Re: Tuning/performance issue...

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От Christopher Browne
Тема Re: Tuning/performance issue...
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Msg-id m3ad8hybge.fsf@wolfe.cbbrowne.com
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Ответ на Re: Tuning/performance issue...  (Oleg Lebedev <oleg.lebedev@waterford.org>)
Список pgsql-performance
Centuries ago, Nostradamus foresaw when pgman@candle.pha.pa.us (Bruce Momjian) would write:
> I have updated the FAQ to be:
>
>       In comparison to MySQL or leaner database systems, we are
>       faster for multiple users, complex queries, and a read/write query
>       load.  MySQL is faster for SELECT queries done by a few users.
>
> Is this accurate?  It seems so.

I would think it more accurate if you use the phrase "faster for
simple SELECT queries."

MySQL uses a rule-based optimizer which, when the data fits the rules
well, can pump queries through lickety-split without any appreciable
pause for evaluation (or reflection :-).  That's _quite_ a successful
strategy when users are doing what loosely amounts to evaluating
association tables.

select * from table where key = value;

Which is just like tying a Perl variable to a hash table, and doing
   $value = $TABLE{$key};

In web applications where they wanted something a _little_ more
structured than hash tables, that may 'hit the spot.'

Anything hairier than that gets, of course, hairier.  If you want
something that's TRULY more structured, you may lose a lot of hair
:-).
--
output = reverse("gro.gultn" "@" "enworbbc")
http://www.ntlug.org/~cbbrowne/oses.html
"If you want to talk with some experts about something, go to the bar
where they hang out, buy a round of beers, and they'll surely talk
your ear off, leaving you wiser than before.

If you, a stranger, show up at the bar, walk up to the table, and ask
them to fax you a position paper, they'll tell you to call their
office in the morning and ask for a rate sheet." -- Miguel Cruz

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