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ALTER STREAMING TABLE

  • Άρθρο

Applies to: check marked yes Databricks SQL

Allows you to either:

  • Add a schedule for refreshing an existing streaming table.
  • Alter an existing refresh schedule for a streaming table.
  • Drop the refresh schedule for a streaming table. If the schedule is dropped, the object needs to be refreshed manually to reflect the latest data.

Syntax

ALTER STREAMING TABLE table_name
  {
    { ADD | ALTER } SCHEDULE [ REFRESH ] schedule_clause |
    DROP SCHEDULE
  }

  schedule_clause
  { EVERY number { HOUR | HOURS | DAY | DAYS | WEEK | WEEKS } |
    CRON cron_string [ AT TIME ZONE timezone_id ] }

Parameters

  • table_name

    The name of the streaming table to alter the definition of. The name must not include a temporal specification.

  • SCHEDULE [ REFRESH ] schedule_clause

    Allows you to add a schedule to or alter the schedule of a streaming table.

    • EVERY number { HOUR | HOURS | DAY | DAYS | WEEK | WEEKS }

      Important

      This feature is in Public Preview.

      To schedule a refresh that occurs periodically, use EVERY syntax. If EVERY syntax is specified, the streaming table or materialized view is refreshed periodically at the specified interval based on the provided value, such as HOUR, HOURS, DAY, DAYS, WEEK, or WEEKS. The following table lists accepted integer values for number.

      Time unit Integer value
      HOUR or HOURS 1 <= H <= 72
      DAY or DAYS 1 <= D <= 31
      WEEK or WEEKS 1 <= W <= 8

      Note

      The singular and plural forms of the included time unit are semantically equivalent.

    • CRON cron_string [ AT TIME ZONE timezone_id ]

      To schedule a refresh using a quartz cron value. Valid time_zone_values are accepted. AT TIME ZONE LOCAL is not supported.

      If AT TIME ZONE is absent, the session time zone is used. If AT TIME ZONE is absent and the session time zone is not set, an error is thrown. SCHEDULE is semantically equivalent to SCHEDULE REFRESH.

Examples

-- Adds a schedule to refresh the streaming table once a day
-- at midnight in Los Angeles
> ALTER STREAMING TABLE my_st
  ADD SCHEDULE CRON '0 0 0 * * ? *' AT TIME ZONE 'America/Los_Angeles';

-- Alters the schedule to run every 15 minutes for a streaming table
> ALTER STREAMING TABLE my_st
  ALTER SCHEDULE CRON '0 0/15 * * * ? *';

-- Drops the schedule for a streaming table
> ALTER STREAMING TABLE my_st
  DROP SCHEDULE;