TUNING METHODS

Similar Questions

• SQL Tuning for Exadata

  Hello
  
  I would like to know specific to Oracle exadata SQL Tuning methods so that they could improve the performance of the database?
  I am aware that oracle exadata works with Oracle 11 g, but I would like to know weather there any s w.r.t. to SQL tuning on exadata?
  
  concerning
  Sunil

  Well, there are some things that are very different on Exadata. Remember all the standard Oracle SQL tuning you have already learned as Exadata runs the code of database 11g standard, but there are many optimizations that were added that you should be aware of. At a high level, if you make the OLTP type work you should try to make sure you enjoy Exadata Smart Flash Cache that will greatly accelerate your small I / O of the but long-running queries are where appear the great benefits. The high level tuning approach for them is the following:

  1. check if you have found smart Scans.
  2. If you are not, difficulty that never prevents them being used.

  We have been involved in somewhere between 25-30 DB now machinery facilities and in many cases, a little bit of effort changes performance considerably. If you get only 2 to 3 X improvement on your previous platform on these long term requests you get probably not all the benefits of the Exadata optimizations. So the first step is to learn how to determine if you've found the smart analysis or not, and what parts of the statement. Wait events, session statistics, V$ SQL, SQL monitoring are viable tools that can show you this information.

• slowly decreasing oscillation for PID

  In my project, now I am facing a very interesting problem, and I would like to ask the opinion of others.

  I control the temperature of a phyiscal object using the LabView PID toolkit, with good results, I set my controller manually using the Ziegler-Nichols closed loop adjustment rule. The process value (PV) reaches the set point (SP) quick (about a year and a half period time and swing left), and I've reached the ultimate accuracy (deviation around SP) fast enough.

  However, I realized that in fact, in my experience, a swing slowly decline would be beneficial at the beginning of the process because of certain physical phenomena.

  I guess I should use some kind of hourly? For example, I would that my control system having an oscillation decreases with only 5% of amplitude in a period time.

  All tips are welcome!

  Kind regards

  I think that the right adjustment of the values, you could get the controller for you to do. Try to increase the proportional gain - but do not forget that with the LabVIEW PID, which will also affect the gain full and derived, then you may need to set those too. You know, Ziegler-Nichols tuning approach, that there is a proportional gain during which you get stable sustained oscillations, so looking for a proportional gain below the ultimate gain which allows you the degrowth in oscillations that you want.

  For more info on math, try a search on "rate of decay PID. Conventional tuning methods aim ratio of disintegration of a quarter - each successive swing has an amplitude of 1/4 of the previous swing. Looks that you want your controller tuned for a greater ratio decomposition, where each successive swing has an amplitude of only slightly lower than the previous.

  Alternatively you could overlay a swing decaying about to set. This might be easier.

  Gain scheduling is used when you want the different PID gains according to the set point. From your description, I think not hourly is a solution to your problem.

• PID control with big delay in the process variable

  Hello

  My goal is to control the temperature via a valve and heat exchanger. I proceeded variable (temperature) measured from a hose. This temperature should be raised a few degrees with a heat exchanger. So basically I need to order a valve that allows the water to flow through the heat exchanger to raise the temperature to the desired level.

  My original plan was to use a base PID regulation to operate the dispenser. However, it is about 0.5 to 1 minute of delay time in the temperature probe after I opened the valve, which increases the temperature. This leads to a situation where the PID regulation valve fully open during this period (trying to get the temperature rise). Then once the temperature begins to rise it fires quite quickly. PID begins turning the tap off almost immediately, but because of the time delay in the sensor, the temperature exceeds seriously. This led to severe oscillation and at worst unstable processes. I tried to adjust the PID control to "predict" the timer to close the valve in advance to minimize the excess, but failed.

  I would appreciate if anyone has any ideas how to make this type of control with Labview PID functions. I also wonder if there is a better type of control procedure for this scenario as a PID control?

  -Lars

  This is a very common situation in the heating control, and generally PID can be adjusted to make it work. How do you do the tuning? If you do it by trial and errors, you have little chance to succeed. For a slow process with time delay, I like to use the method Cohen Coons, or similar open Ziegler-Nichols-loop method. The idea is that you temporarily remove or disable the PID. Set the valve in a fixed position and wait for the temperature to stabilize. Then, change the setting of the valve and record temperature at regular intervals data until the temperature is stable again to a new value. Use these data to get the initial values of PID using the equations provided by the tuning method you choose.

• During a planned migration, which method of database migration is the best?  Data Pump or RMAN?

