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Re: Is PostgreSQL good?

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Mladen Gogala wrote:
> As for my insults, I will have to refer you back to this:
> http://tinyurl.com/68gu822
> That, in my humble opinion, is a work of an idiot, period. That isn't an
> insult, that is just a statement of fact.

I guess you feel insulted by his comments about "older DBAs" and their
habits. It is probably exaggerated, but I think he is refering to people
who say "let's use hints" before they even start to think properly.

>> That's not your fault -- whoever planed that migration project should
>> have known better than to assume that you just have to rewrite a couple
>> of triggers and the system will perform well.
>
> Actually, that is precisely the punch line of the Postgres promotors.
> EnterpriseDB even sells a product that is supposed to make it easier
> still. They are saying that similarities are such that it is fairly easy
> to do just that, change few things, recompile and, voila.

You have to be able to tell marketing talk from reality.
And for simple applications it might work well enough.

> I can only see that PostgreSQL is much less popular than MySQL
> and I can see that it isn't getting better.

First, be patient. And second, popularity is not always the measure
of quality (ever heard of Microsoft?).

>> Free open source software works differently in many ways. Don't consider
>> it as something to save money primarily.
>
> Unfortunately, if I have to spend money for the pilot project to succeed,
> it will not be on PostgreSQL. If we are talking about spending money,
> there are other databases which are commercial from scratch. That is
> probably the reason for such a low popularity of PostgreSQL.

Well, you said that you spent months learning PostgreSQL. That's an
investment that can be measured in money, right?

Commercial software has a different and enticing pricing model. You'll
get the thing for a moderate price at first (or you get a crippled free
version), then you realize that without (expensive) support you can't
even get patches for the showstopping bugs, and the next time you'll have
to negotiate license fees you'll have to pay more.

With open source software you may have a higher initial cost: you will
have to spend more money on integrating it into your environment, you
might have to invest more into education, you might have to develop
add-ons that you need and that are not supplied. But once this is done,
costs will drop rapidly, and in the long run you'll be cheaper.

Furthermore, you'll get added values with open source: the ability to
influence decisions (the only enhancement request I ever made for
Oracle years ago did not even receive an answer), the ability to help
yourself if you run into a bug or need a feature.

>> "Nobody uses PgSQL for benchmarks (see www.tpc.org) because of the
>> performance problems."
>>
>> Can you justify this statement?
>
> Yes, of course I can. I was unable to find even a single TPC benchmark on
> the TPC site, done by using Postgres. TPC (stands for "Transaction
> Processing Council") is the place where people place TPC benchmarks.
> Databases used for benchmarks are the usual suspects: Oracle, MS SQL,
> DB2, Sybase and some more exotic versions EXASQL. I didn't find any
> Postgres benchmark there, feel free to correct me if I'm wrong.

Maybe there are other reasons besides terrible performance?
Do you have to pay for TPC? Is it expensive?

>> "... the much better performing commercial databases like Oracle or
>> DB2."
>>
>> Can you justify that?
>
> Yes, I can. The reasons why both Oracle and DB2 are, generally speaking,
> much faster than Postgres are
> - proper partitioning
> - the ability to parallelize queries
> Both of those abilities are missing from Postgres. In particular, Oracle
> can do many things that Postgres cannot. Here I have in mind things like
> the star schema, bitmap indexes are still somewhat painful topic, index
> organized tables, index clusters, hash clusters, full index scan, fast
> index scan or a skip scan. And I didn't even mention RAC, "AS OF" queries
> or flashback.

PostgreSQL has some of these things.
Even if Oracle has some performance related features that PostgreSQL does not,
that does not prove that it will always perform better. I'm sure that Oracle
will sometimes be faster than PostgreSQL, but I don't accept a general statement
like that.

> The "reasonable comparison" must start with the fact that Oracle is the
> 2nd largest software company in the world and that its resources are many
> times larger than the resources at the disposal to the Postgres
> developers. If Postgres wants to compete with Oracle, it can do so only
> based on price, definitely not on the features or performance. Even so,
> if you want people to consider Postgres being alternative at all, which
> wast majority of companies is not doing, you have to ask corporate users
> what do they want.

