system.metrics

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Querying in ClickHouse Cloud

The data in this system table is held locally on each node in ClickHouse Cloud. Obtaining a complete view of all data, therefore, requires the `clusterAllReplicas` function. See [here](/docs/operations/system-tables/overview#system-tables-in-clickhouse-cloud) for further details.

Contains metrics which can be calculated instantly, or have a current value. For example, the number of simultaneously processed queries or the current replica delay. This table is always up to date.

Columns:

- `metric` ([String](/docs/sql-reference/data-types)) — Metric name.
- `value` ([Int64](/docs/sql-reference/data-types)) — Metric value.
- `description` ([String](/docs/sql-reference/data-types)) — Metric description.

You can find all supported metrics in source file [src/Common/CurrentMetrics.cpp](https://github.com/ClickHouse/ClickHouse/blob/master/src/Common/CurrentMetrics.cpp).

**Example**

```
SELECT * FROM system.metrics LIMIT 10
```

```
┌─metric───────────────────────────────┬─value─┬─description────────────────────────────────────────────────────────────┐
│ Query                                │     1 │ Number of executing queries                                            │
│ Merge                                │     0 │ Number of executing background merges                                  │
│ PartMutation                         │     0 │ Number of mutations (ALTER DELETE/UPDATE)                              │
│ ReplicatedFetch                      │     0 │ Number of data parts being fetched from replicas                       │
│ ReplicatedSend                       │     0 │ Number of data parts being sent to replicas                            │
│ ReplicatedChecks                     │     0 │ Number of data parts checking for consistency                          │
│ BackgroundMergesAndMutationsPoolTask │     0 │ Number of active merges and mutations in an associated background pool │
│ BackgroundFetchesPoolTask            │     0 │ Number of active fetches in an associated background pool              │
│ BackgroundCommonPoolTask             │     0 │ Number of active tasks in an associated background pool                │
│ BackgroundMovePoolTask               │     0 │ Number of active tasks in BackgroundProcessingPool for moves           │
└──────────────────────────────────────┴───────┴────────────────────────────────────────────────────────────────────────┘
```

## Metric descriptions[​](#metric-descriptions "Direct link to Metric descriptions")

### ASTFuzzerAccumulatedFragments[​](#astfuzzeraccumulatedfragments "Direct link to ASTFuzzerAccumulatedFragments")

Number of AST fragments accumulated by the server-side AST fuzzer for use in future mutations.

### ActiveTimersInQueryProfiler[​](#activetimersinqueryprofiler "Direct link to ActiveTimersInQueryProfiler")

Number of Active thread local timers in QueryProfiler

### AddressesActive[​](#addressesactive "Direct link to AddressesActive")

Total count of addresses which are used for creation connections with connection pools

### AddressesBanned[​](#addressesbanned "Direct link to AddressesBanned")

Total count of addresses which are banned as faulty for creation connections with connection pools

### AggregatorThreads[​](#aggregatorthreads "Direct link to AggregatorThreads")

Number of threads in the Aggregator thread pool.

### AggregatorThreadsActive[​](#aggregatorthreadsactive "Direct link to AggregatorThreadsActive")

Number of threads in the Aggregator thread pool running a task.

### AggregatorThreadsScheduled[​](#aggregatorthreadsscheduled "Direct link to AggregatorThreadsScheduled")

Number of queued or active jobs in the Aggregator thread pool.

### AsyncInsertCacheSize[​](#asyncinsertcachesize "Direct link to AsyncInsertCacheSize")

Number of async insert hash id in cache

### AsynchronousInsertQueueBytes[​](#asynchronousinsertqueuebytes "Direct link to AsynchronousInsertQueueBytes")

Number of pending bytes in the AsynchronousInsert queue.

### AsynchronousInsertQueueSize[​](#asynchronousinsertqueuesize "Direct link to AsynchronousInsertQueueSize")

Number of pending tasks in the AsynchronousInsert queue.

### AsynchronousInsertThreads[​](#asynchronousinsertthreads "Direct link to AsynchronousInsertThreads")

Number of threads in the AsynchronousInsert thread pool.

