Nobody asks for pg_dump to be a schema comparison tool. As you tell
yourself
it is a most reliable schema capturing tool. All I am asking is that if
pg_dump is executed
on two databases with the identical schemas and security it should be
able to produce
the identical SQL dumps of these schemas and security. As you have
mentioned in other e-mail
pg_dump actually rewrites some statements for consistency. It just
doesn't do it consistently everywhere.
I can't say anything about priorities of development for pg_dump. The
proposed change seems to be
a low hanging fruit, it isn't difficult to add ORDER BY in the
appropriate places. The other question is if
this is a useful enhancement. The existence of the third party tools
doesn't seem to be very relevant here.
Should be stopped the development of pgAdmin or psql because exist the
third party tools with the similar functionality?
:-)
Sergei
On 04/17/2016 01:10 PM, Sergei Agalakov 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?
I don't think that is what is being said, more the right tool for the
right job. pg_dump --> pg_restore/psql are for capturing some or all of
the information(including possibly data) in a database at a point in
time so that information can be recreated at another point in time.
While by necessity that includes capturing schema data (or not in the
case of -a) it is not really a schema comparison tool. While that is in
the realm of doable it means developer time to replicate something that
other tools do. Given the ever lengthening list of requested features in
general, this request might have difficulty reaching a sufficient level
of priority, esp. in light of the presence of existing tools.
>
> 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?
>
>
--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com
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