ClickHouse/docs/en/operations/system-tables/asynchronous_metrics.md

---
slug: /en/operations/system-tables/asynchronous_metrics
---
# asynchronous_metrics

Contains metrics that are calculated periodically in the background. For example, the amount of RAM in use.

Columns:

- `metric` ([String](../../sql-reference/data-types/string.md)) — Metric name.
- `value` ([Float64](../../sql-reference/data-types/float.md)) — Metric value.
- `description` ([String](../../sql-reference/data-types/string.md) - Metric description)

**Example**

``` sql
SELECT * FROM system.asynchronous_metrics LIMIT 10
```

``` text
┌─metric──────────────────────────────────┬──────value─┬─description────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ AsynchronousMetricsCalculationTimeSpent │ 0.00179053 │ Time in seconds spent for calculation of asynchronous metrics (this is the overhead of asynchronous metrics).                                                                                                                                              │
│ NumberOfDetachedByUserParts             │          0 │ The total number of parts detached from MergeTree tables by users with the `ALTER TABLE DETACH` query (as opposed to unexpected, broken or ignored parts). The server does not care about detached parts and they can be removed.                          │
│ NumberOfDetachedParts                   │          0 │ The total number of parts detached from MergeTree tables. A part can be detached by a user with the `ALTER TABLE DETACH` query or by the server itself it the part is broken, unexpected or unneeded. The server does not care about detached parts and they can be removed. │
│ TotalRowsOfMergeTreeTables              │    2781309 │ Total amount of rows (records) stored in all tables of MergeTree family.                                                                                                                                                                                   │
│ TotalBytesOfMergeTreeTables             │    7741926 │ Total amount of bytes (compressed, including data and indices) stored in all tables of MergeTree family.                                                                                                                                                   │
│ NumberOfTables                          │         93 │ Total number of tables summed across the databases on the server, excluding the databases that cannot contain MergeTree tables. The excluded database engines are those who generate the set of tables on the fly, like `Lazy`, `MySQL`, `PostgreSQL`, `SQlite`. │
│ NumberOfDatabases                       │          6 │ Total number of databases on the server.                                                                                                                                                                                                                   │
│ MaxPartCountForPartition                │          6 │ Maximum number of parts per partition across all partitions of all tables of MergeTree family. Values larger than 300 indicates misconfiguration, overload, or massive data loading.                                                                       │
│ ReplicasSumMergesInQueue                │          0 │ Sum of merge operations in the queue (still to be applied) across Replicated tables.                                                                                                                                                                       │
│ ReplicasSumInsertsInQueue               │          0 │ Sum of INSERT operations in the queue (still to be replicated) across Replicated tables.                                                                                                                                                                   │
└─────────────────────────────────────────┴────────────┴────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
```

**See Also**

- [Monitoring](../../operations/monitoring.md) — Base concepts of ClickHouse monitoring.
- [system.metrics](../../operations/system-tables/metrics.md#system_tables-metrics) — Contains instantly calculated metrics.
- [system.events](../../operations/system-tables/events.md#system_tables-events) — Contains a number of events that have occurred.
- [system.metric_log](../../operations/system-tables/metric_log.md#system_tables-metric_log) — Contains a history of metrics values from tables `system.metrics` and `system.events`.