Re: Enhancement request for pg_dump - Mailing list pgsql-general

I hardly can see that a sorting of the grants by users will create a
measurable impact on the pg_dump performance in a real database.
One can imaging a database with tens of thousands of objects and tens of
thousands of users and almost no data, but it would be quite unusual.
Anyway, if a sorting behavior is initiated by a command line parameter,
and isn't a default behavior of pg_dump then this argument doesn't work.
After all pg_dump isn't the tool to do _just_ reliable backup. It can be
used for migration, it can be used for schema cloning, to initiate a
standby...
There are many flags for pg_dump that are absolutely unnecessary for
full database backup. So they do
"... might also overcomplicate it, making it more difficult to maintain
reliably" but they do exists, and serve a purpose.

I don't understand why people have started to create the theories about
our development process? Had I requested a tool to magically synchronize
DEV and PROD? No, I asked about a tool to _find_ the unexpected
differences between databases. If you never encountered a situation when
in the
dozens of environments the databases has diverged because somebody has
done something manually - good for you, you are lucky guy then.
I did.

Sergei
> On Sun, 17 Apr 2016 14:10:50 -0600
> Sergei Agalakov <Sergei(dot)Agalakov(at)getmyle(dot)com> wrote:
>
> > I don't see how these questions are related to the proposed pg_dump
> > improvement.
> > I suggest to improve pg_dump so it can be used instead of the third
> > party tools like DBSteward and SQLWorkbench/J etc.
> > to compare two different databases or existing dumps, and to identify
> > the differences. The use cases will be exactly
> > the same as for the third party tools. The positive difference will be
> > that pg_dump is a very reliable, always available and supports all the
> > latest PostgreSQL features.
> > Do you imply that there shouldn't be any reasons to compare different
> > databases to find the differences between them?
>
> Nobody has weighed in on this, but I have a theory ...
>
> I (personally) worry that adding features like you suggest to pg_dump
> would interfere with its ability to perform complete dump of a large
> database in a _rapid_ manner. Using pg_dump as a backup tool has an
> inherent desire for the tool to be as fast and low-impact on the
> operation of the database as possible.
>
> Features that would force pg_dump to care about ordering that isn't
> necessary to its core functionality of providing a reliable backup
> are liable to slow it down. They might also overcomplicate it, making
> it more difficult to maintain reliably.
>
> When you consider that possibility, and the fact that pg_dump isn't
> _supposed_ to be a tool to help you with schema maintenance, it's easy
> to see why someone would look for different approach to the problem.
>
> And I feel that's what all the answers have attempted to do: suggest
> ways to get what you want without asking them to be implemented in a
> tool that isn't really the right place for them anyway. While your
> arguments toward making this change are valid, I'm not sure that
> they are compelling enough to justify adding a feature where it
> doesn't really belong.
>
> Another side to this, is that your request suggests that your
> development process is suboptimal. Of course, I can't be 100% sure
> since you haven't explained your process ... but my experience is
> that people who feel the need to automagically sync prod and dev
> databases have a suboptimal development process. Thus, the suggestions
> are also biased toward helping you improve your process instead of
> adjusting a tool to better support a suboptimal process.
>
> Of course, if the people actually doing the work on the code disagree
> with me, then they'll make the change. I'm just expressing an opinion.
>
> > Sergei
> >
> > > > On Apr 17, 2016, at 12:41 PM, Sergei Agalakov
> <Sergei(dot)Agalakov(at)getmyle(dot)com> wrote:
> > > >
> > > > I know about DBSteward. I don't like to bring PHP infrastructure
> only to be able to compare two dumps,
> > > > and to deal with potential bugs in the third party tools. The
> pg_dump in other hand is always here, and is always trusted.
> > > > SQLWorkbench/J also can compare two schemas, and requires only
> Java. Again, I trust pg_dump more.
> > > >http://www.sql-workbench.net/
> > > >
> > > > May be pg_dump was never INTENDED to generate the dump files
> with the determined order of the statements,
> > > > but it CAN do it with the minor changes, and be more useful to
> administrators. Why rely on the third party tools
> > > > for the tasks that can be done with the native, trusted tools?
> > > >
> > > > Sergei
> > > Does it matter if they differ if you cannot recreate the correct
> one exactly from source-controllled DDL?  Or know how they are
> supposed to differ if this is a migration point?
> >
> >
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>
> --
> Bill Moran