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From Brian McCallister <mccallis...@forthillcompany.com>
Subject Re: RsIterator - performance issue
Date Sat, 24 Jul 2004 20:03:48 GMT
If its not breaking anything, go for it!

-Brian

On Jul 24, 2004, at 3:58 PM, Jakob Braeuchi wrote:

> hi armin,
>
> the overhead for non-cached objects is imo not a big issue when 
> compared with the better performance for cached objects.
>
> +1 for this patch
>
> jakob
>
> Armin Waibel schrieb:
>
>> Hi all,
>> I'm wondering about some lines in RsIterator#getObjectFromResultSet() 
>> method when query objects.
>> In line 428 always the whole result set row was mapped to an internal 
>> map, independent from a match in the cache. Why not map the PK values 
>> first from the result set, then check against the cache and only if 
>> not found in cache we map the whole row from the result set.
>> I locally change this behavior and all tests pass, additionally I 
>> wrote a simple performance test:
>> First time the query read from the DB (no cached objects), second 
>> time the objects can be found in cache.
>> against MaxDB             new  old
>> Time query 10000 objects: 762  752 [ms]
>> Time fetch 10000 objects: 161  472 [ms]
>> against hsql              new  old
>> Time query 10000 objects: 600  556 [ms]
>> Time fetch 10000 objects: 250  354 [ms]
>> The first read of the new implementation is a bit slower, because 
>> when the object was not found in cache the whole result set row was 
>> read again (with all PK values). A more performant solution will be 
>> to read the non-PK fields only, instead of all fields. But therefor 
>> we have to change the RowReader interface.
>> Any objections against the patched RsIterator version?
>> regards,
>> Armin
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