… cluster section, and it’s important to understand that this tool only currently connections to a single node (by default, localhost… values here can be an indicator that this node is slow to apply replication writesets. Ops Ops are simply replication transactions… control. This is a general indicator that flow control is slowing replication (and hence overall cluster writes) down. snt wsrep_flow…
Post: Realtime stats to pay attention to in Percona XtraDB Cluster and Galera
November 26, 2012 By 4 Comments
Post: How To Test Your Upgrades - pt-upgrade
December 29, 2011 By 7 Comments
… one important step when upgrading your servers. pt-upgrade This tool lets you test your SELECT queries against multiple MySQL servers… pt-table-checksum. Capture your production queries, we recommend either slow query log (use long_query_time = 0) or tcpdump (other… as source of queries # –print simply returns the queries in slow log format and –sample # limits this to 100 queries only…
Post: Percona Server with XtraDB Case Study, Behind the Scenes
October 21, 2010 By 13 Comments
… about diagnosing the problem correctly. I used a variety of tools to help with this, foremost among them “stalk” and “collect…. InnoDB was also dying under mutex contention. Each spike of slow queries I found was caused by different things. Sometimes GDB… are occurring. I used ad-hoc slow-query-log analysis with awk and other tools to discover and investigate unusual patterns, and…
Post: Logging MySQL queries from the client instead of the server
February 2, 2011 By 2 Comments
… that you can’t gather on the server with the slow query log, such as information in the TCP protocol that… the slow-query-log format, so you can analyze it easily with tools such as Maatkit’s mk-query-digest. These tools can…-query-digest. You can even make it print out a “slow query log file” format with the “–print” option.
Post: Percona Toolkit 2.1.8 released today with beta support for MySQL 5.6
January 9, 2013 By Leave a Comment
…: pt-query-digest fails to parse timestamp with no query. Slow logs which include timestamps but no query–which can happen if using slow_query_log_timestamp_always in Percona Server–were misparsed, resulting…. Since MyISAM tables can’t have foreign keys, and the tool uses the information_schema to find child tables, this could…
Post: Three ways that the poor man's profiler can hurt MySQL
December 2, 2011 By 19 Comments
… of using GDB as a profiler has become a key tool in helping us analyze MySQL when customers are having trouble… wrong, and was still trying to determine whether the sudden slowness was due to some cause such as an increase in… others at Facebook and beyond, have developed a variety of tools that can help them get stack traces less intrusively. I…
Post: Recovery after DROP & CREATE
August 22, 2012 By 1 Comment
…_PAGE_INDEX/0-1 LOAD DATA INFILE ‘/root/src/recovery-tool/s_tools/dumps/default/SYS_INDEXES’ REPLACE INTO TABLE `SYS_TABLES… 15 | grep PRIMARY LOAD DATA INFILE ‘/root/src/recovery-tool/s_tools/dumps/default/SYS_INDEXES’ REPLACE INTO TABLE `SYS_INDEXES` FIELDS… drawbacks: It assumes a lot of manual work and thus slow There is no way to differentiate tables based on values…
Comment: How to Identify Bad Queries in MySQL
January 11, 2011 By 16 Comments
… cannot be determined easily. You can get away with a slow system, but when customers start to run away, you’re… running ” is useless to me. What is your definition of slow, bad user experience, too much load? I have done many… gut-feelings. Maatkit’s mk-query-digest is a good tool for this. Can you explain what you mean with : “In…
Post: MySQL Stored Procedures problems and use practices
June 12, 2007 By 21 Comments
… a Language Which is ancient ugly for algorithmic programming and slow. It is also forces you to use a lot of… blocks even before you start fighting with debugging. No Profiling tools If you’re interested in Performance you need a way… of SQL queries – you do not get these logged, instead slow query log will contain full stored procedure calls. On the…
Post: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
… not like solutions proposed by original article ether. PEAR is slow as well as other complex conectors. I have not yet… easily overload methods and get debugging and profiling tools, as well as have tools which protect you from SQL Injections. For example… EXPLAIN for your queries, especially if you see them in slow query log. If you have trouble understanding EXPLAIN or optimizing…
