… temporary table will be faster as you can add proper indexes to the table in this case. Consider using temporary views instead of derived tables If you really need to use subselect in from clause consider creating view…
Post: MySQL VIEW as performance troublemaker
August 12, 2007 By 53 Comments
…same problem having things more modular and using MySQL VIEWs ? mysql> create view user_counts as select user_id,count(*) cnt…derived tables it will become nightmare. So be very careful implementing MySQL VIEWs in your application, especially ones which require temporary table execution method. VIEWs…
Post: A workaround for the performance problems of TEMPTABLE views
May 19, 2010 By 7 Comments
… conditions to the query. Lets start by creating a parameter table. This table might be view specific or you could construct it in such… | NULL | NULL | NULL | NULL | 1 | | | 2 | DERIVED | p | const | PRIMARY | PRIMARY | 260 | | 1 | | | 2 | DERIVED | t2 | ref | c1 | c1 | 5 | const | 130…
Comment: Derived Tables and Views Performance
September 1, 2006 By 14 Comments
… execution – Views are executed (in this case) by query rewriting, so effectively query becomes same as on base table. Inline views/derived tables however can’t do it they always have to materialize table. Creating view you can also force…
Post: Air traffic queries in InfiniDB: early alpha
November 2, 2009 By 19 Comments
… DERIVED TABLES, which is big limitation from my point of view. As workaround I tried to create temporary table, but got another error: mysql> create temporary table… DERIVED TABLES, as not supported by InfiniDB. Other queries: (again look on comparison with other engines in Google Spreadsheet or in summary table…
Comment: Derived Tables and Views Performance
September 1, 2006 By 14 Comments
… is no reason for derived tables to be materialized. It is design deficiency in MySQL 5.0. Speaking about Views with group by… require temporary table even if it is possible to avoid it. Hopefully it will be improved in the future: mysql> create view v1… | table | type | possible_keys | key | key_len | ref | rows | Extra | +—-+————-+————+——-+—————+——+———+——+———+————-+ | 1 | PRIMARY | | ALL | NULL | NULL | NULL | NULL | 1638400 | Using where | | 2 | DERIVED…
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
…tables is elevated, however there are still cases when it may take too long. Most practically important one is if Derived tables…sort or creates temporary table and so how much rows will be stored to temporary table. Sometimes… so we need at least an alternative view. If you want to find more …
