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  • Subterranean IL: Exception handler semantics

    - by Simon Cooper
    In my blog posts on fault and filter exception handlers, I said that the same behaviour could be replicated using normal catch blocks. Well, that isn't entirely true... Changing the handler semantics Consider the following: .try { .try { .try { newobj instance void [mscorlib]System.Exception::.ctor() // IL for: // e.Data.Add("DictKey", true) throw } fault { ldstr "1: Fault handler" call void [mscorlib]System.Console::WriteLine(string) endfault } } filter { ldstr "2a: Filter logic" call void [mscorlib]System.Console::WriteLine(string) // IL for: // (bool)((Exception)e).Data["DictKey"] endfilter }{ ldstr "2b: Filter handler" call void [mscorlib]System.Console::WriteLine(string) leave.s Return } } catch object { ldstr "3: Catch handler" call void [mscorlib]System.Console::WriteLine(string) leave.s Return } Return: // rest of method If the filter handler is engaged (true is inserted into the exception dictionary) then the filter handler gets engaged, and the following gets printed to the console: 2a: Filter logic 1: Fault handler 2b: Filter handler and if the filter handler isn't engaged, then the following is printed: 2a:Filter logic 1: Fault handler 3: Catch handler Filter handler execution The filter handler is executed first. Hmm, ok. Well, what happens if we replaced the fault block with the C# equivalent (with the exception dictionary value set to false)? .try { // throw exception } catch object { ldstr "1: Fault handler" call void [mscorlib]System.Console::WriteLine(string) rethrow } we get this: 1: Fault handler 2a: Filter logic 3: Catch handler The fault handler is executed first, instead of the filter block. Eh? This change in behaviour is due to the way the CLR searches for exception handlers. When an exception is thrown, the CLR stops execution of the thread, and searches up the stack for an exception handler that can handle the exception and stop it propagating further - catch or filter handlers. It checks the type clause of catch clauses, and executes the code in filter blocks to see if the filter can handle the exception. When the CLR finds a valid handler, it saves the handler's location, then goes back to where the exception was thrown and executes fault and finally blocks between there and the handler location, discarding stack frames in the process, until it reaches the handler. So? By replacing a fault with a catch, we have changed the semantics of when the filter code is executed; by using a rethrow instruction, we've split up the exception handler search into two - one search to find the first catch, then a second when the rethrow instruction is encountered. This is only really obvious when mixing C# exception handlers with fault or filter handlers, so this doesn't affect code written only in C#. However it could cause some subtle and hard-to-debug effects with object initialization and ordering when using and calling code written in a language that can compile fault and filter handlers.

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  • ODI 11g - Dynamic and Flexible Code Generation

    - by David Allan
    ODI supports conditional branching at execution time in its code generation framework. This is a little used, little known, but very powerful capability - this let's one piece of template code behave dynamically based on a runtime variable's value for example. Generally knowledge module's are free of any variable dependency. Using variable's within a knowledge module for this kind of dynamic capability is a valid use case - definitely in the highly specialized area. The example I will illustrate is much simpler - how to define a filter (based on mapping here) that may or may not be included depending on whether at runtime a certain value is defined for a variable. I define a variable V_COND, if I set this variable's value to 1, then I will include the filter condition 'EMP.SAL > 1' otherwise I will just use '1=1' as the filter condition. I use ODIs substitution tags using a special tag '<$' which is processed just prior to execution in the runtime code - so this code is included in the ODI scenario code and it is processed after variables are substituted (unlike the '<?' tag).  So the lines below are not equal ... <$ if ( "#V_COND".equals("1")  ) { $> EMP.SAL > 1 <$ } else { $> 1 = 1 <$ } $> <? if ( "#V_COND".equals("1")  ) { ?> EMP.SAL > 1 <? } else { ?> 1 = 1 <? } ?> When the <? code is evaluated the code is executed without variable substitution - so we do not get the desired semantics, must use the <$ code. You can see the jython (java) code in red is the conditional if statement that drives whether the 'EMP.SAL > 1' or '1=1' is included in the generated code. For this illustration you need at least the ODI 11.1.1.6 release - with the vanilla 11.1.1.5 release it didn't work for me (may be patches?). As I mentioned, normally KMs don't have dependencies on variables - since any users must then have these variables defined etc. but it does afford a lot of runtime flexibility if such capabilities are required - something to keep in mind, definitely.

