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  • WebLogic Server–Use the Execution Context ID in Applications–Lessons From Hansel and Gretel

    - by james.bayer
    I learned a neat trick this week.  Don’t let your breadcrumbs go to waste like Hansel and Gretel did!  Keep track of the code path, logs and errors for each request as they flow through the system.  Earlier this week an OTN forum post in the WLS – General category by Oracle Ace John Stegeman asked a question how to retrieve the Execution Context ID so that it could be used on an error page that a user could provide to a help desk or use to check with application administrators so they could look up what went wrong.  What is the Execution Context ID (ECID)?  Fusion Middleware injects an ECID as a request enters the system and it says with the request as it flows from Oracle HTTP Server to Oracle Web Cache to multiple WebLogic Servers to the Oracle Database. It’s a way to uniquely identify a request across tiers.  According to the documentation it’s: The value of the ECID is a unique identifier that can be used to correlate individual events as being part of the same request execution flow. For example, events that are identified as being related to a particular request typically have the same ECID value.  The format of the ECID string itself is determined by an internal mechanism that is subject to change; therefore, you should not have or place any dependencies on that format. The novel idea that I see John had was to extend this concept beyond the diagnostic information that is captured by Fusion Middleware.  Why not also use this identifier in your logs and errors so you can correlate even more information together!  Your logging might already identify the user, so why not identify the request so you filter down even more.  All you need to do inside of WebLogic Server to get ahold of this information is invoke DiagnosticConextHelper: weblogic.diagnostics.context.DiagnosticContextHelper.getContextId() This class has other helpful methods to see other values tracked by the diagnostics framework too.  This way I can see even more detail and get information across tiers. In performance profiling, this can be very handy to track down where time is being spent in code.  I’ve blogged and made videos about this before.  JRockit Flight Recorder can use the WLDF Diagnostic Volume in WLS 10.3.3+ to automatically capture and correlate lots of helpful information for each request without installing any special agents and with the out-of-the-box JRockit and WLS settings!  You can see here how information is displayed in JRockit Flight Recorder about a single request as it calls a Servlet, which calls an EJB, which gets a DB connection, which starts a transaction, etc.  You can get timings around everything and even see the SQL that is used. http://download.oracle.com/docs/cd/E21764_01/web.1111/e13714/using_flightrecorder.htm#WLDFC480 Recent versions of the WLS console also are able to visualize this data too, so it works with other JVMs besides JRockit when you turn on WLDF instrumentation. I wrote a little sample application that verified to myself that the ECID did actually cross JVM boundaries.  I invoked a Servlet in one JVM, which acted as an EJB client to Stateless Session Bean running in another JVM.  Each call returned the same ECID.  You need to turn on WLDF Instrumentation for this to work otherwise the framework returns null.  I’m glad John put me on to this API as I have some interesting ideas on how to correlate some information together.

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  • More Denali Execution Plan Warning Goodies

    - by Dave Ballantyne
    In my last blog, I showed how the execution plan in denali has been enhanced by 2 new warnings ,conversion affecting cardinality and conversion affecting seek, which are shown when a data type conversion has happened either implicitly or explicitly. That is not all though, there is more .  Also added are two warnings when performance has been affected due to memory issues. Memory spills to tempdb are a costly operation and happen when SqlServer is under memory pressure and needs to free some up. For a long time you have been able to see these as warnings in a profiler trace as a sort or hash warning event,  but now they are included right in the execution plan.  Not only that but also you can see which operator caused the spill , not just which statement.  Pretty damn handy. Another cause of performance problems relating to memory are memory grant waits.  Here is an informative write up on them,  but simply speaking , SQLServer has to allocate a certain amount of memory for each statement. If it is unable to you get a “memory grant wait”.  Once again there are other methods of analyzing these,  but the plan now shows these too. Don't worry that’s not real production code There is one other new warning that is of interest to me, “Unmatched Indexes”.  Once I find out the conditions under which that fires ill blog about it.

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  • In Social Relationship Management, the Spirit is Willing, but Execution is Weak

