текст |
Ответ на | optimizer and type question (Erik Riedel <riedel+@CMU.EDU>) |
Список | pgsql-hackers |
On Mon, 22 Mar 1999, you wrote: >Question 1 - is intltsel the right thing for selectivity on dates? I think so... dates are really special integers. >Question 2 - is this right? Is the intent for 0 to serve as a >"wildcard", or should it be inserting an entry for each operation >individually? This looks wrong... but I'm not proficient enough to know. >Question 3 - is there any inherent reason it couldn't get this right? >The statistic is in the table 1992 to 1998, so the '1998-09-02' date >should be 90-some% selectivity, a much better guess than 33%. I would imagine that 33% is a result due to the lack of the statistics match. >OK, so let's say we treat 0 as a "wildcard" and stop checking for >1096. Not we let gethilokey() return the two dates from the statistic >table. The immediate next thing that intltsel() does, near lines 122 >in selfuncs.c is call atol() on the strings from gethilokey(). And >guess what it comes up with? This is ridiculous... why does gethilokey() return a string for a field that is internally stored as an integer? *sigh* Just more questions... Taral
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