On 29 Sep 2009, at 10:29pm, Matthew Tippett wrote: > If there is anyone who is interested in assisting in improving the > quality/value/functional interest of the benchmarks, then please > advise.
In SQLite, when you know you are making many changes and don't need to consult the data until you're finished, you surround the changes with BEGIN TRANSACTION and END TRANSACTION. This makes them into one big update rather than lots of little ones, and it means that disk gets updated just once (handwave here) rather than after each command. Naturally, this is hugely faster. No way should 2500 inserts in SQLite take 14 minutes. So much faster that, as Pavel noted upthread, it's suspiciously like what you're seeing in the result for KVM. This suggests that KVM is not really writing results to disk immediately. Putting those INSERTs into one transaction could make Ubuntu 9.10 (not KVM) as fast or faster than the result you're getting for KVM. Sorry, I have no Linux to test it on. You could modify the sqlite test to reflect this. You could perhaps turn sqlite-2500-insertions.txt into 50 transactions, with BEGIN TRANSACTION and END TRANSACTION around each 50 INSERT commands. Or you could have two tests: make two copies of sqlite-2500- insertions.txt, leave one as it is and put BEGIN TRANSACTION and END TRANSACTION at the beginning and end of the other. This would test both 2500 individual INSERT commands and one transaction of 2500 INSERTs, testing SQLite as both kinds of application would need to use it. I know nothing about KVM but I assume that it's operating correctly here: since the entire machine is virtualised it doesn't matter that it's not really writing to real disk. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
