[Tickets #7363] Re: Avoid bitwise operations in the SQL Share driver

bugs at horde.org bugs at horde.org
Mon Oct 6 09:14:47 UTC 2008


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Ticket URL: http://bugs.horde.org/ticket/7363
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  Ticket             | 7363
  Updated By         | Duck <duck at obala.net>
  Summary            | Avoid bitwise operations in the SQL Share driver
  Queue              | Horde Framework Packages
  Version            | FRAMEWORK_3
  Type               | Enhancement
  State              | Accepted
  Priority           | 2. Medium
  Milestone          |
  Patch              |
  Owners             | Horde Developers, Chuck Hagenbuch
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Duck <duck at obala.net> (2008-10-06 05:14) wrote:

Mysql does not uses indexes for bitwise operations. So it performs a  
full table scan. I was aware of this while I was writing the native  
driver. But I let this problem as it is still much better than the DT  
driver and had no time to solve even this. This part is still on my  
TODO...

Another table scan was introduced in in revision 1.35 of mrubinsk by  
adding the DISTINCT statement in the SQL query. And this is the *real*  
performance killer for MySQL. As it must scan the joined table - it  
means that must allocate a new temporary table with all joined data,  
using limit or not. Brrr....

So we must reorganize data  and query to avoid this two table scans.





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