Parallelism in oracle using only one dual-core processor

Hi, is usefull or could i use parallel execution in oracle using only one dual core processor?
Can someone explain me why?

Hi
To take advantage of parallel processing you need enough resources (mainly CPU and I/O). If you run serially and the bottleneck is the CPU, then parallel processing might help. On the contrary, if the bottleneck is located in the I/O sub-system, throwing more CPU to it would not make things better. So, it's a question of balance between the CPU and I/O resources you have.
HTH
Chris

Similar Messages

Database uses only one cpu core from 16 available

Hi,
we have an server with 16 CPU cores, and we discovered from em that it uses only 1 core with 100% and the others are idle.
the initialization parameters for CPU are:
cpu_count 16
parallel_threads_per_cpu 2
resource_manager_cpu_allocation 16.
What can we do to use all 16 cores.
Regards
Nicoale Ancuta

Nicolae Ancuta wrote:
Very interesting poit of view, but since I have for some period of time 1 core on 100% and other cores are idle or 0%,
I don't think that we can say that linux and oracle database 11g is using the best from that server, can you?Well, I did not offer a point of view. I offered fact - a reason why on x86 architecture it is faster to keep threads on the same CPU (if sufficient CPU capacity) then run such threads across CPUs.
As for what you are seeing - we cannot see it. So the only data we have is what you offered. And that does not suffice in making any kind of call as to why you are seeing, or even describing the symptoms correctly.
Why don't you try another example? 3 client server applications. Each client post a request (huge update 100% CPU, small update 0% CPU, huge select 100% CPU). What the server does, it switches between those 2 huge requests an uses only one core on 100% abd the others 15 are sleeping. Why don't use each request on different core and reduce the time?Define "+huge request+". Database operations are typically I/O intensive - not CPU intensive. There are also a number of processes. So if PMON for example is showing high CPU, then that means something different as when DBWR is showing high CPU, versus a dispatcher process showing high CPU.
So you need to provide a lot more detail for us to speculate as to what the problem could be, never mind offering a solution.

Oracle utilizes only one core out of 8 core's.

Dear Team ,
We have noticed that, in oracle database server Oracle processes uses only one core and that goes to 100% usage remains are at idle possition thats the reason the Oracle performance is very poor some time system haults and needs to be started
Please suggest if you can have best solution,
waiting for your valueable response.
Regards,
Naveed Amir

860707 wrote:
We have noticed that, in oracle database server Oracle processes uses only one core and that goes to 100% usage remains are at idle possition thats the reason the Oracle performance is very poor some time system haults and needs to be startedNot unusual. It is often slower running processes across CPUs (e.g. 5 processes on 5 CPUs with 15% CPU utilisation per CPU), than running these processes on the same CPU (e.g. 5 processes on 1 CPU for a 75% CPU utilisation). See Non Uniformed Memory Access (NUMA) for some details on why this is the case.
The kernel deals with CPU scheduling. It decides which process/thread to execute on which CPU. From a s/w perspective, one can code "processor affinity" into your s/w to bind a process or thread to a specific CPU. Oracle only does this with Oracle XE - as this is one of limitation of the free version of Oracle's database s/w. Oracle uses default kernel scheduling for Standard Edition and Enterprise Edition versions.
Oracle uses the number of CPUs/cores to determine the processor load it can create. It does not force its processes to run on a single specific CPU (with XE being the exception).
So "blaming" Oracle for what you are seeing? You are blaming the wrong layer in the s/w stack. You are also very likely misinterpreting what you are seeing.
The #1 reason for poor Oracle performance is shoddy code. Code that you and your cohorts write and run in Oracle. And that is a far likelier candidate to blame for shoddy performance, than blaming Oracle and the kernel's process scheduling across CPUs.
And you have provided not a single shred of evidence that points to a SMP scheduling issue across multiple CPUs/cores.

