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From Jamie <ja...@mailarchiva.com>
Subject Re: search performance
Date Tue, 03 Jun 2014 10:21:23 GMT
Vitaly

See below:

On 2014/06/03, 12:09 PM, Vitaly Funstein wrote:
> A couple of questions.
>
> 1. What are you trying to achieve by setting the current thread's priority
> to max possible value? Is it grabbing as much CPU time as possible? In my
> experience, mucking with thread priorities like this is at best futile, and
> at worst quite detrimental to responsiveness and overall performance of the
> system as a whole. I would remove that line.
Yes,  you are right to be worried about this, especially since thread 
priorities behave differently on different platforms.

>
> 2. This seems suspicious:
>
> if (getPagination()) {
>                  max = start + length;
>              } else {
>                  max = getMaxResults();
>              }
>
> If start is at 100M, and length is 1000 - what do you think Lucene will try
> and do when you pass this max to the collector?
I dont see the problem here. The collector will start from zero to max 
results. I agree that from a performance perspective, ts not ideal to 
return all results from the beginning of the search, but the Lucene API 
us with no choice. I simply do not know the ScoreDoc to start from. If I 
did keep a record of it, then I would need to store all scoredocs for 
the entire result set. When there are 60M+ results, this can be 
problematic in terms of memory consumption. It would be far nicer if 
there was a searchAfter function that took a position as an integer.

Regards

Jamie
>
>


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