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From Shawn Heisey <apa...@elyograg.org>
Subject Re: Optimizing fq query performance
Date Thu, 18 Apr 2019 14:17:28 GMT
On 4/17/2019 11:49 PM, John Davis wrote:
> I did a few tests with our instance solr-7.4.0 and field:* vs field:[* TO
> *] doesn't seem materially different compared to has_field:1. If no one
> knows why Lucene optimizes one but not another, it's not clear whether it
> even optimizes one to be sure.

Queries using a boolean field will be even faster than the all-inclusive 
range query ... but they require work at index time to function 
properly.  If you can do it this way, that's definitely preferred.  I 
was providing you with something that would work even without the 
separate boolean field.

If the cardinality of the field you're searching is very low (only a few 
possible values for that field across the whole index) then a wildcard 
query can be fast.  It is only when the cardinality is high that the 
wildcard query is slow.  Still, it is better to use the range query for 
determining whether the field exists, unless you have a separate boolean 
field for that purpose, in which case the boolean query will be a little 
bit faster.

Thanks,
Shawn

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