There are two filesort algorithms in MySQL for sorting and retriving select queries results. 1. Original Filesort Algorithm : This method uses only the ORDER BY columns. (prior to MySQL 4.1) 2. Modified Filesort Alforithm : This method uses ORDER BY columns and the columns which are used in query. (MySQL 4.1 and newer version) … Continue Reading
Monthly Archives: August 2011
Postgres Plus 8.4 vs. MySQL 5.5
Nice comparison by EnterpriseDB. http://get.enterprisedb.com/whitepapers/Postgres_Plus_8.4_vs_MySQL_5.5.pdf Below Topics are included in this comparison. General Comparison Commentary Core Database Features Database Capacities Transaction Programming and Control Query Capabilities Business Intelligence and Data Warehousing Network/Distributed Services Bulk Data Management/Protection Security Features DBA Tools Developer Functionality Scalability Solutions High Availability Solutions Here, Read more [...]
Why server id important in MySQL Replication
Set server id in my.cnf is one of the necessary steps to implement or start replication. The general rule is, server id must be unique across the environment where we are implementing MySQL replication. Generally while implementing multi-master/circular replication, we are setting option –log-slave-updates= 1. so when any statement of master will be executed on … Continue Reading
Perl script for checking user security in MySQL
This script is used to check the user security in MySQL server. Prerequisites: Perl modules : DBI, Getopt::Long and Text::Table Script will check following details from mysql grant tables. # Looks for anonymous user accounts # Looks for accounts accessible from any host # Looks for accounts with empty password # Looks for accounts with … Continue Reading
How to use mysql_upgrade script
There are 2 kind of upgrade is possible in MySQL. Major version upgrade (i.e MySQL 4.1 to MySQL 5.0) Minor version upgrade (i.e MySQL 5.0.45 to MySQL 5.0.47) In the Major version upgrade, people are generally using very common technique which is, taking backup by mysqldump from MySQL 4.1 and reload into MySQL … Continue Reading