Re: [HACKERS] Change lock requirements for adding a trigger

[Decibel!]

On Jun 3, 2008, at 5:04 PM, Simon Riggs wrote:

On Tue, 2008-06-03 at 16:48 -0500, Decibel! wrote:

On May 30, 2008, at 9:51 AM, Simon Riggs wrote:

On Thu, 2008-05-29 at 19:18 -0500, Decibel! wrote:

Is there a reason that we can't add a trigger to a table while a
select is running? This is a serious pain when trying to setup
londiste or slony.

This is constrained by locking.


with just an ExclusiveLock or ShareLock rather than an
AccessExclusiveLock. Nobody has studied which sub-statements this
might
apply to, but its do-able since CREATE INDEX already does this.

There are a subset of DDL commands that might be able to be performed

Is there a good way to determine this other than depending on
knowledge of the source code?

The source doesn't know yet. So just analysis and thinking.


performed correctly with a lower level of lock.

The mechanism to hold less than an AccessExclusiveLock it doesn't exist yet, but it never will unless we have a list of the things that might be

--
Decibel!, aka Jim C. Nasby, Database Architect  [EMAIL PROTECTED]
Give your computer some brain candy! www.distributed.net Team #1828

Ok, I'll take a stab at such a list. Can anyone think of any reasons why CREATE TRIGGER couldn't get by with ShareLock?

smime.p7s
Description: S/MIME cryptographic signature