Monthly Archives: October 2010

Calculating The Percentage of Max Connections in with MySQL 5.1.9 and higher

For longest time it had bugged me that there wasn’t an easy way to put “SHOW STATUS”, “SHOW VARIABLES”, or “SHOW PROCESSLIST” variables into queries, so I could easily calculate stuff like max connections percentage. Then MySQL 5.1.9 came out and you could final start to do SELECT statements on information_schema.GLOBAL_STATUS, information_schema.SESSION_STATUS, information_schema.GLOBAL_VARIABLES, information_schema.SESSION_VARIABLES and information_schema.PROCESSLIST.

The STATUS and VARIABLES tables have basically two columns VARIABLE_NAME and VARIABLE_VALUE. These correspond with the “SHOW STATUS” and “SHOW VARIABLES” command’s Variable_name and Value. The PROCESSLIST table has all the same columns as the “SHOW PROCESSLIST” command.

So now with that being said here is a quick little query that returns the Max Connection Limit, Connection Count, and Connect Percentage of max allowed connections.

/* requires MySQL 5.1.19 or higher */

SELECT v.VARIABLE_VALUE as “Max Connections”,
s.processcount as “Connection Count”,
((s.processcount/v.VARIABLE_VALUE)*100) as “% of max connections allowed”
FROM information_schema.GLOBAL_VARIABLES v,
(SELECT (@proc_connect:=count(*)) processcount FROM information_schema.PROCESSLIST) s
WHERE v.VARIABLE_NAME = ‘max_connections’;

 

MySQL Functions for Converting IP Address to an Integer and Back Again

So after my MySQL server-id idea. I was asked to come up with a function to Convert IP Address. So here it is.

use test;
DROP FUNCTION IF EXISTS IpToInteger;
DELIMITER //
CREATE FUNCTION IpToInteger ( ipAddress CHAR(15) )
RETURNS INT UNSIGNED
DETERMINISTIC
BEGIN
DECLARE o1,o2,o3,o4 char(3);
DECLARE IpInteger INT UNSIGNED;
SET o1 = REPLACE(SUBSTRING(SUBSTRING_INDEX( ipAddress, ‘.’, 1), LENGTH(SUBSTRING_INDEX( ipAddress, ‘.’, 1 – 1) ) + 1), ‘.’, ” );
SET o2 = REPLACE(SUBSTRING(SUBSTRING_INDEX( ipAddress, ‘.’, 2), LENGTH(SUBSTRING_INDEX( ipAddress, ‘.’, 2 – 1) ) + 1), ‘.’, ” );
SET o3 = REPLACE(SUBSTRING(SUBSTRING_INDEX( ipAddress, ‘.’, 3), LENGTH(SUBSTRING_INDEX( ipAddress, ‘.’, 3 – 1) ) + 1), ‘.’, ” );
SET o4 = REPLACE(SUBSTRING(SUBSTRING_INDEX( ipAddress, ‘.’, 4), LENGTH(SUBSTRING_INDEX( ipAddress, ‘.’, 4 – 1) ) + 1), ‘.’, ” );
SELECT ( o1 << 24 ) + ( o2 << 16 ) + ( o3 << 8 ) + o4 INTO IpInteger;
RETURN IpInteger;
END//
DELIMITER ;

use test;
DROP FUNCTION IF EXISTS IntegerToIp;
DELIMITER //
CREATE FUNCTION IntegerToIp( ipInteger INT UNSIGNED )
RETURNS CHAR(16) DETERMINISTIC
BEGIN
DECLARE o1,o2,o3,o4 INT UNSIGNED;
SET o1 = ( ipInteger >> 24 );
SET o2 = ( ipInteger >> 16 << 16 )-( ipInteger >> 24 << 24) >> 16;
SET o3 = (ipInteger >> 8 << 8 ) – ( ipInteger >> 16 << 16 ) >> 8;
SET o4 = ipInteger – ( ipInteger >> 8 << 8 );
RETURN CONCAT( o1, “.” , o2, “.” , o3, “.”, o4 );
END//
DELIMITER ;

mysql> SELECT IpToInteger ( '10.8.208.30' ); +-------------------------------+ | IpToInteger ( '10.8.208.30' ) | +-------------------------------+ | 168349726 | +-------------------------------+ 1 row in set (0.00 sec) mysql> SELECT IntegerToIp( 168349726 ); +--------------------------+ | IntegerToIp( 168349726 ) | +--------------------------+ | 10.8.208.30 | +--------------------------+ 1 row in set (0.00 sec) mysql>