Mark Mielke wrote:
On 02/26/2010 03:11 PM, Yeb Havinga wrote:
Or instead of letting users give the distribution, gather it
automatically in some plan statistics catalog? I suspect in most
applications queries stay the same for months and maybe years, so
after some number of iterations it is possible to have decent call
statistics / parameter distributions. Maybe the the parameter value
distribution could even be annotated with actual cached plans.
The problem with the last - actual cached plans - is that it implies
the other aspect I have been suggesting: In order to have a custom
cached plan, the primary model must be to use custom plans. If
PREPARE/EXECUTE uses generic plans normally, than the only cached
plans available will be generic plans.
I should have been clearer, with 'actual cached plans' I meant 'cached
plans planned with actual parameters' or 'cached custom plans'. It makes
no sense to annotate points or intervals in a gathered value
distribution with generic plans.
regards,
Yeb Havinga
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