Yes. It seems that if you specify sort="score desc" the collapser recomputes the score of the documents as far as I could understand from the solr's code. Thanks,
Florin Babeş PHP Developer babesflo...@gmail.com În mie., 17 mar. 2021 la 15:52, Joel Bernstein <joels...@gmail.com> a scris: > That is an interesting finding. The default behavior is quite fast compared > to the sort approach. > > > > Joel Bernstein > http://joelsolr.blogspot.com/ > > > On Wed, Mar 17, 2021 at 3:42 AM Florin Babes <babesflo...@gmail.com> > wrote: > > > @Gajendra we used a sort="score desc" even if we only use the head of the > > group. By removing this sort and leaving the default behavior (selecting > > the head with the highest score) our response time dropped with 42% in > our > > synthetic load tests. > > > > > > În joi, 11 mar. 2021 la 20:40 Gajendra Dadheech <gajju3...@gmail.com> a > > scris: > > > > > @florin > > > > > > Great advice. Null key for unique documents is really helpful. Any > other > > > such tricks that you are using to improve collapse performance ? > > > > > > On Tue, Mar 9, 2021, 2:45 PM Parshant Kumar > > > <parshant.ku...@indiamart.com.invalid> wrote: > > > > > > > Hi Joel, > > > > > > > > 1) What are the response times for both methods. Saying one is faster > > is > > > > not specific enough. > > > > > > > > Response time for the grouped method is 167 ms for 0.65 million > > requests. > > > > Response time for the collapsed method is 177 ms for 0.65 million > > > requests. > > > > > > > > 2) What is the cardinality of the collapse field, saying it's high is > > not > > > > specific enough. What is the actual cardinality? > > > > > > > > Cardinality of the collapse field is around 6.2 Million > > > > > > > > [image: image.png] > > > > 3) Is ngroups used in the grouping query > > > > > > > > Yes, ngroups is used in grouping query. > > > > > > > > Thanks > > > > Parshant Kumar > > > > > > > > > > > > > > > > > > > > On Tue, Mar 9, 2021 at 12:30 AM Joel Bernstein <joels...@gmail.com> > > > wrote: > > > > > > > >> Collapse is designed to outperform grouping in the following > scenario: > > > >> > > > >> There is high cardinality on the group field and group.ngroups is > > > needed. > > > >> If either of these conditions is not satisfied grouping will > typically > > > be > > > >> faster. > > > >> > > > >> You will need to provide some more information about your setup to > get > > > an > > > >> answer to the collapse performance question. > > > >> > > > >> 1) What are the response times for both methods. Saying one is > faster > > is > > > >> not specific enough. > > > >> 2) What is the cardinality of the collapse field, saying it's high > is > > > not > > > >> specific enough. What is the actual cardinality? > > > >> 3) Is ngroups used in the grouping query. > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> > > > >> Joel Bernstein > > > >> http://joelsolr.blogspot.com/ > > > >> > > > >> > > > >> On Mon, Mar 8, 2021 at 11:30 AM Gajendra Dadheech < > > gajju3...@gmail.com> > > > >> wrote: > > > >> > > > >> > @prashant Florin means to put null for parentglusrid in documents > > > where > > > >> > this field-value is only present in one document [Group has only > one > > > >> > document]. and then use nullPolicy to include/expand. > > > >> > > > > >> > > > > >> > > > > >> > On Mon, Mar 8, 2021 at 6:55 PM Parshant Kumar > > > >> > <parshant.ku...@indiamart.com.invalid> wrote: > > > >> > > > > >> > > client should set to null the field if it's unique. > > > >> > > > > > >> > > @florin @Gajendra can you please explain more .I am not clear > how > > to > > > >> > > perform this. > > > >> > > > > > >> > > On Mon, Mar 8, 2021 at 6:09 PM Florin Babes < > > babesflo...@gmail.com> > > > >> > wrote: > > > >> > > > > > >> > > > @Gajendra Our response time dropped by 36% and our rps > increased > > > >> with > > > >> > > 27%. > > > >> > > > > > > >> > > > You have to reindex the core and the client should set to null > > the > > > >> > field > > > >> > > if > > > >> > > > it's unique. > > > >> > > > > > > >> > > > În lun., 8 mar. 2021 la 13:18, Parshant Kumar > > > >> > > > <parshant.ku...@indiamart.com.invalid> a scris: > > > >> > > > > > > >> > > > > How can we make group_field null? Using nullPolicy=expand ? > > > >> > > > > > > > >> > > > > On Mon, Mar 8, 2021 at 4:41 PM Florin Babes < > > > >> babesflo...@gmail.com> > > > >> > > > wrote: > > > >> > > > > > > > >> > > > > > We improved the performance of collapse by making the > > > >> group_field > > > >> > > null > > > >> > > > > for > > > >> > > > > > the documents that have an unique value for group_field. > > This > > > >> might > > > >> > > > help/ > > > >> > > > > > > > > >> > > > > > > > > >> > > > > > În lun., 8 mar. 2021 la 12:40, Parshant Kumar > > > >> > > > > > <parshant.ku...