… SELECT Query: —TRANSACTION 12303, ACTIVE 26 sec mysql tables in use 2, locked 0 MySQL thread id 53038, OS thread handle 0x7ff759b22700, query id… IS lock IX is rather lose – I can have multiple update queries running on the table each locking it in IX mode… or auto increment table level lock (mostly with MySQL 5.0 and older MySQL versions). MySQL level locks are entirely different story. Explicitly…
Post: Full Text Search Webinar Questions Followup
August 24, 2012 By 5 Comments
… to the MySQL queries would make them even slower, I’m sure. Indeed, the result set of 20 rows from SphinxQL queries is… choosing a solution. David S. asked: Q: If searching on multiple terms, can you get Sphinx to report which matched? The… to import the result of any SQL query, and if you can form a SELECT query that returns the “new” data (for…
Post: Hidden columns of query_review_history table
August 28, 2012 By Leave a Comment
… can use pt-query-digest to process a MySQL slow query log and store historical values for review trend analysis into query_review_history… slow query log from the another server. Having hostname set might be useful for filtering queries in the database aggregating slow queries from multiple…
Post: Load management Techniques for MySQL
May 6, 2012 By 3 Comments
… need to know it is not MySQL problem, might be even not problem with your MySQL configuration, queries and hardware, even though fixing… push concurrency too high Many developers will test script with multiple level of concurrency and find out doing work from 32… too much in this case throttling by having relatively short queries and introducing “sleeps” between them can be a good idea…
Post: Percona MySQL Webinar: Really Large Queries: Advanced Optimization Techniques, Feb. 27
February 18, 2013 By 2 Comments
…caption id=”attachment_12964″ align=”alignright” width=”285″] Really Large Queries: Advanced Optimization Techniques: Wednesday, February 27, 2013 10 a.m… useful when troubleshooting such queries. We will go through case studies (each case study is made from multiple real-world cases). In these cases we were often able to reduce query execution time from 10s…
Post: Innodb performance gotcha w Larger queries.
August 28, 2009 By 7 Comments
… the application and I was replacing single value UPDATE with multiple value REPLACE (though I also saw the same problem with… && trx->mysql_query_str) { /* Scan the MySQL query string; check if SELECT is the first word there */ ibool success; dict_accept(*trx->mysql_query_str, “SELECT…
Post: Wow. My 6 year old MySQL Bug is finally fixed in MySQL 5.6
August 30, 2012 By 2 Comments
… I reported in Early 2006 (while still being with MySQL) and running MySQL 4.1 I honestly thought this issue was fixed… expect “Impossible Where clause” here Lets look at query execution: | Handler_read_next | 1305742982 | mysql> select count(*) from trunc where i=4147483647… across the bug in the real application which would use multiple table and the column type was inconsistent between them… so…
Post: MySQL Upgrade Webinar Questions Followup
June 28, 2012 By 7 Comments
… getting any significant development since MySQL 4.1, so in-place upgrade of MySQL 5.0 to MySQL 5.5 should be rather… of upgrade, you still need to keep into account possible query changes, replication etc. Q: Is it possible to move MyISAM… (including memory) available. Another thing to mention having multiple instances of different MySQL versions on the same box typically means you will…
Post: Multiple column index vs multiple indexes
August 22, 2008 By 13 Comments
… on Multiple Indexes vs Two Column Index efficiency. I mentioned in most cases when query can use both of the ways using multiple… of low cardinality even though MySQL can’t use index well. You’re right MySQL can’t and MySQL does not – Full table… difference large BETWEEN can make. Conclusion: For benchmarked queries we can see Multiple Column index beats Index Merge in all cases when…
Post: What would make MySQL Multiple Queries Usable ?
September 5, 2007 By 1 Comment
MySQL Has API to run Multiple Queries at once. This feature was designed mainly with saving network …. What would make MySQL Multiple Queries API more usable ? Allow to run queries in parallel – The great benefit of knowning all queries at once is… allow to implement it. Optimize query set The other thing you can do when you get multiple queries to execute at once you…