  I ask this because I recently had to migrate a database to a new feature of ODA and our application developer head was upset because I used pump data to the database to the new platform and it took a few post import scripts to set permissions to what they were before the move.  He suggests to use RMAN, because it will restore the database to exactly how it was previously without having to restore the permissions.  I would like to know what methods are you using and which one is better?

  Thanks in advance ^_^

  He suggests using RMAN

  Yes, absolutely, and not just for the reason you mention: don't have time to stop a problem for you? Re: Tuning RMAN - active database in double with size 1.7 to

• Need your help for sql tuning

  
  Hi gurus

  I really want to learn a few basics against SQL tuning, can you please guide me how will I achieve my goal? Thanks in advance.

  Concerning

  Shu

  I am professional tuner and this for 20 years. Firstly, I think that the best way is always a course with instructor. In other words, you can't ask for books. You have no need to read tuning guide in this case, the instructor he will tell you. If the time and the budget does not allow you a course, you can go online or material and DVD tutorial. As a next steop I would recommend Cary Milsap's "Optimizing Oracle Perforamance". I'll be your right mind game. Jonathan and Chris books you must have if you do practical work. You don't need to read all the chapters in detail from the beginning, but you should check out them if you have any questions when you work on a tuning tasks. If you want to go more advanced subjects discover Wolfgang Breitlings presentation on http://www.centrexcc.com/. Very valuable are also Throw away method of Martin Berg and the SQL Diagraming of Daniel Tow technique.

• Why a method to create a constraint would allow the index to be used, but not another.

  Hi all

  With the help of:

  Oracle Database 11 g Enterprise Edition Release 11.2.0.4.0 - 64 bit Production

  SQL Developer Version 4.0.2.15

  I had to do the following query on a table.

  Select distinct chdrnum, tranno

  of ractpf_pgr;

  I ran the setup of SQL in SQL Developer, who told me that he was doing a full table scan,

  (It's what you get using SEPARATE!)

  After some research, I discovered that if I put in question on columns not null check constraints

  and then recreated the index based on these columns, I'd get a full index scan instead of a table scan.

  Good news - off, I went and tried using the following method (I think it's call a constraint of out-of-line)

  and created one for each colmn using snytax below.

  ALTER table RACTPF_PGR add constraint CS_CHDRNUM_NN check (CHDRNUM is not null) validate;

  Ran my SQL Tuning Advisor again - no joy - a full table scan that was happening.

  Did some more research and recreated the constraints with the help of an online method

  ALTER TABLE RACTPF_PGR CHANGE (CHDRNUM CONSTRAINT CS_CHDRNUM_NN NOT NULL);

  My SQL Tuning Advisor is represented - and yes the index was used.

  
  

  But what I want to know why a method would cause the index to use another does not

  
  

  Thanks in advance.

  
  

  The second is a NOT NULL constraint.

  The a ('is not null') is technically not a NOT NULL constraint.

  Give me a moment to start my database, and I will demonstrate.

  Edit: Here's the demo:

  SQL> create table x (a number null, b number null);                  
  
  Table created.                                                       
  
  SQL> alter table x add constraint a_nn check(a is not null) validate;
  
  Table altered.                                                       
  
  SQL> alter table x modify (b constraint b_nn not null);              
  
  Table altered.                                                       
  
  SQL> select column_name, nullable
    2  from user_tab_cols
    3  where table_name = 'X';                                         
  
  COLUMN_NAME
  ----------------------------------------------------------------------
  
  N
  -
  B
  N                                                                    
  
  A
  Y                                                                    
  

  The index does not store registrations for the lines where all components of the index are null, then the optimizer needs to see that the columns are not nullable to be able to use an index scan.

• Problem with the Paging in VO tuning range

  Hi all
  
  I am having some problems with the Range Paging in VO tuning. My VO questions about 5000 + lines. So I'm going to the range of paging that is the recommended method for managing large data. Here I must also get the current row of the table (which shows the desired result). But when I use the getCurrentRow() method, it results in a value zero. Why this happens?
  
  code
  FacesContext fc = FacesContext.getCurrentInstance ();
  Object returnObject1 = null, fc.getELContext () .getELResolver () .getValue (fc.getELContext (), "links");
  DCBindingContainer bindingsIte = returnObject1 (DCBindingContainer);
  DCIteratorBinding dciter = bindingsIte.findIteratorBinding("ClientsVO1Iterator");
  Line rowClient = dciter.getCurrentRow ();
  String sDisposaltype = rowClient.getAttribute("DividendDispType").toString ();
  
  This method works very well with the scrollable access mode.
  Is there a special way to get the current line with the range Paging?
  
