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system.metrics

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 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) — Metric name.
  • value (Int64) — Metric value.
  • description (String) — Metric description.

You can find all supported metrics in source file 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​

ASTFuzzerAccumulatedFragments​

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

ActiveTimersInQueryProfiler​

Number of Active thread local timers in QueryProfiler

AddressesActive​

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

AddressesBanned​

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

AggregatorThreads​

Number of threads in the Aggregator thread pool.

AggregatorThreadsActive​

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

AggregatorThreadsScheduled​

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

AsyncInsertCacheSize​

Number of async insert hash id in cache

AsynchronousInsertQueueBytes​

Number of pending bytes in the AsynchronousInsert queue.

AsynchronousInsertQueueSize​

Number of pending tasks in the AsynchronousInsert queue.

AsynchronousInsertThreads​

Number of threads in the AsynchronousInsert thread pool.

AsynchronousInsertThreadsActive​

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

AsynchronousInsertThreadsScheduled​

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

AsynchronousReadWait​

Number of threads waiting for asynchronous read.

AttachedDatabase​

Active databases.

AttachedDictionary​

Active dictionaries.

AttachedReplicatedTable​

Active replicated tables.

AttachedTable​

Active tables.

AttachedView​

Active views.

AvroSchemaCacheBytes​

Size of the Avro schema cache in bytes

AvroSchemaCacheCells​

Number of cached Avro schemas

AvroSchemaRegistryCacheBytes​

Size of the Avro schema registry cache in bytes

AvroSchemaRegistryCacheCells​

Number of entries in Avro schema registry cache

AzureRequests​

Number of currently executing Azure requests

BackgroundBufferFlushSchedulePoolSize​

Limit on number of tasks in BackgroundBufferFlushSchedulePool

BackgroundBufferFlushSchedulePoolTask​

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

BackgroundCommonPoolSize​

Limit on number of tasks in an associated background pool

BackgroundCommonPoolTask​

Number of active tasks in an associated background pool

BackgroundDistributedSchedulePoolSize​

Limit on number of tasks in BackgroundDistributedSchedulePool

BackgroundDistributedSchedulePoolTask​

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

BackgroundFetchesPoolSize​

Limit on number of simultaneous fetches in an associated background pool

BackgroundFetchesPoolTask​

Number of active fetches in an associated background pool

BackgroundMergesAndMutationsPoolSize​

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

BackgroundMergesAndMutationsPoolTask​

Number of active merges and mutations in an associated background pool

BackgroundMessageBrokerSchedulePoolSize​

Limit on number of tasks in BackgroundMessageBrokerSchedulePool for message streaming

BackgroundMessageBrokerSchedulePoolTask​

Number of active tasks in BackgroundMessageBrokerSchedulePool for message streaming

BackgroundMovePoolSize​

Limit on number of tasks in BackgroundProcessingPool for moves

BackgroundMovePoolTask​

Number of active tasks in BackgroundProcessingPool for moves

BackgroundSchedulePoolSize​

Limit on number of tasks in BackgroundSchedulePool. This pool is used for periodic ReplicatedMergeTree tasks, like cleaning old data parts, altering data parts, replica re-initialization, etc.

BackgroundSchedulePoolTask​

Number of active tasks in BackgroundSchedulePool. This pool is used for periodic ReplicatedMergeTree tasks, like cleaning old data parts, altering data parts, replica re-initialization, etc.

BackupsIOThreads​

Number of threads in the BackupsIO thread pool.

BackupsIOThreadsActive​

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

BackupsIOThreadsScheduled​

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

BackupsThreads​

Number of threads in the thread pool for BACKUP.

BackupsThreadsActive​

Number of threads in thread pool for BACKUP running a task.

BackupsThreadsScheduled​

Number of queued or active jobs for BACKUP.

BcryptCacheBytes​

Total size of the bcrypt authentication cache in bytes

BcryptCacheSize​

Total number of entries in the bcrypt authentication cache

BlobCopierThreads​

Number of threads in the thread pool of the object storage disk background replication process

BlobCopierThreadsActive​

Number of threads in the thread pool of the object storage disk background replication process running a task

BlobCopierThreadsScheduled​

Number of queued or active tasks in the thread pool of the object storage disk background replication process

BlobKillerThreads​

Number of threads in the thread pool of the object storage disk background removal process

BlobKillerThreadsActive​

Number of threads in the thread pool of the object storage disk background removal process running a task

BlobKillerThreadsScheduled​

Number of queued or active tasks in the thread pool of the object storage disk background removal process

BrokenDisks​

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

BrokenDistributedBytesToInsert​

Number of bytes for asynchronous insertion into Distributed tables that has been marked as broken. Number of bytes for every shard is summed.

BrokenDistributedFilesToInsert​

Number of files for asynchronous insertion into Distributed tables that has been marked as broken. Number of files for every shard is summed.

BuildVectorSimilarityIndexThreads​

Number of threads in the build vector similarity index thread pool.

BuildVectorSimilarityIndexThreadsActive​

Number of threads in the build vector similarity index thread pool running a task.

BuildVectorSimilarityIndexThreadsScheduled​

Number of queued or active jobs in the build vector similarity index thread pool.

