Re: [PROPOSAL] Add SCTP network protocol to postgresql backend and frontend

On 03/23/2016 02:13 PM, Alvaro Herrera wrote:
> Andreas Karlsson escribió:
>> On 03/23/2016 01:55 PM, Eduardo Morras wrote:
>>> Benefits:
>>>
>>> Dynamic multihoming, modifiable at run time, don't need aggregate links at OS level or shutdown servers/clients for a hardware or topology network change.
>>> Message oriented connection.
>>> Message reliability.
>>> Inmune to SYN floods that affect tcp.
>>> Assimetric multihoming, a client with 4 links(3x 1GbEth + wifi) can connect to a server with 1 link (10GbEth).
>>> Metadata connection messages.
>>
>> While SCTP has some nice advantages in general (I think it is a pity it is
>> not used more) I wonder how well these benefits translate into the database
>> space. Many databases are run either in a controlled server environment with
>> no direct access from the Internet, or locally on the same machine as the
>> application. In those environments you generally do not have to worry about
>> SYN floods or asymmetric links.
>
> That might or might not be the most common cases, but replication across
> the ocean and similar long-range setups are a reality today and their use
> will only increase.

Agreed. When I reread my message I realized that I implied things I did
not mean. People run databases today in the cloud and, as you said, long
distance replication will only get more common. What I am actually
curious about is how the advantages of SCTP translate into the database
space.

> I wonder about message ordering. Is it possible to get messages out of
> order in SCTP? Say if you have an ordered resultset stream from the
> server, it would be disastrous to get the data messages out of order.

Message ordering is an optional feature in SCTP, so if you need message
ordering you can get it.

Andreas