… rules are processed. There are some informative flowcharts in addition to the textual explanation. Q: What is my recommendation for MySQL 5… the MySQL world, except maybe MyISAM files on top of a clustered filesystem with an external lock manager. You might say that MySQL… mounted, and went to try to install MySQL. It failed miserably on the mysql_install_db process. Every time I tried, I got…
Post: Percona XtraBackup 2.1.0 'release candidate' for MySQL available for download
May 7, 2013 By Leave a Comment
… for the InnoDB Buffer Pool Preloading introduced in MySQL 5.6. Starting with MySQL 5.6 buffer pool dumps can be produced… taken which speeds up the backup process. Bug fixed #1130145. Due to different implementation in MySQL 5.6 error messages were not… FLUSH TABLES WITH READ LOCK even if xtrabackup would fail when copying logs. Fixed by terminating xtrabackup process immediately on log copying…
Post: Percona XtraBackup 2.0.7 for MySQL available for download
May 6, 2013 By 1 Comment
… partial backup is being taken which speeds up the backup process. Bug fixed #1130145. Percona XtraBackup didn’t initialize per-thread… #1166888. Package dependency has been changed from abstract mysql to real /usr/bin/mysql file, because rpm packages from Oracle no longer… FLUSH TABLES WITH READ LOCK even if xtrabackup would fail when copying logs. Fixed by terminating xtrabackup process immediately on log copying…
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
… ? You can take a look at procfs for MySQL process: root@ubuntu:/var/log/mysql# cat /proc/19018/stat 19018 (mysqld) S 1… median # ============ ======= ======= ======= ======= ======= ======= ======= # Exec time 8338s 1us 284s 5ms 13ms 298ms 185us # Lock time 71s 0 3ms 39us 54us 28us 35us # Rows sent…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
… number of MySQL 5.0 and 5.1 installations that would upgrade or are in the process of upgrading to MySQL 5.5, I thought it necessary to discuss what these implications exactly are. To read what Metadata Locking… one. Note that ALTER is a multi-step process, the old table is locked in shared mode and then something similar to…
Post: ACTIVE with Locks – Now thats a problem !
June 2, 2011 By 2 Comments
…, process no 1098, OS thread id 1224980800 3 lock struct(s), heap size 368, 1 row lock(s), undo log entries 1 MySQL thread id 1720, query id 1011283 10.10.10.10 user —TRANSACTION 2 1418397881, ACTIVE 317 sec, process no 1098, OS thread id 1229596992 3 lock struct(s), heap size 368, 1 row lock(s), undo log…
Post: How to Monitor MySQL with Percona's Nagios Plugins
February 22, 2012 By 11 Comments
…a system reboot. The pmp-check-mysql-pidfile plugin verifies that MySQL‘s PID file exists. Evidence … to open or close tables can indicate LOCK_open contention. Replication is delayed or stopped. … is allocating too much memory. A runaway server process, or poorly optimized queries, can consume too …
Post: Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
… by passing around rows instead of sets? From a distributed processing standpoint, rows are the worst case for performance. Optimal mathematical… materialized view that represents the output. There is no external locking or synchronization required. If a query fails on a storage… SQL, but right now only MySQL storage nodes are supported. Amdahl’s law applies to the distributed processing. The results from the…
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
…: sbtest Last_errno: 0 Killed: 0 # Query_time: 9.031233 Lock_time: 0.000086 Rows_sent: 0 Rows_examined: 10000000 Rows… are found and returned up to the top level MySQL part for processing are counted the Rows_examined remains zero. It looks… but because the access type to the tables is “const” MySQL does not count it as access to two tables. In…
Post: MySQL Limitations Part 4: One thread per connection
October 27, 2010 By 14 Comments
… is about the way MySQL handles connections, allocating one thread per connection to the server. MySQL is a single process with multiple threads. Not all databases are architected this way; some have multiple processes that communicate… MySQL 6.0, but is available now in MariaDB. Unfortunately it isn’t a full solution, because it can cause undesirable lock…
