[rabbitmq-discuss] limit number of messages buffered in memory in new persister

[alex chen]

Matthias,


> I don't see commits as overly burdensome. After all, what you are
suggesting above is in effect a synchronous publish, in which case just
introduce a helper method that does a publish followed by a commit.

We tested publish+commit and found that it is much slower than publish only.
For single client with commit on every publish, it can do about 20 msg/sec.
It took about 40ms for client to get the tx_commit_ok from server.
It seems to me the bottleneck was not fsync, because disk was not busy.
also i tried commenting out file:sync() from the src code and it has no effect.

if commit on 100 publishes, the performance increases to above 1000 msg/sec.
Is there anyway to speed up the performance for commit on every publish?  


thanks.

-alex