morningman opened a new issue, #17413:
URL: https://github.com/apache/doris/issues/17413

   ### Search before asking
   
   - [X] I had searched in the 
[issues](https://github.com/apache/doris/issues?q=is%3Aissue) and found no 
similar issues.
   
   
   ### Description
   
   ## Background
   
   Doris supports [multi catalog 
](https://doris.apache.org/docs/dev/lakehouse/multi-catalog/) to connect to 
external datasource.
   For any catalog, Doris will sync the metadata, such as database, table, 
schema, partition, file from external datasource
   into FE's memory, so that when accessing the catalog, we don' t need to 
access the remote data source' meta service.
   
   But it is a one-time operation, after sync, if the external data source 
change its metadata, such as adding new table, partition,
   Doris can't be aware of it and the newly created metadata can not be 
accessed from Doris.
   
   So we need a way refresh the metadata of the catalog, to sync the metadata 
at fix interval.
   
   ## How to
   
   First, we should set new properties of catalog when creating it, eg:
   ```
   create catalog hive properties (
   ...
   "metadata_refresh_interval_sec" = "7200"
   ...
   );
   ```
   
   which means for this `hive` catalog, its metadata will be refreshed every 
7200s.
   And there will be a daemon thread on Master FE to do this for all catalogs.
   
   ## Tips
   
   1. Related classes: See `makeSureInitialized()` of `ExternalCatalog` class 
to learn how to refresh catalog.
   2. See 
[Refresh](https://doris.apache.org/docs/dev/sql-manual/sql-reference/Utility-Statements/REFRESH)
 command to learn how to refresh catalog manually.
   
   
   
   
   ### Use case
   
   _No response_
   
   ### Related issues
   
   _No response_
   
   ### Are you willing to submit PR?
   
   - [ ] Yes I am willing to submit a PR!
   
   ### Code of Conduct
   
   - [X] I agree to follow this project's [Code of 
Conduct](https://www.apache.org/foundation/policies/conduct)
   


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