[Bizgres-general] Transactional Statement Queuing - Queue Design 1

[Mark Kirkwood]

Mark Kirkwood wrote:

> I'm in the process of coding up an initial cut of this mechanism, which 
> should clarify some of these choices. Note that this is *only* the lock 
> mechanism - attaching queue limits to roles and having the lock know 
> what its limit is, are still TODO.
> 

This is the initial cut for adding a new lock mode (LW_LIMITED) for 
lightweight locks (see attached). There are some issues/bugs to be 
ironed out - like how to handle limited and shared or exclusive waiters 
in the same lock queue (in fact they won't be - read on).

A lively off-list discussion was triggered by the 'pre-initial' version 
of this patch (nothing like having something concrete to pound on), 
culminating in the conclusion that a significant revision of the 
*original* proposal was in order - I'll summarize:

1/ Queuing need to be at the statement level (at least), as opposed to 
the transaction level.

2/ The queuing mechanism needs to be extensible.

This actually echoes some of the early on-list feedback to the original 
proposal (from Jim I think).

The inference to draw from this is that a new proposal is required!

So then, the next steps for me are:

1/ Write up new proposal.
2/ Begin initial design.

Comments/feedback welcome!

Cheers

Mark
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: locking1.1.patch
Url: http://pgfoundry.org/pipermail/bizgres-general/attachments/20060511/738a40f1/attachment.ksh