CacheDetachedFileSegments​

Number of existing detached cache file segments

CacheDictionaryThreads​

Number of threads in the CacheDictionary thread pool.

CacheDictionaryThreadsActive​

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

CacheDictionaryThreadsScheduled​

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

CacheDictionaryUpdateQueueBatches​

Number of 'batches' (a set of keys) in update queue in CacheDictionaries.

CacheDictionaryUpdateQueueKeys​

Exact number of keys in update queue in CacheDictionaries.

CacheFileSegments​

Number of existing cache file segments

CacheWarmerBytesInProgress​

Total size of remote file segments waiting to be asynchronously loaded into filesystem cache.

ColumnsDescriptionsCacheSize​

Size of ColumnsDescriptions cache (per-table cache)

CompiledExpressionCacheBytes​

Total bytes used for the cache of JIT-compiled code

CompiledExpressionCacheCount​

Total entries in the cache of JIT-compiled code

Compressing​

Number of compress operations using internal compression codecs

CompressionThread​

Number of threads in compression thread pools.

CompressionThreadActive​

Number of threads in compression thread pools running a task.

CompressionThreadScheduled​

Number of queued or active jobs in compression thread pools.

ConcurrencyControlAcquired​

Total number of acquired CPU slots

ConcurrencyControlAcquiredNonCompeting​

Total number of acquired CPU slots that are not considered competing (the first thread if fair_round_robin scheduler is in use)

ConcurrencyControlPreempted​

Total number of preempted threads waiting for CPU slot

ConcurrencyControlScheduled​

Total number of CPU slot requests are being scheduled currently

ConcurrencyControlSoftLimit​

Value of soft limit on number of CPU slots

ConcurrentHashJoinPoolThreads​

Number of threads in the thread pool for concurrent hash join.

ConcurrentHashJoinPoolThreadsActive​

Number of threads in the thread pool for concurrent hash join running a task.

ConcurrentHashJoinPoolThreadsScheduled​

Number of queued or active jobs in the thread pool for concurrent hash join.

ConcurrentQueryAcquired​

Total number of acquired query slots

ConcurrentQueryScheduled​

Total number of query slot requests are being scheduled currently

ContextLockWait​

Number of threads waiting for lock in Context. This is global lock.

CoordinatedMergesCoordinatorAssignedMerges​

Number of assigned merges in merge coordinator state.

CoordinatedMergesCoordinatorRunningMerges​

Number of running merges visible for merge coordinator.

CoordinatedMergesWorkerAssignedMerges​

Number of assigned merges in merge worker state.

CreatedTimersInQueryProfiler​

Number of Created thread local timers in QueryProfiler

DDLWorkerThreads​

Number of threads in the DDLWorker thread pool for ON CLUSTER queries.

DDLWorkerThreadsActive​

Number of threads in the DDLWORKER thread pool for ON CLUSTER queries running a task.

DDLWorkerThreadsScheduled​

Number of queued or active jobs in the DDLWORKER thread pool for ON CLUSTER queries.

DNSAddressesCacheBytes​

Size of the DNS addresses cache in bytes

DNSAddressesCacheSize​

Number of cached DNS addresses

DNSHostsCacheBytes​

Size of the DNS hosts cache in bytes

DNSHostsCacheSize​

Number of cached DNS hosts

DatabaseBackupThreads​

Number of threads in the DatabaseBackup thread pool.

DatabaseBackupThreadsActive​

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

DatabaseBackupThreadsScheduled​

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

DatabaseCatalogThreads​

Number of threads in the DatabaseCatalog thread pool.

DatabaseCatalogThreadsActive​

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

DatabaseCatalogThreadsScheduled​

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

DatabaseOnDiskThreads​

Number of threads in the DatabaseOnDisk thread pool.

DatabaseOnDiskThreadsActive​

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

DatabaseOnDiskThreadsScheduled​

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

DatabaseReplicatedCreateTablesThreads​

Number of threads in the threadpool for table creation in DatabaseReplicated.

DatabaseReplicatedCreateTablesThreadsActive​

Number of active threads in the threadpool for table creation in DatabaseReplicated.

DatabaseReplicatedCreateTablesThreadsScheduled​

Number of queued or active jobs in the threadpool for table creation in DatabaseReplicated.

Decompressing​

Number of decompress operations using internal compression codecs

DelayedInserts​

Number of INSERT queries that are throttled due to high number of active data parts for partition in a MergeTree table.

DeltaLakeSnapshotCacheSizeElements​

Size in elements of DeltaLake snapshot cache.

DestroyAggregatesThreads​

Number of threads in the thread pool for destroy aggregate states.

DestroyAggregatesThreadsActive​

Number of threads in the thread pool for destroy aggregate states running a task.

DestroyAggregatesThreadsScheduled​

Number of queued or active jobs in the thread pool for destroy aggregate states.

DictCacheRequests​

Number of requests in fly to data sources of dictionaries of cache type.

DiskConnectionsStored​

Total count of sessions stored in the session pool for disks

DiskConnectionsTotal​

Total count of all sessions: stored in the pool and actively used right now for disks

DiskObjectStorageAsyncThreads​

Obsolete metric, shows nothing.

DiskObjectStorageAsyncThreadsActive​

Obsolete metric, shows nothing.