    - by Mike Stiles
    In our final talk in this series with Aberdeen’s Trip Kucera, we wanted to find out if enterprise organizations are actually doing anything about what they’re learning around the importance of communicating via social and using social listening for a deeper understanding of customers and prospects. We found out that if your brand is lagging behind, you’re not alone. Spotlight: How was Aberdeen able to find out if companies are putting their money where their mouth is when it comes to implementing social across the enterprise? Trip: One way to think about the relative challenges a business has in a given area is to look at the gap between “say” and “do.” The first of those words reveals the brand’s priorities, while the second reveals their ability to execute on those priorities. In Aberdeen’s research, we capture this by asking firms to rank the value of a set of activities from one on the low end to five on the high end. We then ask them to rank their ability to execute those same activities, again on a one to five, not effective to highly effective scale. Spotlight: And once you get their self-assessments, what is it you’re looking for? Trip: There are two things we’re looking for in this analysis. The first is we want to be able to identify the widest gaps between perception of value and execution. This suggests impediments to adoption or simply a high level of challenge, be it technical or otherwise. It may also suggest areas where we can expect future investment and innovation. Spotlight: So the biggest potential pain points surface, places where they know something is critical but also know they aren’t doing much about it. What’s the second thing you look for? Trip: The second thing we want to do is look at specific areas in which high-performing companies, the Leaders, are out-executing the Followers. This points to the business impact of these activities since Leaders are defined by a set of business performance metrics. Put another way, we’re correlating adoption of specific business competencies with performance, looking for what high-performers do differently. Spotlight: Ah ha, that tells us what steps the winners are taking that are making them winners. So what did you find out? Trip: Generally speaking, we see something of a glass curtain when it comes to the social relationship management execution gap. There isn’t a single social media activity in which more than 50% of respondents indicated effectiveness, which would be a 4 or 5 on that 1-5 scale. This despite the fact that 70% of firms indicate that generating positive social media mentions is valuable or very valuable, a 4 or 5 on our 1-5 scale. Spotlight: Well at least they get points for being honest. The verdict they’re giving themselves is that they just aren’t cutting it in these highly critical social development areas. Trip: And the widest gap is around directly engaging with customers and/or prospects on social networks, which 69% of firms rated as valuable but only 34% of companies say they are executing well. Perhaps even more interesting is that these two are interdependent since you’re most likely to generate goodwill on social through happy, engaged customers. This data also suggests that social is largely being used as a broadcast channel rather than for one-to-one engagement. As we’ve discussed previously, social is an inherently personal media. Spotlight: And if they’re still using it as a broadcast channel, that shows they still fail to understand the root of social and see it as just another outlet for their ads and push-messaging. That’s depressing. Trip: A second way to evaluate this data is by using Aberdeen’s performance benchmarking. The story is both a bit different, but consistent in its own way. The first thing we notice is that Leaders are more effective in their execution of several key social relationship management capabilities, namely generating positive mentions and engaging with “influencers” and customers. Based on the fact that Aberdeen uses a broad set of performance metrics to rank the respondents as either “Leaders” (top 35% in weighted performance) or “Followers” (bottom 65% in weighted performance), from website conversion to annual revenue growth, we can then correlated high social effectiveness with company performance. We can also connect the specific social capabilities used by Leaders with effectiveness. We spoke about a few of those key capabilities last time and also discuss them in a new report: Social Powers Activate: Engineering Social Engagement to Win the Hidden Sales Cycle. Spotlight: What all that tells me is there are rewards for making the effort and getting it right. That’s how you become a Leader. Trip: But there’s another part of the story, which is that overall effectiveness, even among Leaders, is muted. There’s just one activity in which more than a majority of Leaders cite high effectiveness, effectiveness being the generation of positive buzz. While 80% of Leaders indicate “directly engaging with customers” through social media channels is valuable, the highest rated activity among Leaders, only 42% say they’re effective. This gap even among Leaders shows the challenges still involved in effective social relationship management. @mikestilesPhoto: stock.xchng

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  • How can I work around SQL Server - Inline Table Value Function execution plan variation based on par

    - by Ovidiu Pacurar
    Here is the situation: I have a table value function with a datetime parameter ,lest's say tdf(p_date) , that filters about two million rows selecting those with column date smaller than p_date and computes some aggregate values on other columns. It works great but if p_date is a custom scalar value function (returning the end of day in my case) the execution plan is altered an the query goes from 1 sec to 1 minute execution time. A proof of concept table - 1K products, 2M rows: CREATE TABLE [dbo].[POC]( [Date] [datetime] NOT NULL, [idProduct] [int] NOT NULL, [Quantity] [int] NOT NULL ) ON [PRIMARY] The inline table value function: CREATE FUNCTION tdf (@p_date datetime) RETURNS TABLE AS RETURN ( SELECT idProduct, SUM(Quantity) AS TotalQuantity, max(Date) as LastDate FROM POC WHERE (Date < @p_date) GROUP BY idProduct ) The scalar value function: CREATE FUNCTION [dbo].[EndOfDay] (@date datetime) RETURNS datetime AS BEGIN DECLARE @res datetime SET @res=dateadd(second, -1, dateadd(day, 1, dateadd(ms, -datepart(ms, @date), dateadd(ss, -datepart(ss, @date), dateadd(mi,- datepart(mi,@date), dateadd(hh, -datepart(hh, @date), @date)))))) RETURN @res END Query 1 - Working great SELECT * FROM [dbo].[tdf] (getdate()) The end of execution plan: Stream Aggregate Cost 13% <--- Clustered Index Scan Cost 86% Query 2 - Not so great SELECT * FROM [dbo].[tdf] (dbo.EndOfDay(getdate())) The end of execution plan: Stream Aggregate Cost 4% <--- Filter Cost 12% <--- Clustered Index Scan Cost 86%

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  • Simple Query tuning with STATISTICS IO and Execution plans

    A great deal can be gleaned from the use of the STATISTICS IO and the execution plan, when you are checking that a query is performing properly. Josef Richberg, the current holder of the 'Exceptional DBA' award, explains how an apparently draconian IT policy turns out to be a useful ways of ensuring that Stored Procedures are carefully checked for performance before they are released

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  • CVE-2012-1182 Arbitrary code execution vulnerability in Samba

    - by chandan
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2012-1182 Arbitrary code execution vulnerability 10 Samba Solaris 10 SPARC: 119757-22 x86: 119758-22 Solaris 11 11/11 SRU 7.5 Solaris 9 SPARC: 114684-18 x86: 114685-18 This notification describes vulnerabilities fixed in third-party components that are included in Oracle's product distributions.Information about vulnerabilities affecting Oracle products can be found on Oracle Critical Patch Updates and Security Alerts page.

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  • CVE-2012-1714 TList 6 ActiveX control remote code execution vulnerability in Hyperion Financial Management

    - by chandan
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2012-1714 Remote code execution vulnerability 10 TList 6 ActiveX control Hyperion Financial Management 11.1.1.4 Contact Support Hyperion Financial Management 11.1.2.1.104 Microsoft Windows (32-bit) Microsoft Windows (64-bit) This notification describes vulnerabilities fixed in third-party components that are included in Sun's product distribution.Information about vulnerabilities affecting Oracle Sun products can be found on Oracle Critical Patch Updates and Security Alerts page.

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  • How do I make this ad execution?

