Distributed Query How Distributed Query Works Configuring Query Thread Pool

You can change the size of thread pool dedicated to query operations using the pool-size property. Each query consumes a single thread from a Generic Operations ThreadPool on each Hazelcast member - let's call it the query-orchestrating thread. That thread is blocked throughout the whole execution-span of a query on the member.

The query-orchestrating thread will use the threads from the query-thread pool in two cases:

• if you run a PagingPredicate - since each page is run as a separate task,
• if you set the system property hazelcast.query.predicate.parallel.evaluation to true - since the predicates are evaluated in parallel.

Please see Filtering with Paging Predicates and System Properties sections for information on paging predicates and for description of the above system property.

Below is an example of that declarative configuration.

<executor-service name="hz:query">
  <pool-size>100</pool-size>
</executor-service>

Below is the equivalent programmatic configuration.

Config cfg = new Config();
cfg.getExecutorConfig("hz:query").setPoolSize(100);