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?

  • Whoa. That's crazy.
    – Adrian Larson
    Sep 19, 2018 at 18:43
  • 2
    I opened a Case with SF Support... it's been escalated to the point where R&D is looking into it. I think it's a winter '19 bug. I hope it gets cleared up before release. I've been the little voice behind a known issue before, but never something like this! Sep 19, 2018 at 19:17
  • 2
    Does it work if you query once with LIMIT 1500 and then another with OFFSET 1500 and merge them? Slapdash non-scalable solution but at least it gets you through the storm.
    – Charles T
    Sep 19, 2018 at 20:07
  • @CharlesT I haven't tried it. A member of our Dev team was heading down that path while we awaited and answer from support. I might get some feedback on this tommorow. "Slapdash", I like that! I'm going to start using that term I learned from Charles T. Sep 19, 2018 at 21:27
  • Has anyone escalated this to the Partner Community?
    – Charles T
    Sep 20, 2018 at 1:22

1 Answer 1


This is a Winter '19 bug. I've heard several other folks have the same issue and they put in tickets.

Known Issue

  • 1
    Confirmed by SFDC... "As informed, this is confirmed as a known issue in Salesforce. This is likely to be fixed by 1st week of October(safe harbour). Until then as a workaround you can try to modify the query to retrieve 2000 records." Sep 20, 2018 at 14:14
  • In case anyone is following.. this appears to be fixed in Winter '19 Oct 1, 2018 at 17:56

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