    - by Maggie
    I am doing research on replicating an ad execution - http://www.digitalbuzzblog.com/gol-airlines-mobile-controlled-banner-game/ It's a simple "game" involving using the phone as a forward/back/left/right controller for a car in flash on the internet. I've started reading on P2P, but I'm finding such a vast amount of information and non specific to what I need that it's hard for me to sort through. Does anyone know any tutorials or can shed some light on how I might go about making a very simple mobile controller for a flash game?

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  • Exporting Execution Plans - SQL Spackle

    A short SQL Spackle article to fill in your knowledge of SQL Server. In this one, Jason Brimhall shows how to export execution plans when you ask for query tuning help. Optimize SQL Server performance“With SQL Monitor, we can be proactive in our optimization process, instead of waiting until a customer reports a problem,” John Trumbul, Sr. Software Engineer. Optimize your servers with a free trial.

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  • CVE-2012-4245 Arbitrary code execution vulnerability in Gimp

    - by Umang_D
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2012-4245 Arbitrary code execution vulnerability 6.8 Gimp Solaris 11 11/11 SRU 12.4 Solaris 10 Contact Support This notification describes vulnerabilities fixed in third-party components that are included in Oracle's product distributions.Information about vulnerabilities affecting Oracle products can be found on Oracle Critical Patch Updates and Security Alerts page.

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  • Deferred execution and eager evaluation

    - by babu M
    Hi Could you please give me an example for Deferred execution with eager evaluation in C#? I read from MSDN that deferred execution in LINQ can be implemented either with lazy or eager evaluation...i could find examples in the internet for Deferred execution with lazy evaluation ,however i could not find any example for Deferred execution with eager evaluation....please help me....its urgent... Moreover,how deferred execution differs from lazy evaluation?In my point of view,both are looking same.Could you please provide any example for this too?

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  • SQL SERVER – Merge Operations – Insert, Update, Delete in Single Execution

    - by pinaldave
    This blog post is written in response to T-SQL Tuesday hosted by Jorge Segarra (aka SQLChicken). I have been very active using these Merge operations in my development. However, I have found out from my consultancy work and friends that these amazing operations are not utilized by them most of the time. Here is my attempt to bring the necessity of using the Merge Operation to surface one more time. MERGE is a new feature that provides an efficient way to do multiple DML operations. In earlier versions of SQL Server, we had to write separate statements to INSERT, UPDATE, or DELETE data based on certain conditions; however, at present, by using the MERGE statement, we can include the logic of such data changes in one statement that even checks when the data is matched and then just update it, and similarly, when the data is unmatched, it is inserted. One of the most important advantages of MERGE statement is that the entire data are read and processed only once. In earlier versions, three different statements had to be written to process three different activities (INSERT, UPDATE or DELETE); however, by using MERGE statement, all the update activities can be done in one pass of database table. I have written about these Merge Operations earlier in my blog post over here SQL SERVER – 2008 – Introduction to Merge Statement – One Statement for INSERT, UPDATE, DELETE. I was asked by one of the readers that how do we know that this operator was doing everything in single pass and was not calling this Merge Operator multiple times. Let us run the same example which I have used earlier; I am listing the same here again for convenience. --Let’s create Student Details and StudentTotalMarks and inserted some records. USE tempdb GO CREATE TABLE StudentDetails ( StudentID INTEGER PRIMARY KEY, StudentName VARCHAR(15) ) GO INSERT INTO StudentDetails VALUES(1,'SMITH') INSERT INTO StudentDetails VALUES(2,'ALLEN') INSERT INTO StudentDetails VALUES(3,'JONES') INSERT INTO StudentDetails VALUES(4,'MARTIN') INSERT INTO StudentDetails VALUES(5,'JAMES') GO CREATE TABLE StudentTotalMarks ( StudentID INTEGER REFERENCES StudentDetails, StudentMarks INTEGER ) GO INSERT INTO StudentTotalMarks VALUES(1,230) INSERT INTO StudentTotalMarks VALUES(2,255) INSERT INTO StudentTotalMarks VALUES(3,200) GO -- Select from Table SELECT * FROM StudentDetails GO SELECT * FROM StudentTotalMarks GO -- Merge Statement MERGE StudentTotalMarks AS stm USING (SELECT StudentID,StudentName FROM StudentDetails) AS sd ON stm.StudentID = sd.StudentID WHEN MATCHED AND stm.StudentMarks > 250 THEN DELETE WHEN MATCHED THEN UPDATE SET stm.StudentMarks = stm.StudentMarks + 25 WHEN NOT MATCHED THEN INSERT(StudentID,StudentMarks) VALUES(sd.StudentID,25); GO -- Select from Table SELECT * FROM StudentDetails GO SELECT * FROM StudentTotalMarks GO -- Clean up DROP TABLE StudentDetails GO DROP TABLE StudentTotalMarks GO The Merge Join performs very well and the following result is obtained. Let us check the execution plan for the merge operator. You can click on following image to enlarge it. Let us evaluate the execution plan for the Table Merge Operator only. We can clearly see that the Number of Executions property suggests value 1. Which is quite clear that in a single PASS, the Merge Operation completes the operations of Insert, Update and Delete. I strongly suggest you all to use this operation, if possible, in your development. I have seen this operation implemented in many data warehousing applications. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Joins, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Merge

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  • Execution plan issue requires reset on SQL Server 2005, how to determine cause?

