August 1, 2008

How adding another table to JOIN can improve performance ?

Posted by peter |

JOINs are expensive and it most typical the fewer tables (for the same database) you join the better performance you will get. As for any rules there are however exceptions :)

The one I’m speaking about comes from the issue with MySQL optimizer stopping using further index key parts as soon as there is a range clause on the previous key part. So if you have INDEX(A,B) and have a where clause A BETWEEN 5 and 10 AND B=6 only the first part (A) of the index will be used which can be seriously affect performance. Of course in this example you can use index (B,A) but there are many similar cases when it is not possible.
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Posted by peter @ 10:10 pm :: bugs, optimizer :: 12 comments
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Percona turns two today !

Posted by peter |

July 31st 2006 was my last day working for MySQL and August 1st I started what later was incorporated Percona with Vadim joining me September 1st as co-founder.

Two years is a significant anniversary for any startup – surviving (and being profitable) for 2 years can be seen as validation of our business model and strategy and we’re quite happy about this.
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Posted by peter @ 7:34 pm :: percona :: 13 comments
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