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This is a implementation of the SPRNG library to MySQL.
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README

+-----------------------------------------------------------------------------+
|                    mysql_sprng for MySQL 5.5 and MariaDB                    |
+-----------------------------------------------------------------------------+


This is a implementation of the SPRNG library to MySQL. We are only supporting 
the SIMPLE INTERFACE! I.e. no multiple streams of random numbers per connection.

SPRNG is found at http://www.sprng.org

To install
----------

1) Download the mysql source corresponding to your installed
   version. Building mysql from scratch is recommended.

   Note: ONLY MYSQL VERSION 5.5 AND ABOVE ARE CURRENTLY 
   	 SUPPORTED

2) edit CMakeList.txt accordingly to point to the directory 
   where mysql is installed.

3) edit CMakeList.txt accordingly to point to the directory
   of the mysql sources

4) mkdir build
   cd build

5) cmake ..

6) make

7) make install

8) log into mysql server as root and execute the commands in 
   install_udfs.sql

   This will setup the neccessary tables, install the plugin
   and create all the UDFs needed to administer the queue.

How to use
----------

mysql_sprng supports the following 5 generators:

1) CMRG: Combined Multiple Recursive Generator
2) LCG: 48 Bit Linear Congruential Generator
3) LCG64: 64 Bit Linear Congruential Generator with Prime Added
4) LFG: Modified Lagged Fibonacci Generator
5) MLFG: Multiplicative Lagged Fibonacci Generator

The PMLCG Prime Modulus Linear Congruential Generator is NOT supported by mysql_sprng!

For a detailed description of these generators, please see http://www.sprng.org


The behaviour of mysql_sprng is governed by these system variables:

GLOBAL:
 - sprng_numNode: number of total nodes in your mysql cluster environment
 - sprng_myId:    current id (starting at 0) of a given node

 The global parameters are read only and can only be set at MySQL start in your
 my.cnf file

CONNECTION VARIABLES:
 - sprng_type:   The current SPRNG generator
 - sprng_seed:   The currently used seed
 - sprng_packed: The packed state of the generator (NOT EDITABLE)

 Connection variables can differ from connection to connection. If you cannot set connection
 variables in a parallel environment, overloaded versions of the SPRNG call can be used to
 update these parameters.


Functions:

sprng_dbl():
sprng_dbl(seed):
sprng_dbl(seed, type):

Generate a double random number using the given parameters (stream number, generator type, and seed).
This will generate distinct independant streams of random numbers on each mysql node. By using the 
overloaded versions of the function call, you can update the seed and type. The generator is only 
initialised, if any of these values change, i.e. the connection variables are updated and the generator 
is reinitialised. The final state of the generator is then packed and saved under sprng_packed. This is
needed to retain the state at the last call to the generator.


sprng_int():
sprng_int(seed):
sprng_int(seed, type):

Same as sprng_dbl but returning an integer number.


sprng_make_seed():

Generates a new seed that then needs to be set equally on all nodes. This will generate a random seed
according to the system time and other parameters. Pass this value on to sprng_dbl(seed) or 
sprng_int(seed)

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