Received: from malur.postgresql.org ([2a02:16a8:dc51::56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1fYeKA-0007Ki-P7 for pgsql-hackers@arkaria.postgresql.org; Thu, 28 Jun 2018 21:19:31 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1fYeK9-0004on-8Q for pgsql-hackers@arkaria.postgresql.org; Thu, 28 Jun 2018 21:19:29 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1fYeK8-0004oc-6k for pgsql-hackers@lists.postgresql.org; Thu, 28 Jun 2018 21:19:29 +0000 Received: from out1-smtp.messagingengine.com ([66.111.4.25]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1fYeK5-0007tt-2s for pgsql-hackers@postgresql.org; Thu, 28 Jun 2018 21:19:26 +0000 Received: from compute7.internal (compute7.nyi.internal [10.202.2.47]) by mailout.nyi.internal (Postfix) with ESMTP id 0C57721F21; 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Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180628113035.GA1716@paquier.xyz> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk On 6/28/18 13:30, Michael Paquier wrote: > On Thu, Jun 28, 2018 at 12:37:14PM +0200, Peter Eisentraut wrote: >> I'm thinking, an SQL query might be more efficient if you want to >> qualify the query further. For example, give me all tables in this tree >> that match '2018'. If you wrote your functions as SQL-language >> functions, the optimizer could perhaps inline them and optimize them >> further. > > Are you thinking about SQL functions here? Here is an example of query > able to fetch an entire partition tree. > WITH RECURSIVE partition_info > (relid, > relname, > relsize, > relispartition, > relkind) AS ( > SELECT oid AS relid, > relname, > pg_relation_size(oid) AS relsize, > relispartition, > relkind > FROM pg_catalog.pg_class > WHERE relname = 'your_parent_table_name_here' AND > relkind = 'p' [...] Yes, this kind of thing should be more efficient than building the entire tree in a C function and then filtering it afterwards. -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services