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From:Kandy Wong Date:April 27 2010 10:17pm
Subject:slow query on replication master and slave
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Is it true that the performance of running a query on a live replication 
master and slave has to be much slower than running a query on a static 

I've tried to run the following query on a replication master and it 
takes 1 min 13.76 sec to finish.
SELECT *, ABS(timeA-1266143632) as distance FROM tableA WHERE timeA - 
1266143632 <= 0  ORDER BY distance LIMIT 1;

And if I run it on the replication slave, it takes 24.15 sec.
But if I dump the whole database to another machine as static, it only 
takes 3.70 sec or even less to finish.

The table has 386 columns and timeA is an index. 

Is there a way to improve the query or any other factors that would 
affect the performance?



slow query on replication master and slaveKandy Wong28 Apr
  • Re: slow query on replication master and slaveJohan De Meersman28 Apr