Bruce Momjian wrote:
>> Maybe I am mixing up separate concepts (are bound variables and prepared
>> statements different concepts?) here. I also do not really understand if
>> that means that oracle does not store a query plan for a prepared query
>> or if it just does some special handling in case it knows that a
>> prepared statement column is known to have a highly varying selectivity
>> per value.
>
> What the Oralce manual means I think is that the plan of the query is
> delayed until the _first_ EXECUTE, so it has some values to use in the
> optimizer. The problem is that later queries might use constants of
> greatly different cardinality.
ok .. which just goes to tell to not use prepared statements for a
column with highly varying selectivity ..?
or is there a realistic shot at fixing this use case?
regards,
Lukas