Received: from magus.postgresql.org ([87.238.57.229]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TMKTr-0004pd-Sd for pgsql-performance@postgresql.org; Thu, 11 Oct 2012 15:15:24 +0000 Received: from forward13.mail.yandex.net ([2a02:6b8:0:801::3]) by magus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TMKTl-0001Jq-F7 for pgsql-performance@postgresql.org; Thu, 11 Oct 2012 15:15:23 +0000 Received: from web6f.yandex.ru (web6f.yandex.ru [95.108.130.103]) by forward13.mail.yandex.net (Yandex) with ESMTP id 57990142FA9; Thu, 11 Oct 2012 19:15:14 +0400 (MSK) Received: from 127.0.0.1 (localhost.localdomain [127.0.0.1]) by web6f.yandex.ru (Yandex) with ESMTP id ECDC56260037; Thu, 11 Oct 2012 19:15:13 +0400 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1349968514; bh=qgxC6F8NMPP8PMqHshqdfUxdwXRbmeMWMEnUyyB/NlY=; h=From:To:Cc:In-Reply-To:References:Subject:MIME-Version:Message-Id: Date:Content-Transfer-Encoding:Content-Type; b=wwpM0hH4DidBYDnRutxyibqIpcGe5sVtdoqeL31/pQ9Dp9fx7m0rvfVPDu0GPuXMx zrxOI2QBs4Ga/b48QLV46lX5MljPvCxHO29YZjP1ByTGs4nop/MgNnXokl3BKXFHKe dgzI78DUGQMccc2LUU1gqhsg1+LO/AgYGCZGB4rk= Received: from [188.168.10.0] ([188.168.10.0]) by web6f.yandex.ru with HTTP; Thu, 11 Oct 2012 19:15:13 +0400 From: Korisk To: Craig Ringer Cc: Sergey Konoplev , "pgsql-performance@postgresql.org" In-Reply-To: <50764D55.2060401@ringerc.id.au> References: <118871349885342@web16f.yandex.ru> <323831349928808@web5g.yandex.ru> <50764D55.2060401@ringerc.id.au> Subject: Re: hash aggregation MIME-Version: 1.0 Message-Id: <53981349968513@web6f.yandex.ru> Date: Thu, 11 Oct 2012 19:15:13 +0400 X-Mailer: Yamail [ http://yandex.ru ] 5.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain X-Pg-Spam-Score: -2.0 (--) X-Archive-Number: 201210/150 X-Sequence-Number: 48109 "IOS scan" ? Index Only Scan What's your seq_page_cost and random_page_cost? hashes=# SELECT name, setting, reset_val FROM pg_settings WHERE setting <> reset_val; name | setting | reset_val -------------------------+----------------+----------- archive_command | (disabled) | enable_bitmapscan | off | on enable_indexscan | off | on enable_seqscan | off | on log_file_mode | 0600 | 384 random_page_cost | 0.1 | 4 seq_page_cost | 0.1 | 1 transaction_isolation | read committed | default unix_socket_permissions | 0777 | 511 (9 rows) Postgresql 9.2.1 was configured and built with default settings. Thank you.