How simple answer are you looking for ?

I’ve got an interesting comment the other day saying “I’ve heard Jay Pipes saying indexes with cardinality lower than 30% are worthless, true?”
That is interesting question and it has different answers depending on who is asking. A lot of people want to hear simple answers to the questions because they would be overwhelmed […]

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PBXT benchmarks

The PBXT Storage Engine (http://www.primebase.com/xt/) is getting stable and we decided to benchmark it in different workloads.
This time I tested only READ queries, similar to ones in benchmark InnoDB vs MyISAM vs Falcon
(https://www.percona.com/blog/2007/01/08/innodb-vs-myisam-vs-falcon-benchmarks-part-1)
The difference is I used new sysbench with Lua scripting language, so all queries were scripted for sysbench.
(more…)

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Using delayed JOIN to optimize count(*) and LIMIT queries

In many Search/Browse applications you would see main (fact) table which contains search fields and dimension tables which contain more information about facts and which need to be joined to get query result.
If you’re executing count(*) queries for such result sets MySQL will perform the join even if you use LEFT JOIN so […]

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