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http://issues.apache.org/bugzilla/show_bug.cgi?id=30442

How to make slide faster - submission





------- Additional Comments From [EMAIL PROTECTED]  2004-08-04 22:19 -------
It would be interesting to know how other DBMSs handle the 'FROM' clause of 
the UPDATE statement.  Mysql doesn't seem to support it, so is mysql just a 
special case?  And using the modified update statement I submitted above I 
actually saw a considerable slowdown in mysql 4.0.20, but if I changed the 
update to a delete/insert I saw an improvement over no optimization.  I'm 
curious to hear how this performs on other systems. 
Oliver was asking about speed improvements so here is what I saw when I 
changed the update to a delete/insert. Below I attached some results that I 
saw when I timed 100 proppatches and got the average time. Each row is a 
separate run, and the times stayed pretty stable. All the times below are in 
milliseconds so you can see that the improvement isn't huge, but times several 
thousand properties, the improvement adds up.  And the more properties you 
have per node the more results you should see.
Are these results enough to bother about?
Tara

Averages of 100 single proppatches on nodes with about 14 properties    
Avg NoOptimizaion     Avg w/ Opt    Improvement
27                      24              3
27                      23              4
27                      22              5
28                      22              6
26                      21              5
26                      22              4
25                      21              4
26                      21              5
                        Avg Improvement 4.5

Averages of 100 single proppatches on nodes with about 24 properties    
Avg No Opt           Avg Opt         Improvement
28                      24              4
28                      23              5
28                      24              4
29                      22              7
28                      22              6
28                      22              6
30                      22              8
30                      22              8
                        Avg Improvement 6

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