Second mac in cluster uses only one core

Hello all. For some reason the second computer in my render farm is using only one core out of eight.
I'm using 2 Mac Pros linked together directly via giga ethernet wire. Mac one is a Quad Core 3ghz. Mac two is a Octo Core 2009 model. Both computers have the same version of FCS3 with different serial numbers.
In the Qmaster preferance pane: Mac one is set to "Quickcluster with services" with the check boxes for Share and Managed next to "Distributed processing for Compressor" checked. 4 instances selected and "Include unmanaged services from other computers" checked. Mac two is set to "Services only" with check box for Share next to "Distributed processing for Compressor" checked. 8 instances selected and "Include unmanaged services from other computers" checked.
I hit submit in Compressor, select the name of the cluster from Mac one, then in the Batch Monitor I see the video divied into 10 sections with Mac one handling 4 and Mac two handling one. On Mac two I see that the cores aren't fired up 100%, more like 30% on average.
I did a test earlier with a dual core mbp, and again only one core. How do I get my Octo core to use all 8 cores?

Solved the problem. The solution was simple, but somehow went under my radar. On Mac two in the Qmaster preferance pane next to the "Options for selected service" button, the selected service was set to off.
Duh

Mathematica 5.2.2 uses only one core

Using Activity Monitor, I have seen that Mathematica 5.2.2 uses only the second core, even if Wolfram says that it supports multi-core calculations.
So, firstly, I use only half of the power of my MBP C2D and secondly this could be dangerous for the processor because I use Mathematica all the day for work and this asymmetric use of the processor could damage it.
Do somebody know how to use both the cores?

This is a Mathematica problem. Contact their technical support. The Apple Discussions are limited to assistance with Apple products. We can't fix a problem with Mathematica software.
Furthermore, there's no reason why the use of one core will damage your processor.

Motion 5 using only one core

Why is motion 5 using only one core during heavy renders, even when all other apps are closed?
Version 5.0.3

coz it uses the GPU to do all the graphics stuff. The cores are only used to process project data.
adam

Toshiba Sattelitte L550D, AMD dual core processor M520, Firefox 3.6 works fine; any later version produces only server not fond for any URL; any one have a fix?

Forgot to mention op system is Windows 7 64 bit; 4 gig memory and a 320 gig 5400 rpm (slow) SATA drive. Have tried Pale Moon with the same result although its site shows the AMD Turion II dual core processor as supported

Yes, the question was poster from my desktop machine which is set to dual boot both windows 7 and Xp. I regularly run spybot scans but I'll try all the others you mentioned.
Thanks

