About the Performance Service
The Performance Service automatically collects and organizes performance diagnostic information into a set of data dictionary tables that can be queried with CQL.
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 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)