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 ](https://amazonaws-china.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/) that was published on June 30, 2025. 

# SYS\_AUTO\_TABLE\_OPTIMIZATION
<a name="r_SYS_AUTO_TABLE_OPTIMIZATION"></a>

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](cm_chap_system-tables.md#c_visibility-of-data).

## Table columns
<a name="r_SYS_AUTO_TABLE_OPTIMIZATION-table-rows"></a>


| 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
<a name="r_SYS_AUTO_TABLE_OPTIMIZATION-sample-queries"></a>

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   |
```