Amazon Redshift will no longer support the creation of new Python UDFs starting Patch 198. Existing Python UDFs will continue to function until June 30, 2026. For more information, 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/). 

# 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   |
```