Thanks for all replays. I did a small test, here are the settings : - FB Super Classic 2.5.1 64 bit - Win7 pro 64 bit - Database size about 640mb - Select something like this : select a.field1, b.field2, sum(c.field3) from table1 a, table2 b, table3 c where .... group by .... - temp directory set to disk - temp cache set to 64mb
Here are the options : 1) Database put on a disk. Page Size 16KB, DefaultDbCache 8192. Execution time is about 1 min. 2) Database put on a RAM. Page Size 4KB, DefaultDbCache 0. (Although DefaultDbCache set to 0, flamerobin indicate the value of Page Buffer = 50) Execution time is about 35 second. 3) Database put on a disk. Page Size 16KB, DefaultDbCache 0. Execution time is more than 2 min. During each test, I reboot the comp. Option 1 consumed 128 MB memory per connection, while option 2 consumed 200KB per connection and 640MB for database file. So, I guess, by having database on RAM (if possible), is the top tweaking possible regarding file I/O. Anto