TASK_HISTORY¶

Syntax¶

TASK_HISTORY(
      [ SCHEDULED_TIME_RANGE_START => <constant_expr> ]
      [, SCHEDULED_TIME_RANGE_END => <constant_expr> ]
      [, RESULT_LIMIT => <integer> ]
      [, TASK_NAME => '<string>' ]
      [, ERROR_ONLY => { TRUE | FALSE } ]
      [, ROOT_TASK_ID => '<string>'] )

Arguments¶

All the arguments are optional.

SCHEDULED_TIME_RANGE_START => constant_expr , . SCHEDULED_TIME_RANGE_END => constant_expr

Time range (in TIMESTAMP_LTZ format), within the last 7 days, in which the task execution was scheduled. If the time range does not fall within the last 7 days, an error is returned.

• If SCHEDULED_TIME_RANGE_END is not specified, the function returns those tasks that have already completed, are currently running, or are scheduled in the future.

• If SCHEDULED_TIME_RANGE_END is CURRENT_TIMESTAMP, the function returns those tasks that have already completed or are currently running. Note that a task that is executed immediately before the current time might still be identified as scheduled.

• To query only those tasks that have already completed or are currently running, include WHERE query_id IS NOT NULL as a filter. The QUERY_ID column in the TASK_HISTORY output is populated only when a task has started running.

Note

If no start or end time is specified, the most recent tasks are returned, up to the specified RESULT_LIMIT value.

RESULT_LIMIT => integer

A number specifying the maximum number of rows returned by the function.

If the number of matching rows is greater than this limit, the task executions with the most recent timestamp are returned, up to the specified limit.

Range: 1 to 10000

Default: 100.

TASK_NAME => string

A case-insensitive string specifying a task. Only non-qualified task names are supported. Only executions of the specified task are returned. Note that if multiple tasks have the same name, the function returns the history for each of these tasks.

ERROR_ONLY => TRUE | FALSE

When set to TRUE, this function returns only task runs that failed or were cancelled.

ROOT_TASK_ID =>string

Unique identifier for the root task in a task graph. This ID matches the ID column value in the SHOW TASKS output for the same task. Specify the ROOT_TASK_ID to show the history of the root task and any child tasks that are part of the task graph.

Usage notes¶

• This function returns results only for the ACCOUNTADMIN role, the task owner, or a role with the global MONITOR EXECUTION privilege. Note that unless a role with the MONITOR EXECUTION privilege also has the USAGE privilege on the database and schema that store the task, the DATABASE_NAME and SCHEMA_NAME values in the output are NULL.

• This function returns a maximum of 10,000 rows, set in the RESULT_LIMIT argument value. The default value is 100. To avoid this limitation, use the TASK_HISTORY view (Account Usage).

• Note that when the TASK_HISTORY function is queried, its task name, time range, and result limit arguments are applied first followed by the WHERE and LIMIT clause, respectively, if specified. In addition, the TASK_HISTORY function returns records in descending SCHEDULED_TIME order. Tasks in a SUCCEEDED, FAILED, or CANCELLED state are usually scheduled earlier, so they are generally returned later in the search results.

• In practice, if you have many tasks running in your account, the results returned by the function could include fewer than expected completed tasks or only scheduled tasks. To query the history of tasks that have already run, use a combination of the SCHEDULED_TIME_RANGE_START => constant_expr and SCHEDULED_TIME_RANGE_END => constant_expr arguments.

• When calling an information schema table function, the session must have an INFORMATION_SCHEMA schema in use or the function name must be fully qualified. For more information, see Snowflake Information Schema.

• This function can return all executions run in the past 7 days or the next scheduled execution within the next 8 days.

• Tasks run during a cloud services failure might appear as duplicate entries in the results of this function. During a cloud services failure, Snowflake might rerun a task causing the task to have two UUIDs with different task SCHEDULED_TIME. TASK_HISTORY view only displays the final UUID of the rerun task.

• All tasks in a task graph run show the same task history output.

Output¶

The function returns the following columns:

Examples¶

Retrieve the 100 most recent task executions (completed, still running, or scheduled in the future) in the account. Note that the maximum number of rows returned by the function is limited to 100 by default:

SELECT *
  FROM TABLE(INFORMATION_SCHEMA.TASK_HISTORY())
  ORDER BY SCHEDULED_TIME;

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Retrieve the execution history for tasks in the account within a specified 30 minute block of time within the past 7 days:

SELECT *
  FROM TABLE(INFORMATION_SCHEMA.TASK_HISTORY(
    SCHEDULED_TIME_RANGE_START=>TO_TIMESTAMP_LTZ('2018-11-9 12:00:00.000 -0700'),
    SCHEDULED_TIME_RANGE_END=>TO_TIMESTAMP_LTZ('2018-11-9 12:30:00.000 -0700')));

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Retrieve the 10 most recent executions of a specified task (completed, still running, or scheduled in the future) scheduled within the last hour:

SELECT *
  FROM TABLE(INFORMATION_SCHEMA.TASK_HISTORY(
    SCHEDULED_TIME_RANGE_START=>DATEADD('hour',-1,current_timestamp()),
    RESULT_LIMIT => 10,
    TASK_NAME=>'mytask'));

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Note

To retrieve only tasks that are completed or still running, filter the query using WHERE query_id IS NOT NULL. Note that this filter is applied after RESULT_LIMIT already reduces the results returned, so the query could return 9 tasks if 1 task was scheduled but had not started yet.

Retrieve the execution history of all tasks in the task graph of the specified root task.

SELECT *
  FROM TABLE(INFORMATION_SCHEMA.TASK_HISTORY(ROOT_TASK_ID=>'d4b89013-c942-465c-bcb8-e7037a932b04'));

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Retrieve the execution history of all tasks in the task graph of the most recently queried root task:

DESC TASK my_task
SET task_id=(SELECT "id" FROM TABLE(RESULT_SCAN(LAST_QUERY_ID())));
SELECT *
  FROM TABLE(INFORMATION_SCHEMA.TASK_HISTORY(ROOT_TASK_ID=>$task_id));

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