  Thank you
  Danesh

  Danesh,

  I have not checked this version or the most recent 11.1.2.1, but in 11.1.1.4, we had this problem and we use workaround:
  1. remove the current selectionlistener in the table (#{... makecurrent}).
  2. set a new headset selection (using the small arrow to the right) in a bean of your choice. The scope of the bean must be seen or pageflow depending on where you need access to the selected line.
  3. in the new selectionListener you get the selected line of the event, get the key in the line and store in an attribute of bean
  4. to the point you need the selected line, you use the stored line button and work with that. If you need attributes from the line you must ask for the line, once again, that you only the key. In our case only pass us the key to a service in the module of the application method, so this works very well for us.

  Here is an example of such a selection listener

      public void singleSelectionListener(SelectionEvent selectionEvent)
      {
          RowKeySet rksAdd = selectionEvent.getAddedSet();
          if (rksAdd.isEmpty())
              return;  // no selection
  
          Object[] it = rksAdd.toArray();
          // as this is for single selection there should only be one, but...
          for (Object obj: (List) it[0])
          {
              mLogger.fine("Selected :" + obj);  // log selected row
              Key k = (Key) obj;   // the object is the row key
              Object[] kv = k.getKeyValues();  // get the key value for later
              // strore the key value in a bean attribute
              mLastSelectedOID = (Integer) kv[0]; // store the key value (if the key has multiple parts you need to store them all)
          }
      }
  

  Timo

• Add a vpn connection in ios 10, method chosen in IKEv2, but I don't have the remote ID. My VPN is created in Sonicwall

  Add a vpn connection in ios 10, method chosen in IKEv2, but I don't have the remote ID. My VPN is created in Sonicwall, waiting for quick reply

  Hi cmscan,

  Thank you for using communities of Apple Support.

  I see that you add a VPN connection using IKEv2, but you do not have the remote ID. I know it's important to be able to set up a virtual private network, you can connect using your iPhone. I'm happy to help you with this.

  You must contact your system administrator to ensure that the settings that you must configure the VPN connection. Please see the iPhone user Guide for more information.

  Have a great day!

• purchase fail because I used to pay by gift card iTunes, so I chose any of the theme of credit card. Credit is danger, I don't like to pay with this method. Can iTunes gift card can't pay inn - app?

  purchase fail to cause I used to pay purchase iTunes gift card, so I chose any of the theme of credit card. Credit card is danger, I don't like to pay with this method. Can iTunes gift card can't pay inn - app?

  You should be able to make in-app purchases with gift cards. What happens when you try to do?

• Hey, need help. I get this in my iPhone that 'there is a problem of billing with a previous purchase. Please update your payment method"in any way I can remove my visa card from iTunes

  Hey, need help. I get this in my iPhone that 'there is a problem of billing with a previous purchase. Please update your payment method"anyway I can remove my visa card from iTunes?

  You must pay your debt first.

• Why can't I change my payment method

  I can't download apps or upgrade of BC., it is said inval map, you need to add another method of payment. OK, that's fine but I put my there debit card and he said declined. So I call the Bank and I have more than enough money in there! What can be the problem

  Not all debit cards are accepted as payment. You can contact the support of iTunes for clarification, but usually when something is denied, it can also be a problem with a game of football with the name, address or other identifying information. support for iTunes, https://www.apple.com/emea/support/itunes/contact.html

• Hi all OneHow can you buy an IBook UK not available in Indian store a store; When you change the status of your country, your billing information and credit cards won't work; is there a solution for this using the same method of billing.

  Hello world

  How can buy you an IBook of UK not available in Indian store a store; When you change the status of your country, your billing information and credit cards won't work; is there a solution for this using the same method of billing

  There is no solution, if it is not available in your area, you can't buy it.

• unlock my method of payment thanks

  unlock my method of payment thanks

  You will need to communicate directly with Apple > http://www.apple.com/contact/

  What is a community of users to anyone here can do for you.

• Why Thuderbird stopped sorting emails by date and added a new sort of his method?

  Yesterday, my emails have been sorted in strict chronological order. Today, they are classified by subject and by date and are in reverse chronological order - oldest first. If all the mails I received from a person in the last two months are grouped, chronologically. I can't imagine what use that method can be anyone.

  When I click on the Date header nothing changes.

  It looks like you might have screwed so turned on.
  Sort by view by Unthreaded