DataStax Enterprise 4.5

Performance Service

Overview of the Performance Service.

The DataStax Enterprise Performance Service automatically collects and organizes performance diagnostic information into a set of data dictionary tables. These tables are stored in the dse_perf keyspace and can be queried with CQL using any CQL-based utility, such as cqlsh, DataStax DevCenter, or any application using a Cassandra CQL driver.

Use this service to obtain database metrics and improve performance. Examples include:
  • Identify slow queries on a cluster to easily find and tune poorly performing queries.
  • View latency metrics for tables on all user (non-system) keyspaces.
  • Collect per node and cluster wide lifetime metrics by table and keyspace.
  • Obtain recent and lifetime statistics about tables, such as the number of SSTables, read/write latency, and partition (row) size.
  • Track read/write activity on a per-client, per-node level for both recent and long-lived activity to identify problematic user and table interactions.

The Performance Service diagnostic table reference contains a complete listing of the available diagnostic tables.

The following is sample output from querying thread pool statistics:

cqlsh:dse_perf> select * from thread_pool;

Result:

 node_ip   | pool_name              | active | all_time_blocked | blocked | completed | pending
-----------+------------------------+--------+------------------+---------+-----------+---------
 127.0.0.1 |       AntiEntropyStage |      0 |                0 |       0 |         0 |       0
 127.0.0.1 |   CacheCleanupExecutor |      0 |                0 |       0 |         0 |       0
 127.0.0.1 |     CompactionExecutor |      0 |                0 |       0 |       819 |       0
 127.0.0.1 |            FlushWriter |      0 |                0 |       0 |       935 |       0
 127.0.0.1 |            GossipStage |      0 |                0 |       0 |         0 |       0
 127.0.0.1 |          HintedHandoff |      0 |                0 |       0 |         0 |       0
 127.0.0.1 |  InternalResponseStage |      0 |                0 |       0 |         0 |       0
 127.0.0.1 |            MemoryMeter |      0 |                0 |       0 |      1673 |       0
 127.0.0.1 |    MemtablePostFlusher |      0 |                0 |       0 |      1041 |       0
 127.0.0.1 |         MigrationStage |      0 |                0 |       0 |        26 |       0
 127.0.0.1 |              MiscStage |      0 |                0 |       0 |         0 |       0
 127.0.0.1 |          MutationStage |      0 |                0 |       0 |      8654 |       0
 127.0.0.1 | PendingRangeCalculator |      0 |                0 |       0 |         1 |       0
 127.0.0.1 |        ReadRepairStage |      0 |                0 |       0 |         0 |       0
 127.0.0.1 |              ReadStage |      0 |                0 |       0 |      2681 |       0
 127.0.0.1 |  ReplicateOnWriteStage |      0 |                0 |       0 |         0 |       0
 127.0.0.1 |   RequestResponseStage |      0 |                0 |       0 |      2589 |       0
 127.0.0.1 |     ValidationExecutor |      0 |                0 |       0 |         0 |       0
 127.0.0.1 |     commitlog_archiver |      0 |                0 |       0 |         0 |       0

(19 rows)
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