DiskPlainRewritableAzureDirectoryMapSize​

Number of local-to-remote path entries in the 'plain_rewritable' in-memory map for AzureObjectStorage.

DiskPlainRewritableAzureFileCount​

Number of file entries in the 'plain_rewritable' in-memory map for AzureObjectStorage.

DiskPlainRewritableLocalDirectoryMapSize​

Number of local-to-remote path entries in the 'plain_rewritable' in-memory map for LocalObjectStorage.

DiskPlainRewritableLocalFileCount​

Number of file entries in the 'plain_rewritable' in-memory map for LocalObjectStorage.

DiskPlainRewritableS3DirectoryMapSize​

Number of local-to-remote path entries in the 'plain_rewritable' in-memory map for S3ObjectStorage.

DiskPlainRewritableS3FileCount​

Number of file entries in the 'plain_rewritable' in-memory map for S3ObjectStorage.

DiskS3NoSuchKeyErrors​

The number of NoSuchKey errors that occur when reading data from S3 cloud storage through ClickHouse disks.

DiskSpaceReservedForMerge​

Disk space reserved for currently running background merges. It is slightly more than the total size of currently merging parts.

DistrCacheAllocatedConnections​

Number of currently allocated connections to Distributed Cache connection pool

DistrCacheBorrowedConnections​

Number of currently borrowed connections to Distributed Cache connection pool

DistrCacheOpenedConnections​

Number of open connections to Distributed Cache

DistrCacheReadBuffers​

Number of distributed cache read buffers

DistrCacheReadRequests​

Number of executed Read requests to Distributed Cache

DistrCacheRegisteredServers​

Number of distributed cache registered servers

DistrCacheRegisteredServersCurrentAZ​

Number of distributed cache registered servers in current az

DistrCacheServerConnections​

Number of open connections to ClickHouse server from Distributed Cache

DistrCacheServerRegistryConnections​

Number of active connections to ClickHouse server from Distributed Cache (not marked as cancelled because of limit)

DistrCacheServerS3CachedClients​

Number of distributed cache S3 cached clients

DistrCacheSharedLimitCount​

Number of opened connections according to DistributedCache::ConnectionPool::SharedLimit

DistrCacheUsedConnections​

Number of currently used connections to Distributed Cache

DistrCacheWriteBuffers​

Number of distributed cache write buffers

DistrCacheWriteRequests​

Number of executed Write requests to Distributed Cache

DistributedBytesToInsert​

Number of pending bytes to process for asynchronous insertion into Distributed tables. Number of bytes for every shard is summed.

DistributedFilesToInsert​

Number of pending files to process for asynchronous insertion into Distributed tables. Number of files for every shard is summed.

DistributedIndexAnalysisThreads​

Number of threads in the thread pool for distributed index analysis.

DistributedIndexAnalysisThreadsActive​

Number of threads in the thread pool for distributed index analysis running a task.

DistributedIndexAnalysisThreadsScheduled​

Number of queued or active jobs in the distributed idnex analysis thread pool.

DistributedInsertThreads​

Number of threads used for INSERT into Distributed.

DistributedInsertThreadsActive​

Number of threads used for INSERT into Distributed running a task.

DistributedInsertThreadsScheduled​

Number of queued or active jobs used for INSERT into Distributed.

DistributedSend​

Number of connections to remote servers sending data that was INSERTed into Distributed tables. Both synchronous and asynchronous mode.

DropDistributedCacheThreads​

Number of threads in the threadpool for drop distributed cache query.

DropDistributedCacheThreadsActive​

Number of active threads in the threadpool for drop distributed cache query.

DropDistributedCacheThreadsScheduled​

Number of queued or active jobs in the threadpool for drop distributed cache.

EphemeralNode​

Number of ephemeral nodes hold in ZooKeeper.

FilesystemCacheDelayedCleanupElements​

Filesystem cache elements in background cleanup queue

FilesystemCacheDownloadQueueElements​

Filesystem cache elements in download queue

FilesystemCacheElements​

Filesystem cache elements (file segments)

FilesystemCacheHoldFileSegments​

Filesystem cache file segment which are currently hold as unreleasable

FilesystemCacheKeys​

Number of keys in filesystem cache

FilesystemCacheReadBuffers​

Number of active cache buffers

FilesystemCacheReserveThreads​

Threads number trying to reserve space in cache

FilesystemCacheSize​

Filesystem cache size in bytes

FilesystemCacheSizeLimit​

Filesystem cache size limit in bytes

FilteringMarksWithPrimaryKey​

Number of threads currently doing filtering of mark ranges by the primary key

FilteringMarksWithSecondaryKeys​

Number of threads currently doing filtering of mark ranges by secondary keys

FormatParsingThreads​

Number of threads in the thread pool used for parsing input.

FormatParsingThreadsActive​

Number of threads in the thread pool used for parsing input running a task.

FormatParsingThreadsScheduled​

Number of queued or active jobs in the thread pool used for parsing input.

FreezePartThreads​

Number of threads in the threadpool for freezing data parts.

FreezePartThreadsActive​

Number of active threads in the threadpool for freezing data parts.

FreezePartThreadsScheduled​

Number of queued or active jobs in the threadpool for freezing data parts.

GlobalThread​

Number of threads in global thread pool.