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  • Bin packing part 6: Further improvements

    - by Hugo Kornelis
    In part 5 of my series on the bin packing problem, I presented a method that sits somewhere in between the true row-by-row iterative characteristics of the first three parts and the truly set-based approach of the fourth part. I did use iteration, but each pass through the loop would use a set-based statement to process a lot of rows at once. Since that statement is fairly complex, I am sure that a single execution of it is far from cheap – but the algorithm used is efficient enough that the entire...(read more)

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  • Would you dump Facebook?

    <b>Dissociated Press:</b> "I love the concept, hate the execution. I've written about that before. Facebook encourages the kind of bad netiquette it's taken years to drum out of people. "Oh, I like this page and look - it has a 'forward to all my friends' button.""

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  • Temporary Tables in Stored Procedures

    - by Paul White
    Ask anyone what the primary advantage of temporary tables over table variables is, and the chances are they will say that temporary tables support statistics and table variables do not. This is true, of course; even the indexes that enforce PRIMARY KEY and UNIQUE constraints on table variables do not have populated statistics associated with them, and it is not possible to manually create statistics or non-constraint indexes on table variables. Intuitively, then, any query that has alternative execution...(read more)

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  • Join the Authors of SSIS Design Patterns at the PASS Summit 2012!

    - by andyleonard
    My fellow authors and I will be presenting a day-long pre-conference session titled SSIS Design Patterns at the PASS Summit 2012 in Seattle Monday 5 Nov 2012! Register to learn patterns for: Package execution Package logging Loading flat file sources Loading XML sources Loading the cloud Dynamic package generation SSIS Frameworks Data warehouse ETL Data flow performance   Presenting this session: Matt Masson Tim Mitchell Jessica Moss Michelle Ufford Andy Leonard I hope to see you in Seattle!...(read more)

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  • List columns where collation doesn't match database collation

    - by TiborKaraszi
    Below script lists all database/table/column where the column collation doesn't match the database collation. I just wrote it for a migration project and thought I'd share it. I'm sure lots of tings can be improved, but below worked just fine for me for a one-time execution on a number of servers. IF OBJECT_ID ( 'tempdb..#res' ) IS NOT NULL DROP TABLE #res GO DECLARE @db sysname , @sql nvarchar ( 2000 ) CREATE TABLE #res ( server_name sysname , db_name sysname , db_collation sysname , table_name...(read more)

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  • Learn SSIS from the Authors of SSIS Design Patterns at the PASS Summit 2012!

    - by andyleonard
    Jessica Moss ( blog | @jessicammoss ), Michelle Ufford ( blog | @sqlfool ), Tim Mitchell ( blog | @tim_mitchell ), Matt Masson ( blog | @mattmasson ), and me – we are all presenting the SSIS Design Patterns pre-conference session at the PASS Summit 2012 ! We will be covering material from, and based upon, the book. We will describe and demonstrate patterns for package execution, package logging, loading flat file and XML sources, loading the cloud, dynamic package generation, SSIS Frameworks, data...(read more)

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  • SQL Server XML Schemas

    - by Dave Ballantyne
    Ever been curious about the schema of , say an SSRS rdl file ?  How about the execution plan ? Not only should you already have the .XSD files , check out the folder ‘Microsoft SQL Server\100\Tools\Binn\schemas\sqlserver’ , but they are also available online here. 

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  • Missing Indexes DMV Report, 3 billion Impact!

    - by Tara Kizer
    We’ve been having some major performance issues with one of the applications that I support.  The database is on SQL Server 2005 and is about 150GB in size.  We’ve identified a couple of issues already on the database side.  The first issue is that some query (or maybe several queries) is getting a bad execution plan at some point in time during the day.  When it occurs, database performance comes to a grinding halt.  We know it’s a bad execution plan as running DBCC FREEPROCCACHE immediately resolves the problem system-wide.  As we have not yet identified the problematic query, we’ve put a temporary solution in place that frees the procedure cache on an hourly basis via a SQL Agent job.  This is not ideal, but it is getting us through the day without a major problem.  We are actively working on identifying the problematic query and hope to disable the SQL Agent job soon. Earlier this week, we had a major slowdown for one of the processes of this application.  I was unable to find any database performance issues, but I continued to investigate it.  One of things that I typically do when investigating database performance issues is run the “Missing Indexes DMV Report” (that’s what I call it at least).  When analyzing the output of that report, I immediately dismiss anything under 1 million “Impact” as I want to target the “low-hanging fruit” initially.  When I ran the report earlier this week, I was shocked to find a suggested index with an impact of over 3 billion! Do I win a prize for the highest impact?  Has anyone seen a value higher than mine?  My exact value was 3154284120.67765. The performance issue from earlier this week ended up being an application problem, but it also brought to light a much needed index.  I had previously seen this index come up in that report but always with a much lower impact.  I had never considered it as the index’s selectivity is very low.  It’s a composite index with three columns.  The first column is not selective, the first two columns are not selective, and the three columns together are not selective.  In fact, no matter how I order it, the index will not be selective at all.  I briefly discussed this with Kimberly Tripp, and she said that this was okay for covering indexes.  Selectivity is irrelevant for a covering index.  She indicated that she’s even created indexes with gender as the first column in the index.  I’ve got lots to learn still!