### AsynchronousInsertThreadsActive[​](#asynchronousinsertthreadsactive "Direct link to AsynchronousInsertThreadsActive")

Number of threads in the AsynchronousInsert thread pool running a task.

### AsynchronousInsertThreadsScheduled[​](#asynchronousinsertthreadsscheduled "Direct link to AsynchronousInsertThreadsScheduled")

Number of queued or active jobs in the AsynchronousInsert thread pool.

### AsynchronousReadWait[​](#asynchronousreadwait "Direct link to AsynchronousReadWait")

Number of threads waiting for asynchronous read.

### AttachedDatabase[​](#attacheddatabase "Direct link to AttachedDatabase")

Active databases.

### AttachedDictionary[​](#attacheddictionary "Direct link to AttachedDictionary")

Active dictionaries.

### AttachedReplicatedTable[​](#attachedreplicatedtable "Direct link to AttachedReplicatedTable")

Active replicated tables.

### AttachedTable[​](#attachedtable "Direct link to AttachedTable")

Active tables.

### AttachedView[​](#attachedview "Direct link to AttachedView")

Active views.

### AvroSchemaCacheBytes[​](#avroschemacachebytes "Direct link to AvroSchemaCacheBytes")

Size of the Avro schema cache in bytes

### AvroSchemaCacheCells[​](#avroschemacachecells "Direct link to AvroSchemaCacheCells")

Number of cached Avro schemas

### AvroSchemaRegistryCacheBytes[​](#avroschemaregistrycachebytes "Direct link to AvroSchemaRegistryCacheBytes")

Size of the Avro schema registry cache in bytes

### AvroSchemaRegistryCacheCells[​](#avroschemaregistrycachecells "Direct link to AvroSchemaRegistryCacheCells")

Number of entries in Avro schema registry cache

### AzureRequests[​](#azurerequests "Direct link to AzureRequests")

Number of currently executing Azure requests

### BackgroundBufferFlushSchedulePoolSize[​](#backgroundbufferflushschedulepoolsize "Direct link to BackgroundBufferFlushSchedulePoolSize")

Limit on number of tasks in BackgroundBufferFlushSchedulePool

### BackgroundBufferFlushSchedulePoolTask[​](#backgroundbufferflushschedulepooltask "Direct link to BackgroundBufferFlushSchedulePoolTask")

Number of active tasks in BackgroundBufferFlushSchedulePool. This pool is used for periodic Buffer flushes

### BackgroundCommonPoolSize[​](#backgroundcommonpoolsize "Direct link to BackgroundCommonPoolSize")

Limit on number of tasks in an associated background pool

### BackgroundCommonPoolTask[​](#backgroundcommonpooltask "Direct link to BackgroundCommonPoolTask")

Number of active tasks in an associated background pool

### BackgroundDistributedSchedulePoolSize[​](#backgrounddistributedschedulepoolsize "Direct link to BackgroundDistributedSchedulePoolSize")

Limit on number of tasks in BackgroundDistributedSchedulePool

### BackgroundDistributedSchedulePoolTask[​](#backgrounddistributedschedulepooltask "Direct link to BackgroundDistributedSchedulePoolTask")

Number of active tasks in BackgroundDistributedSchedulePool. This pool is used for distributed sends that is done in background.

### BackgroundFetchesPoolSize[​](#backgroundfetchespoolsize "Direct link to BackgroundFetchesPoolSize")

Limit on number of simultaneous fetches in an associated background pool

### BackgroundFetchesPoolTask[​](#backgroundfetchespooltask "Direct link to BackgroundFetchesPoolTask")

Number of active fetches in an associated background pool

### BackgroundMergesAndMutationsPoolSize[​](#backgroundmergesandmutationspoolsize "Direct link to BackgroundMergesAndMutationsPoolSize")

Limit on number of active merges and mutations in an associated background pool

### BackgroundMergesAndMutationsPoolTask[​](#backgroundmergesandmutationspooltask "Direct link to BackgroundMergesAndMutationsPoolTask")