Re: [HACKERS] Adding the optional clause 'AS' in CREATE TRIGGER - Mailing list pgsql-hackers

From Okano, Naoki
Subject Re: [HACKERS] Adding the optional clause 'AS' in CREATE TRIGGER
Date
Msg-id 0B4917A40C80E34BBEC4BE1A7A9AB7E27ACD05@g01jpexmbkw05
Whole thread Raw
In response to Re: [HACKERS] Adding the optional clause 'AS' in CREATE TRIGGER  (Peter Eisentraut <peter.eisentraut@2ndquadrant.com>)
Responses Re: [HACKERS] Adding the optional clause 'AS' in CREATE TRIGGER  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Peter Eisentraut wrote:
> On 3/8/17 04:12, Okano, Naoki wrote:
> > Peter Eisentraut wrote:
> >> I have a feeling that this was proposed a few times in the ancient past
> >> but did not go through because of locking issues.  I can't find any
> >> emails about it through.  Does anyone remember?  Have you thought about
> >> locking issues?
> > Is this e-mail you are finding?
> > https://www.postgresql.org/message-id/20140916124537.GH25887%40awork2.anarazel.de
>
> No, that's not the one I had in mind.
I see. But I could only find it. 
Would anyone know e-mails discussed about locking issues? 

> > I am considering to add 'OR REPLACE' clause as a first step.
> > At least, I think there is no need to change the locking level when replacing a trigger with 'EXECUTE PROCEDURE'
clause.
> > In PostgreSQL, we currently have ShareRowExclusiveLock lock on relation on which trigger is created.
ShareRowExclusiveLockis enough to replace a trigger.
 
> > Also, we currently have RowExclusiveLock on pg_trigger. RowExclusiveLock is enough to replace a trigger, too.
> 
> I'm not saying it's not correct.  I was just wondering.
Thank you for your opinion!
I think we do not need to change locking level in this case.
If someone notice a mistake in my understanding, please point out it.

Regards,
Okano Naoki
Fujitsu



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