    - by Tony Brandner
    We have a web application that delivers training to thousands of corporate students running on top of SQL Server 2005. Recently, we started seeing that a single specific query in the application went from 1 second to about 30 seconds in terms of execution time. The application started throwing timeouts in that area. Our first thought was that we may have incorrect indexes, so we reviewed the tables and indexes. However, similar queries elsewhere in the application also run quickly. Reviewing the indexes showed us that they were configured as expected. We were able to narrow it down to a single query, not a stored procedure. Running this query in SQL Studio also runs quickly. We tried running the application in a different server environment. So a different web server with the same query, parameters and database. The query still ran slow. The query is a fairly large one related to determining a student's current list of training. It includes joins and left joins on a dozen tables and subqueries. A few of the tables are fairly large (hundreds of thousands of rows) and some of the other tables are small lookup tables. The query uses a grouping clause and a few where conditions. A few of the tables are quite active and the contents change often but the volume of added rows doesn't seem extreme. These symptoms led us to consider the execution plan. First off, as soon as we reset the execution plan cache with the SQL command 'DBCC FREEPROCCACHE', the problem went away. Unfortunately, the problem started to reoccur within a few days. The problem has continued to plague us for awhile now. It's usually the same query, but we did appear to see the problem occur in another single query recently. It happens enough to be a nuisance. We're having a heck of a time trying to fix it since we can't reproduce it in any other environment other than production. I have downloaded the High Availability guide from Red Gate and I read up more on execution plans. I hope to run the profiler on the live server, but I'm a bit concerned about impact. I would like to ask - what is the best way to figure out what is triggering this problem? Has anyone else seen this same issue?

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  • ssrs: the report execution has expired or cannot be found

    - by Alex Bransky
    Today I got an exception in a report using SQL Server Reporting Services 2008 R2, but only when attempting to go to the last page of a large report: The report execution sgjahs45wg5vkmi05lq4zaee has expired or cannot be found.;Digging into the logs I found this:library!ReportServer_0-47!149c!12/06/2012-12:37:58:: e ERROR: Throwing Microsoft.ReportingServices.Diagnostics.Utilities.ReportServerStorageException: , An error occurred within the report server database.  This may be due to a connection failure, timeout or low disk condition within the database.;I knew it wasn't a network problem or timeout because I could repeat the problem at will.  I checked the disk space and that seemed fine as well.  The real issue was a lack of memory on the database server that had the ReportServer database.  Restarting the SQL Server engine freed up plenty of RAM and the problem immediately went away.

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  • ClearTrace Shows Execution History

    - by Bill Graziano
    The latest release of ClearTrace (Build 38) now shows the execution history of a particular statement. You’ll need to save the trace files to a trace group instead of just using the default.  That’s as easy as typing something into the trace group name when you upload the trace.  I usually put the server name in this field. Build 38 also re-enables support for statement level events.  If your trace includes RPC:StmtCompleted or SQL:StmtCompleted events those will be processed and save.  In the results tab you can choose to view statement level or batch level events.  Please note that saving statement level events in a trace can generate HUGE trace files very quickly.

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  • How can I schedule execution of a program?

    - by Bakhtiyor
    Let's say I have a small "Hello World" Java program compiled in my home directory. I can run it with java helloWorld from my home directory and it executes without any problem. Now I need to schedule to execute this program let's say after 10mins from now. So, I am executing following commands on console: at now+10min warning: commands will be executed using /bin/sh at> java helloWorld Press CTRL+D to finish So it is scheduled properly as I can see it with at -l command. But at this time nothing happens. Why? What is wrong with it? Because, if instead of scheduling the execution my own program I schedule executing of gedit command it opens it at a specified time. But with my own program it doesn't perform anything. How can I change the situation?

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  • Entity Framework: Connecting to a mdf user database file via localDB during script execution

    - by Marko Apfel
    Problem If you run the “Generate database from model” wizard and execute the generated script the destination database could be the wrong one (for instance master of the SQL Server). Solution To use an own mdf attachable user database some connection information must specified during script execution. Execute your script opens the dialog “Connect to Server”. Press “Options” and go to the second tab “Connection Properties”. Select “Browse server” in the “Connect to database” dropdown box: Confirm the information dialog with “Yes”. In the following dialog you could choose your user database. Now the schema is created in the user database.

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  • Chrome 10 rend possible l'exécution d'applications Web en arrière plan, Google publie un exemple

    Chrome 10 rend possible l'exécution d'applications Web en arrière plan Même quand le navigateur est fermé, Google publie un exemple Mise à jour du 24/02/11 par Gordon Fowler Google vient de dévoiler une nouvelle fonctionnalité disponible dans la version 10 (en beta) de son navigateur Chrome. La fonctionnalité, baptisée « Background Pages », bien que n'ayant pas été mise en avant lors de la sortie Chrome 10, est bel et bien là. Elle permet d'exécuter des pages Web en arrière-plan de façon totalement transparente pour l'utilisateur. Certaines applications (qualifiées « d'applications d'arrière plan ») peuvent ainsi continuer à tourn...

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  • Web Page Execution Internals

    - by octopusgrabbus
    My question is what is the subject area that covers web page execution/loading. I am looking to purchase a book by subject area that covers when things execute or load in a web page, whether it's straight html, html and Javascript, or a PHP page. Is that topic covered by a detailed html book, or should I expect to find information like that in a JavaScript of PHP book? I understand that PHP and Perl execute on the server and that Javascript is client side, and I know there is a lot of on-line documentation describing <html>, <head>, <body>, and so on. I'm just wondering what subject area a book would be in to cover all that, not a discussion of the best book or someone's favorite book, but the subject area.

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  • Transparent PHP script execution using mod_rewrite

    - by tori3852
    I am looking for a solution for this a problem: I need that every HTTP request (method is irrelevant) in Apache http server would be served only after execution of specific PHP script. This is needed because I need to gather some information about requests, etc. As far as I understand - this could be achieved using mod_rewrite module. So far I have done this (in .htaccess file): RewriteEngine on RewriteRule ^(.*)$ script.php [C] script.php is executed, but I need that after this original request would be executed. Thanks - any help is appreciated.

