On 1/14/14, 8:20 PM, Simon Riggs wrote:
We've discussed previously the negative impact of large bulk
operations, especially wrt WAL writes. Patch here allows maintenance
operations to have their WAL generation slowed down as a replication
lag prevention feature.
I believe there was originally intended to be some work on I/O rate
limiting, but that hasn't happened and is in some ways orthogonal to
this patch and we will likely eventually want both.
Single new parameter works very similarly to vacuum_cost_delay
wal_rate_limit_delay = Xms
From a replication standpoint, I think it would be a lot nicer if this also (or
instead) considered the replication delay we were currently experiencing.
Related to that... it would be extremely useful to us if we could similarly
rate limit certain backend operations, for the purpose of not overloading the
database or replication. That's fairly unrelated except that sometimes you
might want to WAL rate limit a backend operation, besides just COPY.
--
Jim C. Nasby, Data Architect j...@nasby.net
512.569.9461 (cell) http://jim.nasby.net
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