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MySQL related posts.
Recently I found the following script pretty handy for calculating the maximum amount of memory mysql could use, based on the current buffers configuration. This is the source: #!/bin/sh# you might want to add some user authentication here mysql -e “show variables; show status” | awk ‘ { VAR[$1]=$2 } END { MAX_CONN =… Continue reading Calculate Maximum MySQL Memory Usage
Stored Procedures in MySQL are the typical primer for great ideas and bad implementation. Even that I have stored procedures, because of their performance penalties, recently I had to write one. The procedure itself was very simple, but there were some catchy stages I would like to describe in case I need to write such… Continue reading MySQL – Creating stored procedures
There was a very handful tool for checking on mysql performance – mysqlreport. The tool was available for download from here: http://hackmysql.com/mysqlreport Currently the site and the development process of mysqlreport is suspended in flavor of Percona Toolkit. Despite this, the author has uploaded the latest versions of mysqlreport in his github account. … Continue reading mysqlreport – Missing download
Here I will write down some frequently used SQL examples , which I happen to search for again and again. SELECT records from date column before or after a given DAYS Select all records from a table “some_table” from MORE THAN 30 DAYS select some_field from some_table where some_date <= ( CURDATE() – INTERVAL 30… Continue reading SQL Queries – Cheat Sheat
Some background… Recently we’ve made some migrations from Percona MySQL Server 5.1 to MySQL 5.5. It seems that Percona MySQL Server, have additional collations, which if used will cause problems after migrating to pure MySQL. In my case the problematic collation was: utf8_general50_ci –> Corresponding to id #253 in MySQL collations After the migration,… Continue reading MySQL – ERROR 1273 (HY000): Unknown collation ‘#253’ in table ‘some-table’ definition