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  • Free eBook: SQL Server Execution Plans, Second Edition

    Every day, out in the various online forums devoted to SQL Server, and on Twitter, the same types of questions come up repeatedly: Why is this query running slowly? Why is SQL Server ignoring my index? Why does this query run quickly sometimes and slowly at others? My response is the same in each case: have you looked at the execution plan? "A real time saver" Andy Doyle, Head of IT ServicesAndy and his team saved time by automating backup and restores with SQL Backup Pro. Find out how much time you could save. Download a free trial now.

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  • ParallelWork: Feature rich multithreaded fluent task execution library for WPF

    - by oazabir
    ParallelWork is an open source free helper class that lets you run multiple work in parallel threads, get success, failure and progress update on the WPF UI thread, wait for work to complete, abort all work (in case of shutdown), queue work to run after certain time, chain parallel work one after another. It’s more convenient than using .NET’s BackgroundWorker because you don’t have to declare one component per work, nor do you need to declare event handlers to receive notification and carry additional data through private variables. You can safely pass objects produced from different thread to the success callback. Moreover, you can wait for work to complete before you do certain operation and you can abort all parallel work while they are in-flight. If you are building highly responsive WPF UI where you have to carry out multiple job in parallel yet want full control over those parallel jobs completion and cancellation, then the ParallelWork library is the right solution for you. I am using the ParallelWork library in my PlantUmlEditor project, which is a free open source UML editor built on WPF. You can see some realistic use of the ParallelWork library there. Moreover, the test project comes with 400 lines of Behavior Driven Development flavored tests, that confirms it really does what it says it does. The source code of the library is part of the “Utilities” project in PlantUmlEditor source code hosted at Google Code. The library comes in two flavors, one is the ParallelWork static class, which has a collection of static methods that you can call. Another is the Start class, which is a fluent wrapper over the ParallelWork class to make it more readable and aesthetically pleasing code. ParallelWork allows you to start work immediately on separate thread or you can queue a work to start after some duration. You can start an immediate work in a new thread using the following methods: void StartNow(Action doWork, Action onComplete) void StartNow(Action doWork, Action onComplete, Action<Exception> failed) For example, ParallelWork.StartNow(() => { workStartedAt = DateTime.Now; Thread.Sleep(howLongWorkTakes); }, () => { workEndedAt = DateTime.Now; }); Or you can use the fluent way Start.Work: Start.Work(() => { workStartedAt = DateTime.Now; Thread.Sleep(howLongWorkTakes); }) .OnComplete(() => { workCompletedAt = DateTime.Now; }) .Run(); Besides simple execution of work on a parallel thread, you can have the parallel thread produce some object and then pass it to the success callback by using these overloads: void StartNow<T>(Func<T> doWork, Action<T> onComplete) void StartNow<T>(Func<T> doWork, Action<T> onComplete, Action<Exception> fail) For example, ParallelWork.StartNow<Dictionary<string, string>>( () => { test = new Dictionary<string,string>(); test.Add("test", "test"); return test; }, (result) => { Assert.True(result.ContainsKey("test")); }); Or, the fluent way: Start<Dictionary<string, string>>.Work(() => { test = new Dictionary<string, string>(); test.Add("test", "test"); return test; }) .OnComplete((result) => { Assert.True(result.ContainsKey("test")); }) .Run(); You can also start a work to happen after some time using these methods: DispatcherTimer StartAfter(Action onComplete, TimeSpan duration) DispatcherTimer StartAfter(Action doWork,Action onComplete,TimeSpan duration) You can use this to perform some timed operation on the UI thread, as well as perform some operation in separate thread after some time. ParallelWork.StartAfter( () => { workStartedAt = DateTime.Now; Thread.Sleep(howLongWorkTakes); }, () => { workCompletedAt = DateTime.Now; }, waitDuration); Or, the fluent way: Start.Work(() => { workStartedAt = DateTime.Now; Thread.Sleep(howLongWorkTakes); }) .OnComplete(() => { workCompletedAt = DateTime.Now; }) .RunAfter(waitDuration);   There are several overloads of these functions to have a exception callback for handling exceptions or get progress update from background thread while work is in progress. For example, I use it in my PlantUmlEditor to perform background update of the application. // Check if there's a newer version of the app Start<bool>.Work(() => { return UpdateChecker.HasUpdate(Settings.Default.DownloadUrl); }) .OnComplete((hasUpdate) => { if (hasUpdate) { if (MessageBox.Show(Window.GetWindow(me), "There's a newer version available. Do you want to download and install?", "New version available", MessageBoxButton.YesNo, MessageBoxImage.Information) == MessageBoxResult.Yes) { ParallelWork.StartNow(() => { var tempPath = System.IO.Path.Combine( Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), Settings.Default.SetupExeName); UpdateChecker.DownloadLatestUpdate(Settings.Default.DownloadUrl, tempPath); }, () => { }, (x) => { MessageBox.Show(Window.GetWindow(me), "Download failed. When you run next time, it will try downloading again.", "Download failed", MessageBoxButton.OK, MessageBoxImage.Warning); }); } } }) .OnException((x) => { MessageBox.Show(Window.GetWindow(me), x.Message, "Download failed", MessageBoxButton.OK, MessageBoxImage.Exclamation); }); The above code shows you how to get exception callbacks on the UI thread so that you can take necessary actions on the UI. Moreover, it shows how you can chain two parallel works to happen one after another. Sometimes you want to do some parallel work when user does some activity on the UI. For example, you might want to save file in an editor while user is typing every 10 second. In such case, you need to make sure you don’t start another parallel work every 10 seconds while a work is already queued. You need to make sure you start a new work only when there’s no other background work going on. Here’s how you can do it: private void ContentEditor_TextChanged(object sender, EventArgs e) { if (!ParallelWork.IsAnyWorkRunning()) { ParallelWork.StartAfter(SaveAndRefreshDiagram, TimeSpan.FromSeconds(10)); } } If you want to shutdown your application and want to make sure no parallel work is going on, then you can call the StopAll() method. ParallelWork.StopAll(); If you want to wait for parallel works to complete without a timeout, then you can call the WaitForAllWork(TimeSpan timeout). It will block the current thread until the all parallel work completes or the timeout period elapses. result = ParallelWork.WaitForAllWork(TimeSpan.FromSeconds(1)); The result is true, if all parallel work completed. If it’s false, then the timeout period elapsed and all parallel work did not complete. For details how this library is built and how it works, please read the following codeproject article: ParallelWork: Feature rich multithreaded fluent task execution library for WPF http://www.codeproject.com/KB/WPF/parallelwork.aspx If you like the article, please vote for me.

