Re: Re: equal operator for _int4 (array of int4)
От | Oleg Bartunov |
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Тема | Re: Re: equal operator for _int4 (array of int4) |
Дата | |
Msg-id | Pine.GSO.3.96.SK.1001221194304.19999m-100000@ra обсуждение исходный текст |
Ответ на | Re: equal operator for _int4 (array of int4) (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Re: equal operator for _int4 (array of int4)
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Список | pgsql-hackers |
On Thu, 21 Dec 2000, Tom Lane wrote: > Date: Thu, 21 Dec 2000 11:32:47 -0500 > From: Tom Lane <tgl@sss.pgh.pa.us> > To: Oleg Bartunov <oleg@sai.msu.su> > Cc: pgsql-hackers@postgresql.org > Subject: [HACKERS] Re: equal operator for _int4 (array of int4) > > Oleg Bartunov <oleg@sai.msu.su> writes: > > this call produces core when one of the PointerGetDatum(ev0p->pred) > > or PointerGetDatum(datum) is NULL > > We use internal postgres function for array comparison - > > &giststate->equalFn is references to array_eq > > array_eq is marked strict, so it's not expecting to get a NULL input. > > It's impossible to pass a true SQL NULL through FunctionCall3() anyway > --- no, a null pointer is not an SQL null. So if you want to use > a coding convention that equates null pointer with SQL null, you'll > have to implement that within your own code and avoid calling array_eq > when you have a null. ok. one check isn't difficult to add :-) > > IIRC, the rtree and/or gist index types are fairly sloppy about this > point at the moment. I do not like that, because I do not think an > index type should depend on the assumption that all datatypes it can > handle are pass-by-reference. If you're going to support nulls then > there needs to be a separate isnull flag for each datum, *not* an > assumption that all-zero-bits can't be a valid datum value. But I > didn't get around to changing the code yet. > Tom, this task is too complex for our current understanding of postgres internals. What will happens if we ignore NULLs ? We need to provide vacuum some information about numbers of NULL values. Oleg > regards, tom lane > _____________________________________________________________ Oleg Bartunov, sci.researcher, hostmaster of AstroNet, Sternberg Astronomical Institute, Moscow University (Russia) Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/ phone: +007(095)939-16-83, +007(095)939-23-83
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