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  1. Doc: clarify how triggers relate to transactions.

  1. Clarify how triggers relate to transactions

    The Post Office <noreply@postgresql.org> — 2021-04-27T14:26:48Z

    The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/13/sql-createtrigger.html
Description:

https://www.postgresql.org/docs/current/sql-createtrigger.html mentions the
word "transaction" only once, in reference specifically to constraint
triggers: "They can be fired either at the end of the statement causing the
triggering event, or at the end of the containing transaction; in the latter
case they are said to be deferred."

If I understand correctly, it would be helpful to add this sentence or a
corrected version of it: "Triggers always execute in the same transaction as
the triggering event, and if a trigger fails, the transaction is rolled
back."

  2. Re: Clarify how triggers relate to transactions

    Laurenz Albe <laurenz.albe@cybertec.at> — 2021-04-28T11:24:53Z

    On Tue, 2021-04-27 at 14:26 +0000, PG Doc comments form wrote:
> The following documentation comment has been logged on the website:
> 
> Page: https://www.postgresql.org/docs/13/sql-createtrigger.html
> Description:
> 
> https://www.postgresql.org/docs/current/sql-createtrigger.html mentions the
> word "transaction" only once, in reference specifically to constraint
> triggers: "They can be fired either at the end of the statement causing the
> triggering event, or at the end of the containing transaction; in the latter
> case they are said to be deferred."
> 
> If I understand correctly, it would be helpful to add this sentence or a
> corrected version of it: "Triggers always execute in the same transaction as
> the triggering event, and if a trigger fails, the transaction is rolled
> back."

Good idea in principle, but I'd put that information on
https://www.postgresql.org/docs/current/trigger-definition.html

Yours,
Laurenz Albe

  3. Re: Clarify how triggers relate to transactions

    Nathan Long <him@nathanmlong.com> — 2021-04-28T17:18:40Z

    Gotcha. Where would I go to make the PR?

On Wed, Apr 28, 2021, 7:24 AM Laurenz Albe <laurenz.albe@cybertec.at> wrote:

> On Tue, 2021-04-27 at 14:26 +0000, PG Doc comments form wrote:
> > The following documentation comment has been logged on the website:
> >
> > Page: https://www.postgresql.org/docs/13/sql-createtrigger.html
> > Description:
> >
> > https://www.postgresql.org/docs/current/sql-createtrigger.html mentions
> the
> > word "transaction" only once, in reference specifically to constraint
> > triggers: "They can be fired either at the end of the statement causing
> the
> > triggering event, or at the end of the containing transaction; in the
> latter
> > case they are said to be deferred."
> >
> > If I understand correctly, it would be helpful to add this sentence or a
> > corrected version of it: "Triggers always execute in the same
> transaction as
> > the triggering event, and if a trigger fails, the transaction is rolled
> > back."
>
> Good idea in principle, but I'd put that information on
> https://www.postgresql.org/docs/current/trigger-definition.html
>
> Yours,
> Laurenz Albe
>
>

  4. Re: Clarify how triggers relate to transactions

    Laurenz Albe <laurenz.albe@cybertec.at> — 2021-04-28T18:17:49Z

    On Wed, 2021-04-28 at 13:18 -0400, Nathan Long wrote:
> Gotcha. Where would I go to make the PR?

You'd create a patch against Git master and send it to this
mailing list or pgsql-hackers.  If you don't want it to fall
between the cracks, register in the next commitfest where it
can undergo peer review.

Yours,
Laurenz Albe

  5. Re: Clarify how triggers relate to transactions

    Euler Taveira <euler@eulerto.com> — 2021-05-02T15:45:45Z

    On Wed, Apr 28, 2021, at 2:18 PM, Nathan Long wrote:
> Gotcha. Where would I go to make the PR?
> 
There is no such PR feature; we don't use GitHub despite of having a mirror
there. As Laurenz said you should create a patch (using your preferred git
command) and attach to this thread. If you prefer, you can also send the patch
to pgsql-hackers ML (add the link to this thread). The next step is to register
your patch to the next commitfest [1] so we don't lose track of it. For a
complete reference about submitting a patch, take a look at [2].

[1] https://commitfest.postgresql.org/33/
[2] https://wiki.postgresql.org/wiki/Submitting_a_Patch

Regards,

--
Euler Taveira
EDB   https://www.enterprisedb.com/

  6. Re: Clarify how triggers relate to transactions

    Laurenz Albe <laurenz.albe@cybertec.at> — 2021-05-05T09:55:20Z

    On Wed, 2021-04-28 at 13:24 +0200, Laurenz Albe wrote:
> On Tue, 2021-04-27 at 14:26 +0000, PG Doc comments form wrote:
> > https://www.postgresql.org/docs/current/sql-createtrigger.html mentions the
> > word "transaction" only once, in reference specifically to constraint
> > triggers: "They can be fired either at the end of the statement causing the
> > triggering event, or at the end of the containing transaction; in the latter
> > case they are said to be deferred."
> > 
> > If I understand correctly, it would be helpful to add this sentence or a
> > corrected version of it: "Triggers always execute in the same transaction as
> > the triggering event, and if a trigger fails, the transaction is rolled
> > back."
> 
> Good idea in principle, but I'd put that information on
> https://www.postgresql.org/docs/current/trigger-definition.html

Here is a proposed patch for this.

