Database » November 18, 2007

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• November 19, 2007
• 8:12

  New Oracle Wiki page - for bloggers

   » ‎ OraBlogs
  To assist new and existing Oracle bloggers on how to participate in the Oracle blogging community, I've taken the chance to create a Bloggers page on the Oracle Wiki. It's a rudimentary start at the moment, but I'm hoping the other Oracle bloggers will take time out to include any tidbits they'd like to share around. For example I've listed the Oracle RSS aggregators I'm familiar with, and some information on who to contact to get your blog added to the associated aggregation feed.
  
  Happy blogging!

• 6:26

  Temporary Post Used For Style Detection (d4c7d32e-cb55-4047-8771-8d85c28a5062)

   » ‎ Eddie Awad's Blog

  This is a temporary post that was not deleted. Please delete this manually. (615c35b0-2189-45d9-bae4-8d3aa8d66447)

  ---
  Related Articles at Eddie Awad's Blog:

  • Infinite Scrolling at OraNA.info and New Oracle Bloggers Group
  • Oracle Trace Analyzer is TKPROF on Steroids
  • Cursors Again
  • Read XML from an HTTP POST
  • Browse 188+ Feeds The Grazr Way

  
  

• 6:26

  Temporary Post Used For Style Detection (d4c7d32e-cb55-4047-8771-8d85c28a5062)

   » ‎ OraBlogs
  This is a temporary post that was not deleted. Please delete this manually. (615c35b0-2189-45d9-bae4-8d3aa8d66447) ---Related Articles at Eddie Awad's Blog:Infinite Scrolling at OraNA.info and New Oracle Bloggers GroupOracle Trace Analyzer is TKPROF on SteroidsCursors AgainRead XML from an HTTP POSTBrowse 188+ Feeds The Grazr Way
• 5:58

  New Oracle Mix development groups - Apex, Forms, JDev, SQL Dev

   » ‎ OraBlogs
  Oracle's new Oracle Mix site is enjoying an explosion of new users and shows potential for interesting times ahead in Oracle customer participation in the future of Oracle products.
  
  I've taken the opportunity to create some new groups along the development lines, and I hope readers will join the groups to start pushing new ideas for the products:
  
  Oracle Application Express (Apex)
  Oracle Forms
  Oracle JDeveloper
  Oracle SQL Developer
  
  Note participation requires membership of OTN.
  
  I've also taken the chance to create a user group-group for the local Aussie chapter:
  
  Australian Oracle User Group (AUSOUG)
• 1:00

  [misc] ????

   » ‎ OraBlogs
  ???????????????????????????????(???????????????) ?????????????????????????????????????PC?????1GB??????? ????????PC????????PC2-5300 DDR2 SDRAM?
• 1:00

  [web20][ruby] Oracle Mix (Beta) ???? / JRuby on Rails

   » ‎ OraBlogs
  ?????????????????????????????????????????????????? ????????????????????????Oracle OpenWorld 2007????????????????Oracle Mix???????????????Oracle Mix?

• November 18, 2007
• 23:25

  Giving a talk in Zurich

   » ‎ MySQL Performance Blog

  I'm visiting customer in Zurich next week and also was invited to give a talk on MySQL Performance Wednesday November 21.
  If you're in the area please feel free to drop by I'll start by talking about Query Optimization and we'll keep it interactive to see what else audience would like to know.

  Entry posted by peter | One comment

  Add to: | | | |

• 18:02

  MySQL: Data Storage or Data Processing

   » ‎ MySQL Performance Blog

  I was thinking today of how people tend to use MySQL in modern applications and it stroke me in many cases MySQL is not used to process the data, at least not on the large scale - instead it is used for data storage and light duty data retrieval. Even in this case however the cache (ie memcache) is often implemented to offload MySQL.

  When it comes to large scale data processing other techniques are used. Google uses some bigtable based technologies for search and Google Analytics (which is quite typical log processing application), when you look at recommendation task as well as a lot of other personalized services they may not use MySQL (and SQL at all). In many cases you would see absolutely custom solutions are implemented, in other cases you would see Hadoop or Sphinx used to crunch data in parallel or it even could be special wrapper on top of MySQL do do the work

  The reason for this is not only because many tasks are not well expressed in SQL or map to relational data structure to well, but also because of lack of build in parallel processing. When you need high data processing speed you simply can't do it on single CPU especially since systems are getting wider more than CPU cores get faster, though even single node does not take you that far.

  MySQL concept of Single Query=Single Thread works well when few rows needs to be analyzed which often forces us to do tricky optimizations because if query has to analyze 10.000.000 of rows you're busted - it simply will take too long for user to wait for reply (especially in modern age of AJAX applications with sub second response requirements). Note you will have to solve this problem even if it is relatively rare case and in most cases it will take much shorter time. This is why we have to do careful indexing build summary/cache tables hunt queries which traverse a lot of data and kill them.

  Now think what happens if you Search Google or engage in any other processing intensive activity. If result is not served from cache you will have many CPU seconds if not minutes used processing your request, but you get reply fast because hundreds and thousands of CPUs were handling data for you in parallel.

  You may argue limited number of applications needs so serious data crunches - could be, however the number of such applications would likely grow in the future. Mobile Internet is to seriously increase number of global Internet users, plus we see more and more personalized services in terms of information provisioning, advertisement, social interactions etc which will need to employ more and more complex algorithms as they mature.

  Interesting enough so far MySQL does not have anything which tackles this need, even on the roadmap.

  Indeed MySQL has MySQL Cluster but it is quite different. MySQL Cluster at this point is a cluster in terms of Storage - only minor aspects such as data filtering can be offloaded and performed in parallel while a lot of other jobs such as sorting, unions/instersections have to be performed on the SQL node.

