Tag Archives: MySQL

27 May

xtrabackup_51: not found & no ‘mysqld’ group in MySQL options

Recently I happen to setup a new MySQL instance with my tools – a standard MySQL 5.1+, xtrabackup setup and last-hotbackup.tar.gz.

To restore from the backup we used xtrabackup binaries and ran into issues following standard commands (assuming no changes):

To prepare the backup I used apply-log as follows:

$] innobackupex-1.5.1 --defaults-file=/usr/local/mysql/data/backup-my.cnf --apply-log  /usr/local/mysql/data --ibbackup xtrabackup_51

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10 Jan

MySQL variable innodb_flush_method – summarized

innodb_flush_method

innodb_flush_method variable specifies how InnoDB opens and flushes log and data files. In Innodb optimization, setting the variable innodb_flush_method tweaks the performance most of the times but there are cases of otherwise though. If innodb_flush_method is set to O_DIRECT it’d avoid double buffering and reduce swap pressure and helps improving performance.
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17 Dec

Is your backup complete? – backup MySQL users privileges / grants – pt-show-grants

Everybody knows the criticality of backup. You might have had your database dumped, data directory copied, flat files exported and even config and binary log files backed-up. But did you backup your MySQL user privileges?

One can easily forget to backup the user privileges but it is much easier to do and you should backup your MySQL server user privileges / grants regularly.

1. Backup MySQL user privileges using mysqldump:

$] mysqldump -uUSER -pPASS --databases mysql > mysql.sql
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13 Sep

MySQL function returns dates of specified day & between date range

This mysql stored function will return you all the dates between given dates having specified day.
In short if you say: give me all Sundays in this month.

I have following for you:

mysql> select Give_Me_Dates_Days(1,'2012-09-01','2012-10-01') as All_Sundays;
+--------------------------------------------------------+
| All_Sundays |
+--------------------------------------------------------+
| 2012-09-02,2012-09-09,2012-09-16,2012-09-23,2012-09-30 |
+--------------------------------------------------------+

The function parameters are as follows: Give_Me_Dates_Days(DAY_IDENTIFIER,START_DATE,END_DATE)

Sunday = 1 (and rest you can figure-out).
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05 Jul

Generate random test data for MySQL using routines

At times you’ll find yourself responsible for generating test data for newly created tables for testing or sampling purpose. There are tools that will generate random data for you but they’re not free. At-times you’ll write scripts to generate data but those will be table specific.

I hate generating dummy data, yes I do and I assume you do too! I think that’s the major reason I wrote these MySQL functions and procedures for Generating dummy test data.
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-- Kedar Vaijanapurkar --