Priotitizing searching accross multiple Indices

Elastic Stack Elasticsearch
#1

Hi All,

I have multiple indices created in my elastic search. I am using 2.1.1 version. of ES.
My search requirement is like user will enter a keyword and search should happen against all indexes. But i want to prioritize the records returned. I mean ,I need only 10 matching records. From Index A i need 5 record, from index B i need 3 record, and from index C i need 2 record.
This is max count in case all indices fetch matching results. But in case index B and C doesn't have any matching record, i need all 10 from index A if it has more records. Similarly if there is no matching record from index B, then 8 record from index A and 2 record from index B should be returned.

Is this kind of segregation possible in ES?

#2

Hi soorajhere,

I guess that you could do that by adding some logic (by logic i mean code) in Java for example and filter results as you wish. I am not aware of such a built-in feature in Elastic.

#3

I am not aware of any way of doing this with a single query either, but you could send 3 separate queries, each returning 10 results, as part of a multi search request and then select the ones to use at the application layer.

#4

I think index boost would help you. Not sure it will allow you to do exactly what you need, but something along those lines for sure. It is not a very popular feature but it's there: https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-index-boost.html .

Cheers
Luca

1 Like
#5

Hi illiasse,

Thank you for your reply.
I have created a wcf wrapper service in .net and is calling ElasticSearch REST API from this service. I also had similar thought of retrieving all results from ES and then do the filtering from .net code. But the search query which I use is a single multi_match query and I mention fields from multiple indexes in it. Also the search i need is a phrase_prefix search and i limit size to 10 in the query.
As you mentioned, if i do the filtering from .net code, i might have to get all search results(remove size from query?) from ES instead of limiting it to 10, right? I think ES by default return 10 hits, and if more results are required, we need to mention size value. But how can we have a particular value for size upfront? What if more matching search records are present? OR is it like i need to provide a huge number say, 10K or something?

#6

Hi Christian_Dahlqvist ,
Thank you for your reply.
Is it a good idea to hit ES server multiple times with different search query? I thought performance will degrade using this method, so was trying to use fields property in the search query and mention fields from multiple indices in the query.

#7

Hi Luca Cavanna,

Thank you for your reply. I will give a try with index boost.

#8