…to Galera is existence of a replication feedback mechanism, unlike anything you find in standard async MySQL replication. It is my belief that the…the certification index, which is a hash table. A small fc_limit does however keep the certification index smaller in memory. It keeps the…
Post: Percona Server 5.5.30-30.2 rerelease fixes non-restart issue
April 24, 2013 By Leave a Comment
…index with the same name. Fixed by detecting such cases and omitting the… Bychko). Reduced the overhead from innodb_pass_corrupt_table value checks by …in the MySQL client because the help tables were missing. Bug fixed #1041981 (Alexey Bychko). Fixed the upstream bug #68197 that caused InnoDB to…
Comment: How to recover table structure from InnoDB dictionary
May 8, 2013 By 4 Comments
…check the docs how to do it http://www.percona.com/docs/wiki/innodb-data-recovery-tool:mysql-data-recovery:start . The biggest challenge here is to find index…
Post: Find unused indexes
June 30, 2012 By Leave a Comment
…MySQL we should try another approach. Percona Toolkit has a tool to check the usage of our index from the slow query log. The concept is easy to…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 5 Comments
…index_length) | +——————————-+ | 126984 | +——————————-+ 1 row in set (0.00 sec) You can even go deeper to check which sessions have created which temporary tables (both in memory and not): mysql…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
…the index. In this case you can use trick mentioned in the presentation to convert sort to the union for small ranges. Q: In the…MySQL optimizer restrictions in how well it can deal with primary key appended to the index column, especially in such case as you’re suggesting. In the…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
I have been working with Peter in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are… at. Index Condition Pushdown Traditional B-Tree index lookups have some limitations in cases such as range scans, where index parts after the part on…
Post: Scaling problems still exist in MySQL 5.5 and Percona Server 5.5
May 20, 2011 By 11 Comments
… relevant for your situation. In this example I spotted the query pattern responsible for large portion of the load in the application by aggregating query…,btr_cur_search_to_nth_level,btr_pcur_open_with_no_init_func,row_s earch_for_mysql,ha_innobase::index_read,handler… in this workload and innodb_adaptive_hash_index_partitions=16 available for partitioning adaptive hash index does not help because everything hits the same index…
Post: How to recover deleted rows from an InnoDB Tablespace
February 20, 2012 By 4 Comments
…The index information can also be taken directly from MySQL using the InnoDB Tablespace Monitor. This monitor will write all the…the same result, 0-26 is our primary key. After identifying the Primary Key don’t forget to remove the innodb_table_monitor. C) Check the…
Post: The case for getting rid of duplicate “sets”
May 17, 2011 By 2 Comments
… in set (5.49 sec) Now, what if I structure my data differently? We can “compress” the table in the database by removing the duplicates: mysql… using the “search set” trick above. Also, notice that it takes a long time to delete. There is no index on this table. mysql… | 35417088 | +—–+——————–+ 4 rows in set (39.82 sec) We can also check to see if any two numbers sum to zero: mysql> select a.val…
