From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | chris(at)bitmead(dot)com |
Cc: | Don Baccus <dhogaza(at)pacifier(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgreSQL(dot)org, pgsql-sql(at)postgreSQL(dot)org |
Subject: | Re: [HACKERS] Re: [SQL] Proposed Changes to PostgreSQL |
Date: | 2000-02-03 12:09:18 |
Message-ID: | 200002031209.HAA20081@candle.pha.pa.us |
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Thread: | |
Lists: | pgsql-general pgsql-hackers pgsql-sql |
> Don Baccus wrote:
> >
> > At 09:55 PM 2/2/00 -0500, Tom Lane wrote:
> >
> > >There is also a nontrivial performance penalty that would be paid
> > >for reversing this default, because then every ordinary SQL query
> > >would suffer the overhead of looking to see whether there are
> > >child tables for each table named in the query. That *really*
> > >doesn't strike me as a good idea.
> >
> > Thank you for pointing this out, because my first reaction to
> > the proposal was "what's the overhead for SQL users"?
>
>
> I just did a performance check on this. I found that the overhead
> is one tenth of a millisecond on a Sun desktop workstation. Pretty
> trivial, and I'm sure it can be improved.
Good point. Has to be non-mearurable performance penalty because most
people don't use it. Maybe you will need a system cache entry for this.
--
Bruce Momjian | http://www.op.net/~candle
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
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