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  • How do I run (execute) a .bin file in Linux (Ubuntu) ?

    - by Paula DiTallo
    If you are on a desktop version of Ubuntu, you can right-click on the file icon, click the permissions tab and click on "allow execution". If you are on a server copy without the desktop bells and whistles (or you would rather work with a command line in a terminal window), then do the following: sudo chmod +x myProgram.bin after you enter your password and get the prompt back type: ./myProgram.bin

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  • List columns where collation doesn't match database collation

    - by TiborKaraszi
    Below script lists all database/table/column where the column collation doesn't match the database collation. I just wrote it for a migration project and thought I'd share it. I'm sure lots of tings can be improved, but below worked just fine for me for a one-time execution on a number of servers. IF OBJECT_ID ( 'tempdb..#res' ) IS NOT NULL DROP TABLE #res GO DECLARE @db sysname , @sql nvarchar ( 2000 ) CREATE TABLE #res ( server_name sysname , db_name sysname , db_collation sysname , table_name...(read more)

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  • Is there an appropriate coding style for implementing an algorithm during an interview?

    - by GlenPeterson
    I failed an interview question in C years ago about converting hex to decimal by not exploiting the ASCII table if (inputDigitByte > 9) hex = inputDigitByte - 'a'. The rise of Unicode has made this question pretty silly, but the point was that the interviewer valued raw execution speed above readability and error handling. They tell you to review algorithms textbooks to prepare for these interviews, yet these same textbooks tend to favor the implementation with the fewest lines of code, even if it has to rely on magic numbers (like "infinity") and a slower, more memory-intensive implementation (like a linked list instead of an array) to do that. I don't know what is right. Coding an algorithm within the space of an interview has at least 3 constraints: time to code, elegance/readability, and efficiency of execution. What trade-offs are appropriate for interview code? How much do you follow the textbook definition of an algorithm? Is it better to eliminate recursion, unroll loops, and use arrays for efficiency? Or is it better to use recursion and special values like "infinity" or Integer.MAX_VALUE to reduce the number of lines of code needed to write the algorithm? Interface: Make a very self-contained, bullet-proof interface, or sloppy and fast? On the one extreme, the array to be sorted might be a public static variable. On the other extreme, it might need to be passed to each method, allowing methods to be called individually from different threads for different purposes. Is it appropriate to use a linked-list data structure for items that are traversed in one direction vs. using arrays and doubling the size when the array is full? Implementing a singly-linked list during the interview is often much faster to code and easier remember for recursive algorithms like MergeSort. Thread safety - just document that it's unsafe, or say so verbally? How much should the interviewee be looking for opportunities for parallel processing? Is bit shifting appropriate? x / 2 or x >> 1 Polymorphism, type safety, and generics? Comments? Variable and method names: qs(a, p, q, r) vs: quickSort(theArray, minIdx, partIdx, maxIdx) How much should you use existing APIs? Obviously you can't use a java.util.HashMap to implement a hash-table, but what about using a java.util.List to accumulate your sorted results? Are there any guiding principals that would answer these and other questions, or is the guiding principal to ask the interviewer? Or maybe this should be the basis of a discussion while writing the code? If an interviewer can't or won't answer one of these questions, are there any tips for coaxing the information out of them?

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  • sys.dm_exec_query_profiles – FAQ

    - by Michael Zilberstein
    As you probably know, this DMV is new in SQL Server 2014. It had been first announced in CTP1 but only in BOL . Now in CTP2 everyone can “play” with it. Since BOL is a little bit unclear (understatement detected), I’ve prepared this small FAQ as a result of discussion with Adam Machanic ( blog | twitter ) and Matan Yungman ( blog | twitter ). Q: What did you expect from sys.dm_exec_query_profiles? A: Expectations were very high – it promised, for the first time, ability to see _actual_ execution...(read more)

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  • SolidQ Journal - free SQL goodness for February

    - by Greg Low
    The SolidQ Journal for February just made it out by the end of February 28th. But again, it's great to see the content appearing. I've included the second part of the article on controlling the execution context of stored procedures. The first part was in December. Also this month, along with Fernando Guerrero's editorial, Analysis Services guru Craig Utley has written about aggregations, Herbert Albert and Gianluca Holz have continued their double-act and described how to automate database migrations,...(read more)

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  • How to have many Ubuntu workstations centrally managed?

