Re: why partition pruning doesn't work?

On 16 July 2018 at 12:12, Robert Haas <robertmhaas@gmail.com> wrote:
> On Sun, Jul 15, 2018 at 1:02 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> What we'd be better off doing, if we go this route, is to install an
>> assertion-build-only test that verifies during relation_open(NoLock)
>> that some kind of lock is already held on the rel.  That would protect
>> not only the executor, but a boatload of existing places that open
>> rels with NoLock on the currently-unverified assumption that a lock is
>> already held.
>
> +1.  In fact, maybe we ought to go a little further and have a
> relation_reopen(oid, mode) that verifies that a lock in the specified
> mode is held.

Wouldn't it be better to just store the Relation indexed by its relid
somewhere the first time we opened it? Then just do a direct array
lookup on that rather than looking up by hashtable in syscache?

-- 
 David Rowley                   http://www.2ndQuadrant.com/
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