# Revision history [back]

Solved by myself - changing subscriber's queue_size works out for me. Using the code example on my environment I described in the question, I increased it from 1 to 5 in the problematic code (the one in python). Btw the queue_size in the publisher is not showing influence here.

PS. However I still don't get why...I've read documents including this QA though. Is my understanding below correct...? I'll give a vote if someone corrects it.

Increasing queue_size means the number of msgs processed in one callback increases, and that number is greater than calling callback during the same period.

Solved by myself - changing subscriber's queue_size works out for me. Using the code example on my environment I described in the question, I increased it from 1 to 5 in the problematic code (the one in python). Btw the queue_size in the publisher is not showing influence here.

PS. However I still don't get why...I've read documents including this QA though. Is my understanding below correct...? I'll give a vote if someone corrects it.

Increasing queue_size means the number of msgs processed in one callback increases, and that number is could be greater than calling callback during the exactly same length of period.