Tom Lane <[EMAIL PROTECTED]> writes:

> > I suppose it makes more sense to optimize this on the basis of what's used 
> > in
> > the planner and executor rather than ALTER TABLE commands though.
> 
> No, definitely not.  Syscaches only exist to support hard-wired lookups
> in the backend C code.  Indexes on system catalogs are of interest to
> the planner, but not syscaches.  (So it is legitimate to have indexes
> with no associated syscache.  The other way is not possible, though,
> because the syscache mechanism depends upon having a matching index.)

I imagine the planner and/or executor have to execute hard-wired lookups in C
code all day long to check for children of tables before they can execute
queries on those tables. I meant that the performance of those lookups was
undoubtedly more critical than the performance of DDL.

-- 
greg


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