"Samuel R. Neff" <[EMAIL PROTECTED]> wrote: > Are there any tools to help analyze the performance of > components with a particular SQLite statement? I'm > aware of the EXPLAIN option which can show what VBDE > code was used to execute a statement, but afaik there > is no way to tell the time each step took. > > Basically I want to know how long the different > components of a single SQL statement took relative > to the whole statement. Provide for more fine-grained > analysis than just comparing two SQL statements based > on total execution time. >
You used to be able to compile with -DVDBE_PROFILE=1 to enable some special assembly-language instructions that would use hi-res timers on ix586 chips to provide the cycle counts needed to execute each instruction in a VDBE program. But I haven't used that feature in years so I don't know if it still works or not. As a general rule of thumb, most VDBE opcodes require about 100 processor cycles (IIRC), except for those that do disk I/O which require around 50,000 cycles. So you could run with "PRAGMA vdbe_trace=ON", count the number of VDBE opcodes executed, multiply by the constants above, and that would give you a good first-order approximation. Another good rule of thumb is that COMMIT is really slow and that everything else is really fast. :-) -- D. Richard Hipp <[EMAIL PROTECTED]> ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