    - by Richard Zak
    I have about a dozen Alienware workstations that are used for CUDA development and for execution of MPI jobs. What is the best way to manage them? I'd like to have something like an apt-get but for several systems, and a way to reimage a system simply and centrally. It seems that a combination of Landscape and Canonical's MAAS would be a good fit, but I need an open source solution. Any thoughts?

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  • JetBrains met à disposition la version 5.1 de l'outil d'intégration continue TeamCity comprenant not

    Bonjour, Je vous propose une petite sélection des ajouts / améliorations : Les templates de notification peuvent s'écrire avec Freemarker Support de notifications mail au format HTML Réorganisation des déclencheurs de build pour inclusion dans les templates de configuration Possibilité d'activer la détection automatique de timezone Amélioration du support DotNET (.NET 4.0, Visual Studio 2010, TFS 2010, NAnt 0.90 alpha 1, NUnit 2.5.3 and 2.5.4, etc.) Publication d'un ensemble de fichiers en zip / tar.gz Nouveau plugin consistant en un agent de détection de l'environnement Java et d'initialisation des paramètres d'environnement Exécution distante avec configuration de variables d'environnement pour...

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  • Oracle Enterprise Manager Ops Center : Using Operational Profiles to Install Packages and other Content

    - by LeonShaner
    Oracle Enterprise Manager Ops Center provides numerous ways to deploy content, such as through OS Update Profiles, or as part of an OS Provisioning plan or combinations of those and other "Install Software" capabilities of Deployment Plans.  This short "how-to" blog will highlight an alternative way to deploy content using Operational Profiles. Usually we think of Operational Profiles as a way to execute a simple "one-time" script to perform a basic system administration function, which can optionally be based on user input; however, Operational Profiles can be much more powerful than that.  There is often more to performing an action than merely running a script -- sometimes configuration files, packages, binaries, and other scripts, etc. are needed to perform the action, and sometimes the user would like to leave such content on the system for later use. For shell scripts and other content written to be generic enough to work on any flavor of UNIX, converting the same scripts and configuration files into Solaris 10 SVR4 package, Solaris 11 IPS package, and/or a Linux RPM's might be seen as three times the work, for little appreciable gain.   That is where using an Operational Profile to deploy simple scripts and other generic content can be very helpful.  The approach is so powerful, that pretty much any kind of content can be deployed using an Operational Profile, provided the files involved are not overly large, and it is not necessary to convert the content into UNIX variant-specific formats. The basic formula for deploying content with an Operational Profile is as follows: Begin with a traditional script header, which is a UNIX shell script that will be responsible for decoding and extracting content, copying files into the right places, and executing any other scripts and commands needed to install and configure that content. Include steps to make the script platform-aware, to do the right thing for a given UNIX variant, or a "sorry" message if the operator has somehow tried to run the Operational Profile on a system where the script is not designed to run.  Ops Center can constrain execution by target type, so such checks at this level are an added safeguard, but also useful with the generic target type of "Operating System" where the admin wants the script to "do the right thing," whatever the UNIX variant. Include helpful output to show script progress, and any other informational messages that can help the admin determine what has gone wrong in the case of a problem in script execution.  Such messages will be shown in the job execution log. Include necessary "clean up" steps for normal and error exit conditions Set non-zero exit codes when appropriate -- a non-zero exit code will cause an Operational Profile job to be marked failed, which is the admin's cue to look into the job details for diagnostic messages in the output from the script. That first bullet deserves some explanation.  If Operational Profiles are usually simple "one-time" scripts and binary content is not allowed, then how does the actual content, packages, binaries, and other scripts get delivered along with the script?  More specifically, how does one include such content without needing to first create some kind of traditional package?   All that is required is to simply encode the content and append it to the end of the Operational Profile.  The header portion of the Operational Profile will need to contain the commands to decode the embedded content that has been appended to the bottom of the script.  