There you go. PostgreSQL with its limited resources has to concentrate
on the core system. It is not out to provide everything that Oracle does,
but it is out to do the things it does better than everybody else.
I believe that PostgreSQL is quite interested in what corporate users want.
Think of in-core replication. But that does not imply that PostgreSQL can
and wants to provide everything that corporate users ask for.

> The topic of hints have popped up again and again. And
> will not go away. As a matter of fact, I once stated that I will write a
> hint system myself. The project that I am currently working on and is
> consuming the most of my spare time will be done by August the 1st. I
> will then renew my C programming, I used to be pretty good at that, and
> write it, even if it takes me a full year to do so.

I am sure that you'll find the community helpful if you have questions.
However, it will be pretty difficult to get that into core.
You'd have to be patient at least.
But as long as you can scratch your itch, that's a minor inconvenience.

> What allows me to make such a broad comparison is the fact that PostgreSQL
> has no tuning methodology. If, for instance, the two of us are given the
> same SQL statement to make faster, you on Postgres and me on Oracle, I
> will have a method to follow and will, most likely, end up with a
> solution, much, much before you. If all else fails, I will be able to
> just force the execution plan that I like. You will still be waiting for
> an answer from the mailing list.

As I mentioned, there *are* other things you can do.
- You can examine the output of EXPLAIN ANALYZE yourself and figure out
  where and why things go wrong.
- You can influence statistics levels on a per-column basis.
- You can influence query planning with a number of parameters.
  And they don't have to "stay around" after the query is done.
  There is SET LOCAL which takes effect only in the current transaction.
- Often a simple change in an SQL statement will get the planner on the
  right track.

> Finally, let me explain what am I doing here. What I've set out to do is
> to warn anybody who wants to replace Oracle by Postgres that it will not
> be as easy as it looks and that there are terminal deficiencies in the
> mentality of PostgreSQL developer which will never allow it to gain much
> popularity or become a real alternative to Oracle. Had I been properly
> warned, I wouldn't have ended with such an egg on my face. I will only
> react if someone mentions conversion from Oracle. People ought to be
> warned.

That's ok, share your experiences.
But if you want your opinion to be heard, refrain from insult and sweeping
generalizations with no more proof than your authority.

