> Given the various complexities of the optimizer, would there be
> any way of allowing developers to specify strategy, or give
> hints. This is allowed in Dec (now Oracle) RDB, and in some
> fashion in both SQL/Server and Sybase.
> The sorts of things that might be desirable are: which index to
> join on and the order of joining the tables.
> Digital Equipment Corp used to maintain that the optimizer should
> know best, and that developers make more mistakes, and that is
> true. But an experienced DBA, along with details of common
> transactions, can almost always do better than an optimizer.
Usually hand-tuning joins is a symtom of a bad optimizer. Rdb never had
a world-class optimizer, as far as I remember.
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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