Advanced Querying

Advanced Querying

This section includes advanced querying topics such as using query indexes, using query bind parameters, querying partitioned regions and query debugging.

  • Performance Considerations
    This topic covers considerations for improving query performance.
  • Monitoring Low Memory When Querying
    The query monitoring feature prevents out-of-memory exceptions from occurring when you execute queries or create indexes.
  • Timeouts for Long-Running Queries
    GemFire can monitor and throw an exception when a query runs longer than a configured amount of time. This feature is enabled by setting the critical-heap-percentage attribute which detects that the JVM has too little heap memory.
  • Using Query Bind Parameters
    Using query bind parameters in GemFire queries is similar to using prepared statements in SQL where parameters can be set during query execution. This allows user to build a query once and execute it multiple times by passing the query conditions during run time.
  • Working with Indexes
    The GemFire query engine supports indexing. An index can provide significant performance gains for query execution.
  • Querying Partitioned Regions
    GemFire allows you to manage and store large amounts of data across distributed nodes using partitioned regions. The basic unit of storage for a partitioned region is a bucket, which resides on a GemFire node and contains all the entries that map to a single hashcode. In a typical partitioned region query, the system distributes the query to all buckets across all nodes, then merges the result sets and sends back the query results.
Parent topic: Querying