WAL bandwidth

Hi,

time and again I need to build indexes. If they are big, that generates
a lot of WAL data that needs to be replicated to streaming replication
slaves. Usually these slaves don't lag behind noticeably. So, the
application often reads from them. Well, unless I build indexes and,
thus, create a huge amount of WAL in a short period of time.

What I'd like to have is something where I can set the max. bandwidth
with which the index generating backend may generate WAL data. I seem to
remember to have seen a discussion about something similar but can't
recall where.

Is there anything I can do about that problem in 9.3 or 9.4?

I already have a function that waits for the streaming slaves to catch
up. But that mitigates the problem only at a very crude level. I'd like
to be able to set that bandwidth to, say, 10mbit/sec. Then I can be sure
that all my replicas are fine. How long the index creation takes, does
not matter.

Thanks,
Torsten