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From Alessandro Benedetti <abenede...@apache.org>
Subject Re: Faceting and Grouping Performance Degradation in Solr 5
Date Tue, 31 May 2016 16:57:43 GMT
Interesting developments :

https://issues.apache.org/jira/browse/SOLR-9176

I think we found why term Enum seems slower in recent Solr !
In our case it is likely to be related to the commit I mention in the Jira.
Have a check Joel !

On Wed, May 25, 2016 at 12:30 PM, Alessandro Benedetti <
abenedetti@apache.org> wrote:

> I am investigating this scenario right now.
> I can confirm that the enum slowness is in Solr 6.0 as well.
> And I agree with Joel, it seems to be un-related with the famous faceting
> regression :(
>
> Furthermore with the legacy facet approach, if you set docValues for the
> field you are not going to be able to try the enum approach anymore.
>
> org/apache/solr/request/SimpleFacets.java:448
>
> if (method == FacetMethod.ENUM && sf.hasDocValues()) {
>   // only fc can handle docvalues types
>   method = FacetMethod.FC;
> }
>
>
> I got really horrible regressions simply using term enum in both Solr 4
> and Solr 6.
>
> And even the most optimized fcs approach with docValues and
> facet.threads=nCore does not perform as the simple enum in Solr 4 .
>
> i.e.
>
> For some sample queries I have 40 ms vs 160 ms and similar...
> I think we should open an issue if we can confirm it is not related with
> the other.
> A lot of people will continue using the legacy approach for a while...
>
> On Wed, May 18, 2016 at 10:42 PM, Joel Bernstein <joelsolr@gmail.com>
> wrote:
>
>> The enum slowness is interesting. It would appear on the surface to not be
>> related to the FieldCache issue. I don't think the main emphasis of the
>> JSON facet API has been the enum approach. You may find using the JSON
>> facet API and eliminating the use of enum meets your performance needs.
>>
>> With the CollapsingQParserPlugin top_fc is definitely faster during
>> queries. The tradeoff is slower warming times and increased memory usage
>> if
>> the collapse fields are used in faceting, as faceting will load the field
>> into a different cache.
>>
>> Joel Bernstein
>> http://joelsolr.blogspot.com/
>>
>> On Wed, May 18, 2016 at 5:28 PM, Solr User <solrcal@gmail.com> wrote:
>>
>> > Joel,
>> >
>> > Thank you for taking the time to respond to my question.  I tried the
>> JSON
>> > Facet API for one query that uses facet.method=enum (since this one has
>> a
>> > ton of unique values and performed better with enum) but this was way
>> > slower than even the slower Solr 5 times.  I did not try the new API
>> with
>> > the non-enum queries though so I will give that a go.  It looks like
>> Solr
>> > 5.5.1 also has a facet.method=uif which will be interesting to try.
>> >
>> > If these do not prove helpful, it looks like I will need to wait for
>> > SOLR-8096 to be resolved before upgrading.
>> >
>> > Thanks also for your comment on top_fc for the CollapsingQParser.  I use
>> > collapse/expand for some queries but traditional grouping for others
>> due to
>> > performance.  It will be interesting to see if those grouping queries
>> > perform better now using CollapsingQParser with top_fc.
>> >
>> > On Wed, May 18, 2016 at 11:39 AM, Joel Bernstein <joelsolr@gmail.com>
>> > wrote:
>> >
>> > > Yes, SOLR-8096 is the issue here.
>> > >
>> > > I don't believe indexing with docValues is going to help too much with
>> > > this. The enum slowness may not be related, but I'm not positive about
>> > > that.
>> > >
>> > > The major slowdowns are likely due to the removal of the top level
>> > > FieldCache from general use and the removal of the FieldValuesCache
>> which
>> > > was used for multi-value field faceting.
>> > >
>> > > The JSON facet API covers all the functionality in the traditional
>> > > faceting, and it has been developed to be very performant.
>> > >
>> > > You may also want to see if Collapse/Expand can meet your applications
>> > > needs rather Grouping. It allows you to specify using a top level
>> > > FieldCache if performance is a blocker without it.
>> > >
>> > >
>> > >
>> > >
>> > > Joel Bernstein
>> > > http://joelsolr.blogspot.com/
>> > >
>> > > On Wed, May 18, 2016 at 10:42 AM, Solr User <solrcal@gmail.com>
>> wrote:
>> > >
>> > > > Does anyone know the answer to this?
>> > > >
>> > > > On Wed, May 4, 2016 at 2:19 PM, Solr User <solrcal@gmail.com>
>> wrote:
>> > > >
>> > > > > I recently was attempting to upgrade from Solr 4.8.1 to Solr
5.4.1
>> > but
>> > > > had
>> > > > > to abort due to average response times degraded from a baseline
>> > volume
>> > > > > performance test.  The affected queries involved faceting (both
>> enum
>> > > > method
>> > > > > and default) and grouping.  There is a critical bug
>> > > > > https://issues.apache.org/jira/browse/SOLR-8096 currently open
>> > which I
>> > > > > gather is the cause of the slower response times.  One concern
I
>> have
>> > > is
>> > > > > that discussions around the issue offer the suggestion of indexing
>> > with
>> > > > > docValues which alleviated the problem in at least that one
>> reported
>> > > > case.
>> > > > > However, indexing with docValues did not improve the performance
>> in
>> > my
>> > > > case.
>> > > > >
>> > > > > Can someone please confirm or correct my understanding that this
>> > issue
>> > > > has
>> > > > > no path forward at this time and specifically that it is already
>> > known
>> > > > that
>> > > > > docValues does not necessarily solve this?
>> > > > >
>> > > > > Thanks in advance!
>> > > > >
>> > > > >
>> > > > >
>> > > >
>> > >
>> >
>>
>
>
>
> --
> --------------------------
>
> Benedetti Alessandro
> Visiting card : http://about.me/alessandro_benedetti
>
> "Tyger, tyger burning bright
> In the forests of the night,
> What immortal hand or eye
> Could frame thy fearful symmetry?"
>
> William Blake - Songs of Experience -1794 England
>



-- 
--------------------------

Benedetti Alessandro
Visiting card : http://about.me/alessandro_benedetti

"Tyger, tyger burning bright
In the forests of the night,
What immortal hand or eye
Could frame thy fearful symmetry?"

William Blake - Songs of Experience -1794 England

Mime
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