From: "Christian Smith" <[EMAIL PROTECTED]> > There is going to be some performance penalty, but if it's only 1% of your > request time, you'll have complicated your design for very little > performance gain. > > Always perform benchmarks to back up your assumptions. I'm not saying your > assumptions are necessarily wrong, but just that you should back up your > claims before complicating your design to work round a bottleneck which > may not be there.
Thank you for your help, and sorry for my late response. I have taken the benchmarks. The apache module I am writing is an access controller. It queries the SQLite database and send different contents to clients depending on their IP addresses / cookies. When the apache module was configured to issue SQLite queries, the performance decreased for 45% (it took 72.9 seconds, compared to 50.3 secs when the module was configured not to issue any queries). # test details are shown below > There is going to be some performance penalty, but if it's only 1% of your > request time, you'll have complicated your design for very little > performance gain. (snip) > AFAIK, flock() is a kernel operation, and seek() and read() should not > touch the disk if the data blocks required are already cached, and so all > should be relatively cheap operations (against disk IO and network > latencies.) I also tried using on-memory database of SQLite. When doing so, the decrease was 28% (64.2 seconds). This means that the other 27% decrease is caused by I/O operations of SQLite. My target is to minimize the performance penalty to less than 10%. So it seems I have to cache data by myself (to avoid overhead like compilation of SQL statement, etc.) :-( Benchmark Information: Test Platform: OS: FreeBSD/5.2.1 CPU: Pentium III / 750MHz HDD: 40GB x 2 (softupdates on) apache: 2.0.52 SQLite: 3.0.7 (cvs version downloaded on Oct. 4th) Total time for handing 5000 HTTP requests * 5 times: with SQLite queries: 72.943 seconds wo. SQLite queries: 50.299 seconds with SQLite queries to on-memory database: 64.200 seconds The test was performed from a different server connected by fast ethernet. For the test apachebench 1.3d was used. The options supplied to apachebench were: % ab -k -n 5000 -c 20 http://192.168.10.221:82/ The content sent was the default root document of apache2.