GlobalThreadActive​

Number of threads in global thread pool running a task.

GlobalThreadScheduled​

Number of queued or active jobs in global thread pool.

HTTPConnection​

Number of connections to HTTP server

HTTPConnectionsStored​

Total count of sessions stored in the session pool for http hosts

HTTPConnectionsTotal​

Total count of all sessions: stored in the pool and actively used right now for http hosts

HashedDictionaryThreads​

Number of threads in the HashedDictionary thread pool.

HashedDictionaryThreadsActive​

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

HashedDictionaryThreadsScheduled​

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

HiveFilesCacheBytes​

Size of the hive cache in bytes

HiveFilesCacheFiles​

Number of cached files in the hive cache

HiveMetadataFilesCacheBytes​

Size of the hive metadata cache in bytes

HiveMetadataFilesCacheFiles​

Number of cached files in the hive metadata cache

IDiskCopierThreads​

Number of threads for copying data between disks of different types.

IDiskCopierThreadsActive​

Number of threads for copying data between disks of different types running a task.

IDiskCopierThreadsScheduled​

Number of queued or active jobs for copying data between disks of different types.

IOPrefetchThreads​

Number of threads in the IO prefetch thread pool.

IOPrefetchThreadsActive​

Number of threads in the IO prefetch thread pool running a task.

IOPrefetchThreadsScheduled​

Number of queued or active jobs in the IO prefetch thread pool.

IOThreads​

Number of threads in the IO thread pool.

IOThreadsActive​

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

IOThreadsScheduled​

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

IOUringInFlightEvents​

Number of io_uring SQEs in flight

IOUringPendingEvents​

Number of io_uring SQEs waiting to be submitted

IOWriterThreads​

Number of threads in the IO writer thread pool.

IOWriterThreadsActive​

Number of threads in the IO writer thread pool running a task.

IOWriterThreadsScheduled​

Number of queued or active jobs in the IO writer thread pool.

IcebergCatalogThreads​

Number of threads in the IcebergCatalog thread pool.

IcebergCatalogThreadsActive​

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

IcebergCatalogThreadsScheduled​

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

IcebergMetadataFilesCacheBytes​

Size of the Iceberg metadata cache in bytes

IcebergMetadataFilesCacheFiles​

Number of cached files in the Iceberg metadata cache

IndexMarkCacheBytes​

Total size of mark cache for secondary indices in bytes

IndexMarkCacheFiles​

Total number of mark files cached in the mark cache for secondary indices

IndexUncompressedCacheBytes​

Total size of uncompressed cache in bytes for secondary indices. Uncompressed cache does not usually improve the performance and should be mostly avoided

IndexUncompressedCacheCells​

Total number of entries in the uncompressed cache for secondary indices. Each entry represents a decompressed block of data. Uncompressed cache does not usually improve performance and should be mostly avoided

InterserverConnection​

Number of connections from other replicas to fetch parts

IsServerShuttingDown​

Indicates if the server is shutting down: 0 = no, 1 = yes

KafkaAssignedPartitions​

Number of partitions Kafka tables currently assigned to

KafkaBackgroundReads​

Number of background reads currently working (populating materialized views from Kafka)

KafkaConsumers​

Number of active Kafka consumers

KafkaConsumersInUse​

Number of consumers which are currently used by direct or background reads

KafkaConsumersWithAssignment​

Number of active Kafka consumers which have some partitions assigned.

KafkaLibrdkafkaThreads​

Number of active librdkafka threads

KafkaProducers​

Number of active Kafka producer created

KafkaWrites​

Number of currently running inserts to Kafka

KeeperAliveConnections​

Number of alive connections

KeeperOutstandingRequests​

Number of outstanding requests

LicenseRemainingSeconds​

Remaining seconds of the license validity period.

LocalThread​

Obsolete. Number of threads in local thread pools. The threads in local thread pools are taken from the global thread pool.

LocalThreadActive​

Obsolete. Number of threads in local thread pools running a task.

LocalThreadScheduled​

Obsolete. Number of queued or active jobs in local thread pools.

MMapCacheCells​

The number of files opened with mmap (mapped in memory). This is used for queries with the setting local_filesystem_read_method set to mmap. The files opened with mmap are kept in the cache to avoid costly TLB flushes.

MMappedFileBytes​

Sum size of mmapped file regions.

MMappedFiles​

Total number of mmapped files.

MarkCacheBytes​

Total size of mark cache in bytes

MarkCacheFiles​

Total number of mark files cached in the mark cache

MarksLoaderThreads​

Number of threads in thread pool for loading marks.

MarksLoaderThreadsActive​

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

MarksLoaderThreadsScheduled​

Number of queued or active jobs in the thread pool for loading marks.

MaxAllocatedEphemeralLockSequentialNumber​

The maximum sequential number allocated for ephemeral lock znodes in ZooKeeper. Primarily influenced by the block numbers.

MaxDDLEntryID​

Max processed DDL entry of DDLWorker.

MaxPushedDDLEntryID​

Max DDL entry of DDLWorker that pushed to zookeeper.

MemoryTracking​

Total amount of memory (bytes) allocated by the server.

MemoryTrackingUncorrected​

Total amount of memory (bytes) allocated by the server not corrected by RSS.

