In the Governor limits, there is the following limit:

Number of synchronous concurrent transactions for long-running transactions that last longer than 5 seconds for each org.

If i create a custom Apex REST resource (e.g. using @RestResource(urlMapping='/whatever/v1/*') annotation), and inside this resource in the actions i run some heavy SOQL queries, and i have a few thousand users call this API all at once (they do it via a mobile app in the field), and it so happens that some requests take longer than 5 seconds, are those considered long-running transactions?

Does it mean other users will be denied (what it says on the same page)?

1 Answer 1


Yes. The system will observe that there are too many requests over 5 seconds long and deny any further requests until the long-running ones complete. In that case, you'd need the client to retry.

  • So same limit does not apply to the standard query API, that has a different API limit on 25 requests with each taking more than 20 seconds? But it applies to Apex API?
    – zaitsman
    Jun 5, 2020 at 2:00
  • @zaitsman Right. Long-running transactions count for things like Visualforce, REST API calls, Lightning controllers, etc.
    – sfdcfox
    Jun 5, 2020 at 2:08
  • @sfdcfox I know it applies to custom webservice hosted via apex, but does it also applies to triggers running in backend when using composite apis? May 29, 2022 at 7:15

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