Re: Removing SQLite sessions from the default distribution

On Tue, 2003-07-01 at 16:20, George Schlossnagle wrote: > On Tuesday, July 1, 2003, at 03:49 PM, Sterling Hughes wrote: > > You can't look at raw performance on a simple script in terms of req/s, > > but rather percentages. Most scripts are complex, and will have plenty > > of other logic in them. Having a 1/3 performance decrement can add up. > > This is a completely bogus argument. > > a) a 1/3rd slowdown under high load does not imply a 1/3rd slowdown > under low load - in fact your whole argument is that sqlite suffers > from lock contetnion problems which only manifest under high load. > b) a 1/3rd slowdown in a 3 line test does not work out to a 1/3rd > slowdown on a larger application. Your script was tight enough to > closely reflect the slowdown of using sqlite versus files. In longer > running scripts this overhead is propogated as a constant, not linearly. Not really. The slowdown in locking is still there. Its not an across the board slowdown, but with regards to session handling it is a 1/3 slowdown. What percentage of *total* execution time that is, depends on the script. But when you measure things in a general case, you have to measure the inherent slowdown, not in req/s, but in percentages. Percentage slowdown here is 300%, not 150 req/s. Here, the percentages should a 300% slowdown in SQLite when synch support was used. -Sterling > George -- "People can have the Model T in any colour -- so long as it's black." - Henry Ford