John, Data Engineer, do have technical requirements to refresh the External tables Metadata periodically or in auto mode, which approach John can take to meet this technical specification?

John, Data Engineer, do have technical requirements to refresh the External tables Metadata periodically or in auto mode, which approach John can take to meet this technical specification?
A . John can use AUTO_REFRESH parameter if the underlying External Cloud host sup-ports this for External tables.
B . He can create a task that executes an ALTER EXTERNAL TABLE … REFRESH statement every 5 minutes.
C . External table cannot be scheduled via Snowflake Tasks, 3rd party tools/scripts needs to be used provided by External cloud storage provider.
D . Snowflake implicitly take care this Infrastructure needs, as underlying warehouse layer internally manage the refresh. No action needed from John.

View Answer

Answer: A, B

Explanation:

Both Option A & B are correct.

For Refreshing External Table Metadata on a Auto Mode, John can use the AUTO_REFRESH parameter properties of External table. When an external table is created, the AUTO_REFRESH parameter is set to TRUE by default.

When an external table is created, the AUTO_REFRESH parameter is set to TRUE by default. Snowflake recommend that you accept this default value for external tables that reference data files in either Amazon S3 or Microsoft Azure stages.

However, the automatic refresh option is not available currently for external tables that reference Google Cloud Storage stages.

For these external tables, manually refreshing the metadata on a schedule can be useful.

The following example refreshes the metadata for an external table named snowdb.snowschema.snow_ext_table (using ALTER EXTERNAL TABLE … REFRESH) on a schedule. — Create a task that executes an ALTER EXTERNAL TABLE … REFRESH statement every 5 minutes.