…Query. Each image comes pre-loaded with the data used in the previous Shard-Query blog post. The data in the…in the system. To get an even distribution, the test data was hashed over the values in the date_id column. There will be another blog post about the…
Post: Intro to OLAP
July 12, 2010 By 10 Comments
…the amount of time that it takes to keep the tables updated and in the complexity of the many scripts or jobs which might be necessary to keep the tables in…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
…to get the results you want, but more quickly. More on this later. SQL features used in the query Incremental refresh doesn’t support all of the…gets a special column `mview$pk` which is an auto_increment BIGINT surrogate key for the table…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
…in the table above shows the Count of number of times this query was executed. Now let’s take a look at the values in the 95% column…the query, by using a LIMIT clause or by filtering based on the option_name column, or you might even compress the values stored in the option_value column…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
…the old entries in the Table Cache have to be invalidated, and any query that accesses the table will have to reopen the modified table and there will be new entries in the Table…
Post: Beware the Innodb Table Monitor
November 29, 2011 By 2 Comments
…NAME ID ————————————– Basically you can see every table, every column, and every index in that table. Once you get the output, you just DROP the table…queries in SHOW PROCESSLIST that were stuck in the ‘Opening Tables‘ state, uh-oh. I dug through the…
Post: Shard-Query adds parallelism to queries
November 15, 2010 By 18 Comments
…the queries in that same blog post. The original queries tend to filter on the Year column. I partitioned the table into months using the FlightDate column using the…
Post: Percona Server 5.1.58-12.9
August 17, 2011 By 2 Comments
…in the Slow Query Log patch. Bug Fixed: #794774 (Oleg Tsarev). Querying global_temporary_tables caused the server to crash in some scenarios due to…
Post: Eventual Consistency in MySQL
November 18, 2011 By 8 Comments
…the information in KEY_COLUMN_USAGE, we can write a query to fetch every distinct KEY_COLUMN_USAGE.CONSTRAINT_NAME where the REFERENCED_* columns…
Post: Hijacking Innodb Foreign Keys
January 2, 2012 By 2 Comments
…to get rid of them, yet this leaves you up for a final bite – dropping foreign keys requires table rebuild. Yes you get…table reference in fact and if you create the table with same name again it will need to be able to satisfy foreign key conditions (have column child table…
