On Mon, Nov 30, 2009 at 4:56 AM, Boszormenyi Zoltan <zb(at)cybertec(dot)at> wrote:
> I don't think its reasonable trying to discuss and implement this all
> in one huge patch so I propose implementing at least 1) as a seperate
I agree with this development plan.
> Now there unforatunately are two different schools of thought how to implement transfering base data.
> 1. archive_command like transfer command taking a source path/host and target path/host
> - very flexible (think e.g. not transferring the data for multiple slaves over the whole country)
> - harder to setup
> - more in style of classical wal archiving
> 2. add the capability to the WAL Streaming patch's libpq based protocol
> - no additional configuration needed
> - inflexible
> - makes usage from non streaming replication is impossible
> I favor 1. but only lightly so.
I favor 2 ;) Because I think that it's too hard for users to set up
a transfer command. One of streaming replication's merits is that
users no longer need to specify a transfer command for log-shipping.
So users can configure and use replication without complex settings.
But, #1 would spoil this merit.
> Detail Questions:
> - How to deal with multiple transfer requests at the same time?
> There would be a need for multiple full backup requests for
> individual tables by several clients at once.
> Currently pg_start_backup() isn't allowed from
> two clients in parallel, the second one gets an error.
> We thought that pg_start_backup() and pg_stop_backup()
> can turn into simple reference counts. IIRC, WALs
> are still generated and _shipped to slaves_ during
> a full backup, they are simply not yet applied to
> base table files. So, in this case a pg_stop_backup()
> issued from a slave decreases refcount of the base backups
> and the slave can simply resume applying its newly
> received WALs to base files.
I'm not sure how. But at first multiple online-backup feature
rather than backup-shipping itself might have to be addressed.
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center
In response to
pgsql-hackers by date
|Next:||From: Fujii Masao||Date: 2009-11-30 03:20:53|
|Subject: Re: Application name patch - v4|
|Previous:||From: Jeff Davis||Date: 2009-11-30 03:01:59|
|Subject: Re: [PATCH 4/4] Add tests to dblink covering use of COPY