…: Can you compare the use of subqueries/multiple joins vs. multiple queries (e.g. temp tables)? For performance, it’s hard to make… there are different types of subqueries (correlated, non-correlated, derived tables, scalar subqueries) and we saw in my presentation that sometimes… were using the tuple syntax to look up values against multiple columns in a compound index, then the order would matter…
Comment: How number of columns affects performance ?
May 25, 2013 By 12 Comments
… be more efficient to have multiple ( 7-10 ) different tables and minimize the record count in each table or would it be faster… types of data and put them all in the same table. The only difference is the data type…all the rest… same. There would be 15 columns of data in the multiple column scenario and 16 if I had to add a…
Post: Choosing a MySQL HA Solution - Post-Webinar Q&A
June 7, 2013 By Leave a Comment
… which will allow you to stripe a TCP connection over multiple ports, and with a two-NIC bonded pair you’ll… replicate a specific database, a set of databases, or specific tables; you can also configure the slave to replicate everything EXCEPT a specified set of databases and tables. With this method, every event is still written to the…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…. It does NOT mean you can’t modify data on multiple cluster nodes simultaneously. You can. It does NOT set an… application. These are maintained in separate tables and there also exists a users_groups table to define the relationship between them. When…_user_id=100 WHERE id=1; COMMIT; How often might multiple users join the same group? Results In both of the…
Comment: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
… main performance win of TokuDB is indexes. If you add multiple multi-column indexes the difference with InnoDB will be even more notable. Also it allows multiple clustering indexes that give additional huge win on selects. We… 3.x and 4.x). It really shines on large tables and index scan like queries.
Post: Follow these basics when migrating to Percona XtraDB Cluster for MySQL
May 1, 2013 By 10 Comments
… May Lead to Inconsistencies and May Not Even Work! MyISAM tables are supported within Percona XtraDB Cluster, however, MyISAM has only… you are planning to write on multiple nodes. Have PRIMARY KEYS If you still have tables without PRIMARY KEYs, then its time… fixed on latest release (5.5.30-23.7.4), table without PK imposes an additional overhead, and because cluster performance…
Comment: Why MySQL Performance at Low Concurrency is Important
March 27, 2013 By 8 Comments
… 8 threads and multiple of them because you are running sysbench with 8 tables and certain number of threads per table if I…
Post: Why MySQL Performance at Low Concurrency is Important
March 27, 2013 By 8 Comments
… offers the best response times (MySQL server does not use multiple threads to execute query in parallel at this point). Response… some use cases. Many database maintenance operations such as “alter table” are run in single-thread too. In fact, chances are… of benchmarks, Mark Callaghan published an example where 8 sysbench tables are used which means the lowest concurrency you can run…
Post: Using Multiple Key Caches for MyISAM Scalability
November 26, 2008 By 8 Comments
… have chosen a way of using Multiple Tables to solve Table Locks problem you can also use multiple Key Caches to reduce or virtually eliminate key cache contention. Too bad you can only map single table to single key cache – it would be so much more helpful if you could use multiple key caches for the same table…
Post: Researching your MySQL table sizes
March 17, 2008 By 28 Comments
… by particular table “type” in sharded environment when multiple tables with same structure and similar name exists: SELECT count(*) tables, concat(round(sum(table_rows… (0.03 sec) Find biggest databases SELECT count(*) tables, table_schema,concat(round(sum(table_rows)/1000000,2),’M') rows, concat(round(sum…
