Re: [HACKERS] [PROPOSAL] Add SCTP network protocol to postgresql backend and frontend
On Wed, 23 Mar 2016 10:13:42 -0300 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. > > 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 optional, server decides if clients can use messages out of order as received or strictly in the same order as sended. > -- > Álvaro Herrerahttp://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services --- --- Eduardo Morras -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PROPOSAL] Add SCTP network protocol to postgresql backend and frontend
On Wed, 23 Mar 2016 14:03:31 +0100 Andreas Karlsson wrote: > 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. > > Do you have any specific use case in mind? The main use case is change the network topology on the fly, without shutting down postgresql server, postgresql middleware, or any of the applications that uses it through libpq. Specific use case, backup is backup server on OS level or pgdump, not postgresql slave, (hope it don't wraps) backup <-> postgresql <-> middleware <-> client apps <-> backup At peak times you need all nics connected between postgresql servers and middleware and client apps, backup <-> postgresql <=> middleware <=> client apps <-> backup at night or idle time or while backup, you can reassign the nics to get more network bandwith to backup server backup <=> postgresql <-> middleware <-> client apps <=> backup On a crash restore, all nics are used from backup to servers backup postgresql < > middleware < > client apps backup > Andreas --- --- Eduardo Morras -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [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 -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PROPOSAL] Add SCTP network protocol to postgresql backend and frontend
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. 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. -- Álvaro Herrerahttp://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PROPOSAL] Add SCTP network protocol to postgresql backend and frontend
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. Do you have any specific use case in mind? Andreas -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
