private Region<?, ?> verifyRegionExists(Cache cache, String regionName) {
    Region<?, ?> result = cache.getRegion(regionName);
    if (result == null) {
      throw new IllegalStateException(
          "create jdbc-mapping requires that the region \"" + regionName + "\" exists.");
    }
    return result;
  }
Create an async-event-queue with the given name.
For a partitioned region a parallel queue is created.
Otherwise a serial queue is created.
geode-connectors/src/main/java/org/apache/geode/connectors/jdbc/internal/cli/CreateMappingFunction.java