attached is the patch split into two parts, as proposed by Simon. 0001 just adds the stuff to relcache, 0002 actually uses it for estimation.

On 04/04/2016 12:03 PM, Amit Langote wrote:
On 2016/04/04 17:25, Simon Riggs wrote:
The rel cache code you're adding uses a flag called "rd_fkeyvalid"
which indicates that the relcache is correctly filled. That is
confusing, since it has nothing to do with the concept of
constraint validity. We should rename that to rd_fkeycachefilled or

Maybe I'm missing something, but is a separate bool required at all
in this case? Wouldn't simply doing the following suffice?

    /* Quick exit if we already computed the list. */
    if (relation->rd_fkeylist)
        return list_copy(relation->rd_fkeylist);

ISTM, rd_fkeyvalid is modeled on rd_indexvalid, where the latter
serves to convey more info than simply whether the index list is
valid or not, so the extra field is justified.

I think you're right. I've copied the logic for indexes, but clearly for foreign keys we don't need this flag. I've removed it.

Also, it seems the patch forgot to update RelationDestroyRelation().

Right. Fixed.


Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Attachment: 0001-add-foreign-key-info-into-relcache.patch
Description: binary/octet-stream

Attachment: 0002-use-fkeys-in-join-estimation.patch
Description: binary/octet-stream

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