The header code can do whatever else is needed, and finally clean up any intermediate files that were created during the decoding and extraction of the content. One way to encode binary and other content for inclusion in a script is to use the "uuencode" utility to convert the content into simple base64 ASCII text -- a form that is suitable to be appended to an Operational Profile.   The behavior of the "uudecode" utility is such that it will skip over any parts of the input that do not fit the uuencoded "begin" and "end" clauses.  For that reason, your header script will be skipped over, and uudecode will find your embedded content, that you will uuencode and paste at the end of the Operational Profile.  You can have as many "begin" / "end" clauses as you need -- just separate each embedded file by an empty line between "begin" and "end" clauses. Example:  Install SUNWsneep and set the system serial number Script:  deploySUNWsneep.sh ( <- right-click / save to download) Highlights: #!/bin/sh # Required variables: OC_SERIAL="$OC_SERIAL" # The user-supplied serial number for the asset ... Above is a good practice, showing right up front what kind of input the Operational Profile will require.   The right-hand side where $OC_SERIAL appears in this example will be filled in by Ops Center based on the user input at deployment time. The script goes on to restrict the use of the program to the intended OS type (Solaris 10 or older, in this example, but other content might be suitable for Solaris 11, or Linux -- it depends on the content and the script that will handle it). A temporary working directory is created, and then we have the command that decodes the embedded content from "self" which in scripting terms is $0 (a variable that expands to the name of the currently executing script): # Pass myself through uudecode, which will extract content to the current dir uudecode $0 At that point, whatever content was appended in uuencoded form at the end of the script has been written out to the current directory.  In this example that yields a file, SUNWsneep.7.0.zip, which the rest of the script proceeds to unzip, and pkgadd, followed by running "/opt/SUNWsneep/bin/sneep -s $OC_SERIAL" which is the command that stores the system serial for future use by other programs such as Explorer.   Don't get hung up on the example having used a pkgadd command.  The content started as a zip file and it could have been a tar.gz, or any other file.  This approach simply decodes the file.  The header portion of the script has to make sense of the file and do the right thing (e.g. it's up to you). The script goes on to clean up after itself, whether or not the above was successful.  Errors are echo'd by the script and a non-zero exit code is set where appropriate. Second to last, we have: # just in case, exit explicitly, so that uuencoded content will not cause error OPCleanUP exit # The rest of the script is ignored, except by uudecode # # UUencoded content follows # # e.g. for each file needed, #  $ uuencode -m {source} {source} > {target}.uu5 # then paste the {target}.uu5 files below # they will be extracted into the workding dir at $TDIR # The commentary above also describes how to encode the content. Finally we have the uuencoded content: begin-base64 444 SUNWsneep.7.0.zip UEsDBBQAAAAIAPsRy0Di3vnukAAAAMcAAAAKABUAcmVhZG1lLnR4dFVUCQADOqnVT7up ... VXgAAFBLBQYAAAAAAgACAJEAAADTNwEAAAA= ==== That last line of "====" is the base64 uuencode equivalent of a blank line, followed by "end" and as mentioned you can have as many begin/end clauses as you need.  Just separate each embedded file by a blank line after each ==== and before each begin-base64. Deploying the example Operational Profile looks like this (where I have pasted the system serial number into the required field): The job succeeded, but here is an example of the kind of diagnostic messages that the example script produces, and how Ops Center displays them in the job details: This same general approach could be used to deploy Explorer, and other useful utilities and scripts. Please let us know what you think?  Until next time...\Leon-- Leon Shaner | Senior IT/Product ArchitectSystems Management | Ops Center Engineering @ Oracle The views expressed on this [blog; Web site] are my own and do not necessarily reflect the views of Oracle. For more information, please go to Oracle Enterprise Manager  web page or  follow us at :  Twitter | Facebook | YouTube | Linkedin | Newsletter

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  • Calculating 2D (screen) coordinates from 3D positions in XNA 4.0

    - by NDraskovic
    I have a program that draws some items to the scene by loading their positions from a file. Now I want to place a Ray on the same location where the items are drawn. So my question is how can I calculate the position of the ray (it's 2D components) by using 3D coordinates of each particular item? The items don't move anywhere, so once they are placed they stay until the end of the programs execution. Thanks.

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  • Possible SWITCH Optimization in DAX – #powerpivot #dax #tabular

