Emacs offers many functionalities natively; I routinely use it for writing, email, news, chat, programming, web browsing, image viewing, and much more. Sharing the same environment and the same keyboard shortcuts everywhere is good for productivity. However, what if one uses a standalone GTK application such as Chromium or Pidgin …
MySQL Replication Repairing
MySQL replication stopped due to a disk full situation on MySQL server. Here are notes on how I repaired it.
Due to /opt being full on DB master, the replication crashed. Symptoms, on DB slave:
PCUDSSW1513> sudo tail -100 /var/log/mysqld.log 120524 9:43:48 [ERROR] Got fatal …
MySQL Replication Purging
How to purge old unnecessary MySQL binary log files on DB master, after checking replication status.
On DB master (PCUDSSX1501), did:
mysql> SHOW MASTER STATUS; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000075 | 277790 | | | +------------------+----------+--------------+------------------+
On DB slave (PCUDSSW1513), did:
mysql> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 137.138.198.204 …MySQL Replication Setup
Notes on how to set up MySQL replication.
Firstly, stop web application nodes and redirect users to "please come back later" web page.
Secondly, on DB node (PCUDSSX1501), switch on log-bin in /etc/my.cnf if not done yet, then perform in one DB client connection:
mysql> TRUNCATE session; mysql …
MySQL In-Memory Temporary File System
If a MySQL application uses many tables containing TEXT columns, then for various JOIN and GROUP BY operations on these tables, MySQL cannot use in-memory temporary tables and need to resort to using on-disk ones. The in-memory vs on-disk speed difference is considerable in these cases. Introducing a special in-memory …