@indiamart.com.invalid> a scris: > > > >> > > > > > > > > >> > > > > > > yes,group_field is having high cardinality. > > > >> > > > > > > > > > >> > > > > > > > > > >> > > > > > > Thanks > > > >> > > > > > > Parshant Kumar > > > >> > > > > > > > > > >> > > > > > > On Mon, Mar 8, 2021 at 4:06 PM Florin Babes < > > > >> > babesflo...@gmail.com > > > >> > > > > > > >> > > > > > wrote: > > > >> > > > > > > > > > >> > > > > > > > Your group_field has a high cardinality? > > > >> > > > > > > > Thanks, > > > >> > > > > > > > Florin Babes > > > >> > > > > > > > > > > >> > > > > > > > În lun., 8 mar. 2021 la 10:35, Parshant Kumar > > > >> > > > > > > > <parshant.ku...@indiamart.com.invalid> a scris: > > > >> > > > > > > > > > > >> > > > > > > > > Hi florin, > > > >> > > > > > > > > > > > >> > > > > > > > > I am using below. > > > >> > > > > > > > > > > > >> > > > > > > > > 1) fq={!collapse field=parentglusrid} > > > >> > > > > > > > > 2) expand.rows=4 > > > >> > > > > > > > > 3) expand=true > > > >> > > > > > > > > > > > >> > > > > > > > > Size of index is around 100GB. > > > >> > > > > > > > > Solr version is 6.5 > > > >> > > > > > > > > > > > >> > > > > > > > > On Mon, Mar 8, 2021 at 1:46 PM Florin Babes < > > > >> > > > babesflo...@gmail.com > > > >> > > > > > > > > >> > > > > > > > wrote: > > > >> > > > > > > > > > > > >> > > > > > > > > > Hello, > > > >> > > > > > > > > > First let's call the field you collapse on > > group_field > > > >> > > > > > > > > > If group_field has a high cardinality you should > > make > > > >> > > > group_field > > > >> > > > > > > null > > > >> > > > > > > > > for > > > >> > > > > > > > > > those documents that have a unique group_field and > > set > > > >> > > > > > > > nullPolicy=expand. > > > >> > > > > > > > > > By doing that solr will use less memory for it's > > > >> internal > > > >> > > maps > > > >> > > > > (so > > > >> > > > > > > > faster > > > >> > > > > > > > > > gc) and the head selecting will be faster. > > > >> > > > > > > > > > What is your head selecting strategy? Can you > share > > > >> your fq > > > >> > > > which > > > >> > > > > > you > > > >> > > > > > > > use > > > >> > > > > > > > > > for collapsing? > > > >> > > > > > > > > > > > > >> > > > > > > > > > Thanks, > > > >> > > > > > > > > > Florin Babes > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > În lun., 8 mar. 2021 la 06:44, Parshant Kumar > > > >> > > > > > > > > > <parshant.ku...@indiamart.com.invalid> a scris: > > > >> > > > > > > > > > > > > >> > > > > > > > > > > anyone please help > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > On Wed, Mar 3, 2021 at 4:55 PM Parshant Kumar < > > > >> > > > > > > > > > > parshant.ku...@indiamart.com> > > > >> > > > > > > > > > > wrote: > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > Hi all, > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > We have implemented collapse queries in place > of > > > >> > grouped > > > >> > > > > > queries > > > >> > > > > > > on > > > >> > > > > > > > > our > > > >> > > > > > > > > > > > production solr. As mentioned in solr > > > documentation > > > >> > > > collapse > > > >> > > > > > > > queries > > > >> > > > > > > > > > are > > > >> > > > > > > > > > > > recommended in place of grouped queries in > terms > > > of > > > >> > > > > > performance . > > > >> > > > > > > > But > > > >> > > > > > > > > > > after > > > >> > > > > > > > > > > > switching to collapsed queries from grouped > > > queries > > > >> > > > response > > > >> > > > > > time > > > >> > > > > > > > of > > > >> > > > > > > > > > > > queries have increased. This is unexpected > > > >> behaviour, > > > >> > the > > > >> > > > > > > response > > > >> > > > > > > > > time > > > >> > > > > > > > > > > > should have been improved but results are > > > opposites. > > > >> > > > > > > > > > > > Please someone help why response time is > > increased > > > >> for > > > >> > > > > > collapsed > > > >> > > > > > > > > > queries. > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > Thanks > > > >> > > > > > > > > > > > Parshant Kumar > > > >> > > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > -- > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > -- > > > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > -- > > > >> > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > -- > > > >> > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > -- > > > >> > > > > > >> > > > > > >> > > > > >> > > > > > > > > > > > > > >
