1. Graph Developer's Guide for Property Graph
  2. Getting Started with Oracle Property Graphs
  3. Property Graph Query Language (PGQL)
  4. Executing PGQL Queries Against the In-Memory Graph Server (PGX)
  5. Best Practices for Tuning PGQL Queries

6.8.9 Best Practices for Tuning PGQL Queries

This section describes best practices regarding memory allocation, parallelism, and query planning.

  • Memory Allocation
    The In-Memory Analyst (PGX) has on-heap and off-heap memory, the earlier being the standard JVM heap while the latter being a separate heap that is managed by PGX. Just like graph data, intermediate and final results of PGQL queries are partially stored on-heap and partially off-heap. Therefore, both heaps are needed.
  • Parallelism
    By default, all available processor threads are used to process PGQL queries. However, if needed, the number of threads can be limited by setting the parallelism option of the In-Memory Analyst (PGX).
  • Query Plan Explaining
    The PgxGraph.explainPgql(String query) method is used to get insight into the query plan of the query. The method returns an instance of Operation (package oracle.pgx.api) which has the following methods:

Parent topic: Executing PGQL Queries Against the In-Memory Graph Server (PGX)