> My understanding of the shared cache model was that it just ist intended > for solving our problem by relaxing the locking a little and that there > should not be any mutexes at all when using the uncomitted read mode. > > Have I missed anything?
Yes, you are involved in a "magical" thinking. All that you said would be true if any change that SQLite does in the database cache was atomic. I.e. let's say SQLite needs to add a row, zing, and the row is in there and all necessary cache pages are changed without other thread ever noticing any inconsistent state during the process. Also let's say SQLite needs to find some row in the table, zing, and it already knows where that row is and other thread didn't change anything during the search... All this cannot happen, thus mutex is held. BTW, if you just read data then locking cannot be an issue for you. Turn off shared cache and you will be okay. Pavel On Fri, May 6, 2011 at 3:56 PM, Ole Reinhardt <ole.reinha...@embedded-it.de> wrote: > Hi Pavel, > >> >> Any other chance to speed this up (apart from the obvious "optimize the >> >> query, do not use distinct on large tables....)= >> > >> > Without seeing the query or database schema? Not really... Depending >> > on the exact query an index on "xyz" might help. >> >> Another suggestion could be to turn off shared cache mode. > > Oh ok :) > > My understanding of the shared cache model was that it just ist intended > for solving our problem by relaxing the locking a little and that there > should not be any mutexes at all when using the uncomitted read mode. > > Have I missed anything? > > Bye, > > Ole > > -- > > Thermotemp GmbH, Embedded-IT > > Embedded Hard-/ Software and Open Source Development, > Integration and Consulting > > http://www.embedded-it.de > > Geschäftsstelle Siegen - Steinstraße 67 - D-57072 Siegen - > tel +49 (0)271 5513597, +49 (0)271-73681 - fax +49 (0)271 736 97 > > Hauptsitz - Hademarscher Weg 7 - 13503 Berlin > Tel +49 (0)30 4315205 - Fax +49 (0)30 43665002 > Geschäftsführer: Jörg Friedrichs, Ole Reinhardt > Handelsregister Berlin Charlottenburg HRB 45978 UstID DE 156329280 > > _______________________________________________ > 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
