Re: DROP INHERITS

From: Greg Stark <gsstark(at)mit(dot)edu>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Greg Stark <gsstark(at)mit(dot)edu>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: DROP INHERITS
Date: 2006-06-07 05:11:08
Message-ID: 87ejy17doz.fsf@stark.xeocode.com
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Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> 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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