Yours,
Laurenz Albe

  7. Re: Clarify how triggers relate to transactions

    Laurenz Albe <laurenz.albe@cybertec.at> — 2021-05-20T15:53:40Z

    On Wed, 2021-05-05 at 11:55 +0200, Laurenz Albe wrote:
> On Wed, 2021-04-28 at 13:24 +0200, Laurenz Albe wrote:
> > On Tue, 2021-04-27 at 14:26 +0000, PG Doc comments form wrote:
> > > https://www.postgresql.org/docs/current/sql-createtrigger.html mentions the
> > > word "transaction" only once, in reference specifically to constraint
> > > triggers: "They can be fired either at the end of the statement causing the
> > > triggering event, or at the end of the containing transaction; in the latter
> > > case they are said to be deferred."
> > > 
> > > If I understand correctly, it would be helpful to add this sentence or a
> > > corrected version of it: "Triggers always execute in the same transaction as
> > > the triggering event, and if a trigger fails, the transaction is rolled
> > > back."
> > 
> > Good idea in principle, but I'd put that information on
> > https://www.postgresql.org/docs/current/trigger-definition.html
> 
> Here is a proposed patch for this.

Replying to -hackers for the commitfest app.

Yours,
Laurenz Albe

  8. Re: Clarify how triggers relate to transactions

    Tom Lane <tgl@sss.pgh.pa.us> — 2021-07-30T20:20:23Z

    Laurenz Albe <laurenz.albe@cybertec.at> writes:
> On Wed, 2021-04-28 at 13:24 +0200, Laurenz Albe wrote:
>> On Tue, 2021-04-27 at 14:26 +0000, PG Doc comments form wrote:
>>> If I understand correctly, it would be helpful to add this sentence or a
>>> corrected version of it: "Triggers always execute in the same transaction as
>>> the triggering event, and if a trigger fails, the transaction is rolled
>>> back."

>> Good idea in principle, but I'd put that information on
>> https://www.postgresql.org/docs/current/trigger-definition.html

> Here is a proposed patch for this.

I think this is a good idea, but I felt like you'd added the extra
sentences in not-terribly-well-chosen places.  For instance, your
first addition in trigger.sgml is adding to a para that talks about
triggers for tables, while the next para talks about triggers for
views.  So it seems unclear whether the statement is meant to apply
to view triggers too.

I think it'd work out best to make this a separate para after the
one that defines before/after/instead-of triggers.  How do you
like the attached?

			regards, tom lane

  9. Re: Clarify how triggers relate to transactions

    Laurenz Albe <laurenz.albe@cybertec.at> — 2021-08-18T11:06:05Z

    On Fri, 2021-07-30 at 16:20 -0400, Tom Lane wrote:
> Laurenz Albe <laurenz.albe@cybertec.at> writes:
> > On Wed, 2021-04-28 at 13:24 +0200, Laurenz Albe wrote:
> > > On Tue, 2021-04-27 at 14:26 +0000, PG Doc comments form wrote:
> > > > If I understand correctly, it would be helpful to add this sentence or a
> > > > corrected version of it: "Triggers always execute in the same transaction as
> > > > the triggering event, and if a trigger fails, the transaction is rolled
> > > > back."
> >
> > Here is a proposed patch for this.
> 
> I think this is a good idea, but I felt like you'd added the extra
> sentences in not-terribly-well-chosen places.  For instance, your
> first addition in trigger.sgml is adding to a para that talks about
> triggers for tables, while the next para talks about triggers for
> views.  So it seems unclear whether the statement is meant to apply
> to view triggers too.
> 
> I think it'd work out best to make this a separate para after the
> one that defines before/after/instead-of triggers.  How do you
> like the attached?

That is better, and I like your patch.  Thanks!
Keeping paragraphs short is a good thing.

Yours,
Laurenz Albe

  10. Re: Clarify how triggers relate to transactions

    Tom Lane <tgl@sss.pgh.pa.us> — 2021-09-01T21:25:57Z

    Laurenz Albe <laurenz.albe@cybertec.at> writes:
> On Fri, 2021-07-30 at 16:20 -0400, Tom Lane wrote:
>> I think it'd work out best to make this a separate para after the
>> one that defines before/after/instead-of triggers.  How do you
>> like the attached?

> That is better, and I like your patch.  Thanks!
> Keeping paragraphs short is a good thing.

Pushed like that, then.

			regards, tom lane