    - by Marco Russo (SQLBI)
    In one of the Advanced DAX Workshop I taught this year, I had an interesting discussion about how to optimize a SWITCH statement (which could be frequently used checking a slicer, like in the Parameter Table pattern). Let’s start with the problem. What happen when you have such a statement? Sales :=     SWITCH (         VALUES ( Period[Period] ),         "Current", [Internet Total Sales],         "MTD", [MTD Sales],         "QTD", [QTD Sales],         "YTD", [YTD Sales],          BLANK ()     ) The SWITCH statement is in reality just syntax sugar for a nested IF statement. When you place such a measure in a pivot table, for every cell of the pivot table the IF options are evaluated. In order to optimize performance, the DAX engine usually does not compute cell-by-cell, but tries to compute the values in bulk-mode. However, if a measure contains an IF statement, every cell might have a different execution path, so the current implementation might evaluate all the possible IF branches in bulk-mode, so that for every cell the result from one of the branches will be already available in a pre-calculated dataset. The price for that could be high. If you consider the previous Sales measure, the YTD Sales measure could be evaluated for all the cells where it’s not required, and also when YTD is not selected at all in a Pivot Table. The actual optimization made by the DAX engine could be different in every build, and I expect newer builds of Tabular and Power Pivot to be better than older ones. However, we still don’t live in an ideal world, so it could be better trying to help the engine finding a better execution plan. One student (Niek de Wit) proposed this approach: Selection := IF (     HASONEVALUE ( Period[Period] ),     VALUES ( Period[Period] ) ) Sales := CALCULATE (     [Internet Total Sales],     FILTER (         VALUES ( 'Internet Sales'[Order Quantity] ),         'Internet Sales'[Order Quantity]             = IF (                 [Selection] = "Current",                 'Internet Sales'[Order Quantity],                 -1             )     ) )     + CALCULATE (         [MTD Sales],         FILTER (             VALUES ( 'Internet Sales'[Order Quantity] ),             'Internet Sales'[Order Quantity]                 = IF (                     [Selection] = "MTD",                     'Internet Sales'[Order Quantity],                     -1                 )         )     )     + CALCULATE (         [QTD Sales],         FILTER (             VALUES ( 'Internet Sales'[Order Quantity] ),             'Internet Sales'[Order Quantity]                 = IF (                     [Selection] = "QTD",                     'Internet Sales'[Order Quantity],                     -1                 )         )     )     + CALCULATE (         [YTD Sales],         FILTER (             VALUES ( 'Internet Sales'[Order Quantity] ),             'Internet Sales'[Order Quantity]                 = IF (                     [Selection] = "YTD",                     'Internet Sales'[Order Quantity],                     -1                 )         )     ) At first sight, you might think it’s impossible that this approach could be faster. However, if you examine with the profiler what happens, there is a different story. Every original IF’s execution branch is now a separate CALCULATE statement, which applies a filter that does not execute the required measure calculation if the result of the FILTER is empty. I used the ‘Internet Sales’[Order Quantity] column in this example just because in Adventure Works it has only one value (every row has 1): in the real world, you should use a column that has a very low number of distinct values, or use a column that has always the same value for every row (so it will be compressed very well!). Because the value –1 is never used in this column, the IF comparison in the filter discharge all the values iterated in the filter if the selection does not match with the desired value. I hope to have time in the future to write a longer article about this optimization technique, but in the meantime I’ve seen this optimization has been useful in many other implementations. Please write your feedback if you find scenarios (in both Power Pivot and Tabular) where you obtain performance improvements using this technique!

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  • Why people don't patch and upgrade?!?

