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

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