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SYS_AUTO_TABLE_OPTIMIZATION - Amazon Redshift
Table columnsSample queries

Amazon Redshift will no longer support the use of Python UDFs after June 30, 2026. We will start enforcing it in phases. For more information on the details of Python end of life and migration options, see the blog post that was published on June 30, 2025.

SYS_AUTO_TABLE_OPTIMIZATION

Records automated actions taken by Amazon Redshift on tables defined for automatic optimization.

SYS_AUTO_TABLE_OPTIMIZATION is visible only to superusers. For more information, see Visibility of data in system tables and views.

Table columns

Column name Data type Description
transaction_id long The transaction identifier.
session_id int The session identifier of the process that executed the alter command.
table_id int The table identifier.
alter_table_type character(32) The type of recommendation. Possible values are distkey, sortkey, and encode.
status character(128) The completion status of the recommendation. Possible values are Start, Complete, Skipped, Abort, Checkpoint, and Failed.
event_time timestamp The timestamp of the status column.
alter_from character(200) The previous distribution style and sort keys of the table before applying the recommendation. The value is truncated into 200-character increments.

Sample queries

In the following example, the rows in the result show actions taken by Amazon Redshift. 

SELECT table_id, alter_table_type, status, event_time, alter_from
FROM SYS_AUTO_TABLE_OPTIMIZATION;
                
 table_id |  alter_table_type   |                        status                        |         event_time          |  alter_from
----------+---------------------+------------------------------------------------------+-----------------------------+-----------------
   118082 | sortkey             | Start                                                | 2020-08-22 19:42:20.727049  | 
   118078 | sortkey             | Start                                                | 2020-08-22 19:43:54.728819  | 
   118082 | sortkey             | Start                                                | 2020-08-22 19:42:52.690264  | 
   118072 | sortkey             | Start                                                | 2020-08-22 19:44:14.793572  | 
   118082 | sortkey             | Failed                                               | 2020-08-22 19:42:20.728917  | 
   118078 | sortkey             | Complete                                             | 2020-08-22 19:43:54.792705  |  SORTKEY: None;
   118086 | sortkey             | Complete                                             | 2020-08-22 19:42:00.72635   |  SORTKEY: None;
   118082 | sortkey             | Complete                                             | 2020-08-22 19:43:34.728144  |  SORTKEY: None;
   118072 | sortkey             | Skipped:Retry exceeds the maximum limit for a table. | 2020-08-22 19:44:46.706155  | 
   118086 | sortkey             | Start                                                | 2020-08-22 19:42:00.685255  | 
   118082 | sortkey             | Start                                                | 2020-08-22 19:43:34.69531   | 
   118072 | sortkey             | Start                                                | 2020-08-22 19:44:46.703331  | 
   118082 | sortkey             | Checkpoint: progress 14.755079%                      | 2020-08-22 19:42:52.692828  | 
   118072 | sortkey             | Failed                                               | 2020-08-22 19:44:14.796071  |   
   116723 | sortkey             | Abort:This table is not AUTO.                        | 2020-10-28 05:12:58.479233  | 
   110203 | distkey             | Abort:This table is not AUTO.                        | 2020-10-28 05:45:54.67259   |