Archive for the ‘MySQL feature’ Category

If you copy a MyISAM table with PRIMARY key, don’t forget to order the rows first

In a case that you copy (INSERT INTO .. SELECT ..) a MyISAM table that have a PRIMARY key, it is much faster to insert the new rows in the primary key order:

The battle between FORCE INDEX and the QUERY OPTIMIZER

Query Optimizer is a part of the server that takes a parsed SQL query and produces a query execution plan. MySQL Query Optimizer uses (as one of its parameters) the stored key distribution (Cardinality) mechanism to determine the order in which tables should be joined, when you perform a join on something other than a [...]

MySQL User Defined Variables

When I have discovered MySQL User-defined variables at the first time, I didn’t pay much attention to them and didn’t realize their strength. At first, one can think that they are just one of the many unnoticed MySQL features. Well, I was wrong. Here, I will try to summarize their strength, though I think there is [...]

The fading of Query Cache limitations

There is no question about the MySQL Query Cache greatness.  The MySQL Query Cache feature started his way with some limitations.  However, in time, there were a lot of improvements (fixing) for those limitations.