On 21 Aug 2009, at 3:26am, pierr wrote: > I did not know the sequence in defining the field matters. This is > what I should have done.
Sorry, I should have explained better. You were right: there is no difference. I was just rearranging the fields in the classic way: with the primary key column as the first column. It helps me think about how the database works. You did nothing wrong. >> Whichever one of these is at fault, a delete command selecting on an >> indexed column and deleting 90000 records from a five column table >> should not take 17 seconds. > > I am sorry, I should have mentioned It (17 seconds to delete 90000) > was > tested on a 350M MIPS CPU. And after changing to the schema you > suggested, > it still take 17 seconds to delete 90000 records. > On my 1.8G Hz Ubuntu desktop it tooks 800ms. So is this delete > performance > is the limit we can achieve? Any other options I can improve this? Ah. Okay, less than 1 second is reasonable for a standard computer. If your code performs at this speed then there's no evidence of any problem with your code. > BTW: I used following option to build the libarary. Is there any > thing I > can expore here? (-O2 and -Os seem has no big difference on > performance.) > mips24k-linux-gcc -Os -fPIC -c *.c > mips24k-linux-gcc -shared -o mips_libsqlite3.so.1 sqlite3.o Putting these together, your 350 MIPS CPU machine is a MIPS 24K machine. There are various things to consider: not only CPU speed but also memory bandwidth, memory speed, hard disk throughput, and other things I have no idea about. And I have no idea what part threading would pay on such a platform. Sorry but I have no experience with these. Perhaps someone else here does. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
