| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
 |
 | |||
| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
|
| |||
Home -> Community -> Mailing Lists -> Oracle-L -> RE: SMP/MPP and PQO
<FONT face=Arial color=#0000ff
size=2>:)
<FONT face=Arial color=#0000ff
size=2>
Yea,
it was me.
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Arial color=#0000ff
size=2>
heh
heh
<FONT face=Tahoma
size=2>-----Original Message-----From: Henry Poras
[mailto:Henry.Poras_at_ctp.com]Sent: Wednesday, June 13, 2001 1:06
PMTo: Multiple recipients of list ORACLE-LSubject: RE:
SMP/MPP and PQO
Oh
oh. Ross, were you the one who initially recommended this? Did I follow your
advice? Who knew.
<FONT face=Tahoma
size=2>-----Original Message-----From: Mohan, Ross
[mailto:MohanR_at_STARS-SMI.com]Sent: Tuesday, June 12, 2001 5:19
PMTo: Multiple recipients of list ORACLE-LSubject: RE:
SMP/MPP and PQO
I
think it was just updated, too.
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Arial color=#0000ff
size=2>Great book.....
<FONT face=Tahoma
size=2>-----Original Message-----From: Henry Poras
[mailto:Henry.Poras_at_ctp.com]Sent: Tuesday, June 12, 2001 3:04
PMTo: Multiple recipients of list ORACLE-LSubject:
RE: SMP/MPP and PQO
<SPAN
class=537200618-12062001>Lisa,
<SPAN
class=537200618-12062001>If you are interested in more detail on the
differences between SMP, NUMA, and clusters, there is a great book "In
search of clusters". It's one of the best technical books I've read. I
can't remember the author's name, but maybe another list member can help.
I picked it up because someone else on the list recomended it a while
ago.
<SPAN
class=537200618-12062001>
<SPAN
class=537200618-12062001>Henrh
<FONT face=Tahoma
size=2>-----Original Message-----From:
Riyaj_Shamsudeen_at_i2.com [mailto:Riyaj_Shamsudeen_at_i2.com]Sent:
Tuesday, June 12, 2001 12:48 PMTo: Multiple recipients of
list ORACLE-LSubject: Re: SMP/MPP and
PQOHi Lisa
SMP -
In SMP many CPUs share the same memory. Typical example would be E450, 4
processors, 4GB memory. Only L2 cache in the CPUs need to be
co-ordinated when a memory buffer is changed or intended to
change.
MPP - In MPP each CPU has its own memory and its own disks that
they control (typically). An example would be nCUBE or IBM RS6000, where
each processor runs its own OS and messaging is used heavily to
coordinate the access to the resources. <FONT face=sans-serif
size=2> NUMA - Nun -uniform memory access -
Group of CPUs share the same memory and the messaging is used between
the group of the CPUs to coordinate the access to the resource. An
example would be Sequent NUMA-Q, where there are multiple quads and each
quad has 4 cpus and 2GB memory (typically) and IQ-link coordinates the
access to the resources between the quads. HP has ccNUMA for
this.
Now, I don't think, E10k domain would qualify for a MPP, since
there is no coordination or access restrictions between the domains ( at
least that I know of). Each domain can manipulate its own disk / memory
/devices without any messaging between the domains, in a non-clustered
environment.
PQ architecture splits the FTS or long running operations
on non-partitioned tables, in to multiple chunks based upon the rowid
ranges. It is not a simple split though. First, work is divided in to
degree of parallelism. For example, if the QC process determines that it
has to scan 100,000 blocks and parallelism is determined as 4 then 25000
would be the split. But not all 25000 block is handed over to the slave
processes. QC uses 9/13 rule. QC hands over 9/13 of the work (i.e. 25000
* 9/13=17307) blocks equally to the slave processes. When the slave
processes finishes up the 9/13 work, then they get 3/13 of the work
(25000 *3/13=5769) blocks and 1/13 of the work when the second set of
3/13s are exhausted. This is done to evenly distribute the load. For
example, there could data skew such that one process could finish up its
9/13 work much faster than other processes and hence those processes can
take up the rema! in! ! ing work. <FONT face=sans-serif
size=2> The suitability of PQO parallelism
should be defined by IO sub system in conjunction with CPU power. If you
have many spindles in 2 cpu server my take on it would be to use
parallelism of 2 to4 depending upon the cpu clock speed, disk speed,
memory etc..
ThanksRiyaj
"Re-yas" ShamsudeenCertified Oracle DBAi2 technologies
www.i2.com
"Koivu, Lisa"
<lisa.koivu_at_efairfield.com> <FONT
face=sans-serif size=1>Sent by: root_at_fatcity.com
06/12/01 09:17 AM <FONT
face=sans-serif size=1>Please respond to ORACLE-L
To: Multiple recipients of list
ORACLE-L <ORACLE-L_at_fatcity.com> <FONT
face=sans-serif size=1> cc:
<FONT face=sans-serif
size=1> Subject:
SMP/MPP and PQO<FONT
face="Book Antiqua" size=2>Hello everyone,
I was reading up on the differences
between SMP, MPP and how they may affect PQO (Parallel
Query).
My understanding is that MPP is a
host with defined domains (like an e10k with virtual machines on it).
SMP is a standalone host with no domains and multiple processors.
I am not considering clustering here.
It seemed to me the only requirement
that you really need to run PQO is to have available resources to power
it. For example, a little 2-cpu box that is pinned a majority of
the time is only going to suffer if PQO is turned on. However, if
we had a 16-cpu box with abundant resources, turning on PQO would help
fts and large index scans in a dw-type environment. (At least this
is what I saw in the past).
Also, I was taught that PQO should
not be used when a table/index is not partitioned. However, upon
reading the doco, it states that the slaves split up work by blocks (or
was it extents?). Seems to me this could cause more problems than
it's worth (i/o contention?) and partitioning, if done carefully, would
be the smarter way to go. Would the slaves really be smart enough
to divy up work intelligently on a non-partitioned object? My
initial thought is NO.
In addition, on metalink they even
went so far as to state it is OK to use PQO on a 2-processor NT machine.
Seems to me the statement that 'PQO provides no benefit on a SMP
machine' is not warranted, unless Oracle Support was just pacifying the
customer who wanted to see PQO work.
Maybe my idea of SMP is too simple.
If I am off my rocker can someone please set me
straight?
Thanks<FONT
face="Times New Roman" size=3>
Lisa Koivu<FONT
face="Times New Roman" size=3> <FONT face="Book Antiqua"
size=2>Oracle Database Administrator<FONT
face="Times New Roman" size=3> <FONT face=Tahoma
size=2>954-935-4117
The information in the electronic mail
message is Cendant confidential and may be legally privileged, it is
intended solely for the addressee(s) access to this internet electronic
mail message by anyone else is unauthorized. If you are not the intended
recipient, any disclosure, copying, distribution or any action taken or
omitted to be taken in reliance on it is prohibited and may be
unlawful.
The sender believes that this E-mail and any
attachments were free of any virus, worm, Trojan horse, and/or malicious
code when sent. This message and its attachments could have been
infected during transmission. By reading the message and opening any
attachments, the recipient accepts full responsibility for taking
protective and remedial action about viruses and other defects. Cendant
Corporation or Affiliates are not liable for any loss or damage arising
in any way from this message or its attachments.
Received on Thu Jun 14 2001 - 10:10:52 CDT
 |
 |