Merge​

Number of executing background merges

MergeJoinBlocksCacheBytes​

Total bytes used for cached blocks in MergeJoin

MergeJoinBlocksCacheCount​

Total cached blocks in MergeJoin

MergeParts​

Number of source parts participating in current background merges

MergeTreeAllRangesAnnouncementsSent​

The current number of announcement being sent in flight from the remote server to the initiator server about the set of data parts (for MergeTree tables). Measured on the remote server side.

MergeTreeBackgroundExecutorThreads​

Number of threads in the MergeTreeBackgroundExecutor thread pool.

MergeTreeBackgroundExecutorThreadsActive​

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

MergeTreeBackgroundExecutorThreadsScheduled​

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

MergeTreeDataSelectExecutorThreads​

Number of threads in the MergeTreeDataSelectExecutor thread pool.

MergeTreeDataSelectExecutorThreadsActive​

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

MergeTreeDataSelectExecutorThreadsScheduled​

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

MergeTreeFetchPartitionThreads​

Number of threads for ALTER TABLE FETCH PARTITION

MergeTreeFetchPartitionThreadsActive​

Number of threads for ALTER TABLE FETCH PARTITION fetching part

MergeTreeFetchPartitionThreadsScheduled​

Number of queued or active part fetches in ALTER TABLE FETCH PARTITION

MergeTreeOutdatedPartsLoaderThreads​

Number of threads in the threadpool for loading Outdated data parts.

MergeTreeOutdatedPartsLoaderThreadsActive​

Number of active threads in the threadpool for loading Outdated data parts.

MergeTreeOutdatedPartsLoaderThreadsScheduled​

Number of queued or active jobs in the threadpool for loading Outdated data parts.

MergeTreePartsCleanerThreads​

Number of threads in the MergeTree parts cleaner thread pool.

MergeTreePartsCleanerThreadsActive​

Number of threads in the MergeTree parts cleaner thread pool running a task.

MergeTreePartsCleanerThreadsScheduled​

Number of queued or active jobs in the MergeTree parts cleaner thread pool.

MergeTreePartsLoaderThreads​

Number of threads in the MergeTree parts loader thread pool.

MergeTreePartsLoaderThreadsActive​

Number of threads in the MergeTree parts loader thread pool running a task.

MergeTreePartsLoaderThreadsScheduled​

Number of queued or active jobs in the MergeTree parts loader thread pool.

MergeTreeReadTaskRequestsSent​

The current number of callback requests in flight from the remote server back to the initiator server to choose the read task (for MergeTree tables). Measured on the remote server side.

MergeTreeSnapshotCommitThreads​

Number of threads used to commit snapshot

MergeTreeSnapshotCommitThreadsActive​

Number of active threads used to commit snapshot

MergeTreeSnapshotCommitThreadsScheduled​

Number of scheduled threads used to commit snapshot

MergeTreeSubcolumnsReaderThreads​

Number of threads in the thread pool used for subcolumns reading in MergeTree.

MergeTreeSubcolumnsReaderThreadsActive​

Number of threads in the thread pool used for subcolumns reading in MergeTree running a task.

MergeTreeSubcolumnsReaderThreadsScheduled​

Number of queued or active jobs in the thread pool used for subcolumns reading in MergeTree.

MergeTreeUnexpectedPartsLoaderThreads​

Number of threads in the threadpool for loading Unexpected data parts.

MergeTreeUnexpectedPartsLoaderThreadsActive​

Number of active threads in the threadpool for loading Unexpected data parts.

MergeTreeUnexpectedPartsLoaderThreadsScheduled​

Number of queued or active jobs in the threadpool for loading Unexpected data parts.

MergesMutationsMemoryTracking​

Total amount of memory (bytes) allocated by background tasks (merges and mutations).

MetadataFromKeeperCacheObjects​

Number of objects in disk metadata cache.

Move​

Number of currently executing moves

MySQLConnection​

Number of client connections using MySQL protocol

NamedCollection​

Number of named collections

NetworkReceive​

Number of threads receiving data from network. Only ClickHouse-related network interaction is included, not by 3rd party libraries.

NetworkSend​

Number of threads sending data to network. Only ClickHouse-related network interaction is included, not by 3rd party libraries.

ObjectStorageAzureThreads​

Number of threads in the AzureObjectStorage thread pool.

ObjectStorageAzureThreadsActive​

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

ObjectStorageAzureThreadsScheduled​

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

ObjectStorageQueueMetadataCacheSizeBytes​

Size in bytes of ObjectStorageQueue metadata cache.

ObjectStorageQueueMetadataCacheSizeElements​

Size in elements of ObjectStorageQueue metadata cache.

ObjectStorageQueueRegisteredServers​

Number of registered servers in StorageS3(Azure)Queue

ObjectStorageQueueShutdownThreads​

Number of threads in object storage queue shutdown pool.

ObjectStorageQueueShutdownThreadsActive​

Number of threads in object storage queue shutdown pool running a task.

ObjectStorageQueueShutdownThreadsScheduled​

Number of queued or active jobs in object storage queue shutdown pool.

ObjectStorageS3Threads​

Number of threads in the S3ObjectStorage thread pool.

ObjectStorageS3ThreadsActive​

Number of threads in the S3ObjectStorage thread pool running a task.

