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Re: Can we expect an enhancement for derived table merge optimization?
Posted by: Rick James
Date: January 14, 2013 09:54AM

Roy, thanks again.

> views are pretty well integrated into the optimizer code by now

When I can stop saying that VIEWs are poorly optimized? That is, what version fixed most of the VIEW code? Most people don't run 5.6 (yet). On these forums, I estimate that nearly half are not up to 5.5 yet, and only a few percent are using 5.6. At my work, we are struggling to get 5.5 deployed. (That's our problem, not Oracle's.)

> If you see deviations between handling of views and base tables, please file bug reports for them.

Sure.

> 5a) ... and choose the least costly plan.

:)

> The WHERE conditions are merged in an early stage of the optimizer
> I think that JOIN conditions are also merged correctly

:)

> and some wrong results with outer joins combined with views in a few circumstances

Do you mean incorrect resultset? Or merely inefficient optimization?

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