Re: Better, consistent instrumentation for postgreSQL using a similar API as Oracle

Mladen,

Shame on u lecturing a top notch guy in the PostgreSQL world, Laurenz Albe. I think Laurenz knows “a little bit” about
Oraclehaving written the popular extension, fdw_oracle, among his many other contributions to the PG world. So ironic
thatLaurenz was just named “PostgReSQL person of the week”, and then has to be subjected to this “tirade” of yours! 

Follow the PG protocol in submitting your change requests to core PG and stop your Bitchin!

Michael Vitale


Sent from my iPad

> On Oct 4, 2021, at 9:51 PM, Mladen Gogala <gogala.mladen@gmail.com> wrote:
>
> 
>> On 10/4/21 02:34, Laurenz Albe wrote:
>>> On Fri, 2021-10-01 at 15:06 -0500, Jeff Holt wrote:
>>> TLDR; If I spend the time necessary to instrument the many functions that are the equivalent
>>> of the Oracle counterparts, would anyone pull those changes and use them?
>>> Specifically, for those who know Oracle, I'm talking about implementing:
>>>    1. The portion of the ALTER SESSION that enables extended SQL trace
>>>    2. Most of the DBMS_MONITOR and DBMS_APPLICATION_INFO packages
>>>    3. Instrument the thousand or so functions that are the equivalent of those found in Oracle's V$EVENT_NAME
>>>    4. Dynamic performance view V$DIAG_INFO
>>> For the last 35 years, I've made my living helping people solve Oracle performance problems by looking at it
>>>
>> [...]
>>> Now looking closely at postgreSQL, I see an opportunity to more quickly implement Oracle's current feature list.
>> Anything that improves user experience in that respect is welcome, but consider
>> that each database has different approaches to solve the same problems.
>>
>> Before you go to the length of implementing a lot of stuff, check in with
>> the -hackers list and discuss your ideas.
>>
>> Please be a lot more specific than in this e-mail.  While it is certainly
>> fine to sketch your ambitios vision, focus on one specific thing you can
>> imagine implementing and come up with a design for that.
>>
>> Note that "Oracle has it" is not a good enough reason for a PostgreSQL
>> feature.  We think we can do better than they do (at least in many respects).
>> Also, don't assume that everyone on the -hackers list will be familiar with
>> certain PostgreSQL features.
>>
>> One think that you should keep in mind is that Oracle has to provide different
>> features in that area because they are not open source.  In PostgreSQL, I can
>> simply read the code or attach a debugger to a backend, and when it comes to
>> profiling, "perf" works pretty well.  So there is less need for these things.
>>
>> I don't want to discourage you, but contributing to PostgreSQL can be a lengthy
>> and tedious process.  On the upside, things that make it into core are usually
>> fairly mature.
>>
>> Yours,
>> Laurenz Albe
>
> Laurenz, you are obviously not aware who are you talking to. Let me introduce you: Cary Millsap and Jeff Holt are
authorsof the "Optimizing Oracle for Performance", one of the most influential books in the entire realm of  Oracle
literature. The book describes the method of tuning Oracle applications by examining where are they spending time and
whatare they waiting for. The book can be found on Amazon and I would seriously advise you to read it: 
>
>
https://www.amazon.com/Optimizing-Oracle-Performance-Practitioners-Response-ebook/dp/B00BJ9A8SU/ref=sr_1_1?dchild=1&keywords=Optimizing+Oracle+for+Performance&qid=1633395886&s=books&sr=1-1
>
> Haughty lectures about "Oracle has it" not being good enough could hardly be more out of place here. To put it as
politelyas is possible in this case, shut your pie hole. What Jeff is asking for is not something that "Oracle has",
it'ssomething that customers want. That was the case few years ago when I was asking for the optimizer hints. I was
castigatedby the former pastry baker turned Postgres guru and my reaction was simple: I threw Postgres out of the
companythat I was a working for as the lead DBA. You see, customer is always right, whether the database is open source
ornot. Needless to say, Postgres has optimizer hints these days. It still has them in "we do not want" part of the
Wiki,which is hilarious. 
>
> You see, without proper event instrumentation, and knowing where the application spends time, it is not possible to
exactlytune that application. Oracle used to have a witchcraft based lore like that, where the performance was
estimated,based on buffer cache hit ratio, the famous "BCHR". That was known as "Method C". The name comes from Cary's
andJeff's book. Jeff and Cary are the ones who made the BCHR based black magic - obsolete. 
>
> In other words, Jeff is asking for a method to fine tune the applications with precision. Instead of being an
a....rrogantperson, you should have given him the answer: 
>
> https://github.com/postgrespro/pg_wait_sampling
>
> Postgres already has an extension which implements around 60% of what Oracle has. Of course, Oracle's mechanism is
somewhatmore refined but it is also 20 years older. Cary Millsap, Anjo Kolk and Jeff Holt were implementing the
instrumentationfor Oracle 7. There was a huge pile of paper, printed off Metalink, a predecessor of "My Oracle
Support",describing Oracle 7 events and explaining what Oracle was actually waiting for. At that time Cary Millsap was
aVP in Oracle development. The book came out for Oracle8. You see, Jeff Holt really knows what he's asking for. You are
theignorant one, the one who engaged in talking at Jeff, not knowing that there already is an answer. There is no shame
innot knowing something, people ask questions all the time. Arrogantly talking at someone and giving unsolicited
lecturesin what is appropriate and what is not is another thing altogether. 
>
> Finally, about the tone of this message: you really pissed me off. I had to restrain myself from using even stronger
language,that was surprisingly hard to do. I wouldn't be surprised to see you giving haughty lectures about programming
toBrian Kernighan or Dennis Ritchie. And yes, those two have allegedly also written a book. 
>
> Regards
>
>
> --
> Mladen Gogala
> Database Consultant
> Tel: (347) 321-1217
> https://dbwhisperer.wordpress.com
>
>
>