CODEWITHSUNDEEP
javalucenethread-safetyquery-parser
Robert Tupelo-Schneck
Robert Tupelo-Schneck

Reputation: 10544

Lucene QueryParser in multiple threads: synchronize or construct new each time?

I have a web application where users submit queries to a Lucene index. The queries are parsed by a Lucene QueryParser. I learned the hard way that QueryParser is not thread-safe.

Is it better to use a single QueryParser instance, and synchronize on calls to its parse() method? Or is it better to construct a new instance for each query? (Or would I be better served by a pool of QueryParsers?)

I know that in general questions like this depend on the particulars and require profiling, but maybe someone out there can say definitively "QueryParsers are extremely inexpensive/expensive to construct"?

Upvotes: 6

Views: 2084

Answers (1)

Joel
Joel

Reputation: 30146

Create a new one each time. These are lightweight objects and the JVM handles object creation and garbage collection very well. Definitely do not use an object pool.

Upvotes: 7

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