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Re: Poor Oracle performance? getting rid of bind variables


Le 07-08-21 à 16:07, Wiktor Moskwa a écrit :

Ken Anderson wrote:
According to the DBA, we're using the Rule Based Optimizer, not the Cost
Based Optimizer, so therefore, no statistics. 

Well, RBO is deprecated in 10g and CBO is far superior to it.
It's completely off-topic but I can't understand why one could prefer
RBO to CBO, which is around since release 7.

Speaking of, last week I found out the hard way that you really have to keep your statistics up to date or else everything will be slow. Our test server, where we don't collect statistics at all (so I guess it was using COB), was returning results faster than our production server (even if the prod server is like 4x more powerful).

The reason ? The statistics on the prod server were 10 months old. As a example, a SELECT was taking 4 minutes with the old stats, after a refresh of the stats, the same query would take ... 500 ms. If you do an EXPLAIN on a SELECT and you see some CARTESIAN JOINT, check your table stats !

Now I just have to found where the PL/SQL package to update the stats don't actually update them... _______________________________________________
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References: 
 >Re: Poor Oracle performance? getting rid of bind variables (From: Ken Anderson <email@hidden>)
 >Re: Poor Oracle performance? getting rid of bind variables (From: Wiktor Moskwa <email@hidden>)
 >Re: Poor Oracle performance? getting rid of bind variables (From: Ken Anderson <email@hidden>)
 >Re: Poor Oracle performance? getting rid of bind variables (From: Wiktor Moskwa <email@hidden>)
 >Re: Poor Oracle performance? getting rid of bind variables (From: Guido Neitzer <email@hidden>)
 >Re: Poor Oracle performance? getting rid of bind variables (From: Wiktor Moskwa <email@hidden>)
 >Re: Poor Oracle performance? getting rid of bind variables (From: Ken Anderson <email@hidden>)
 >Re: Poor Oracle performance? getting rid of bind variables (From: Wiktor Moskwa <email@hidden>)



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