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From Alexander Rosemann <alexander.rosem...@gmail.com>
Subject Re: multiple small indexes or one big index?
Date Thu, 02 Jun 2011 13:48:37 GMT
No worries, I'll keep that in mind now.
In addition I am going to switch to another collector as well. ATM I 
collect the results and then sort them using the std. Collections.sort 
approach... I have to look what Lucene offers and switch to something else.

Thanks,
Alex

On 02.06.2011 15:36, Erick Erickson wrote:
> Sounds good, just be sure to keep your (now single) searcher open! Also,
> be sure to measure queries after a while. The first few queries will fill up
> caches etc, so the time should improve after the first few.
>
> Best
> Erick
>
> On Thu, Jun 2, 2011 at 9:28 AM, Alexander Rosemann
> <alexander.rosemann@gmail.com>  wrote:
>> Hi Erick, caching the IndexSearchers didn't took too much effort and
>> decreased searching already by 30%!
>>
>> I am busy changing the code to use a single index as you suggested atm.
>> Still a few things left to be done but once I have it working I let you know
>> how much faster it is for me.
>>
>> Thanks,
>> Alex
>>
>> On 02.06.2011 13:04, Erick Erickson wrote:
>>>
>>> At this size, really consider going to a single index. The lack of
>>> administrative headaches alone is probably well worth the effort....
>>>
>>> I almost guarantee that the time you spend re-writing things to keep
>>> the searchers open (and finding the bugs!) will be far more than just
>>> putting all the data in a single index.
>>>
>>> But that might just be my preferences showing....
>>>
>>> Best
>>> Erick
>>>
>>> On Wed, Jun 1, 2011 at 5:37 PM, Alexander Rosemann
>>> <alexander.rosemann@gmail.com>    wrote:
>>>>
>>>> Many thanks for the tips, Erick! I do close each searcher after a
>>>> search...
>>>> I will change that first thing tmrw. and let you know how that went.
>>>> Multi-threaded searching will be next and if that hasn't helped, I will
>>>> switch to one big index.
>>>> All indexes together are rather small, ~200MB and 50.000 documents.
>>>>
>>>> -Alex
>>>>
>>>> On 01.06.2011 23:26, Erick Erickson wrote:
>>>>>
>>>>> I'd start by putting them all in one index. There's no penalty
>>>>> in Lucene for having empty fields in a document, unlike an
>>>>> RDBMS.
>>>>>
>>>>> Alternately, if you're opening then closing searchers each
>>>>> time, that's very expensive. Could you open the searchers
>>>>> once and keep them open (all 90 of them)? That alone might
>>>>> do the trick and be less of a change to your program. You
>>>>> could also fire multiple threads at the searches, but check if
>>>>> you're CPU bound first (if you are, multiple threads won't
>>>>> help much/at all).
>>>>>
>>>>> You haven't said how big these indexes are nor how many
>>>>> documents you're talking about here, so this advice is suspect.
>>>>>
>>>>> Do look at putting it all in one index though, let us know if you
>>>>> have some data indicating how big stuff is/would be.
>>>>>
>>>>> Best
>>>>> Erick
>>>>>
>>>>> On Wed, Jun 1, 2011 at 4:35 PM, Alexander Rosemann
>>>>> <alexander.rosemann@gmail.com>      wrote:
>>>>>>
>>>>>> Hi all, I was wondering whether you could give me some advice on
how to
>>>>>> improve my search performance.
>>>>>>
>>>>>> I have 90 lucene indexes, each having different fields (~5 per
>>>>>> Document).
>>>>>> When I search, I always have to go through all indexes to build my
>>>>>> result
>>>>>> set. Searching one index takes approx. 100ms, thus searching all
>>>>>> indexes
>>>>>> takes 9s in total.
>>>>>>
>>>>>> How can I reduce the time it needs to search?
>>>>>>
>>>>>> I decided to create this many indexes because putting all data in
one
>>>>>> index
>>>>>> would mean that a document would have ~400 fields, with most of them
>>>>>> left
>>>>>> empty. Is that ok? Would a single index be faster compared to multiple
>>>>>> small
>>>>>> ones?
>>>>>>
>>>>>> Any pointers are much appreciated.
>>>>>>
>>>>>> Regards,
>>>>>> Alex
>>>>>>
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>>>>>>
>>>>>
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>>>>
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>>>>
>>>
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>>
>
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