Re: [PORTS] Port Bug Report: Suggestion: Allow users to specify optimizer hints or strategies.

От:

Bruce Momjian <maillist@candle.pha.pa.us>

Дата:

13 апреля 1999 г. в 11:02:13

> 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.

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