Re: Transaction Snapshot Cloning - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Transaction Snapshot Cloning
Date
Msg-id 47934083.5050904@enterprisedb.com
Whole thread Raw
In response to Re: Transaction Snapshot Cloning  (Simon Riggs <simon@2ndquadrant.com>)
Responses Re: Transaction Snapshot Cloning  (Simon Riggs <simon@2ndquadrant.com>)
List pgsql-hackers
Simon Riggs wrote:
> On Sat, 2008-01-12 at 18:46 +0000, Gregory Stark wrote:
> 
>> To do something like that the user would have to create a prepared transaction
>> to save the snapshot. I think that makes sense though since effectively it's
>> just requiring that the user explicitly do what would otherwise be a hidden
>> implicit requirement -- that the user do something to hold globalxmin back to
>> avoid having the snapshots expire.
> 
> This is a good idea which I will want to develop in the future, not yet
> though.

I haven't been following this thread in detail, but I'd just like to 
point out that there's a couple features in the XA spec that we don't 
currently support:

- ability to "stop" a transaction, and resume it later, executing other 
transactions in between.
- ability to stop a transaction, and resume it later in another connection.

Neither of these are essential for two-phase commit, which is what the 
spec is for, but if they happened to fall out of some other work, it 
would be nice...

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com


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