Perhaps the rowid index cache gets too big? I assume you don't have any indexes of your own?
Does the knee change if you say, double your cache_size? Default should be 2000; pragma cache_size=4000; -----Original Message----- From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Dan Frankowski Sent: Friday, December 28, 2012 3:34 PM To: sqlite-users@sqlite.org Subject: [sqlite] Fwd: Write performance question for 3.7.15 I am running a benchmark of inserting 100 million (100M) items into a table. I am seeing performance I don't understand. Graph: http://imgur.com/hH1Jr. Can anyone explain: 1. Why does write speed (writes/second) slow down dramatically around 28M items? 2. Are there parameters (perhaps related to table size) that would change this write performance? ======================= Create and insert statements: create table if not exists t_foo ( key binary(16) primary key, value binary(16)); insert or replace into t_foo (key, value) values (?, ?) key and value are each 16-byte arrays. I turn auto-commit off and commit every 1000 inserts. I set synchronous mode to OFF and journaling mode to WAL (write-ahead log). I am using sqlite 3.7.15 through the Xerial JDBC driver (see https://bitbucket.org/xerial/sqlite-jdbc). I built it myself, due to a glibc incompatibility (see https://groups.google.com/d/msg/Xerial/F9roGuUjH6c/6RuxqmG6UK4J). I am running on Gentoo. Output of uname -a: Linux mymachine 3.2.1-c42.31 #1 SMP Mon Apr 30 10:55:12 CDT 2012 x86_64 Quad-Core AMD Opteron(tm) Processor 1381 AuthenticAMD GNU/Linux It has 8G of memory. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
