Re: WAL segment question

On Sat, Aug 04, 2007 at 12:00:52AM +0100, Donald Fraser wrote:
> Our company has two sites, a master and a disaster recovery site.
> I am trying to assess whether data has been lost during a fail-over, due to the asynchronous method of transporting WAL file data between sites (we use DRBD).
>
> Disaster recovery node start-up log:
> user= pid=9907 timestamp=[2007-08-01 17:09:51 BST] tid= LOG: record with zero length at 0/7C62F52C
> user= pid=9907 timestamp=[2007-08-01 17:09:51 BST] tid= LOG: redo done at 0/7C62F4E8
>
> My question is: given the above WAL segment information, can I use it to decide whether information was lost in the master database site, at the point of failure, without starting the database up?

I'm not sure, but you could try md5-ing the appropriate WAL file on the
master and slave; if the files are identical then you shouldn't have
lost any data... if they are then you probably have.
--
Decibel!, aka Jim Nasby decibel(at)decibel(dot)org
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)