system.metrics

### DeltaLakeSnapshotCacheSizeElements[​](#deltalakesnapshotcachesizeelements "Direct link to DeltaLakeSnapshotCacheSizeElements")

Size in elements of DeltaLake snapshot cache.

### DestroyAggregatesThreads[​](#destroyaggregatesthreads "Direct link to DestroyAggregatesThreads")

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

### DestroyAggregatesThreadsActive[​](#destroyaggregatesthreadsactive "Direct link to DestroyAggregatesThreadsActive")

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

### DestroyAggregatesThreadsScheduled[​](#destroyaggregatesthreadsscheduled "Direct link to DestroyAggregatesThreadsScheduled")

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

### DictCacheRequests[​](#dictcacherequests "Direct link to DictCacheRequests")

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

### DiskConnectionsStored[​](#diskconnectionsstored "Direct link to DiskConnectionsStored")

Total count of sessions stored in the session pool for disks

### DiskConnectionsTotal[​](#diskconnectionstotal "Direct link to DiskConnectionsTotal")

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

### DiskObjectStorageAsyncThreads[​](#diskobjectstorageasyncthreads "Direct link to DiskObjectStorageAsyncThreads")

Obsolete metric, shows nothing.

### DiskObjectStorageAsyncThreadsActive[​](#diskobjectstorageasyncthreadsactive "Direct link to DiskObjectStorageAsyncThreadsActive")

Obsolete metric, shows nothing.

### DiskPlainRewritableAzureDirectoryMapSize[​](#diskplainrewritableazuredirectorymapsize "Direct link to DiskPlainRewritableAzureDirectoryMapSize")

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

### DiskPlainRewritableAzureFileCount[​](#diskplainrewritableazurefilecount "Direct link to DiskPlainRewritableAzureFileCount")

Number of file entries in the 'plain\_rewritable' in-memory map for AzureObjectStorage.

### DiskPlainRewritableLocalDirectoryMapSize[​](#diskplainrewritablelocaldirectorymapsize "Direct link to DiskPlainRewritableLocalDirectoryMapSize")

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

### DiskPlainRewritableLocalFileCount[​](#diskplainrewritablelocalfilecount "Direct link to DiskPlainRewritableLocalFileCount")

Number of file entries in the 'plain\_rewritable' in-memory map for LocalObjectStorage.

### DiskPlainRewritableS3DirectoryMapSize[​](#diskplainrewritables3directorymapsize "Direct link to DiskPlainRewritableS3DirectoryMapSize")

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

### DiskPlainRewritableS3FileCount[​](#diskplainrewritables3filecount "Direct link to DiskPlainRewritableS3FileCount")

Number of file entries in the 'plain\_rewritable' in-memory map for S3ObjectStorage.

### DiskS3NoSuchKeyErrors[​](#disks3nosuchkeyerrors "Direct link to DiskS3NoSuchKeyErrors")

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

### DiskSpaceReservedForMerge[​](#diskspacereservedformerge "Direct link to DiskSpaceReservedForMerge")

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

### DistrCacheAllocatedConnections[​](#distrcacheallocatedconnections "Direct link to DistrCacheAllocatedConnections")

Number of currently allocated connections to Distributed Cache connection pool

### DistrCacheBorrowedConnections[​](#distrcacheborrowedconnections "Direct link to DistrCacheBorrowedConnections")

Number of currently borrowed connections to Distributed Cache connection pool

### DistrCacheOpenedConnections[​](#distrcacheopenedconnections "Direct link to DistrCacheOpenedConnections")

Number of open connections to Distributed Cache

### DistrCacheReadBuffers[​](#distrcachereadbuffers "Direct link to DistrCacheReadBuffers")

Number of distributed cache read buffers

### DistrCacheReadRequests[​](#distrcachereadrequests "Direct link to DistrCacheReadRequests")

Number of executed Read requests to Distributed Cache

### DistrCacheRegisteredServers[​](#distrcacheregisteredservers "Direct link to DistrCacheRegisteredServers")

Number of distributed cache registered servers

### DistrCacheRegisteredServersCurrentAZ[​](#distrcacheregisteredserverscurrentaz "Direct link to DistrCacheRegisteredServersCurrentAZ")

Number of distributed cache registered servers in current az

### DistrCacheServerConnections[​](#distrcacheserverconnections "Direct link to DistrCacheServerConnections")

Number of open connections to ClickHouse server from Distributed Cache

### DistrCacheServerRegistryConnections[​](#distrcacheserverregistryconnections "Direct link to DistrCacheServerRegistryConnections")

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

### DistrCacheServerS3CachedClients[​](#distrcacheservers3cachedclients "Direct link to DistrCacheServerS3CachedClients")

Number of distributed cache S3 cached clients

### DistrCacheSharedLimitCount[​](#distrcachesharedlimitcount "Direct link to DistrCacheSharedLimitCount")

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

### DistrCacheUsedConnections[​](#distrcacheusedconnections "Direct link to DistrCacheUsedConnections")

Number of currently used connections to Distributed Cache

### DistrCacheWriteBuffers[​](#distrcachewritebuffers "Direct link to DistrCacheWriteBuffers")

Number of distributed cache write buffers

### DistrCacheWriteRequests[​](#distrcachewriterequests "Direct link to DistrCacheWriteRequests")

Number of executed Write requests to Distributed Cache

### DistributedBytesToInsert[​](#distributedbytestoinsert "Direct link to DistributedBytesToInsert")

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

### DistributedFilesToInsert[​](#distributedfilestoinsert "Direct link to DistributedFilesToInsert")

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

### DistributedIndexAnalysisThreads[​](#distributedindexanalysisthreads "Direct link to DistributedIndexAnalysisThreads")

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

### DistributedIndexAnalysisThreadsActive[​](#distributedindexanalysisthreadsactive "Direct link to DistributedIndexAnalysisThreadsActive")

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

### DistributedIndexAnalysisThreadsScheduled[​](#distributedindexanalysisthreadsscheduled "Direct link to DistributedIndexAnalysisThreadsScheduled")

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

### DistributedInsertThreads[​](#distributedinsertthreads "Direct link to DistributedInsertThreads")

Number of threads used for INSERT into Distributed.

### DistributedInsertThreadsActive[​](#distributedinsertthreadsactive "Direct link to DistributedInsertThreadsActive")

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

### DistributedInsertThreadsScheduled[​](#distributedinsertthreadsscheduled "Direct link to DistributedInsertThreadsScheduled")

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

### DistributedSend[​](#distributedsend "Direct link to DistributedSend")

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

### DropDistributedCacheThreads[​](#dropdistributedcachethreads "Direct link to DropDistributedCacheThreads")

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

### DropDistributedCacheThreadsActive[​](#dropdistributedcachethreadsactive "Direct link to DropDistributedCacheThreadsActive")

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