_______                          .__ .__   .__   .__                 
      \      \    ____   __ __ _______ |__||  |  |  |  |__|  ____    ____  
      /   |   \ _/ __ \ |  |  \\_  __ \|  ||  |  |  |  |  | /  _ \  /    \ 
     /    |    \\  ___/ |  |  / |  | \/|  ||  |__|  |__|  |(  <_> )|   |  \
     \____|__  / \___  >|____/  |__|   |__||____/|____/|__| \____/ |___|  /
    =========\/======\/=================================================\/==
  v0.01 04/JUL/2007 (C) Copyright 2007-2007 Scott D. Yelich SOME RIGHTS RESERVED
 .,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.-*~'`^`'~*-,._.,-*~'`^`'~*-,. 



The software is released under Creative Commons - Attribution 3.0 unported 
see: http://creativecommons.org/licenses/by/3.0/legalcode

You can grab the Makefile to see how I compile the programs with SuSE and
GCC 4.x.  Basically, each program is compiled and linked against sqlite3
with -lsqlite3, etc.

Compile the programs -- then run concurrency to create the database.
Once the database has been created, the lock program can be run either
without a command line parameter so that it uses the default setting
or with a command line parameter that represents how many times a
second to lock and unlock the database.  For instance "lock 1" sets
the maximum of 1/2 a second locked, 1/2 a second unlocked.  It's
possible to run more than one lock program at the same time -- and the
lock program will display how many attempts it took before it obtained
a lock.  For instance, run "lock 1" for maximum lock time and "lock
30" for 15 locks and 15 unlocks a second.  All of these lock times are
much greater than the amount of lock time used by sql and are
therefore good for testing concurrency.

The Xql3 program uses a simple usleep time between tries -- it doesn't
do anything fancy like try more often after more counts, etc.  Also,
the retry count is not even a parameter -- it's hard coded at 200.
Perhaps later versions will allow these values to be
set/configured/passed, if there is a need.


Enjoy!

Scott