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system.user_processes

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.

Description​

This system table can be used to get overview of memory usage and ProfileEvents of users.

Columns​

  • user (String) — User name.
  • memory_usage (Int64) — Sum of RAM used by all processes of the user. It might not include some types of dedicated memory. See the max_memory_usage setting.
  • peak_memory_usage (Int64) — The peak of memory usage of the user. It can be reset when no queries are run for the user.
  • ProfileEvents (Map(LowCardinality(String), UInt64)) — Summary of ProfileEvents that measure different metrics for the user. The description of them could be found in the table system.events

Example​

SELECT * FROM system.user_processes LIMIT 10 FORMAT Vertical;

Row 1:
──────
user:              default
memory_usage:      9832
peak_memory_usage: 9832
ProfileEvents:     {'Query':5,'SelectQuery':5,'QueriesWithSubqueries':38,'SelectQueriesWithSubqueries':38,'QueryTimeMicroseconds':842048,'SelectQueryTimeMicroseconds':842048,'ReadBufferFromFileDescriptorRead':6,'ReadBufferFromFileDescriptorReadBytes':234,'IOBufferAllocs':3,'IOBufferAllocBytes':98493,'ArenaAllocChunks':283,'ArenaAllocBytes':1482752,'FunctionExecute':670,'TableFunctionExecute':16,'DiskReadElapsedMicroseconds':19,'NetworkSendElapsedMicroseconds':684,'NetworkSendBytes':139498,'SelectedRows':6076,'SelectedBytes':685802,'ContextLock':1140,'RWLockAcquiredReadLocks':193,'RWLockReadersWaitMilliseconds':4,'RealTimeMicroseconds':1585163,'UserTimeMicroseconds':889767,'SystemTimeMicroseconds':13630,'SoftPageFaults':1947,'OSCPUWaitMicroseconds':6,'OSCPUVirtualTimeMicroseconds':903251,'OSReadChars':28631,'OSWriteChars':28888,'QueryProfilerRuns':3,'LogTrace':79,'LogDebug':24}

1 row in set. Elapsed: 0.010 sec.