On Mon, 24 Sep 2007 07:13:51 -0700, Gururaja Nittur wrote: >Sqlite experts, > >I am running Sqlite version 3.4.1. I ran some performance tests and >observed that sqlite sometimes consumes more CPU than normal (I am >using same dataset, all inserts and recreating new database for each >test). Tried running oprofiile and got the following result. The >function 'syncJournal' is taking around 60% of total Sqlite's CPU >usage. > > 1. Is this normal behaviour? If not, is there a known fix for this?
Do you use transactions? If not, every INSERT or UPDATE is a separate transaction, causing a lot of overhead because the journal is flushed for every transaction. > 2. Are there any tunables that can be used to ease the issue? Several pragma's are available, the documentation is quite clear: http://www.sqlite.org/pragma.html Also read: http://www.sqlite.org/cvstrac/wiki?p=PerformanceConsiderations >PS: My database is pretty small. >I am setting max_page_count=896 and >page_size = 512 (Max database size = 3.5MB). I don't understand that one. 512 Bytes * 896 Pages would be 458752 Bytes. I think you would need 7168 pages of 512 bytes to accomodate 3.5 MByte. Ideally, the page_size should equal the allocation unit (for Window: the cluster size of the formatted disk). Also, if your rows can be large, a too small page_size would cause overflow pages, and thus additional overhead. >Thanks in advance. I hope this helps. -- ( Kees Nuyt ) c[_] ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