ObjectStorageS3ThreadsScheduled​

Number of queued or active jobs in the S3ObjectStorage thread pool.

OpenFileForRead​

Number of files open for reading

OpenFileForWrite​

Number of files open for writing

OutdatedPartsLoadingThreads​

Number of threads in the threadpool for loading Outdated data parts.

OutdatedPartsLoadingThreadsActive​

Number of active threads in the threadpool for loading Outdated data parts.

OutdatedPartsLoadingThreadsScheduled​

Number of queued or active jobs in the threadpool for loading Outdated data parts.

PageCacheBytes​

Total size of userspace page cache in bytes

PageCacheCells​

Total number of entries in the userspace page cache

ParallelCompressedWriteBufferThreads​

Number of threads in all instances of ParallelCompressedWriteBuffer - these threads are doing parallel compression and writing

ParallelCompressedWriteBufferWait​

Number of threads in all instances of ParallelCompressedWriteBuffer that are currently waiting for buffer to become available for writing

ParallelFormattingOutputFormatThreads​

Number of threads in the ParallelFormattingOutputFormatThreads thread pool.

ParallelFormattingOutputFormatThreadsActive​

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

ParallelFormattingOutputFormatThreadsScheduled​

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

ParallelWithQueryActiveThreads​

Number of active threads in the threadpool for processing PARALLEL WITH queries.

ParallelWithQueryScheduledThreads​

Number of queued or active jobs in the threadpool for processing PARALLEL WITH queries.

ParallelWithQueryThreads​

Number of threads in the threadpool for processing PARALLEL WITH queries.

ParquetEncoderThreads​

Number of threads in ParquetBlockOutputFormat thread pool.

ParquetEncoderThreadsActive​

Number of threads in ParquetBlockOutputFormat thread pool running a task.

ParquetEncoderThreadsScheduled​

Number of queued or active jobs in ParquetBlockOutputFormat thread pool.

ParquetMetadataCacheBytes​

Size of the Parquet metadata cache in bytes

ParquetMetadataCacheFiles​

Number of cached files in the Parquet metadata cache

PartMutation​

Number of mutations (ALTER DELETE/UPDATE)

PartsActive​

Active data part, used by current and upcoming SELECTs.

PartsCommitted​

Deprecated. See PartsActive.

PartsCompact​

Compact parts.

PartsDeleteOnDestroy​

Part was moved to another disk and should be deleted in own destructor.

PartsDeleting​

Not active data part with identity refcounter, it is deleting right now by a cleaner.

PartsOutdated​

Not active data part, but could be used by only current SELECTs, could be deleted after SELECTs finishes.

PartsPreActive​

The part is in data_parts, but not used for SELECTs.

PartsPreCommitted​

Deprecated. See PartsPreActive.

PartsTemporary​

The part is generating now, it is not in data_parts list.

PartsWide​

Wide parts.

PendingAsyncInsert​

Number of asynchronous inserts that are waiting for flush.

PolygonDictionaryThreads​

Number of threads in the threadpool for polygon dictionaries.

PolygonDictionaryThreadsActive​

Number of active threads in the threadpool for polygon dictionaries.

PolygonDictionaryThreadsScheduled​

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

PostgreSQLConnection​

Number of client connections using PostgreSQL protocol

PrimaryIndexCacheBytes​

Total size of primary index cache in bytes

PrimaryIndexCacheFiles​

Total number of index files cached in the primary index cache

Query​

Number of executing queries

QueryCacheBytes​

Total size of the query cache in bytes

QueryCacheEntries​

Total number of entries in the query cache

QueryConditionCacheBytes​

Total size of the query condition cache in bytes

QueryConditionCacheEntries​

Total number of entries in the query condition cache

QueryNonInternal​

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

QueryPipelineExecutorThreads​

Number of threads in the PipelineExecutor thread pool.

QueryPipelineExecutorThreadsActive​

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

QueryPipelineExecutorThreadsScheduled​

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

QueryPreempted​

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

QueryThread​

Number of query processing threads

RWLockActiveReaders​

Number of threads holding read lock in a table RWLock.

RWLockActiveWriters​

Number of threads holding write lock in a table RWLock.

RWLockWaitingReaders​

Number of threads waiting for read on a table RWLock.

RWLockWaitingWriters​

Number of threads waiting for write on a table RWLock.

Read​

Number of read (read, pread, io_getevents, etc.) syscalls in fly

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​

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

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​

Number materialized views with periodic refreshing (REFRESH)

RefreshingViews​

Number of materialized views currently executing a refresh

RemoteRead​

Number of read with remote reader in fly

ReplicaReady​

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

ReplicatedChecks​

Number of data parts checking for consistency

ReplicatedFetch​

Number of data parts being fetched from replica

ReplicatedSend​

Number of data parts being sent to replicas

RestartReplicaThreads​

Number of threads in the RESTART REPLICA thread pool.

RestartReplicaThreadsActive​

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

RestartReplicaThreadsScheduled​

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

RestoreThreads​

Number of threads in the thread pool for RESTORE.

RestoreThreadsActive​

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

RestoreThreadsScheduled​

Number of queued or active jobs for RESTORE.