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  • Using SQL Execution Plans to discover the Swedish alphabet

    - by Rob Farley
    SQL Server is quite remarkable in a bunch of ways. In this post, I’m using the way that the Query Optimizer handles LIKE to keep it SARGable, the Execution Plans that result, Collations, and PowerShell to come up with the Swedish alphabet. SARGability is the ability to seek for items in an index according to a particular set of criteria. If you don’t have SARGability in play, you need to scan the whole index (or table if you don’t have an index). For example, I can find myself in the phonebook easily, because it’s sorted by LastName and I can find Farley in there by moving to the Fs, and so on. I can’t find everyone in my suburb easily, because the phonebook isn’t sorted that way. I can’t even find people who have six letters in their last name, because also the book is sorted by LastName, it’s not sorted by LEN(LastName). This is all stuff I’ve looked at before, including in the talk I gave at SQLBits in October 2010. If I try to find everyone who’s names start with F, I can do that using a query a bit like: SELECT LastName FROM dbo.PhoneBook WHERE LEFT(LastName,1) = 'F'; Unfortunately, the Query Optimizer doesn’t realise that all the entries that satisfy LEFT(LastName,1) = 'F' will be together, and it has to scan the whole table to find them. But if I write: SELECT LastName FROM dbo.PhoneBook WHERE LastName LIKE 'F%'; then SQL is smart enough to understand this, and performs an Index Seek instead. To see why, I look further into the plan, in particular, the properties of the Index Seek operator. The ToolTip shows me what I’m after: You’ll see that it does a Seek to find any entries that are at least F, but not yet G. There’s an extra Predicate in there (a Residual Predicate if you like), which checks that each LastName is really LIKE F% – I suppose it doesn’t consider that the Seek Predicate is quite enough – but most of the benefit is seen by its working out the Seek Predicate, filtering to just the “at least F but not yet G” section of the data. This got me curious though, particularly about where the G comes from, and whether I could leverage it to create the Swedish alphabet. I know that in the Swedish language, there are three extra letters that appear at the end of the alphabet. One of them is ä that appears in the word Västerås. It turns out that Västerås is quite hard to find in an index when you’re looking it up in a Swedish map. I talked about this briefly in my five-minute talk on Collation from SQLPASS (the one which was slightly less than serious). So by looking at the plan, I can work out what the next letter is in the alphabet of the collation used by the column. In other words, if my alphabet were Swedish, I’d be able to tell what the next letter after F is – just in case it’s not G. It turns out it is… Yes, the Swedish letter after F is G. But I worked this out by using a copy of my PhoneBook table that used the Finnish_Swedish_CI_AI collation. I couldn’t find how the Query Optimizer calculates the G, and my friend Paul White (@SQL_Kiwi) tells me that it’s frustratingly internal to the QO. He’s particularly smart, even if he is from New Zealand. To investigate further, I decided to do some PowerShell, leveraging the Get-SqlPlan function that I blogged about recently (make sure you also have the SqlServerCmdletSnapin100 snap-in added). I started by indicating that I was going to use Finnish_Swedish_CI_AI as my collation of choice, and that I’d start whichever letter cam straight after the number 9. I figure that this is a cheat’s way of guessing the first letter of the alphabet (but it doesn’t actually work in Unicode – luckily I’m using varchar not nvarchar. Actually, there are a few aspects of this code that only work using ASCII, so apologies if you were wanting to apply it to Greek, Japanese, etc). I also initialised my $alphabet variable. $collation = 'Finnish_Swedish_CI_AI'; $firstletter = '9'; $alphabet = ''; Now I created the table for my test. A single field would do, and putting a Clustered Index on it would suffice for the Seeks. Invoke-Sqlcmd -server . -data tempdb -query "create table dbo.collation_test (col varchar(10) collate $collation primary key);" Now I get into the looping. $c = $firstletter; $stillgoing = $true; while ($stillgoing) { I construct the query I want, seeking for entries which start with whatever $c has reached, and get the plan for it: $query = "select col from dbo.collation_test where col like '$($c)%';"; [xml] $pl = get-sqlplan $query "." "tempdb"; At this point, my $pl variable is a scary piece of XML, representing the execution plan. A bit of hunting through it showed me that the EndRange element contained what I was after, and that if it contained NULL, then I was done. $stillgoing = ($pl.ShowPlanXML.BatchSequence.Batch.Statements.StmtSimple.QueryPlan.RelOp.IndexScan.SeekPredicates.SeekPredicateNew.SeekKeys.EndRange -ne $null); Now I could grab the value out of it (which came with apostrophes that needed stripping), and append that to my $alphabet variable.   if ($stillgoing)   {  $c=$pl.ShowPlanXML.BatchSequence.Batch.Statements.StmtSimple.QueryPlan.RelOp.IndexScan.SeekPredicates.SeekPredicateNew.SeekKeys.EndRange.RangeExpressions.ScalarOperator.ScalarString.Replace("'","");     $alphabet += $c;   } Finally, finishing the loop, dropping the table, and showing my alphabet! } Invoke-Sqlcmd -server . -data tempdb -query "drop table dbo.collation_test;"; $alphabet; When I run all this, I see that the Swedish alphabet is ABCDEFGHIJKLMNOPQRSTUVXYZÅÄÖ, which matches what I see at Wikipedia. Interesting to see that the letters on the end are still there, even with Case Insensitivity. Turns out they’re not just “letters with accents”, they’re letters in their own right. I’m sure you gave up reading long ago, and really aren’t that fazed about the idea of doing this using PowerShell. I chose PowerShell because I’d already come up with an easy way of grabbing the estimated plan for a query, and PowerShell does allow for easy navigation of XML. I find the most interesting aspect of this as the fact that the Query Optimizer uses the next letter of the alphabet to maintain the SARGability of LIKE. I’m hoping they do something similar for a whole bunch of operations. Oh, and the fact that you know how to find stuff in the IKEA catalogue. Footnote: If you are interested in whether this works in other languages, you might want to consider the following screenshot, which shows that in principle, it should work with Japanese. It might be a bit harder to run this in PowerShell though, as I’m not sure how it translates. In Hiragana, the Japanese alphabet starts ?, ?, ?, ?, ?, ...

