system.metrics

### PartsPreActive[​](#partspreactive "Direct link to PartsPreActive")

The part is in data\_parts, but not used for SELECTs.

### PartsPreCommitted[​](#partsprecommitted "Direct link to PartsPreCommitted")

Deprecated. See PartsPreActive.

### PartsTemporary[​](#partstemporary "Direct link to PartsTemporary")

The part is generating now, it is not in data\_parts list.

### PartsWide[​](#partswide "Direct link to PartsWide")

Wide parts.

### PendingAsyncInsert[​](#pendingasyncinsert "Direct link to PendingAsyncInsert")

Number of asynchronous inserts that are waiting for flush.

### PolygonDictionaryThreads[​](#polygondictionarythreads "Direct link to PolygonDictionaryThreads")

Number of threads in the threadpool for polygon dictionaries.

### PolygonDictionaryThreadsActive[​](#polygondictionarythreadsactive "Direct link to PolygonDictionaryThreadsActive")

Number of active threads in the threadpool for polygon dictionaries.

### PolygonDictionaryThreadsScheduled[​](#polygondictionarythreadsscheduled "Direct link to PolygonDictionaryThreadsScheduled")

Number of queued or active jobs in the threadpool for polygon dictionaries.

### PostgreSQLConnection[​](#postgresqlconnection "Direct link to PostgreSQLConnection")

Number of client connections using PostgreSQL protocol

### PrimaryIndexCacheBytes[​](#primaryindexcachebytes "Direct link to PrimaryIndexCacheBytes")

Total size of primary index cache in bytes

### PrimaryIndexCacheFiles[​](#primaryindexcachefiles "Direct link to PrimaryIndexCacheFiles")

Total number of index files cached in the primary index cache

### Query[​](#query "Direct link to Query")

Number of executing queries

### QueryCacheBytes[​](#querycachebytes "Direct link to QueryCacheBytes")

Total size of the query cache in bytes

### QueryCacheEntries[​](#querycacheentries "Direct link to QueryCacheEntries")

Total number of entries in the query cache

### QueryConditionCacheBytes[​](#queryconditioncachebytes "Direct link to QueryConditionCacheBytes")

Total size of the query condition cache in bytes

### QueryConditionCacheEntries[​](#queryconditioncacheentries "Direct link to QueryConditionCacheEntries")

Total number of entries in the query condition cache

### QueryNonInternal[​](#querynoninternal "Direct link to QueryNonInternal")

Number of executing non-internal queries (queries initiated by users, excluding internal queries from ClickHouse)

### QueryPipelineExecutorThreads[​](#querypipelineexecutorthreads "Direct link to QueryPipelineExecutorThreads")

Number of threads in the PipelineExecutor thread pool.

### QueryPipelineExecutorThreadsActive[​](#querypipelineexecutorthreadsactive "Direct link to QueryPipelineExecutorThreadsActive")

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

### QueryPipelineExecutorThreadsScheduled[​](#querypipelineexecutorthreadsscheduled "Direct link to QueryPipelineExecutorThreadsScheduled")

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

### QueryPreempted[​](#querypreempted "Direct link to QueryPreempted")

Number of running tasks which are paused and waiting due to 'priority' setting.

### QueryThread[​](#querythread "Direct link to QueryThread")

Number of query processing threads

### RWLockActiveReaders[​](#rwlockactivereaders "Direct link to RWLockActiveReaders")

Number of threads holding read lock in a table RWLock.

### RWLockActiveWriters[​](#rwlockactivewriters "Direct link to RWLockActiveWriters")

Number of threads holding write lock in a table RWLock.

### RWLockWaitingReaders[​](#rwlockwaitingreaders "Direct link to RWLockWaitingReaders")

Number of threads waiting for read on a table RWLock.

### RWLockWaitingWriters[​](#rwlockwaitingwriters "Direct link to RWLockWaitingWriters")

Number of threads waiting for write on a table RWLock.