Only one CPU core high sys usage when create database instance via dbca

when using dbca to create database instance
JUST ONLY ONE CPU core high sys usage
how to troubleshoot it
see this:
top - 09:28:19 up 55 days, 20:38, 10 users, load average: 1.00, 1.08, 1.31
Tasks: 1231 total,   2 running, 1228 sleeping,   0 stopped,   1 zombie
Cpu(s): 0.0%us, 1.3%sy, 0.0%ni, 98.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 57588328k total, 55028620k used, 2559708k free,   196852k buffers
Swap: 16386292k total,    23156k used, 16363136k free, 23011232k cached
PID USER      PR NI VIRT RES SHR S %CPU %MEM    TIME+ COMMAND
11343 oracle    25   0 1771m 30m 23m R 99.7 0.1   5:36.39 oracle
3692 oracle    16   0 13948 2348 816 S 1.6 0.0 17:00.94 top
11432 root      15   0 13540 2024 820 R 1.3 0.0   0:00.21 top
11034 oracle    16   0 737m 171m 33m S 0.3 0.3   0:52.39 java
11435 oracle    15   0 66056 1596 1180 S 0.3 0.0   0:00.01 bash
    1 root      15   0   784 172 160 S 0.0 0.0 38:56.76 init
    2 root      RT -5     0    0    0 S 0.0 0.0   0:00.58 migration/0
    3 root      34 19     0    0    0 S 0.0 0.0   0:00.75 ksoftirqd/0
    4 root      RT -5     0    0    0 S 0.0 0.0   0:00.00 watchdog/0
    5 root      RT -5     0    0    0 S 0.0 0.0   0:00.81 migration/1
    6 root      34 19     0    0    0 S 0.0 0.0   0:00.00 ksoftirqd/1
    7 root      RT -5     0    0    0 S 0.0 0.0   0:00.00 watchdog/1
    8 root      RT -5     0    0    0 S 0.0 0.0   0:02.53 migration/2    mpstat info
[root@localhost ~]# mpstat -P ALL 2
Linux 2.6.18-164.el5 (localhost.localdomain)    09/12/12
09:29:09     CPU   %user   %nice    %sys %iowait    %irq   %soft %steal   %idle    intr/s
09:29:11     all    0.01    0.00    1.27    0.01    0.00    0.01    0.00   98.69   1658.29
09:29:11       0    0.50    0.00    0.00    0.00    0.00    0.50    0.00   98.99   1657.29
09:29:11      73    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:11      74    0.00    0.00 100.00    0.00    0.00    0.00    0.00    0.00      0.00
09:29:11      75    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:11      76    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:11      77    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:11      78    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:11      79    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:11     CPU   %user   %nice    %sys %iowait    %irq   %soft %steal   %idle    intr/s
09:29:13     all    0.01    0.00    1.26    0.01    0.00    0.02    0.00   98.70   1761.19
09:29:13       0    0.50    0.00    0.50    1.00    0.00    1.99    0.00   96.02   1761.19
09:29:13      71    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:13      72    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:13      73    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:13      74    0.00    0.00 100.00    0.00    0.00    0.00    0.00    0.00      0.00
09:29:13      75    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:13      76    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:13      77    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:13      78    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:13      79    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00          you can see there is only one CPU CORE (core 74 but is random , other core have same status but just one CPU core)
[root@localhost ~]# vmstat -S m 2
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
r b   swpd   free   buff cache   si   so    bi    bo   in   cs us sy id wa st
3 0     23   1861    203 24267    0    0     8    12    0    0 0 0 99 0 0
4 0     23   1845    203 24262    0    0   602 16460 3682 8121 2 2 96 1 0
3 0     23   1842    203 24276    0    0   692 7520 3297 6610 2 2 97 0 0
3 0     23   1830    203 24277    0    0   786 3040 3302 7118 2 2 97 0 0
4 0     23   1829    203 24277    0    0   126 3144 3247 7343 2 1 97 0 0
3 0     23   1827    203 24279    0    0    76 2944 3292 7502 2 2 96 0 0
3 0     23   1823    203 24281    0    0     0 3248 3164 7656 2 1 97 0 0
2 0     23   1827    203 24279    0    0     0 3646 3080 7480 2 1 97 0 0
2 0     23   1828    203 24279    0    0     0   476 2942 5648 1 1 98 0 0
3 0     23   1824    203 24281    0    0     2 7476 3377 8111 2 2 97 0 0iostat infor
avg-cpu: %user   %nice %system %iowait %steal   %idle
           1.28    0.00    1.29    0.00    0.00   97.43
Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
hda               0.00         0.00         0.00          0          0
sda               5.47         0.00        83.58          0        168
sda1              0.00         0.00         0.00          0          0
sda2              5.47         0.00        83.58          0        168
sda3              0.00         0.00         0.00          0          0
sda4              0.00         0.00         0.00          0          0
sda5              0.00         0.00         0.00          0          0
sdb               8.96         0.00       123.38          0        248
sdb1              8.96         0.00       123.38          0        248
avg-cpu: %user   %nice %system %iowait %steal   %idle
           1.27    0.00    1.27    0.00    0.00   97.46
Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
hda               0.00         0.00         0.00          0          0
sda               0.00         0.00         0.00          0          0
sda1              0.00         0.00         0.00          0          0
sda2              0.00         0.00         0.00          0          0
sda3              0.00         0.00         0.00          0          0
sda4              0.00         0.00         0.00          0          0
sda5              0.00         0.00         0.00          0          0
sdb              17.50         0.00       236.00          0        472
sdb1             17.50         0.00       236.00          0        472
avg-cpu: %user   %nice %system %iowait %steal   %idle
           1.29    0.00    1.30    0.01    0.00   97.41
Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
hda               0.00         0.00         0.00          0          0
sda               0.50         0.00        16.00          0         32
sda1              0.00         0.00         0.00          0          0
sda2              0.50         0.00        16.00          0         32
sda3              0.00         0.00         0.00          0          0
sda4              0.00         0.00         0.00          0          0
sda5              0.00         0.00         0.00          0          0
sdb               7.50         0.00       144.00          0        288
sdb1              7.50         0.00       144.00          0        288more detail:
database version 11.2.0.2.0
system version
[root@localhost ~]# cat /etc/issue
Red Hat Enterprise Linux Server release 5.4 (Tikanga)
Kernel \r on an \m
[root@localhost ~]# lsb_release
LSB Version:    :core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch
[root@localhost ~]# uname -a
Linux localhost.localdomain 2.6.18-164.el5 #1 SMP Tue Aug 18 15:51:48 EDT 2009 x86_64 x86_64 x86_64 GNU/Linuxhardware info
vendor_id       : GenuineIntel
cpu family      : 6
model           : 47
model name      :        Intel(R) Xeon(R) CPU E7- 4860 @ 2.27GHz
stepping        : 2
cpu MHz         : 2261.057
cache size      : 24576 KB
physical id     : 3
siblings        : 20
core id         : 18
cpu cores       : 10
apicid          : 229
fpu             : yes
fpu_exception   : yes
cpuid level     : 11
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx pdpe1gb rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx smx est tm2 cx16 xtpr popcnt lahf_lm
bogomips        : 4522.11
clflush size    : 64
cache_alignment : 64
address sizes   : 44 bits physical, 48 bits virtual
[root@localhost ~]# free -m
             total       used       free     shared    buffers     cached
Mem:         56238      55892        346          0        196      23645
-/+ buffers/cache:      32050      24188
Swap:        16002         22      15979
[root@localhost ~]# df -h
Filesystem            Size Used Avail Use% Mounted on
/dev/sda2              19G 4.9G   14G 27% /
/dev/sda5             230G   27G 192G 12% /home
/dev/sda1              99M   12M   83M 13% /boot
/dev/sdb1             2.9T 2.3T 464G 84% /arrayEdited by: JOhnLiu on Sep 11, 2012 7:31 PM