    - by Mike Dietrich
    Discussing the topic "Why Upgrade" or "Why not Upgrade" is not always fun. Actually the arguments repeat from customer to customer. Typically we hear things such as: A PSU or Patch Set introduces new bugs A new PSU or Patch Set introduces new features which lead to risk and require application verification  Patching means risk Patching changes the execution plans Patching requires too much testing Patching is too much work for our DBAs Patching costs a lot of money and doesn't pay out And to be very honest sometimes it's hard for me to stay calm in such discussions. Let's discuss some of these points a bit more in detail. A PSU or Patch Set introduces new bugsWell, yes, that is true as no software containing more than some lines of code is bug free. This applies to Oracle's code as well as too any application or operating system code. But first of all, does that mean you never patch your OS because the patch may introduce new flaws? And second, what is the point of saying "it introduces new bugs"? Does that mean you will never get rid of the mean issues we know about and we fixed already? Scroll down from MOS Note:161818.1 to the patch release you are on, no matter if it's 10.2.0.4 or 11.2.0.3 and check for the Known Issues And Alerts.Will you take responsibility to know about all these issues and refuse to upgrade to 11.2.0.4? I won't. A new PSU or Patch Set introduces new featuresOk, we can discuss that. Offering new functionality within a database patch set is a dubious thing. It has advantages such as in 11.2.0.4 where we backported Database Redaction to. But this is something you will only use once you have an Advanced Security license. I interpret that statement I've heard quite often from customers in a different way: People don't want to get surprises such as new behaviour. This certainly gives everybody a hard time. And we've had many examples in the past (SESSION_CACHED_CURSROS in 10.2.0.4,  _DATAFILE_WRITE_ERRORS_CRASH_INSTANCE in 11.2.0.2 and others) where those things weren't documented, not even in the README. Thanks to many friends out there I learned about those as well. So new behaviour is the topic people consider as risky - not really new features. And just to point this out: A PSU never brings in new features or new behaviour by definition! Patching means riskDoes it really mean risk? Yes, there were issues in the past (and sometimes in the present as well) where a patch didn't get installed correctly. But personally I consider it way more risky to not patch. Keep that in mind: The day Oracle publishes an PSU (or CPU) containing security fixes all the great security experts out there go public with their findings as well. So from that day on even my grandma can find out about those issues and try to attack somebody. Now a lot of people say: "My database does not face the internet." And I will answer: "The enemy is sitting already behind your firewalls. And knows potentially about these things." My statement: Not patching introduces way more risk to your environment than patching. Seriously! Patching changes the execution plansDo they really? I agree - there's a very small risk for this happening with Patch Sets. But not with PSUs or CPUs as they contain no optimizer fixes changing behaviour (but they may contain fixes curing wrong-query-result-bugs). But what's the point of a changing execution plan? In Oracle Database 11g it is so simple to be prepared. SQL Plan Management is a free EE feature - so once that occurs you'll put the plan into the Plan Baseline. Basta! Yes, you wouldn't like to get such surprises? Than please use the SQL Performance Analyzer (SPA) from Real Application Testing and you'll detect that easily upfront in minutes. And not to forget this, a plan change can also be very positive!Yes, there's a little risk with a database patchset - and we have many possibilites to detect this before patching. Patching requires too much testingWell, does it really? I have seen in the past 12 years how people test. There are very different efforts and approaches on this. I have seen people spending a hell of money on licenses or on project team staffing. And I have seen people sailing blindly without any tests just going the John-Wayne-approach.Proper tools will allow you to test easily without too much efforts. See the paragraph above. We have used Real Application Testing in so many customer projects reducing the amount of work spend on testing by over 50%. But apart from that at some point you will have to stop testing. If you don't you'll get lost and you'll burn money. There's no 100% guaranty. You will have to deal with a little risk as reaching the final 5% of certainty will cost you the same as it did cost to reach 95%. And doing this will lead to abnormal long product cycles that you'll run behind forever. And this will cost even more money. Patching is too much work for our DBAsPatching is a lot of work. I agree. And it's no fun work. It's boring, annoying. You don't learn much from that. That's why you should try to automate this task. Use the Database's Lifecycle Management Pack. And don't cry about the fact that it costs money. Yes it does. But it will ease the process and you'll save a lot of costs as you don't waste your valuable time with patching. Or use Oracle Database 12c Oracle Multitenant and patch either by unplug/plug or patch an entire container database with all PDBs with one patch in one task. We have customer reference cases proofing it saved them 75% of time, effort and cost since they've used Lifecycle Management Pack. So why don't you use it? Patching costs a lot of money and doesn't pay outWell, see my statements in the paragraph above. And it pays out as flying with a database with 100 known critical flaws in it which are already fixed by Oracle (such as in the Oct 2013 PSU for Oracle Database 12c) will cost ways more in case of failure or even data loss. Bet with me? Let me finally ask you some questions. What cell phone are you using and which OS does it run? Do you have an iPhone 5 and did you upgrade already to iOS 7.0.3? I've just encountered on mine that the alarm (which I rely on when traveling) has gotten now a dependency on the physical switch "sound on/off". If it is switched to "off" physically the alarm rings "silently". What a wonderful example of a behaviour change coming in with a patch set. Will this push you to stay with iOS5 or iOS6? No, because those have security flaws which won't be fixed anymore. What browser are you surfing with? Do you use Mozilla 3.6? Well, congratulations to all the hackers. It will be easy for them to attack you and harm your system. I'd guess you have the auto updater on.  Same for Google Chrome, Safari, IE. Right? -Mike The T.htmtableborders, .htmtableborders td, .htmtableborders th {border : 1px dashed lightgrey ! important;} html, body { border: 0px; } body { background-color: #ffffff; } img, hr { cursor: default }