  May be MySQL Cluster will evolve and data storage nodes will be able to perform all kinds of operations, in which case it will become much more helpful. Of course if it also drops a lot of its other limits and will be able to scale to thousands of nodes.

  Entry posted by peter | 8 comments

  Add to: | | | |

• 15:37

  ADF Faces 11g: Reloading the Matrix - using the Pivot Table component

   » ‎ OraBlogs
  In the past months I have been writing several times about the Matrix component I developed for ADF Faces to be used in several of our projects. Yesterday I demonstrated this component in my presentation at OOW 2007 on ADF Faces. This morning I decided to take a look the the new PivotTable component that [...]
• 15:12

  Clarifying Two Distinct Kinds of Polymorphic View Objects

   » ‎ OraBlogs

  A user wrote in asking for clarification on polymorphic view objects. He had started by creating a base Emp entity object without a Comm attribute, having its Job attribute marked as the discriminator attribute. Then, he extended Emp to create Clerk entity object as well as a Salesman entity object, in both cases overriding the Job discriminator attribute to set the appropriate default value for that subtype. In the Salesman entity, he added the additional Comm attribute for commission. He wanted to know why his polymorphic view object was not giving him access on the client side to the additional Comm attribute in rows where the Job was equal to 'SALESMAN', the discriminator attribute value for the Saleman entity object. In this entry I try to clarify why the behavior he was seeing is correct, and how to achieve what he wanted to do.

  There are two kinds of polymorphic view objects that we support. These two types are documented in Dev Guide sections:

  • 27.6.1 What is a Polymorphic Entity Usage?
  • 27.6.5 What are Polymorphic View Rows?

  When you use the first kind of polymorphic view object, as this reader was doing, the different entity usage subtypes are opaque to the client. As far as the client layer is concerned, every row in the view object's result set has the same set of attributes and row type, even though under the covers ADFBC ensures that the correct EO row subtype is created based on the discriminator attribute value. In other words, with a polymorphic entity usage, only the entity row parts of a view row are changing type, but the view row type is constant.
  
  The second type of polymorphic view object involves defining a hierarchy of view objects, and then configuring the application module to allow one or more view row subtypes in the result. Only the second type of polymorphism produces different subtypes of client-visible view row types. Only this type allows the client to "see" a subtype of a client view row with an additional attributes.

  You can use either type of polymorphism on its own, or combine the two, at your choice. So, to achieve that the reader wanted to accomplish, he would need to define a base EmpView having his base Emp entity object as its entity usage. Then, create ClerkView VO that extends EmpView and SalesmanView that extends Emp. Finally, in the application module editor, he would need to configure ClerkView and SalesmanView as view subtypes to allow for the EmpView view instance. Then, in the client layer, rows for salesmen would have an additional Comm attribute available. 
  
  P.S. Another thing that came up in answering his question was that he was allowing the ADF polymorphic discriminator attribute filtering to narrow down the query to only contain the expected subtypes. However, it's not best practice to rely solely on the discriminators to perform type filtering in the query as this will effectively end up querying all rows and then "throwing away" rows that don't qualify any of the disciminator values in the middle tier. See section 27.6.4.1 Your Query Must Limit Rows to Expected Entity Subtypes in the dev guide for more info.

• 15:00

  VMware fires back at Oracle's VM performance claims

   » ‎ Databases News
  Oracle CEO Larry Ellison said Wednesday the company will provide benchmark numbers to back its claims, but as of Friday, those figures were not available.

  

  

• 14:21

  Day 2, 3, and 4 at OpenWorld

   » ‎ OraBlogs
  I thought the first day of OpenWorld with my own two presentations (here and here) was a busy one. How wrong could I have been… I’ve been to a couple of Oracle conventions by now and each time you get to now a few new people. That really adds up and by now you just walk around a convention like this and meet people you know every time. This means you spend a lot of time talking to a lot of people. That’s absolutely great and one of the most important reasons why I love attending these things. The only downside is that is leaves you little or no time to blog about what’s happening.
  Between all the social activities (drinks, dinners, and even a sailing trip on the bay - thanks Hylke) I even managed to find some time for attending a couple of sessions. The first one was moving beyond project level SOA. The presentation talked about the difference between “Project-Level SOA”, “Infrastructure SOA” and “Enterprise SOA”. Many organizations, including ours, start with project oriented SOA. The presentation talked about “upgrading” this approach to Enterprise level SOA. They made a number of valid points, but I guess (hope) [Read more...]
• 13:44

  Oracle VM, Part 2

   » ‎ OraBlogs
  I was browsing the blogosphere this morning and ran across this link on Doug Burns blog to Pat Shuff's Blog: Oracle VM. This entry really answers the question I had the other day. It looks like the answer is a reasonably priced, supportable stack. Fair enough. I

• 9:34

  Hollywood Hurting: SNL @ Oracle OpenWorld

   » ‎ MR. ED's blog

  When I watched Sunday Night Live--the Keynote with Larry Ellison from Oracle OpenWorld 2007--I thought it was interesting that they had current and former cast members of Saturday Night Live. Typical corporate event for famous people, I suppose. Kevin Nealon did a good job, considering the nature of the material. Victoria Jackson was great, too.

  But now I read about the writer's strike affecting SNL, and how they just fired a large portion of their production staff. Don't know how this affects the actors, but it can't be good for them, either. Good thing some (one?) of them got a few extra Hamiltons to help them get through this season.

  And don't forget: Tom Kite is a great professional golfer, but Tom Kyte is also a great professional Oracle employee.