Mailing List Archive: Filter question

Hi

I'm constructing a BooleanQuery with an optional filter query and a
mandatory content query, plus some optional boost queries.

In effect, what I am doing is implementing this shorthand:

BooleanQuery.Builder qb = new BooleanQuery.Builder();

if (filter) {

qb.add(filterquery, Occur.FILTER);

}

qb.add(contentquery, Occur.MUST);

if (boost)

qb.add(boostquery, Occur.SHOULD);

..

}

Query fullquery = qb.build();

Typically the content query will be constructed from something like
"title:word OR text:word" and the filter query, if it exists, will be built
from something like "product:a". (The boost queries serve to push recent
content higher in the results, they don't really matter for this question.)

There will always be a content query. My question relates to the filter
query. I know that a query which has no 'positive' clauses will not return
any results. That although the two queries

product:a or product:b or product:d

and

NOT product:c

might be logically identical, the first will return results and the second
will not.

However would a query like "NOT product:c" be OK as a filter query if it was
combined with other queries as per the pseudocode above?

I don't think it's significant but for what it's worth this application is
still using Lucene 8_6.3.

cheers

T

Hi Trevor
Well, you may negate it via
qb.add(product_c_positive, Occur.MUST_NOT);
it will work only if there is a sibling MUST/SHOULD clause.
Regarding
qb.add(BooleanQuery.Builder().add(product_c_positive,
Occur.MUST_NOT).build(), Occur.FILTER);
It may hardly work unless Lucene "adjusts pure negative query" somewhere
that some search servers do or did under certain conditions.

On Wed, Nov 22, 2023 at 7:46?AM Trevor Nicholls <trevor@castingthevoid.com>
wrote:

> Hi
>
>
>
> I'm constructing a BooleanQuery with an optional filter query and a
> mandatory content query, plus some optional boost queries.
>
>
>
> In effect, what I am doing is implementing this shorthand:
>
>
>
> BooleanQuery.Builder qb = new BooleanQuery.Builder();
>
> if (filter) {
>
> qb.add(filterquery, Occur.FILTER);
>
> }
>
> qb.add(contentquery, Occur.MUST);
>
> if (boost)
>
> qb.add(boostquery, Occur.SHOULD);
>
> ..
>
> }
>
> Query fullquery = qb.build();
>
>
>
> Typically the content query will be constructed from something like
> "title:word OR text:word" and the filter query, if it exists, will be built
> from something like "product:a". (The boost queries serve to push recent
> content higher in the results, they don't really matter for this
> question.)
>
>
>
> There will always be a content query. My question relates to the filter
> query. I know that a query which has no 'positive' clauses will not return
> any results. That although the two queries
>
>
>
> product:a or product:b or product:d
>
>
>
> and
>
>
>
> NOT product:c
>
>
>
> might be logically identical, the first will return results and the second
> will not.
>
>
>
> However would a query like "NOT product:c" be OK as a filter query if it
> was
> combined with other queries as per the pseudocode above?
>
>
>
> I don't think it's significant but for what it's worth this application is
> still using Lucene 8_6.3.
>
>
>
> cheers
>
> T
>
>
>
>

--
Sincerely yours
Mikhail Khludnev