From: | "Vadim B(dot) Mikheev" <vadim(at)sable(dot)krasnoyarsk(dot)su> |
---|---|
To: | Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us> |
Cc: | hackers(at)postgreSQL(dot)org |
Subject: | Re: [PATCHES] Re: [HACKERS] Query->hasSubLinks is always FALSE... |
Date: | 1998-02-09 16:28:13 |
Message-ID: | 34DF2E9D.2A8B87F4@sable.krasnoyarsk.su |
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Lists: | pgsql-hackers |
Bruce Momjian wrote:
>
> You know, after all our lengthy discussions, this SubLink thing looks
> pretty clean to me.
>
> How are subselects going? Are you having to write a lot of code to get
> it working? I would say after all our discussions and thinking, it took
Mmm ... =~ 1000 lines of code :)
> me about two or three days to do the parser and rewrite for sublinks.
> How many coding days is the rest taking? I am curious.
All was near ready Feb 6, but ... I got problems from canonification
routines in optimizer: 'where A AND B OR C ' becomes 'where (A OR C) AND (B OR C)'
and if C is subselect then ... C has to be processed twice (sometime) ...
I remember your question about handling 'A AND (B OR SubSelect)' - unfortunately,
I didn't see problems here (actually, there is no problem with this
conjunctive normal form :), but there are troubles in common case.
Ideas ?
For the moment I could leave this un-optimized, with possibility
of double subselect processing...
Vadim
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