How often will the cache be cleared by this data group which using sql_trigger?

[honghai_sg99-16]

If I have a datagroup with a sql_trigger of ‘SELECT CURRENT_TIMESTAMP" (that is, it selects the
current date, hour, minute, and second), then how often will the cache be cleared by this datagroup? 

[Dawid · Accepted solution]

Based on the information in the documentation: https://docs.looker.com/reference/model-params/datagroup#sql_trigger I would say that it would run cache every time (or every second) because the value returned will be different each time. 

For PostgreSQL, for example  the value of CURRENT_TIMESTAMP is:

2022-08-09 11:16:56.715328 +00:00

which means unless I have two queries in a microsecond, I wouldn’t hit the cache

[n_davis]

Depends on how often your instance is set to check datagroup triggers, but whenever it checks it’ll clear cache and rebuild PDTs in that scenario

[honghai_sg99-16]

As often as the regenerator runs, which defaults to every 5 minutes.

[thinh96-1657593]

Based on the information in the documentation: https://docs.looker.com/reference/model-params/datagroup#sql_trigger I would say that it would run cache every time (or every second) because the value returned will be different each time. 

For PostgreSQL, for example  the value of CURRENT_TIMESTAMP is:

2022-08-09 11:16:56.715328 +00:00

which means unless I have two queries in a microsecond, I wouldn’t hit the cache

I believe the answer is every 5 minutes. Because the SQL_trigger run base on regenerator schedule. 

https://community.looker.com/technical-tips-tricks-1021/the-pdt-regenerator-process-23715