---
sourceDocument: Australia ServiceNow AI Platform Administration
sourceDocumentLink: https://servicenow-prod.fluidtopics.net/r/platform-administration

 Release :

    - australia

ft:locale :

    - en-US

ft:publication_title :

    - Australia ServiceNow AI Platform Administration

ft:clusterId :

    - platadm

bundleId :

    - platadm

workflow :

    - Platform


---

# Table extension

# Table extension {#ariaid-title1}

Release version: Australia  
Updated March 12, 2026  
![](https://www.servicenow.com/docs/portal-asset/ico-clock) 1 minute to read  
Partition and preserve data sets for extended periods without overwriting.

Table extension is based around a base table and a number of shards. The shards are given a duration which determines the period of time across which data is written to each shard. Shards in a table extension don't rotate. Instead of the oldest shard being truncated and re-used, an extension creates new shards indefinitely. This way, data remains logically separated across shards due to creation date and no data is ever deleted.

## Advantages

Table extension partitions data across tables, which allows you to archive data while ensuring that tables stay reasonably-sized. The working set of data is reduced when queries include date-range filters that limit results to specific shards.

## Disadvantages

Table extension requires a union query when you query for a time range that spans multiple tables. Union queries are less efficient than queries against a single table. Improperly configured table extensions can cause the system to query across multiple extension tables unnecessarily, resulting in slower query performance and higher database load.
* **[Apply table extension](https://servicenow-prod.fluidtopics.net/npWnbrjEyfsDn6DHi5zxHA)**   
  Preserve data sets using table extension.

**Related concepts**   

* [Table rotation](https://servicenow-prod.fluidtopics.net/of_VusygcBpwPLuWLJnkCQ "Optimize performance and manage data lifecycle by rotating tables, allowing older data to be systematically archived while maintaining system efficiency.")  
**Related tasks**   

* [Activate database rotation](https://servicenow-prod.fluidtopics.net/yLCUX0RLzPpetB_MSNMWMg "Learn how to activate database rotation.")