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### OSOpenFiles[​](#osopenfiles "Direct link to OSOpenFiles")

The total number of opened files on the host machine. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server.

### OSProcessesBlocked[​](#osprocessesblocked "Direct link to OSProcessesBlocked")

Number of threads blocked waiting for I/O to complete (`man procfs`). This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server.

### OSProcessesCreated[​](#osprocessescreated "Direct link to OSProcessesCreated")

The number of processes created. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server.

### OSProcessesRunning[​](#osprocessesrunning "Direct link to OSProcessesRunning")

The number of runnable (running or ready to run) threads by the operating system. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server.

### OSSoftIrqTime[​](#ossoftirqtime "Direct link to OSSoftIrqTime")

The ratio of time spent for running software interrupt requests on the CPU. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server. A high number of this metric may indicate inefficient software running on the system. The value for a single CPU core will be in the interval [0..1]. The value for all CPU cores is calculated as a sum across them [0..num cores].

### OSSoftIrqTimeCPU\_*N*[​](#ossoftirqtimecpu_n "Direct link to ossoftirqtimecpu_n")

The ratio of time spent for running software interrupt requests on the CPU. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server. A high number of this metric may indicate inefficient software running on the system. The value for a single CPU core will be in the interval [0..1]. The value for all CPU cores is calculated as a sum across them [0..num cores].

### OSSoftIrqTimeNormalized[​](#ossoftirqtimenormalized "Direct link to OSSoftIrqTimeNormalized")

The value is similar to `OSSoftIrqTime` but divided to the number of CPU cores to be measured in the [0..1] interval regardless of the number of cores. This allows you to average the values of this metric across multiple servers in a cluster even if the number of cores is non-uniform, and still get the average resource utilization metric. If specified, the Cgroup CPU quota divided by its period can be used instead of the actual number of CPU cores, and in that case the value of this metric may exceed 1 at some moments.

### OSStealTime[​](#osstealtime "Direct link to OSStealTime")

The ratio of time spent in other operating systems by the CPU when running in a virtualized environment. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server. Not every virtualized environments present this metric, and most of them don't. The value for a single CPU core will be in the interval [0..1]. The value for all CPU cores is calculated as a sum across them [0..num cores].

### OSStealTimeCPU\_*N*[​](#osstealtimecpu_n "Direct link to osstealtimecpu_n")

The ratio of time spent in other operating systems by the CPU when running in a virtualized environment. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server. Not every virtualized environments present this metric, and most of them don't. The value for a single CPU core will be in the interval [0..1]. The value for all CPU cores is calculated as a sum across them [0..num cores].

### OSStealTimeNormalized[​](#osstealtimenormalized "Direct link to OSStealTimeNormalized")

The value is similar to `OSStealTime` but divided to the number of CPU cores to be measured in the [0..1] interval regardless of the number of cores. This allows you to average the values of this metric across multiple servers in a cluster even if the number of cores is non-uniform, and still get the average resource utilization metric. If specified, the Cgroup CPU quota divided by its period can be used instead of the actual number of CPU cores, and in that case the value of this metric may exceed 1 at some moments.

### OSSystemTime[​](#ossystemtime "Direct link to OSSystemTime")

The ratio of time the CPU core was running OS kernel (system) code. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server. The value for a single CPU core will be in the interval [0..1]. The value for all CPU cores is calculated as a sum across them [0..num cores].

### OSSystemTimeCPU\_*N*[​](#ossystemtimecpu_n "Direct link to ossystemtimecpu_n")

The ratio of time the CPU core was running OS kernel (system) code. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server. The value for a single CPU core will be in the interval [0..1]. The value for all CPU cores is calculated as a sum across them [0..num cores].

### OSSystemTimeNormalized[​](#ossystemtimenormalized "Direct link to OSSystemTimeNormalized")

The value is similar to `OSSystemTime` but divided to the number of CPU cores to be measured in the [0..1] interval regardless of the number of cores. This allows you to average the values of this metric across multiple servers in a cluster even if the number of cores is non-uniform, and still get the average resource utilization metric. If specified, the Cgroup CPU quota divided by its period can be used instead of the actual number of CPU cores, and in that case the value of this metric may exceed 1 at some moments.

### OSThreadsRunnable[​](#osthreadsrunnable "Direct link to OSThreadsRunnable")

The total number of 'runnable' threads, as the OS kernel scheduler seeing it.

### OSThreadsTotal[​](#osthreadstotal "Direct link to OSThreadsTotal")

The total number of threads, as the OS kernel scheduler seeing it.

### OSUptime[​](#osuptime "Direct link to OSUptime")

The uptime of the host server (the machine where ClickHouse is running), in seconds.

### OSUserTime[​](#osusertime "Direct link to OSUserTime")

The ratio of time the CPU core was running userspace code. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server. This includes also the time when the CPU was under-utilized due to the reasons internal to the CPU (memory loads, pipeline stalls, branch mispredictions, running another SMT core). The value for a single CPU core will be in the interval [0..1]. The value for all CPU cores is calculated as a sum across them [0..num cores].

### OSUserTimeCPU\_*N*[​](#osusertimecpu_n "Direct link to osusertimecpu_n")

The ratio of time the CPU core was running userspace code. This is a system-wide metric, it includes all the processes on the host machine, not just clickhouse-server. This includes also the time when the CPU was under-utilized due to the reasons internal to the CPU (memory loads, pipeline stalls, branch mispredictions, running another SMT core). The value for a single CPU core will be in the interval [0..1]. The value for all CPU cores is calculated as a sum across them [0..num cores].

### OSUserTimeNormalized[​](#osusertimenormalized "Direct link to OSUserTimeNormalized")

The value is similar to `OSUserTime` but divided to the number of CPU cores to be measured in the [0..1] interval regardless of the number of cores. This allows you to average the values of this metric across multiple servers in a cluster even if the number of cores is non-uniform, and still get the average resource utilization metric. If specified, the Cgroup CPU quota divided by its period can be used instead of the actual number of CPU cores, and in that case the value of this metric may exceed 1 at some moments.

### PostgreSQLThreads[​](#postgresqlthreads "Direct link to PostgreSQLThreads")

Number of threads in the server of the PostgreSQL compatibility protocol.

### ReplicasMaxAbsoluteDelay[​](#replicasmaxabsolutedelay "Direct link to ReplicasMaxAbsoluteDelay")