…lock_wait_timeout because that now conflicts, or is at least confused with, lock_wait_timeout (introduced in MySQL 5.5) for metadata locks…queries on a server. Granted, this can take…query-digest 2.2 has fewer options now. Basically, we re-focused it on its primary objective: analyzing MySQL query…long…
Post: Return of the Query Cache, win a Percona Live ticket
August 26, 2011 By 4 Comments
… scalability problems and locking, but there have been some important changes recently. Let’s take a look at …. As of MySQL 5.5, the query cache mutex isn’t hit at all if query_cache_type is … the early-bird discount (but don’t wait too long: it expires September 18th). Our tutorial schedule is 100…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… may be other ways to get this information, too. The last three commands are for giving me … For an example, take a look at this bug report (not a bug). Looking at MySQL status Now we’…has long-running queries, it can be pretty easy to catch. Maybe they’re long-running because they’re in Locked status…
Post: Slow Query Log analyzes tools
September 6, 2006 By 84 Comments
…queries before queries are executed (and even parsed) so it can’t contain query execution information such as execution and lock…mysql-slow.log | mysql_slow_log_filter -T 0.5 -R 1000″ will look at queries as they come and will print out queries taking…query takes long…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
…query accessed, the length of time query waited for row locks…query logging and set a low enough value for long_query_time. We normally use a value of long_query…queries that you can use to gather more data about the underlying tables involved and the query execution plan used by MySQL…
Post: Working with large data sets in MySQL
July 5, 2007 By 12 Comments
… data sets in mySQL teach you ? Of course you have to learn a lot about query optimization, art… about 500GB table for example – ALTER TABLE make take days or even weeks depending on your storage… simply run ALTER TABLE because table will stay locked for too long you would need to do careful process…
Post: The two even more fundamental performance metrics
May 5, 2011 By 6 Comments
…take about the same time to process and send back the response, with a “long tail” of requests that take…longer. This is common in MySQL servers I work with …queries with longer service times arrive in a clump. If it had stalled due to some lock… post, because it’s too long already. My intention was …
Post: Is your server's performance about to degrade?
May 18, 2010 By 13 Comments
… it won’t be a moment too soon. In the meantime, how …_id: 3329398998 Schema: app_db # Query_time: 0.306486 Lock_time: 0.000000 Rows_sent:…queries, which don’t touch any tables, are all taking almost exactly the same (very long)…and that’s where improvements to the MySQL source code are necessary. But …
Post: Managing Slave Lag with MySQL Replication
October 12, 2007 By 15 Comments
…Locks – MySQL Replication SQL Thread executes queries same as any other thread and it has to grab the locks needed for query…Long Queries – MySQL Replication executes queries one after another on the slave, so if you have query which takes…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
… LOCK can be quite large because of the time it may take … to be blocked too, which among other tools used by mysql client, so…lock priority problem with pending WRITE query blocks any READ queries to execute on the table. mysql… WITH READ LOCK and fail backup or kill long running SELECT queries to let…
