Return-Path: X-Original-To: apmail-cassandra-commits-archive@www.apache.org Delivered-To: apmail-cassandra-commits-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 8D41F1191F for ; Tue, 22 Apr 2014 21:32:36 +0000 (UTC) Received: (qmail 39427 invoked by uid 500); 22 Apr 2014 21:32:25 -0000 Delivered-To: apmail-cassandra-commits-archive@cassandra.apache.org Received: (qmail 39401 invoked by uid 500); 22 Apr 2014 21:32:24 -0000 Mailing-List: contact commits-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@cassandra.apache.org Delivered-To: mailing list commits@cassandra.apache.org Received: (qmail 39387 invoked by uid 99); 22 Apr 2014 21:32:24 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 22 Apr 2014 21:32:24 +0000 Date: Tue, 22 Apr 2014 21:32:24 +0000 (UTC) From: "Benedict (JIRA)" To: commits@cassandra.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (CASSANDRA-4175) Reduce memory, disk space, and cpu usage with a column name/id map MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/CASSANDRA-4175?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13977467#comment-13977467 ] Benedict commented on CASSANDRA-4175: ------------------------------------- See also CASSANDRA-6917 - IMO the best solution to this problem is an enum data type, and then to convert all column names to that type. > Reduce memory, disk space, and cpu usage with a column name/id map > ------------------------------------------------------------------ > > Key: CASSANDRA-4175 > URL: https://issues.apache.org/jira/browse/CASSANDRA-4175 > Project: Cassandra > Issue Type: Improvement > Reporter: Jonathan Ellis > Assignee: Jason Brown > Labels: performance > Fix For: 3.0 > > > We spend a lot of memory on column names, both transiently (during reads) and more permanently (in the row cache). Compression mitigates this on disk but not on the heap. > The overhead is significant for typical small column values, e.g., ints. > Even though we intern once we get to the memtable, this affects writes too via very high allocation rates in the young generation, hence more GC activity. > Now that CQL3 provides us some guarantees that column names must be defined before they are inserted, we could create a map of (say) 32-bit int column id, to names, and use that internally right up until we return a resultset to the client. -- This message was sent by Atlassian JIRA (v6.2#6252)