lucene.net的IN运算符

Question

SQL server can query using IN operator for the specific IDs like:

ID in (2,23,122,44,22) 

I was using the same query for displaying related results in another page. I have to move to lucene.net for increasing speed of display so I need to replace the old code I used above. I searched a lot on Google but did not find any alternative for it.

I tried composing boolean query in lucene.net like:

ID:1 OR ID:2 OR ID:3 

... but due to limitation of 1024 expressions I am unable to use this way too. Please suggest how can I resolve this problem.

Answer 1

The maximum number of clauses in a boolean query is 1024 by default.

You can increase this limit.

There would be performance penalty, though. or you can index the values on the document and search for them (lucene will do an OR operation on different fields with the same name).

You can change the limit using a static property on BooleanQuery class:

 BooleanQuery.MaxClauseCount = 99999;

Omri

Answer 2

By default all terms in a query are ORed by default:

ID: 1 2 3

This will return a list of all documents with ids 1, 2 and 3.

You can use a simple query,

var ids = new[] { "1", "2", "3" };
var query = new QueryParser(version, idProperty, analyzer).Parse(string.Join(" ", ids));