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  • Same SELECT used in an INSERT has different execution plan

    - by amacias
    A customer complained that a query and its INSERT counterpart had different execution plans, and of course, the INSERT was slower. First lets look at the SELECT : SELECT ua_tr_rundatetime,        ua_ch_treatmentcode,        ua_tr_treatmentcode,        ua_ch_cellid,        ua_tr_cellid FROM   (SELECT DISTINCT CH.treatmentcode AS UA_CH_TREATMENTCODE,                         CH.cellid        AS UA_CH_CELLID         FROM    CH,                 DL         WHERE  CH.contactdatetime > SYSDATE - 5                AND CH.treatmentcode = DL.treatmentcode) CH_CELLS,        (SELECT DISTINCT T.treatmentcode AS UA_TR_TREATMENTCODE,                         T.cellid        AS UA_TR_CELLID,                         T.rundatetime   AS UA_TR_RUNDATETIME         FROM    T,                 DL         WHERE  T.treatmentcode = DL.treatmentcode) TRT_CELLS WHERE  CH_CELLS.ua_ch_treatmentcode(+) = TRT_CELLS.ua_tr_treatmentcode;  The query has 2 DISTINCT subqueries.  The execution plan shows one with DISTICT Placement transformation applied and not the other. The view in Step 5 has the prefix VW_DTP which means DISTINCT Placement. -------------------------------------------------------------------- | Id  | Operation                    | Name            | Cost (%CPU) -------------------------------------------------------------------- |   0 | SELECT STATEMENT             |                 |   272K(100) |*  1 |  HASH JOIN OUTER             |                 |   272K  (1) |   2 |   VIEW                       |                 |  4408   (1) |   3 |    HASH UNIQUE               |                 |  4408   (1) |*  4 |     HASH JOIN                |                 |  4407   (1) |   5 |      VIEW                    | VW_DTP_48BAF62C |  1660   (2) |   6 |       HASH UNIQUE            |                 |  1660   (2) |   7 |        TABLE ACCESS FULL     | DL              |  1644   (1) |   8 |      TABLE ACCESS FULL       | T               |  2744   (1) |   9 |   VIEW                       |                 |   267K  (1) |  10 |    HASH UNIQUE               |                 |   267K  (1) |* 11 |     HASH JOIN                |                 |   267K  (1) |  12 |      PARTITION RANGE ITERATOR|                 |   266K  (1) |* 13 |       TABLE ACCESS FULL      | CH              |   266K  (1) |  14 |      TABLE ACCESS FULL       | DL              |  1644   (1) -------------------------------------------------------------------- Query Block Name / Object Alias (identified by operation id): -------------------------------------------------------------    1 - SEL$1    2 - SEL$AF418D5F / TRT_CELLS@SEL$1    3 - SEL$AF418D5F    5 - SEL$F6AECEDE / VW_DTP_48BAF62C@SEL$48BAF62C    6 - SEL$F6AECEDE    7 - SEL$F6AECEDE / DL@SEL$3    8 - SEL$AF418D5F / T@SEL$3    9 - SEL$2        / CH_CELLS@SEL$1   10 - SEL$2   13 - SEL$2        / CH@SEL$2   14 - SEL$2        / DL@SEL$2 Predicate Information (identified by operation id): ---------------------------------------------------    1 - access("CH_CELLS"."UA_CH_TREATMENTCODE"="TRT_CELLS"."UA_TR_TREATMENTCODE")    4 - access("T"."TREATMENTCODE"="ITEM_1")   11 - access("CH"."TREATMENTCODE"="DL"."TREATMENTCODE")   13 - filter("CH"."CONTACTDATETIME">SYSDATE@!-5) The outline shows PLACE_DISTINCT(@"SEL$3" "DL"@"SEL$3") indicating that the QB3 is the one that got the transformation. Outline Data -------------   /*+       BEGIN_OUTLINE_DATA       IGNORE_OPTIM_EMBEDDED_HINTS       OPTIMIZER_FEATURES_ENABLE('11.2.0.3')       DB_VERSION('11.2.0.3')       ALL_ROWS       OUTLINE_LEAF(@"SEL$2")       OUTLINE_LEAF(@"SEL$F6AECEDE")       OUTLINE_LEAF(@"SEL$AF418D5F") PLACE_DISTINCT(@"SEL$3" "DL"@"SEL$3")       OUTLINE_LEAF(@"SEL$1")       OUTLINE(@"SEL$48BAF62C")       OUTLINE(@"SEL$3")       NO_ACCESS(@"SEL$1" "TRT_CELLS"@"SEL$1")       NO_ACCESS(@"SEL$1" "CH_CELLS"@"SEL$1")       LEADING(@"SEL$1" "TRT_CELLS"@"SEL$1" "CH_CELLS"@"SEL$1")       USE_HASH(@"SEL$1" "CH_CELLS"@"SEL$1")       FULL(@"SEL$2" "CH"@"SEL$2")       FULL(@"SEL$2" "DL"@"SEL$2")       LEADING(@"SEL$2" "CH"@"SEL$2" "DL"@"SEL$2")       USE_HASH(@"SEL$2" "DL"@"SEL$2")       USE_HASH_AGGREGATION(@"SEL$2")       NO_ACCESS(@"SEL$AF418D5F" "VW_DTP_48BAF62C"@"SEL$48BAF62C")       FULL(@"SEL$AF418D5F" "T"@"SEL$3")       LEADING(@"SEL$AF418D5F" "VW_DTP_48BAF62C"@"SEL$48BAF62C" "T"@"SEL$3")       