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  • Data Auditor by Example

    - by Jinjin.Wang
    OWB has a node Data Auditors under Oracle Module in Projects Navigator. What is data auditor and how to use it? I will give an introduction to data auditor and show its usage by examples. Data auditor is an important tool in ensuring that data quality levels meet business requirements. Data auditor validates data against a set of data rules to determine which records comply and which do not. It gathers statistical metrics on how well the data in a system complies with a rule by auditing and marking how many errors are occurring against the audited table. Data auditors are typically scheduled for regular execution as part of a process flow, to monitor the quality of the data in an operational environment such as a data warehouse or ERP system, either immediately after updates like data loads, or at regular intervals. How to use data auditor to monitor data quality? Only objects with data rules can be monitored, so the first step is to define data rules according to business requirements and apply them to the objects you want to monitor. The objects can be tables, views, materialized views, and external tables. Secondly create a data auditor containing the objects. You can configure the data auditor and set physical deployment parameters for it as optional, which will be used while running the data auditor. Then deploy and run the data auditor either manually or as part of the process flow. After execution, the data auditor sets several output values, and records that are identified as not complying with the defined data rules contained in the data auditor are written to error tables. Here is an example. We have two tables DEPARTMENTS and EMPLOYEES (see pic-1 and pic-2. Click here for DDL and data) imported into OWB. We want to gather statistical metrics on how well data in these two tables satisfies the following requirements: a. Values of the EMPLOYEES.EMPLOYEE_ID attribute are three-digit numbers. b. Valid values for EMPLOYEES.JOB_ID are IT_PROG, SA_REP, SH_CLERK, PU_CLERK, and ST_CLERK. c. EMPLOYEES.EMPLOYEE_ID is related to DEPARTMENTS.MANAGER_ID. Pic-1 EMPLOYEES Pic-2 DEPARTMENTS 1. To determine legal data within EMPLOYEES or legal relationships between data in different columns of the two tables, firstly we define data rules based on the three requirements and apply them to tables. a. The first requirement is about patterns that an attribute is allowed to conform to. We create a Domain Pattern List data rule EMPLOYEE_PATTERN_RULE here. The pattern is defined in the Oracle Database regular expression syntax as ^([0-9]{3})$ Apply data rule EMPLOYEE_PATTERN_RULE to table EMPLOYEES.

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  • Is it good to review programs with seniors and boss even if it is working fine?

    - by Himanshu
    In my company, before delivery of any project, my boss asks my seniors to review programs written by me or other team members or sometimes boss also sits with us for review. I think it is a good way of getting knowledge, but sometimes when programs are working fine, they don't work same after review and I need to look again into my program. They says that review helps to optimize program and query execution, but can we prefer optimization over actual functioning of program?

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  • Automate RAC Cluster Upgrades using EM12c

    - by HariSrinivasan
    One of the most arduous processes  in DB maintenance is upgrading Databases across major versions, especially for complex RAC Clusters.With the release of Database Plug-in  (12.1.0.5.0), EM12c Rel 3 (12.1.0.3.0)  now supports automated upgrading of RAC Clusters in addition to Standalone Databases. This automation includes: Upgrade of the complete Cluster across the nodes. ( Example: 11.1.0.7 CRS, ASM, RAC DB  ->   11.2.0.4 or 12.1.0.1 GI, RAC DB)  Best practices in tune with your operations, where you can automate upgrade in steps: Step 1: Upgrade the Clusterware to Grid Infrastructure (Allowing you to wait, test and then move to DBs). Step 2: Upgrade RAC DBs either separately or in group (Mass upgrade of RAC DB's in the cluster). Standard pre-requisite checks like Cluster Verification Utility (CVU) and RAC checks Division of Upgrade process into Non-downtime activities (like laying down the new Oracle Homes (OH), running checks) to Downtime Activities (like Upgrading Clusterware to GI, Upgrading RAC) there by lowering the downtime required. Ability to configure Back up and Restore options as a part of this upgrade process. You can choose to : a. Take Backup via this process (either Guaranteed Restore Point (GRP) or RMAN) b. Set the procedure to pause just before the upgrade step to allow you to take a custom backup c. Ignore backup completely, if there are external mechanisms already in place.  High Level Steps: Select the Procedure "Upgrade Database" from Database Provisioning Home page. Choose the Target Type for upgrade and the Destination version Pick and choose the Cluster, it picks up the complete topology since the clusterware/GI isn't upgraded already Select the Gold Image of the destination version for deploying both the GI and RAC OHs Specify new OH patch, credentials, choose the Restore and Backup options, if required provide additional pre and post scripts Set the Break points in the procedure execution to isolate Downtime activities Submit and track the procedure's execution status.  The animation below captures the steps in the wizard.  For step by step process and to understand the support matrix check this documentation link. Explore the functionality!! In the next blog, will talk about automating rolling Upgrades of Databases in Physical Standby Data Guard environment using Transient Logical Standby.

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