### Read[​](#read "Direct link to Read")

Number of read (read, pread, io\_getevents, etc.) syscalls in fly

### ReadTaskRequestsSent[​](#readtaskrequestssent "Direct link to ReadTaskRequestsSent")

The current number of callback requests in flight from the remote server back to the initiator server to choose the read task (for s3Cluster table function and similar). Measured on the remote server side.

### ReadonlyDisks[​](#readonlydisks "Direct link to ReadonlyDisks")

Number of disks that were marked as readonly during disk check.

### ReadonlyReplica[​](#readonlyreplica "Direct link to ReadonlyReplica")

Number of Replicated tables that are currently in readonly state due to re-initialization after ZooKeeper session loss or due to startup without ZooKeeper configured.

### RefreshableViews[​](#refreshableviews "Direct link to RefreshableViews")

Number materialized views with periodic refreshing (REFRESH)

### RefreshingViews[​](#refreshingviews "Direct link to RefreshingViews")

Number of materialized views currently executing a refresh

### RemoteRead[​](#remoteread "Direct link to RemoteRead")

Number of read with remote reader in fly

### ReplicaReady[​](#replicaready "Direct link to ReplicaReady")

Indicates if the replica is ready for queries: 0 = no, 1 = yes

### ReplicatedChecks[​](#replicatedchecks "Direct link to ReplicatedChecks")

Number of data parts checking for consistency

### ReplicatedFetch[​](#replicatedfetch "Direct link to ReplicatedFetch")

Number of data parts being fetched from replica

### ReplicatedSend[​](#replicatedsend "Direct link to ReplicatedSend")

Number of data parts being sent to replicas

### RestartReplicaThreads[​](#restartreplicathreads "Direct link to RestartReplicaThreads")

Number of threads in the RESTART REPLICA thread pool.

### RestartReplicaThreadsActive[​](#restartreplicathreadsactive "Direct link to RestartReplicaThreadsActive")

Number of threads in the RESTART REPLICA thread pool running a task.

### RestartReplicaThreadsScheduled[​](#restartreplicathreadsscheduled "Direct link to RestartReplicaThreadsScheduled")

Number of queued or active jobs in the RESTART REPLICA thread pool.

### RestoreThreads[​](#restorethreads "Direct link to RestoreThreads")

Number of threads in the thread pool for RESTORE.

### RestoreThreadsActive[​](#restorethreadsactive "Direct link to RestoreThreadsActive")

Number of threads in the thread pool for RESTORE running a task.

### RestoreThreadsScheduled[​](#restorethreadsscheduled "Direct link to RestoreThreadsScheduled")

Number of queued or active jobs for RESTORE.

### Revision[​](#revision "Direct link to Revision")

Revision of the server. It is a number incremented for every release or release candidate except patch releases.

### S3CachedCredentialsProviders[​](#s3cachedcredentialsproviders "Direct link to S3CachedCredentialsProviders")

Total number of cached credentials providers

### S3Requests[​](#s3requests "Direct link to S3Requests")

S3 requests count

### SchedulerIOReadScheduled[​](#schedulerioreadscheduled "Direct link to SchedulerIOReadScheduled")

Number of IO reads are being scheduled currently

### SchedulerIOWriteScheduled[​](#scheduleriowritescheduled "Direct link to SchedulerIOWriteScheduled")

Number of IO writes are being scheduled currently

### SendExternalTables[​](#sendexternaltables "Direct link to SendExternalTables")

Number of connections that are sending data for external tables to remote servers. External tables are used to implement GLOBAL IN and GLOBAL JOIN operators with distributed subqueries.

### SendScalars[​](#sendscalars "Direct link to SendScalars")

Number of connections that are sending data for scalars to remote servers.

### SerializationCacheBytesInMemory[​](#serializationcachebytesinmemory "Direct link to SerializationCacheBytesInMemory")

Total size of the serialization cache in bytes including only the values

### SerializationCacheBytesInMemoryAllocated[​](#serializationcachebytesinmemoryallocated "Direct link to SerializationCacheBytesInMemoryAllocated")

Total size of the serialization cache in bytes including keys and overhead from empty slots

### SerializationCacheCount[​](#serializationcachecount "Direct link to SerializationCacheCount")

Total number of entries in the serialization cache