RE: replication followup - Mailing list pgsql-general

From Justin Banks
Subject RE: replication followup
Date
Msg-id 14938.15873.254425.290397@flotsam.cops.wamnet.com
Whole thread Raw
In response to RE: replication followup  ("Mikheev, Vadim" <vmikheev@SECTORBASE.COM>)
List pgsql-general
>>>>> "Mikheev" == Mikheev, Vadim <vmikheev@SECTORBASE.COM> writes:

 Mikheev> Two comments about sync replication:

 Mikheev> 1. You cannot do true sync replication without two-phase
 Mikheev> commit protocol. (What if transaction will be committed on
 Mikheev> slave but master will be stopped/crashed/whatever? Databases
 Mikheev> will be out of sync).

I have addressed this in the code I have working now. I was hoping to
get the current code out to some interested parties today, but I fell
into a couple meetings, and it may be a day or so.

 Mikheev> 2. You cannot do bi-directional sync replication without
 Mikheev> distributed lock manager. (You'll get deadlock when
 Mikheev> attempting update "same" record - ie with the same key - on
 Mikheev> two sites at the same time).

I encountered that realization today ;) I think I'm going to have to
stick with unidirectional, but I need to think about it some
more. There may be ways that I can do it properly in my particular
case, but I'm sure you're right in the general case. I have some
ideas, though, if you'd be interested we could take that discussion
off the list somewhere?

 Mikheev> Vadim P.S. Are you sure that -general is right list for this
 Mikheev> stuff?

Nope, as I stated in my original email, but I wasn't sure. Is -hackers
perhaps a better place?

-justinb

--
Justin Banks - WAM!NET Inc., Eagan MN justinb@wamnet.com
"I can't stand this proliferation of paperwork.  It's useless to fight the
forms.  You've got to kill the people producing them."  --Vladimir Kabaidze,
General Director of Ivanovo Machine Building Works


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