Hi Faraz, When you say query without sort, I assume that you mean you omit sort so you expect it to be sorted by score. It is expected to be slower than equal query without calculating score - e.g. run same query as fq. What you observe can be explained with: * Solr is calculating score even not sorted by score and not returning it (do you return score? Plus I am not sure about this - did not check the code) * Field that you are using for sorting do not have doc values so have to be uninverted * Fileld that you are using for sorting are not in OS cache so are read from disk.
Try comparing same query running as q=..,. and fq=… Make sure that your filter cache is disabled if you are repeating the same queries and averaging. HTH, Emir -- Monitoring - Log Management - Alerting - Anomaly Detection Solr & Elasticsearch Consulting Support Training - http://sematext.com/ > On 4 Dec 2017, at 14:54, Faraz Fallahi <faraz.fall...@googlemail.com> wrote: > > Hi guys, > > Sorry to bother you again, but i am really confused: > > Ive used solr admin website and created a query with lots of ORs using solr > 4.7. > > When i execute the query without a sort it executes in round about 3.5 - 4 > seconds. > When i execute it with a sort on a field called pubdate it takes about > 4-4.5 seconds. > When i execute it with a sort on the guid field it takes about 7 - 8 > seconds !!! > > After your explanations i was expecting the query without a sort to be the > slowest. What am i missing here? > > Beat regards > Faraz > > Am 30.11.2017 09:29 schrieb "Faraz Fallahi" <faraz.fall...@googlemail.com>: > >> Uff... I See.. thx dir the explanation :) >> >> Am 30.11.2017 3:13 nachm. schrieb "Emir Arnautović" < >> emir.arnauto...@sematext.com>: >> >>> Hi Faraz, >>> It is a bit worse than that - it also needs to calculate score, so for >>> each matching doc of one query part it has to check if it appears in >>> results of other query parts. If you use term query parser, you avoid >>> calculating score - all doc will have score 1. >>> Solr is based on lucene, which is mainly inverted index: >>> https://en.wikipedia.org/wiki/Inverted_index < >>> https://en.wikipedia.org/wiki/Inverted_index> so knowing that helps >>> understand how expensive some queries are. It is relatively easy to figure >>> out what steps are needed for different query types. Of course, Lucene >>> includes a lot smartness, and it is probably not using the naive approach, >>> but it cannot avoid limitations of inverted index. >>> >>> HTH, >>> Emir >>> -- >>> Monitoring - Log Management - Alerting - Anomaly Detection >>> Solr & Elasticsearch Consulting Support Training - http://sematext.com/ >>> >>> >>> >>>> On 30 Nov 2017, at 02:39, Faraz Fallahi <faraz.fall...@googlemail.com> >>> wrote: >>>> >>>> Hi Toke, >>>> >>>> Just to be clear and to understand. Does this mean that a query of the >>> form >>>> author:name1 OR author:name2 OR author:name3 >>>> >>>> Is being processed like e.g. >>>> >>>> 1 query against the index with author:name1 getting 4 result >>>> Then 1 query against the index with author:name2 getting 3 result >>>> Then 1 query against the index with author:name3 getting 1 result >>>> >>>> And in the end all results are merged and i get a result of 8 ? >>>> >>>> So a query of thousand authors will be splitted into thousand single >>>> queries against the index? >>>> >>>> Do i understand this correctly? >>>> >>>> Thx for the help >>>> Faraz >>>> >>>> >>>> Am 28.11.2017 15:39 schrieb "Toke Eskildsen" <t...@kb.dk>: >>>> >>>> On Tue, 2017-11-28 at 11:07 +0100, Faraz Fallahi wrote: >>>>> I have a question regarding solr queries. >>>>> My query basically contains thousand of OR conditions for authors >>>>> (author:name1 OR author:name2 OR author:name3 OR author:name4 ...) >>>>> The execution time on my index is huge (around 15 sec). When i tag >>>>> all the associated documents with a custom field and value like >>>>> authorlist:1 and then i change my query to just search for >>>>> authorlist:1 it executes in 78 ms. How come there is such a big >>>>> difference in exec-time? >>>> >>>> Due to the nature of inverted indexes (which lies at the heart of >>>> Solr), your thousands of OR-queries means thousands of lookups, whereas >>>> your authorlist means a single lookup. Adding to this the results for >>>> each author needs to be merged with the other author-results - for >>>> authorlist the results are there directly. >>>> >>>> If your author lists are static, indexing them as you did in your test >>>> is the best solution. >>>> >>>> If they are not static, using a filter-query will ensure that they are >>>> at least cached subsequently, so that only the first call will be >>>> slow. >>>> >>>> If they are semi-static and there are not too many of them, you could >>>> do warm-up filter-queries for all the different groups so that the >>>> users does not pay the first-call penalty. This requires your filter- >>>> cache to be large enough to hold all the author lists. >>>> >>>> - Toke Eskildsen, Royal Danish Library >>> >>>