Revision​

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

S3CachedCredentialsProviders​

Total number of cached credentials providers

S3Requests​

S3 requests count

SchedulerIOReadScheduled​

Number of IO reads are being scheduled currently

SchedulerIOWriteScheduled​

Number of IO writes are being scheduled currently

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​

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

SharedCatalogDropDetachLocalTablesErrors​

Number of errors that occurred when attempting to drop or detach local tables in Shared Catalog.

SharedCatalogDropLocalThreads​

Number of threads in the threadpool for drop of local tables in Shared Catalog.

SharedCatalogDropLocalThreadsActive​

Number of active threads in the threadpool for drop of local tables in Shared Catalog.

SharedCatalogDropLocalThreadsScheduled​

Number of queued or active jobs in the threadpool for drop of local tables in Shared Catalog.

SharedCatalogDropZooKeeperThreads​

Number of threads in the threadpool for drop of object in ZooKeeper in Shared Catalog.

SharedCatalogDropZooKeeperThreadsActive​

Number of active threads in the threadpool for drop of object in ZooKeeper in Shared Catalog.

SharedCatalogDropZooKeeperThreadsScheduled​

Number of queued or active jobs in the threadpool for drop of object in ZooKeeper in Shared Catalog.

SharedCatalogNumberOfObjectsInState​

Number of objects in the current state of Shared Catalog.

SharedCatalogStateApplicationThreads​

Number of threads in the threadpool for state application in Shared Catalog.

SharedCatalogStateApplicationThreadsActive​

Number of active threads in the threadpool for state application in Shared Catalog.

SharedCatalogStateApplicationThreadsScheduled​

Number of queued or active jobs in the threadpool for state application in Shared Catalog.

SharedDatabaseCatalogTablesInLocalDropDetachQueue​

Number of tables in the queue for local drop or detach in Shared Catalog.

SharedMergeTreeAssignedCurrentParts​

Number of parts locked by merge or mutation

SharedMergeTreeBrokenCondemnedPartsInKeeper​

How many broken condemned part records stored in keeper

SharedMergeTreeCondemnedPartsInKeeper​

How many condemned part records stored in keeper

SharedMergeTreeFetch​

Number of fetches in progress

SharedMergeTreeMaxActiveReplicas​

The maximum number of active replicas registered in Keeper

SharedMergeTreeMaxInactiveReplicas​

The maximum number of inactive replicas registered in Keeper

SharedMergeTreeMaxPartitions​

The maximum number of partitions registered in Keeper across all SharedMergeTree tables

SharedMergeTreeMaxReplicas​

The maximum number of replicas registered in Keeper across all tables. Note it might not be a sum of SharedMergeTreeMaxActiveReplicas and SharedMergeTreeMaxInactiveReplicas

SharedMergeTreeMinActiveReplicas​

The minimum number of active replicas registered in Keeper

SharedMergeTreeMinInactiveReplicas​

The minimum number of inactive replicas registered in Keeper

SharedMergeTreeMinPartitions​

The minimum number of partitions registered in Keeper across all SharedMergeTree tables

SharedMergeTreeMinReplicas​

The minimum number of replicas registered in Keeper across all tables. Note it might not be a sum of SharedMergeTreeMinActiveReplicas and SharedMergeTreeMinInactiveReplicas

SharedMergeTreeOutdatedPartsInKeeper​

How many outdated part records stored in keeper

SharedMergeTreeThreads​

Number of threads in the thread pools in internals of SharedMergeTree

SharedMergeTreeThreadsActive​

Number of threads in the thread pools in internals of SharedMergeTree running a task

SharedMergeTreeThreadsScheduled​

Number of queued or active threads in the thread pools in internals of SharedMergeTree

StartupScriptsExecutionState​

State of startup scripts execution: 0 = not finished, 1 = success, 2 = failure.

StartupSystemTablesThreads​

Number of threads in the StartupSystemTables thread pool.

StartupSystemTablesThreadsActive​

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

StartupSystemTablesThreadsScheduled​

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

StatelessWorkerThreads​

Number of threads in the stateless worker thread pool.

StatelessWorkerThreadsActive​

Number of threads in the stateless worker thread pool running a task.

StatelessWorkerThreadsScheduled​

Number of queued or active jobs in the stateless worker thread pool.

StorageBufferBytes​

Number of bytes in buffers of Buffer tables

StorageBufferFlushThreads​

Number of threads for background flushes in StorageBuffer

StorageBufferFlushThreadsActive​

Number of threads for background flushes in StorageBuffer running a task

StorageBufferFlushThreadsScheduled​

Number of queued or active threads for background flushes in StorageBuffer

StorageBufferRows​

Number of rows in buffers of Buffer tables

StorageConnectionsStored​

Total count of sessions stored in the session pool for storages

StorageConnectionsTotal​

Total count of all sessions: stored in the pool and actively used right now for storages

StorageDistributedThreads​

Number of threads in the StorageDistributed thread pool.

StorageDistributedThreadsActive​

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

StorageDistributedThreadsScheduled​

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

StorageHiveThreads​

Number of threads in the StorageHive thread pool.

StorageHiveThreadsActive​

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

StorageHiveThreadsScheduled​

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

StorageObjectStorageThreads​

Number of threads in the remote table engines thread pools.

