…, which should affect execution plan of TPC-H queries. In reality only two queries (from 22) have significantly better execution time (about… so big we could speak about big improvements with using MRR here. What is interesting is iostat -dx 5 output during query execution… all time. As you see 1285 rkB/s is pretty small for RAID 10 system we have on this server. This…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
… in memory changed things here is small example with numbers. If you have …table. The times for full table scan vs range scan by index: mysql> select count… be a lot of help for big scans. This will reduce the gap …requests one by one for query execution, which means if single query execution time is …
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
… I should note MySQL 5.0 vs 4.1 has a lot … Flash. SSD Drives would be big win for TableSpace files but …opened about multi-core scalability (concurrent queries, autoincrement, concurrent inserts, instrumentation, etc.). … reorganize which locks and reorganizes small portions of table online. Q38: …
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 17 Comments
…to the question is: for small tables, everything can reside within a single extent. For big tables, a secondary …locks) the rows if they were not matched by query where clause when it was not resolved by …3x performance boost and it would write at 100MBps vs 33MBps. Any plans to enable tuning of the …
Comment: Database access Optimization in Web Applications.
September 17, 2006 By 10 Comments
…can be too small to be noticed. There are a lot of factors besides BLOB columns: – Query can be index…000.000 row result set having 100 float columns, vs selecting only couple of them 
So instead of …to the list – of course. I write a big deal about query optimization in the blog. This list is to…
