Re: Rethinking representation of sort/hash semantics in queries and plans
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dimitri Fontaine <dimitri@2ndQuadrant.fr>
Cc: pgsql-hackers@postgresql.org
Date: 2010-11-28T21:20:19Z
Lists: pgsql-hackers
Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes: > Tom Lane <tgl@sss.pgh.pa.us> writes: >> So to fix these problems we'd need to replace sort operator OIDs in >> SortGroupClause and plan nodes with those three items. Obviously, this >> would be slightly bulkier, but the extra cost added to copying parse and >> plan trees should be tiny compared to the avoided syscache lookups. > My understanding is that opfamily+datatype gives an opclass. What about > storing the opclass OID there? Then you'd just need to look up the opfamily again. Opclasses are too small a division to be useful. regards, tom lane