On Wed, Feb 22, 2006 at 01:13:19AM +0200, Ulrich Sch??bel wrote: > I don't think it's an interface problem. I'm using Tcl, more or less > the 'natural' language for sqlite. Tcl doesn't have a garbage > collection.
Tcl certainly *does* have garbage collection: <http://wiki.tcl.tk/3096> <http://wiki.tcl.tk/12144> > The strangest thing is, I can reproduce this behaviour. > I'm absolutely clueless. I stumbled over it by coincidence. > Tried 1000 repetitions, was quite fast, so I tried 10000, > which was even faster. This led me to the (obviously wrong) > conclusion, that sqlite spends some time parsing the sql. > Next I tried 100 repetitions, expecting a bit more than > 76 microseconds. 310 microsecs didn't bother me really, > I tried the 10 reps expecting even more. Then came the surprise: > only 67 microsecs. > > My first feeling was, something like a busy disk or so came > in just when I tried the 100 reps. But the results were reproducible, > deviating only by a few microseconds. Try running the following script and see if there's an odd pattern to the timing variations: #!/usr/bin/env tclsh package require sqlite3 if {[file exists aho.db]} { file delete aho.db } sqlite3 db aho.db db eval {create table cust_persons ( first_name string, last_name string )} db eval {insert into cust_persons values ('Adrian','Ho')} db eval {insert into cust_persons values ('Thunder','Lightning')} foreach rounds {1 5 10 50 100 500 1000 5000 10000} { puts "t($rounds)=[time {db eval {select * from cust_persons where first_name = 'Adrian'}} $rounds]" } db close - Adrian
