[rds-devel] RDS IB transport software flow control?
Richard Frank
richard.frank at oracle.com
Tue Nov 6 10:26:46 PST 2007
Memory consumption is bounded by so_sndbuf + so_rcvbuf * number of
active endpoints.
We can tune these values - as in any other socket - to bound memory.
Zach Brown wrote:
>> RDS can be quite memory
>> hungry, if you let it run unchecked; and once you do run into a congestion
>> scenario, things will actually get quite slow, as congestion updates
>> involve sending the entire 8K congestion map down all RCs.
>>
>
> The input I was given is that it's acceptable to require that
> deployments very carefully tune the amount of data they'll have in the
> network. It's like tuning the database's SGA size. If you get it wrong
> the system will be very unhappy.
>
> That's why congestion updates are trivial but expensive. If they're
> happening its a fundamental mistuning of a closed system that should be
> lighting up pagers, not some natural side-effect of load like it is for
> TCP over the big-bad-internet.
>
> - z
>
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