JOhnLiu wrote:
thanks for reply sb92075
[root@localhost ~]# mpstat -P ALL 2
Linux 2.6.18-164.el5 (localhost.localdomain)    09/12/12
09:29:09     CPU   %user   %nice    %sys %iowait    %irq   %soft %steal   %idle    intr/s
09:29:11     all    0.01    0.00    1.27    0.01    0.00    0.01    0.00   98.69   1658.29
09:29:11       0    0.50    0.00    0.00    0.00    0.00    0.50    0.00   98.99   1657.29
09:29:11      73    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:11      74    0.00    0.00 100.00    0.00    0.00    0.00    0.00    0.00      0.00
09:29:11      75    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:29:11      76    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00I think you don't understand what i mean .
there just have ONLY ONE CORE %sys 100
the top command show average of all cpu core sys% usage
when the one core sys% is 100%
the system are very slow .
e.g: when I create a database instance used for a long time . over 2 hours
but generally it will be done at most 1 hours or shorteris any type of OS virtualization involved in this environment?

Problem with dual core processors: 50% ressources are not used.

Hello all,
I have noticed, that the java app cannot get normally more than 50% of the system ressources. I use different threads in my application, but the app still does't achieve 100% of system power. Max 50-60%.
If I run two processes, I get 100%, but I can't share memory space between this two process. Or I can?
What is the best way to write an application, that can use 100%, in other words, full power of dual core processors.
Thanks in advance.

Try thread.setPriority() method. I am making guess
and any comments
from experts on this method will be highly
acknowledged.Yeah. Don't do that, it's a bad idea.
Back to the original post, there are two reasons this can be happening.
1) Your code is not efficient multi-threading wise. If you are for example running two thread that are in theory parallel but in actual fact provide linear execution so that one is almost blocked by the other then multiple threads and multiple cores will underutilized. It's hard to speculate further on this without seeing your code.
2) The OS. First of all there is the issue of how the oS shares up the processor between processes. This varies and may or may not be configurable. The bottom line on this point is that your OS may be capping the utilization of the processor by process. Again there's not enough information give by you to expand on this point. The second OS issue regards how the OS deals with multi-core. Just because you have a multicore processor does not mean that your OS automatically can take advantage of it.

