CompiledExpressionCacheCount -- number or compiled cached expression (if CompiledExpressionCache is enabled) jemalloc -- parameters of jemalloc allocator, they are not very useful, and not interesting MarkCacheBytes / MarkCacheFiles -- there are cache for .mrk files (default size is 5GB), you can see is it use all 5GB or not MemoryCode -- how much memory allocated for ClickHouse executable MemoryDataAndStack -- virtual memory allocated for data and stack MemoryResident -- real memory used by ClickHouse ( the same as top RES/RSS) MemoryShared -- shared memory used by ClickHouse MemoryVirtual -- virtual memory used by ClickHouse ( the same as top VIRT) NumberOfDatabases NumberOfTables ReplicasMaxAbsoluteDelay -- important parameter - replica max absolute delay in seconds ReplicasMaxRelativeDelay -- replica max relative delay (from other replicas) in seconds ReplicasMaxInsertsInQueue -- max number of parts to fetch for a single Replicated table ReplicasSumInsertsInQueue -- sum of parts to fetch for all Replicated tables ReplicasMaxMergesInQueue -- max number of merges in queue for a single Replicated table ReplicasSumMergesInQueue -- total number of merges in queue for all Replicated tables ReplicasMaxQueueSize -- max number of tasks for a single Replicated table ReplicasSumQueueSize -- total number of tasks in replication queue UncompressedCacheBytes/UncompressedCacheCells -- allocated memory for uncompressed cache (disabled by default) Uptime -- uptime seconds