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://aws.amazon.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. 

# STL\_WINDOW
<a name="r_STL_WINDOW"></a>

Analyzes query steps that perform window functions.

STL\_WINDOW is visible to all users. Superusers can see all rows; regular users can see only their own data. For more information, see [Visibility of data in system tables and views](cm_chap_system-tables.md#c_visibility-of-data).

**Note**  
STL\_WINDOW only contains queries run on main provisioned clusters. It doesn't contain queries run on concurrency scaling clusters or on serverless namespaces. To access explain plans for queries run on both main clusters, concurrency scaling clusters, and serverless namespaces, we recommend that you use the SYS monitoring view [SYS\_QUERY\_DETAIL](SYS_QUERY_DETAIL.md) . The data in the SYS monitoring view is formatted to be easier to use and understand.

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


| Column name  | Data type  | Description  | 
| --- | --- | --- | 
| userid | integer | ID of the user who generated the entry. | 
| query | integer | Query ID. The query column can be used to join other system tables and views. | 
| slice | integer | Number that identifies the slice where the query was running. | 
| segment | integer | Number that identifies the query segment. | 
| step | integer | Query step that ran. | 
| starttime | timestamp | Time in UTC that the query started. Total time includes queuing and execution. with 6 digits of precision for fractional seconds. For example: 2009-06-12 11:29:19.131358. | 
| endtime | timestamp | Time in UTC that the query finished. Total time includes queuing and execution. with 6 digits of precision for fractional seconds. For example: 2009-06-12 11:29:19.131358. | 
| tasknum | integer | Number of the query task process that was assigned to run the step. | 
| rows | bigint | Total number of rows that were processed. | 
| is\_diskbased | character(1) | If true (t), the query was performed as a disk-based operation. If false (f), the query was performed in memory. | 
| workmem | bigint | Total number of bytes in working memory that were assigned to the step. | 

## Sample queries
<a name="r_STL_WINDOW-sample-queries"></a>

The following example returns window function results for slice 0 and segment 3. 

```
select query, tasknum, rows, is_diskbased, workmem
from stl_window
where slice=0 and segment=3;
```

```
 query | tasknum | rows | is_diskbased | workmem
-------+---------+------+--------------+----------
 86326 |      36 | 1857 | f            | 95256616
   705 |      15 | 1857 | f            | 95256616
 86399 |      27 | 1857 | f            | 95256616
   649 |      10 |    0 | f            | 95256616
(4 rows)
```