2011/11/2 Black, Michael (IS) > Then, when you restart the file is on system disk and it is flushing each > insert to system disk on the WAL file slowing things down dramaticalliy. >
I do not use WAL, since I have turned 'journal_mode' off (to improve insert performance), and as far as I know WAL is only usefull when you need to keep a journal? I also have 'synchronous' off, so SQLite shouldn't be waiting for any filesystem flushes. I hoped it was writing all the newly inserted rows to disk using a single operation, as soon as I call 'commit'. But I observed it, and found out its already writing the rows as soon as soon as they are inserted, not batching them for when I call commit. So that could be part of the problem. I don't have a real Windows machine at hand, so I will build one tomorrow, but if your expectations are correct, than it will be even slower than inside a virtual machine, because it will do individiual writes for the 1 million rows too, making performance even worse than it is now. Anothing thing is that I don't expect the slow performance have anything to do with slow disk writes, only with disk reads. I know this because when I make the index UNIQUE, and try to insert 10.000 duplicate rows (which are all ignored), it has the same bad performance, even though there are zero bytes written to disk. So it points in the direction of the reads making it slow, not the writes. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
