… cause is some batch jobs, reports and other non response time critical activities are overloading the system causing user experience to… problem, might be even not problem with your MySQL configuration, queries and hardware, even though fixing these does help in many… too much in this case throttling by having relatively short queries and introducing “sleeps” between them can be a good idea…
Comment: Too many connections? No problem!
March 15, 2012 By 28 Comments
… default-time-zone=America/Caracas log-slow-queries=/var/log/mysql-slow-queries.log long_query_time=15 log-queries-not-using-indexes query_cache_type=1 query_cache…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… of 40 (InnoDB dataset size ~95G), because the query was taking far too long to execute, ~11 hours in case of MySQL… workload is IO bound, the query time is decreased from ~11min to under a minute. The query time is reduced further when the buffer…, then query times remain under a minute. So when the correct query execution plan is not used, there is no difference in query times between…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
…query blocks any READ queries to execute on the table. mysql> show processlist; +——-+——+———–+———-+————+——+——————————+——————————+———–+—————+———–+ | Id | User | Host | db | Command | Time…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
…and Com_stmt_send_long_data to see whenever sending long data feature is…implicit MEMORY tables which are allocated for query execution, which size can be controlled…: 16384 INDEX_LENGTH: 0 CREATE_TIME: NULL UPDATE_TIME: NULL *************************** 2. row *************************** SESSION_ID: …
Post: Introducing new type of benchmark
February 25, 2012 By 16 Comments
… queries with no pause. That rarely happens in real life. There are no systems that are pushed to 100% load all time… what is important for an end user is response time, that is how long the user has to wait on results. E…, affect a response time of queries that handle user load ? The same for mysqldump, how does it affect short user queries ? In fact…
Comment: Joining many tables in MySQL - optimizer_search_depth
April 23, 2012 By 6 Comments
Peter, The above comment was written long time ago, when I was just hired at MySQL. The assumptions … was to provide a conservative limit that guarantees that any query can be optimized quickly no matter how bad the pruning… in MySQL 5.6. Ideally, the server should analyze the query and should determine the search depth based on some syntactic…
Comment: Introducing new type of benchmark
February 26, 2012 By 16 Comments
… 9x percentile response time performance until you use it against your work load with your dataset with your queries; thats what I… benefit immediately in terms of those incremental schema changes or query changes instead of a tool to gage scaling limitations of… to apples there. I did dick around with proxy a long time ago and recall I ran into some problems under high…
Post: MariaDB 5.3 is released as GA!
March 5, 2012 By 17 Comments
…offer flexibility in schemas Microsecond time resolution for DATETIME and similar time-based types, as well as… faster with the binary log enabled Faster queries through speedier joins, faster subqueries, and elimination … news indeed. MariaDB really has come a long way. I remember that a couple years…
Comment: Innodb Performance Optimization Basics
March 28, 2012 By 70 Comments
Hi, I am facing major issues with slow query output. The tables are in InnoDB with MySQL 5 and … is taking too long and all my transactions are locked. select count(1),field1 from Table where REQUEST_TIME >= ’2012-03-26…
