On Wed, Jan 25, 2012 at 4:01 PM, John Elrick <[email protected]>wrote:
> Much better. I wasn't sure which version to incorporate the changes into > (the link is to the source), so I put them into 3.7.9. > > The total mallocs have dropped to 1.5 million -- twice as high as 3.7.5 but > in line. I'll have to run some additional performance testing but visually > the system appears to be a lot closer to expected. > > What was going on? (My client will want a report on the resolution). > The SQLite byte-code engine was being too conservative and was reparsing the schema in places where it was not strictly necessary. The fix was to restrict the places where the schema was reparsed to situations that really needed it. I cannot give more detail without seeing your application, since I still don't know exactly what you are doing to trigger the excess reparsing. The patch above comes from a script of my own that I finally managed to put together that caused unnecessary schema reparsing. It took a specific combination of events: A schema change inside of a transaction followed by DML statements that had been prepared prior to the schema change. > > On Wed, Jan 25, 2012 at 3:44 PM, Richard Hipp <[email protected]> wrote: > > > On Wed, Jan 25, 2012 at 3:39 PM, Richard Hipp <[email protected]> wrote: > > > > > I'm testing a candidate fix for your problem now. I'll send you a link > > > once the tests finish (assuming they all work). > > > > > > Please try http://www.sqlite.org/src/info/11f68d997d and let me know if > it > > solves your problem. Thanks. > > > > -- > > D. Richard Hipp > > [email protected] > > _______________________________________________ > > sqlite-users mailing list > > [email protected] > > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > > > > > > -- > John Elrick > Fenestra Technologies > 540-868-1377 > _______________________________________________ > sqlite-users mailing list > [email protected] > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp [email protected] _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