StorageObjectStorageThreadsActive​

Number of threads in the remote table engines thread pool running a task.

StorageObjectStorageThreadsScheduled​

Number of queued or active jobs in remote table engines thread pool.

StorageS3Threads​

Number of threads in the StorageS3 thread pool.

StorageS3ThreadsActive​

Number of threads in the StorageS3 thread pool running a task.

StorageS3ThreadsScheduled​

Number of queued or active jobs in the StorageS3 thread pool.

SystemDatabaseReplicasThreads​

Number of threads in the system.database_replicas thread pool.

SystemDatabaseReplicasThreadsActive​

Number of threads in the system.database_replicas thread pool running a task.

SystemDatabaseReplicasThreadsScheduled​

Number of queued or active jobs in the system.database_replicas thread pool.

SystemReplicasThreads​

Number of threads in the system.replicas thread pool.

SystemReplicasThreadsActive​

Number of threads in the system.replicas thread pool running a task.

SystemReplicasThreadsScheduled​

Number of queued or active jobs in the system.replicas thread pool.

TCPConnection​

Number of connections to TCP server (clients with native interface), also included server-server distributed query connections

TablesLoaderBackgroundThreads​

Number of threads in the tables loader background thread pool.

TablesLoaderBackgroundThreadsActive​

Number of threads in the tables loader background thread pool running a task.

TablesLoaderBackgroundThreadsScheduled​

Number of queued or active jobs in the tables loader background thread pool.

TablesLoaderForegroundThreads​

Number of threads in the tables loader foreground thread pool.

TablesLoaderForegroundThreadsActive​

Number of threads in the tables loader foreground thread pool running a task.

TablesLoaderForegroundThreadsScheduled​

Number of queued or active jobs in the tables loader foreground thread pool.

TablesToDropQueueSize​

Number of dropped tables, that are waiting for background data removal.

TaskTrackerThreads​

Number of threads used by the distributed query remote task tracker.

TaskTrackerThreadsActive​

Number of threads in the distributed query remote task tracker thread pool running a task.

TaskTrackerThreadsScheduled​

Number of queued or active jobs in the distributed query remote task tracker thread pool.

TemporaryFilesForAggregation​

Number of temporary files created for external aggregation

TemporaryFilesForJoin​

Number of temporary files created for JOIN

TemporaryFilesForMerge​

Number of temporary files for vertical merge

TemporaryFilesForSort​

Number of temporary files created for external sorting

TemporaryFilesUnknown​

Number of temporary files created without known purpose

TextIndexHeaderCacheBytes​

Size of the text index header cache in bytes

TextIndexHeaderCacheCells​

Number of entries in text index header cache

TextIndexPostingsCacheBytes​

Size of the text index posting lists cache in bytes

TextIndexPostingsCacheCells​

Number of entries in the text index posting lists cache

TextIndexTokensCacheBytes​

Size of the text index tokens cache in bytes

TextIndexTokensCacheCells​

Number of entries in the text index tokens cache

ThreadPoolFSReaderThreads​

Number of threads in the thread pool for local_filesystem_read_method=threadpool.

ThreadPoolFSReaderThreadsActive​

Number of threads in the thread pool for local_filesystem_read_method=threadpool running a task.

ThreadPoolFSReaderThreadsScheduled​

Number of queued or active jobs in the thread pool for local_filesystem_read_method=threadpool.

ThreadPoolRemoteFSReaderThreads​

Number of threads in the thread pool for remote_filesystem_read_method=threadpool.

ThreadPoolRemoteFSReaderThreadsActive​

Number of threads in the thread pool for remote_filesystem_read_method=threadpool running a task.

ThreadPoolRemoteFSReaderThreadsScheduled​

Number of queued or active jobs in the thread pool for remote_filesystem_read_method=threadpool.

ThreadsInOvercommitTracker​

Number of waiting threads inside of OvercommitTracker

TotalTemporaryFiles​

Number of temporary files created

UncompressedCacheBytes​

Total size of uncompressed cache in bytes. Uncompressed cache does not usually improve the performance and should be mostly avoided

UncompressedCacheCells​

Total number of entries in the uncompressed cache. Each entry represents a decompressed block of data. Uncompressed cache does not usually improve performance and should be mostly avoided

VectorSimilarityIndexCacheBytes​

Size of the vector similarity index cache in bytes

VectorSimilarityIndexCacheCells​

Number of entries in the vector similarity index cache

VersionInteger​

Version of the server in a single integer number in base-1000. For example, version 11.22.33 is translated to 11022033.

Write​

Number of write (write, pwrite, io_getevents, etc.) syscalls in fly

ZooKeeperConnectionLossStartedTimestampSeconds​

Unix timestamp in seconds when ZooKeeper connection was lost, or 0 if connected successfully.

ZooKeeperRequest​

Number of requests to ZooKeeper in fly.

ZooKeeperSession​

Number of sessions (connections) to ZooKeeper. Should be no more than one, because using more than one connection to ZooKeeper may lead to bugs due to lack of linearizability (stale reads) that ZooKeeper consistency model allows.

ZooKeeperSessionExpired​

Number of expired global ZooKeeper sessions.

ZooKeeperWatch​

Number of watches (event subscriptions) in ZooKeeper.

See Also