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From Walter Underwood <wun...@wunderwood.org>
Subject Re: Number of fields in qf & fq
Date Fri, 20 Nov 2015 00:06:27 GMT
The implementation for fq has changed from 4.x to 5.x, so I’ll let someone else answer that
in detail.

In 4.x, the result of each filter query can be cached. After that, they are quite fast.

wunder
Walter Underwood
wunder@wunderwood.org
http://observer.wunderwood.org/  (my blog)


> On Nov 19, 2015, at 3:59 PM, Steven White <swhite4141@gmail.com> wrote:
> 
> Thanks Walter.  I see your point.  Does this apply to fq as will?
> 
> Also, how does one go about debugging performance issues in Solr to find
> out where time is mostly spent?
> 
> Steve
> 
> On Thu, Nov 19, 2015 at 6:54 PM, Walter Underwood <wunder@wunderwood.org>
> wrote:
> 
>> With one field in qf for a single-term query, Solr is fetching one posting
>> list. With 1500 fields, it is fetching 1500 posting lists. It could easily
>> be 1500 times slower.
>> 
>> It might be even slower than that, because we can’t guarantee that: a)
>> every algorithm in Solr is linear, b) that all those lists will fit in
>> memory.
>> 
>> wunder
>> Walter Underwood
>> wunder@wunderwood.org
>> http://observer.wunderwood.org/  (my blog)
>> 
>> 
>>> On Nov 19, 2015, at 3:46 PM, Steven White <swhite4141@gmail.com> wrote:
>>> 
>>> Hi everyone
>>> 
>>> What is considered too many fields for qf and fq?  On average I will have
>>> 1500 fields in qf and 100 in fq (all of which are OR'ed).  Assuming I can
>>> (I have to check with the design) for qf, if I cut it down to 1 field,
>> will
>>> I see noticeable performance improvement?  It will take a lot of effort
>> to
>>> test this which is why I'm asking first.
>>> 
>>> As is, I'm seeing 2-5 sec response time for searches on an index of 1
>>> million records with total index size (on disk) of 4 GB.  I gave Solr 2
>> GB
>>> of RAM (also tested at 4 GB) in both cases Solr didn't use more then 1
>> GB.
>>> 
>>> Thanks in advanced
>>> 
>>> Steve
>> 
>> 


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