Re: Cost limited statements RFC

On 6/7/13 12:42 PM, Robert Haas wrote:
> GUCs in terms of units that are meaningful to the user. One could
> have something like io_rate_limit (measured in MB/s),
> io_read_multiplier = 1.0, io_dirty_multiplier = 1.0, and I think that
> would be reasonably clear.

There's one other way to frame this:

io_read_limit = 7.8MB/s # Maximum read rate
io_dirty_multiplier = 2.0 # How expensive writes are considered
relative to reads

That still gives all of the behavior I'd like to preserve, as well as
not changing the default I/O pattern. I don't think it's too
complicated to ask people to grapple with that pair.

--
Greg Smith 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
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