View the original community article here
Last tested: May 11, 2020
The creation of PDTs that are persisted using the
persist_for parameter is only triggered manually from an explore query. When a user first queries the PDT via an explore/look/dashboard, a table is created on the scratch schema. When a persist_for PDT is created, it is assigned an expiration time that is equal to the create time + amount of time specified in the
persist_for parameter. For example, if I have a PDT with
persist_for: "5 hours" and I query this PDT for the first time at 12:04 UTC, this PDT will have an expiration time of 17:04 UTC.
When a persist_for PDT reaches its expiration time, the PDT is dropped from the scratch schema by the "PDT reaper."
PDTs that are defined in LookML that have not been pushed to production (dev mode PDTs) are treated as PDTs that have been persisted for 24 hours, even if they are persisted with the
sql_trigger_value parameter. Once the PDT LookML has been pushed to production, PDTs persisted with the
sql_trigger_value parameter will be managed by the PDT regenerator and rebuilt according to their sql triggers.