The time has come when Oracle application tuning is quickly becoming too 
complex to do efficiently. There is the basic optimizer, dynamic 
sampling, then +ACI-adaptive mayhem+ACI as J. Lewis has succintly put it, 
parallel execution and pifalls with direct read vs. buffered read. To add 
insult to injury, there is a whole lot issues with latches and mutexes, 
NUMA architecture and a whole set of new options like in-memory option 
and advanced compression options. 
Of course, since all of that is not complex enough, the database can now 
run +ACI-in the cloud+ACI, so IO times and CPU times may not be what they seem. 
There is not much difference between random access IO and sequential IO 
in the cloud, because VMDK disks are essentially files, which may be 
fragmented. The result will be turning many of a sequential scans 
(scattered reads, as Oracle calls them) into random access IO, which is, 
of course, significantly slower than sequential access, when more than a 
single block is being read.
I am wondering whether it's time to take the +ACI-black box approach+ACI and use 
just the automatic tuning tools. The whole thing is overwhelming and to 
master it takes years. And when you do, it all goes invalid with the new, 
even more complex version.
At the same time, the relevant information is getting more and more scant 
and hard to find. Oracle is getting more and more closed every day. 



-- 
Mladen Gogala
The Oracle Whisperer
http://mgogala.byethost5.com

On 17/12/2016 3:26 @wiz, Mladen Gogala wrote:

> single block is being read.
> I am wondering whether it's time to take the "black box approach" and use
> just the automatic tuning tools. The whole thing is overwhelming and to
> master it takes years. And when you do, it all goes invalid with the new,
> even more complex version.
> At the same time, the relevant information is getting more and more scant
> and hard to find. Oracle is getting more and more closed every day.


I must admit my experience with the adaptive plan option in 12c has been 
positive so far.

I had a problem application (J2EE, of course!) which refused to 
cooperate on the many tuning attempts.  Since moving it to 12c, it's 
been behaving really well.  Nothing fantastic but at least the plans 
stabilized and the overall performance - although far from optimal - has 
been quite acceptable.
I blame it on the adaptive CBO and its ability to tame weird and 
stupidly coded SQL.

Still have to move Oracle's own code to 12c - we got Peoplesoft, 
Hyperion and JDE to move plus the DW.
Shouldn't be a problem but I won't know for sure until mid next year 
when the lot will all be (hopefully) in 12c.

I agree entirely: the whole shebang has become so complex and 
intertwined that the only way to tame it is to let it sort itself out!
As to the closeness, I alerted to it years ago.  Only to be smirked at 
by everyone else in Oracle-L and a few other places.
Ah well, who cares?  Not me, nearly retired!...  :)

On 17/12/2016 3:26 @wiz, Mladen Gogala wrote:

> At the same time, the relevant information is getting more and more scant
> and hard to find. Oracle is getting more and more closed every day.

I hear the Oracle-L "damagement" desperately asked you to rejoin.
Amazing how honest they are, isn't it?  One moment they want everyone 
not toeing the line out, the next they all change their opinion once 
Nuno has left.  Wonders will never cease!   :)

Ah well, it's all part of making information available to everyone 
provided that does not include "recalcitrants".  As if...
Good thing the original author of the thing is now out of Oracle: it 
might change their direction.  Or rather make it worse.  Too soon to call.

On Wed, 21 Dec 2016 20:23:17 +1100, Noons wrote:

> On 17/12/2016 3:26 @wiz, Mladen Gogala wrote:
> 
>> At the same time, the relevant information is getting more and more 
scant
>> and hard to find. Oracle is getting more and more closed every day.
> 
> I hear the Oracle-L "damagement" desperately asked you to rejoin.
> Amazing how honest they are, isn't it?  One moment they want everyone 
> not toeing the line out, the next they all change their opinion once 
> Nuno has left.  Wonders will never cease!   :)
> 
> Ah well, it's all part of making information available to everyone 
> provided that does not include "recalcitrants".  As if...
> Good thing the original author of the thing is now out of Oracle: it 
> might change their direction.  Or rather make it worse.  Too soon to 
call.

I rejoined, that is true, but my activity is very much toned down. The 
plain truth is that the list is no longer very interesting. I am not 
towing the line and I never will. My impression from the list is that 
Oracle is trying to turn itself into a church, from being a corporation. 
They are treating the dissenters like heretics. 

Nobody from the list's early days is active any more. Even Jonathan, for 
whom I have all the respect in the world, has very much toned down his 
activity on the list. The big news is that the activity on the list will 
count as a good deed from Oracle ACE directors. I can assure you of one 
thing: I will never become an Oracle ACE. The reason is very simple: 
Oracle ACE title is, basically, a title of an auxiliary Oracle sales 
person, sales militia, if you want. If I will be selling Oracle, I want 
to get paid.
The reason for my rejoining was to give an appropriate farewell to Steve 
Adams. The mission is now accomplished and I no longer care about the 
list. Steve has ruined it, for everybody. Current "leading members" are 
continuing his good work.
Unfortunately, I don't think that Oracle itself is very interesting any 
longer. That is the reason why the list is dying and why this group is 
dying.




-- 
Mladen Gogala
The Oracle Whisperer
http://mgogala.byethost5.com