How to use Real time execution trace toolkit with Dual-core processor??

hi there
the situation as follows:
i have a computer (PC and Laptop) types with Dual-core processors, and am trying to do simulation using Multi-core technology and based on different simulation scenarios...starting from sequantial processing,.......Piple lining processing strategy. so that i can differentiate the time delay between those types of processing based on (Using 1 processor then dual-core processor Computers)
my question is: As i read through Ni's white papers i saw many notes refer to Real-time execution trace toolkit to investigate the (processing-time , etc) of multi-core processors in processing diffenent algorithms. My algorithms are to be run on 1 computer with dual-core processor BUT, not in real time environments, that is ( No hardware to be connected to my pc) only algorithms running on my pc....
So, is it possible to use Real time execution trace toolkit or anyother tools in LabVIEW to show processing-delays and/or anyother timing critical issues without using my application for real- time hardware.???
in other words: how to use Real time execution trace toolkit in non-hardware and/or real-time scenarios???
please help me in this.
Any suggestion, comments, feedback.....is absolutely highly appreciated
thanks a lot in advance
Labview Lover

Hey,
The Realtime Execution Trace Toolkit only works for NI RT Targets.
But you can use the Desktop Execution Trace Toolkit, just search for it under ni.com.
Christian

HeuristicHazard within a transaction using only one DataSource

We have an ejb 2.0 application running under WL 7.0 SP1. Its CMP beans are
          persisted in two Oracle 9i databases, some beans from different databases
          are related (have CMR). We are using XA Oracle JDriver for both pools.
          The javax.transaction.HeuristicMixedException exception occurred when the
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          the beans. The client is a webapp deployed together with the ejbs in the one
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          The mentioned bean doesn't have any CMR with any bean from the other
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No.
There is a very slight increase in performance if you have two chips of the same size, but it is something that will only really show up in benchmarks.
Get 1GB now and leave the other 256MB chip in there. When you have an extra $80 around doing nothing, grab another stick.

Logic 8 using only one CPU while bouncing

Whenever I bounce a project, Logic 8 uses only one CPU. It also spikes this CPU completely, with the CPU meter going into the red area, which is why I am rather keen on persuading Logic to distribute the load.
Any ideas?
(I've given the support document with tips on how to balance multi-core performance a good read, but it doesn't seem to say anything on this particular subject, and following the advice in the document does nothing to change my CPU load.)

Bouncing is a single core process. Just like rendering is in Final Cut Pro. This won't change until Leopard and Apple's ProApps get better at handling multiple cores.
It's redlining because the processor core is working as fast as it can. Computer processors don't just randomly run slower, they use their resources for the tasks at hand. If it only used 50% of a core, the bounce would take twice as long to process.

Using the 2nd of a dual core processor

I have a dual core processor laptop and currently it isn't using the 2nd one at the moment. The first one is full and I am getting messages saying I have no memory space. How can I use the 2nd processor?

We need to know your full model number, like Satellite A215-S7437, and your Part Number, like PSAFGU-00L002. You can find this information on the Toshiba label on the bottom of your computer. Also, we need your operating system version, like Windows 7 32bit.
In addition, give us the exact error message that you are getting. Do not paraphrase, spelling and syntax are important. A screen shot of the error message would be best.
However, I would mention that your processor(s), your available system RAM (Random Access Memory), and the available space on your HDD (Hard Disk Drive), are three completely different things.
Mike

Is it possible to log an array to a database using only one statement?

I'm using Teststand 2.0.1. Now I can use "database options.." to log single number or string to Oracle database with no problem. But I have the difficulty to log an array to my database by using only one statement. Does Teststand has the ability to loop the stepresult usingthe array size as an index to log the array to the database? Or some other way to log array?

Jingtao -
You have a two options to log array data:
1) Use the Str expression function to convert the array of number property to a string with elements delimited by some character like a comma or space. You could then the single value to a variable string field. To retrieve the data you will have to parse the string to repackage the data.
2) Log the data directly to a binary field. TestStand takes the safearray version of the array and writes it byte for byte out to the field. To retrieve the data, you will have to pull it back into a safearray to repackage it in binary form.
Did you have a different way that you would have liked TestStand to use to store the data? What type of data field and what format of data?
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Consumer Group/Resource Plan to use only one instance of a RAC

What would be the way to create a Consumer Group/Resource Plan to use only one instance of a RAC? I have 10.1.0.5 database
running on 10.1.0.5 RAC.
Thanks,

You should use "services" to limit workload to just one specific node of RAC:
http://download.oracle.com/docs/cd/B14117_01/server.101/b10739/create.htm#sthref400

Parallelism in oracle using only one dual-core processor

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