Yours,
Laurenz Albe 

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migrating oracle to postgres Username <user@domain.tld> - 2011-06-20 19:28 +0200
  Re: migrating oracle to postgres Mladen Gogala <no@email.here.invalid> - 2011-06-20 20:08 +0000
    Re: migrating oracle to postgres Username <user@domain.tld> - 2011-06-20 23:45 +0200
      Re: migrating oracle to postgres Mladen Gogala <no@email.here.invalid> - 2011-06-20 22:37 +0000
      Re: migrating oracle to postgres Mladen Gogala <gogala.mladen@gmail.com> - 2011-06-21 02:01 +0000
  Re: migrating oracle to postgres "Laurenz Albe" <invite@spam.to.invalid> - 2011-06-21 09:18 +0200
    Re: migrating oracle to postgres Mladen Gogala <gogala.mladen@gmail.com> - 2011-06-21 13:38 +0000
      Is PostgreSQL good? (was: migrating oracle to postgres) "Laurenz Albe" <invite@spam.to.invalid> - 2011-06-22 12:30 +0200
        Re: Is PostgreSQL good? Harry Tuttle <OTPXDAJCSJVU@spammotel.com> - 2011-06-22 13:15 +0200
        Re: Is PostgreSQL good? (was: migrating oracle to postgres) Mladen Gogala <gogala.mladen@gmail.com> - 2011-06-22 12:02 +0000
          Re: Is PostgreSQL good? "M. Strobel" <sorry_no_mail_here@nowhere.dee> - 2011-06-22 21:52 +0200
            Re: Is PostgreSQL good? Mladen Gogala <no@email.here.invalid> - 2011-06-22 22:43 +0000
          Re: Is PostgreSQL good? (was: migrating oracle to postgres) "Laurenz Albe" <invite@spam.to.invalid> - 2011-06-24 12:29 +0200
            Re: Is PostgreSQL good? Hans Castorp <REWYRLXHEGHO@spammotel.com> - 2011-06-24 12:57 +0200
              Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-06-24 14:53 +0200
              Re: Is PostgreSQL good? Mladen Gogala <no@email.here.invalid> - 2011-06-24 16:32 +0000
            Re: Is PostgreSQL good? (was: migrating oracle to postgres) Mladen Gogala <gogala.mladen@gmail.com> - 2011-06-24 13:53 +0000
              Re: Is PostgreSQL good? (was: migrating oracle to postgres) "Laurenz Albe" <invite@spam.to.invalid> - 2011-06-27 11:17 +0200
                Re: Is PostgreSQL good? (was: migrating oracle to postgres) Mladen Gogala <gogala.mladen@gmail.com> - 2011-06-28 06:11 +0000
                Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-06-28 10:34 +0200
                Re: Is PostgreSQL good? Mladen Gogala <gogala.mladen@gmail.com> - 2011-06-28 13:30 +0000
                Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-06-29 09:50 +0200
                Re: Is PostgreSQL good? Mladen Gogala <no@email.here.invalid> - 2011-06-29 21:38 +0000
                Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-06-30 09:14 +0200
                Re: Is PostgreSQL good? Mladen Gogala <mgogala@no.address.invalid> - 2011-06-30 13:22 +0000
            Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-06-30 07:05 -0700
              Re: Is PostgreSQL good? Mladen Gogala <no@email.here.invalid> - 2011-06-30 15:41 +0000
                Re: Is PostgreSQL good? Richard Kettlewell <rjk@greenend.org.uk> - 2011-06-30 16:49 +0100
                Re: Is PostgreSQL good? Mladen Gogala <no@email.here.invalid> - 2011-06-30 19:24 +0000
                Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-06-30 13:21 -0700
                Re: Is PostgreSQL good? Mladen Gogala <no@email.here.invalid> - 2011-06-30 22:42 +0000
                Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-07-01 11:57 -0700
                Re: Is PostgreSQL good? Mladen Gogala <gogala.mladen@gmail.com> - 2011-07-01 22:58 +0000
                Re: Is PostgreSQL good? Richard Kettlewell <rjk@greenend.org.uk> - 2011-07-01 14:07 +0100
                Re: Is PostgreSQL good? Mladen Gogala <gogala.mladen@gmail.com> - 2011-07-01 13:29 +0000
                Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-06-30 13:17 -0700
                Re: Is PostgreSQL good? Mladen Gogala <gogala.mladen@gmail.com> - 2011-06-30 23:53 +0000
              Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-07-01 10:13 +0200
                Re: Is PostgreSQL good? Mladen Gogala <gogala.mladen@gmail.com> - 2011-07-01 13:38 +0000
                Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-07-01 16:58 +0200
                Re: Is PostgreSQL good? Mladen Gogala <no@email.here.invalid> - 2011-07-01 15:33 +0000
                Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-07-01 11:39 -0700
                Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-07-04 16:39 +0200
                Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-07-04 12:11 -0700
                Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-07-05 08:58 +0200
                Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-07-05 11:29 -0700
                Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-07-06 09:00 +0200
                Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-07-06 01:00 -0700
                Re: Is PostgreSQL good? "Laurenz Albe" <invite@spam.to.invalid> - 2011-07-07 09:05 +0200
                Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-07-07 00:34 -0700
                Re: Is PostgreSQL good? Matthew Woodcraft <mattheww@chiark.greenend.org.uk> - 2011-07-04 20:12 +0100
                Re: Is PostgreSQL good? Don Y <nowhere@here.com> - 2011-07-04 12:24 -0700
      Re: migrating oracle to postgres Robert Klemme <shortcutter@googlemail.com> - 2011-06-23 17:48 +0200
        Re: migrating oracle to postgres Mladen Gogala <no@email.here.invalid> - 2011-06-23 16:42 +0000
          Re: migrating oracle to postgres Mladen Gogala <no@email.here.invalid> - 2011-06-23 18:57 +0000
          Re: migrating oracle to postgres Robert Klemme <shortcutter@googlemail.com> - 2011-06-26 17:35 +0200
            Re: migrating oracle to postgres Mladen Gogala <gogala.mladen@gmail.com> - 2011-06-26 19:08 +0000
          Re: migrating oracle to postgres Robert Klemme <shortcutter@googlemail.com> - 2011-06-27 00:32 -0700
            Re: migrating oracle to postgres Mladen Gogala <no@email.here.invalid> - 2011-06-28 16:00 +0000
              Re: migrating oracle to postgres Robert Klemme <shortcutter@googlemail.com> - 2011-06-28 22:28 +0200

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