system.view_refreshes

System table containing information about Refreshable Materialized Views.

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

Information about Refreshable Materialized Views. Contains all refreshable materialized views, regardless of whether there’s a refresh in progress or not.

Columns

• database (String) — The name of the database the table is in.
• view (String) — Table name.
• uuid (UUID) — Table uuid (Atomic database).
• status (String) — Current state of the refresh.
• last_success_time (Nullable(DateTime)) — Time when the latest successful refresh started. NULL if no successful refreshes happened since server startup or table creation.
• last_success_duration_ms (Nullable(UInt64)) — How long the latest refresh took.
• last_refresh_time (Nullable(DateTime)) — Time when the latest refresh attempt finished (if known) or started (if unknown or still running). NULL if no refresh attempts happened since server startup or table creation.
• last_refresh_replica (String) — If coordination is enabled, name of the replica that made the current (if running) or previous (if not running) refresh attempt.
• next_refresh_time (Nullable(DateTime)) — Time at which the next refresh is scheduled to start, if status = Scheduled.
• exception (String) — Error message from previous attempt if it failed.
• retry (UInt64) — How many failed attempts there were so far, for the current refresh. Not available if status is RunningOnAnotherReplica.
• progress (Nullable(Float64)) — Progress of the current running or most recently completed refresh at the given replica, between 0 and 1. NULL if status is RunningOnAnotherReplica or the refresh is not running.
• read_rows (Nullable(UInt64)) — Number of rows read by the current running or most recently completed refresh at the given replica. NULL if status is RunningOnAnotherReplica.
• read_bytes (Nullable(UInt64)) — Number of bytes read by the current running or most recently completed refresh at the given replica. NULL if status is RunningOnAnotherReplica
• total_rows (Nullable(UInt64)) — Estimated total number of rows that need to be read by the current running or most recently completed refresh at the given replica. NULL if status is RunningOnAnotherReplica
• written_rows (Nullable(UInt64)) — Number of rows written by the current running or most recently completed refresh at the given replica. NULL if status is RunningOnAnotherReplica
• written_bytes (Nullable(UInt64)) — Number of bytes written by the current running or most recently completed refresh at the given replica. NULL if status is RunningOnAnotherReplica

Example

SELECT
    database,
    view,
    status,
    last_refresh_result,
    last_refresh_time,
    next_refresh_time
FROM system.view_refreshes

┌─database─┬─view───────────────────────┬─status────┬─last_refresh_result─┬───last_refresh_time─┬───next_refresh_time─┐
│ default  │ hello_documentation_reader │ Scheduled │ Finished            │ 2023-12-01 01:24:00 │ 2023-12-01 01:25:00 │
└──────────┴────────────────────────────┴───────────┴─────────────────────┴─────────────────────┴─────────────────────┘