Re: Reviewers Guide to DeferredTransactions/TransactionGuarantee

On Sun, 2007-04-08 at 17:02 +0100, Simon Riggs wrote:

> My concern was this:
> 
> If we flush the currently outstanding deferred transactions then that
> doesn't guarantee they have all reached the clog. Previously, a deferred
> transaction would not release the CheckpointStartLock until after the
> clog had been updated. 
> 
> If we wait for all currently inCommit transactions to end this will
> cover all deferred transactions also. So I think I just need to flush
> deferred transactions prior to the wait and this will be valid. Would
> you agree?

I'm good with this now, sorry for the noise.

>From the existing code in CreateCheckpoint, just need to add a
background flush immediately prior to the newly added waits. That would
replace what I've got in the current patch where I hold the lock across
the calculation the WAL insert pointer for the checkpoint which was too
safe - there is no need for prior WAL to be flushed at that point.

-- 
  Simon Riggs             
  EnterpriseDB   http://www.enterprisedb.com