Back in 2016 we created a Custom Metadata Type with about 3000 rows. There is a trigger that reads all 3000 rows (via SOQL) and creates a map. This has been working for years, until Winter '19.
Now, when we run the test Class for our trigger (in winter '19), we get this error message:
System.QueryException: myCustom__mdt received too many records from the external data source
Summer '18 Orgs work just fine like they always have.
SO! When I try to debug that error message, I find this knowledge article. Too many records received from external data source
This basically says:
When using an External data source configured to use Server Driven Pagination and for a query on an external object from this external source results in server responding with a result page size greater than 2000 records results in the below error - ...
SO! Are Custom Metadata Types treated like external data sources and the limit is only now being enforced in Winter '19? Is there a limit on CMTs that I am violating and can't find a reference to?