system.processes

A read-only snapshot of active requests. A request remains visible until its response write completes, whether it succeeds or fails. Membership does not depend on log_queries.

Columns

Name	Meaning
query_id	Current request identifier.
user	Authenticated user.
interface	TCP or HTTP interface.
current_database	Selected database.
query	Request SQL text.
query_kind	Current statement classification.
elapsed	Elapsed seconds.
address, port	Client network endpoint.
initial_user, initial_query_id, initial_address, initial_port	Initial request identity fields.
is_initial_query	Initial-request flag.
is_internal	Internal-request flag.
is_cancelled	Cancellation status; server-side cancellation is unavailable.
is_all_data_sent	Response-delivery status.
read_rows, read_bytes	Observed read work.
written_rows, written_bytes	Observed write work.
memory_usage, peak_memory_usage	Current and peak accounted SQL memory.
total_rows_approx	Available approximate total row count.
peak_threads_usage	Maximum total query threads observed, including the main query thread.
normalized_query_hash	Hash grouping structurally normalized SQL.

Counters

Memory counters cover accounted SQL allocations across the request's query threads, including when max_memory_usage is zero. Serial execution reports peak_threads_usage of 1.

Physical read counters can include rows later rejected by a filter. Deleted rows do not count as newly written rows. These observations describe work performed, rather than only the final returned row count.

Example

The observing query can see its own request:

sql

SELECT user, interface, query_kind
FROM system.processes
WHERE query LIKE '%processes%'
FORMAT csv;

text

"default","TCP","SELECT"

Always use the system qualifier. See query history for terminal events and request limits for accounting scope.

system.processes ​

Columns ​

Counters ​

Example ​

system.processes

Columns

Counters

Example