| From: | Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us> |
|---|---|
| To: | secret <secret(at)kearneydev(dot)com> |
| Cc: | Jan Wieck <jwieck(at)debis(dot)com>, Patrik Kudo <kudo(at)partitur(dot)se>, pgsql-sql(at)postgreSQL(dot)org |
| Subject: | Re: [SQL] Good Optimization |
| Date: | 1999-07-19 14:37:58 |
| Message-ID: | 199907191437.KAA08753@candle.pha.pa.us |
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| Lists: | pgsql-sql |
> Why not let the user select how much time he wants the DB to spend on
> optimization? maybe an explicit "FAST SELECT ..." will skip the costly steps
> for subsecond queries, or "OPTIMIZE SELECT" for the long(hour) queries that
> really need a lot of help :)... Or even a SET OPTION= for turning it on/off?
In most cases, the optimizer knows much better how long to optimize, and
the time it spends is usually very small. Most time is spent in
executor. Pre-6.5 optimizer had problems, so this was not true then.
--
Bruce Momjian | http://www.op.net/~candle
maillist(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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