Thread: --single-transaction doc clarification
Clarification of when it's not appropriate to use this option. -- Simon Riggs EnterpriseDB http://www.enterprisedb.com
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"Simon Riggs" <simon@2ndquadrant.com> writes:
> Clarification of when it's not appropriate to use this option.
I think it's a fairly bad idea to try to enumerate the commands that
can't be used in a transaction block here, because there is no way
that we will remember to keep such a list up-to-date. Why not just
say "It won't work for commands that can't be used in a transaction
block"?
regards, tom lane
On Mon, 2006-10-30 at 17:32 -0500, Tom Lane wrote: > "Simon Riggs" <simon@2ndquadrant.com> writes: > > Clarification of when it's not appropriate to use this option. > > I think it's a fairly bad idea to try to enumerate the commands that > can't be used in a transaction block here, because there is no way > that we will remember to keep such a list up-to-date. Why not just > say "It won't work for commands that can't be used in a transaction > block"? I agree, but such a comment immediately begs the question: What is the list of commands this applies to? I was surprised how long a list it was myself, hence the patch. (Checks)...The man pages for VACUUM, CREATE TABLESPACE, CLUSTER and REINDEX DATABASE don't mention they are not allowed inside a transaction block at all, so I'm not sure if doing it the other way around helps with maintaining docs... I prefer useful info rather than hidden gotchas, even if the list might possibly be < 100% exactly correct. At least we can say we tried. -- Simon Riggs EnterpriseDB http://www.enterprisedb.com
On Mon, 2006-10-30 at 22:56 +0000, Simon Riggs wrote: > The man pages for VACUUM, CREATE TABLESPACE, CLUSTER and > REINDEX DATABASE don't mention they are not allowed inside a transaction > block at all That should be fixed, I think. Once that is done, I think it's sufficient to just say that --single-transaction won't work for commands that can't be executed in a transaction block. -Neil
Neil Conway <neilc@samurai.com> writes:
> On Mon, 2006-10-30 at 22:56 +0000, Simon Riggs wrote:
>> The man pages for VACUUM, CREATE TABLESPACE, CLUSTER and
>> REINDEX DATABASE don't mention they are not allowed inside a transaction
>> block at all
> That should be fixed, I think. Once that is done, I think it's
> sufficient to just say that --single-transaction won't work for commands
> that can't be executed in a transaction block.
That's what makes sense to me, too.
regards, tom lane
On Mon, 2006-10-30 at 19:28 -0500, Tom Lane wrote: > Neil Conway <neilc@samurai.com> writes: > > On Mon, 2006-10-30 at 22:56 +0000, Simon Riggs wrote: > >> The man pages for VACUUM, CREATE TABLESPACE, CLUSTER and > >> REINDEX DATABASE don't mention they are not allowed inside a transaction > >> block at all > > > That should be fixed, I think. Once that is done, I think it's > > sufficient to just say that --single-transaction won't work for commands > > that can't be executed in a transaction block. > > That's what makes sense to me, too. As requested. -- Simon Riggs EnterpriseDB http://www.enterprisedb.com
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On Tue, 2006-10-31 at 01:07 +0000, Simon Riggs wrote: > As requested. Applied, thanks for the patch. I didn't apply the ON_ERROR_STOP addition: IMHO it's not very useful to say that doing something is "advised" without explaining why it is wise/useful/necessary. If we want to include this point, can you add some elaboration on why/when ON_ERROR_STOP should be used with --single-transaction? -Neil
Neil Conway <neilc@samurai.com> writes:
> On Tue, 2006-10-31 at 01:07 +0000, Simon Riggs wrote:
>> As requested.
> Applied, thanks for the patch.
This patch converted a correct statement into a lie: there is not
anything that will cause begin/commit in a script file to fail just
because you wrapped begin/commit around them. I rewrote the text to
If the script itself uses <command>BEGIN</>, <command>COMMIT</>,
or <command>ROLLBACK</>, this option will not have the desired
effects.
Also, if the script contains any command that cannot be executed
inside a transaction block, specifying this option will cause that
command (and hence the whole transaction) to fail.
regards, tom lane
On Mon, Oct 30, 2006 at 07:18:04PM -0500, Neil Conway wrote: > On Mon, 2006-10-30 at 22:56 +0000, Simon Riggs wrote: > > The man pages for VACUUM, CREATE TABLESPACE, CLUSTER and > > REINDEX DATABASE don't mention they are not allowed inside a transaction > > block at all > > That should be fixed, I think. Once that is done, I think it's > sufficient to just say that --single-transaction won't work for commands > that can't be executed in a transaction block. "What commands aren't allowed in a transaction?" is still a logical question to ask though, so it would be nice if we had such a list hanging around. Is there a standard way these commands test to see if they're in a transaction block? If there is, perhaps something could be created that would pull that info out of the code so that we didn't have to maintain the list by hand. It might also be possible to do this with some SGML magic. -- Jim Nasby jim@nasby.net EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)