Report Download RateExceededError.RATE_EXCEEDED

We are running report downloads in a clustered environment using a custom rate limiter. I have been adjusting QPS in an attempt to avoid rate exceeded errors. I am down to 5 QPS which works fine until enough clustered workers are running, at which point I start to see rate exceeded errors. The errors start occuring at about 20 workers. Each worker runs 4 concurrent report downloads.

Here is the error that I am receiving:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><reportDownloadError><ApiError><type>RateExceededError.RATE_EXCEEDED</type><trigger></trigger><fieldPath></fieldPath></ApiError></reportDownloadError>

Is there another limiting factor at play here besides QPS? What is a good value to use for QPS?

In the version of the error that I am seeing, there is no specified `retryAfterSeconds`, I have been using 30 seconds. Is that a good amount of time to pause?

Thanks,

Jake

--
--
=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~
Also find us on our blog and Google+:
https://googleadsdeveloper.blogspot.com/
https://plus.google.com/+GoogleAdsDevelopers/posts
=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~
 
You received this message because you are subscribed to the Google
Groups "AdWords API Forum" group.
To post to this group, send email to adwords-api@googlegroups.com
To unsubscribe from this group, send email to
adwords-api+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/adwords-api?hl=en
---
You received this message because you are subscribed to the Google Groups "AdWords API Forum" group.
To unsubscribe from this group and stop receiving emails from it, send an email to adwords-api+unsubscribe@googlegroups.com.
Visit this group at https://groups.google.com/group/adwords-api.
To view this discussion on the web visit https://groups.google.com/d/msgid/adwords-api/81ffd0bc-4edc-47c6-a718-2b7f1edf9f04%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.