USE_HASH(@"SEL$AF418D5F" "T"@"SEL$3")       USE_HASH_AGGREGATION(@"SEL$AF418D5F")       FULL(@"SEL$F6AECEDE" "DL"@"SEL$3")       USE_HASH_AGGREGATION(@"SEL$F6AECEDE")       END_OUTLINE_DATA   */ The 10053 shows there is a comparative of cost with and without the transformation. This means the transformation belongs to Cost-Based Query Transformations (CBQT). In SEL$3 the optimization of the query block without the transformation is 6659.73 and with the transformation is 4408.41 so the transformation is kept. GBP/DP: Checking validity of GBP/DP for query block SEL$3 (#3) DP: Checking validity of distinct placement for query block SEL$3 (#3) DP: Using search type: linear DP: Considering distinct placement on query block SEL$3 (#3) DP: Starting iteration 1, state space = (5) : (0) DP: Original query DP: Costing query block. DP: Updated best state, Cost = 6659.73 DP: Starting iteration 2, state space = (5) : (1) DP: Using DP transformation in this iteration. DP: Transformed query DP: Costing query block. DP: Updated best state, Cost = 4408.41 DP: Doing DP on the original QB. DP: Doing DP on the preserved QB. In SEL$2 the cost without the transformation is less than with it so it is not kept. GBP/DP: Checking validity of GBP/DP for query block SEL$2 (#2) DP: Checking validity of distinct placement for query block SEL$2 (#2) DP: Using search type: linear DP: Considering distinct placement on query block SEL$2 (#2) DP: Starting iteration 1, state space = (3) : (0) DP: Original query DP: Costing query block. DP: Updated best state, Cost = 267936.93 DP: Starting iteration 2, state space = (3) : (1) DP: Using DP transformation in this iteration. DP: Transformed query DP: Costing query block. DP: Not update best state, Cost = 267951.66 To the same query an INSERT INTO is added and the result is a very different execution plan. INSERT  INTO cc               (ua_tr_rundatetime,                ua_ch_treatmentcode,                ua_tr_treatmentcode,                ua_ch_cellid,                ua_tr_cellid)SELECT ua_tr_rundatetime,       ua_ch_treatmentcode,       ua_tr_treatmentcode,       ua_ch_cellid,       ua_tr_cellidFROM   (SELECT DISTINCT CH.treatmentcode AS UA_CH_TREATMENTCODE,                        CH.cellid        AS UA_CH_CELLID        FROM    CH,                DL        WHERE  CH.contactdatetime > SYSDATE - 5               AND CH.treatmentcode = DL.treatmentcode) CH_CELLS,       (SELECT DISTINCT T.treatmentcode AS UA_TR_TREATMENTCODE,                        T.cellid        AS UA_TR_CELLID,                        T.rundatetime   AS UA_TR_RUNDATETIME        FROM    T,                DL        WHERE  T.treatmentcode = DL.treatmentcode) TRT_CELLSWHERE  CH_CELLS.ua_ch_treatmentcode(+) = TRT_CELLS.ua_tr_treatmentcode;----------------------------------------------------------| Id  | Operation                     | Name | Cost (%CPU)----------------------------------------------------------|   0 | INSERT STATEMENT              |      |   274K(100)|   1 |  LOAD TABLE CONVENTIONAL      |      |            |*  2 |   HASH JOIN OUTER             |      |   274K  (1)|   3 |    VIEW                       |      |  6660   (1)|   4 |     SORT UNIQUE               |      |  6660   (1)|*  5 |      HASH JOIN                |      |  6659   (1)|   6 |       TABLE ACCESS FULL       | DL   |  1644   (1)|   7 |       TABLE ACCESS FULL       | T    |  2744   (1)|   8 |    VIEW                       |      |   267K  (1)|   9 |     SORT UNIQUE               |      |   267K  (1)|* 10 |      HASH JOIN                |      |   267K  (1)|  11 |       PARTITION RANGE ITERATOR|      |   266K  (1)|* 12 |        TABLE ACCESS FULL      | CH   |   266K  (1)|  13 |       TABLE ACCESS FULL       | DL   |  1644   (1)----------------------------------------------------------Query Block Name / Object Alias (identified by operation id):-------------------------------------------------------------   1 - SEL$1   3 - SEL$3 / TRT_CELLS@SEL$1   4 - SEL$3   6 - SEL$3 / DL@SEL$3   7 - SEL$3 / T@SEL$3   8 - SEL$2 / CH_CELLS@SEL$1   9 - SEL$2  12 - SEL$2 / CH@SEL$2  13 - SEL$2 / DL@SEL$2Predicate Information (identified by operation id):---------------------------------------------------   2 - access("CH_CELLS"."UA_CH_TREATMENTCODE"="TRT_CELLS"."UA_TR_TREATMENTCODE")   5 - access("T"."TREATMENTCODE"="DL"."TREATMENTCODE")  10 - access("CH"."TREATMENTCODE"="DL"."TREATMENTCODE")  12 - filter("CH"."CONTACTDATETIME">SYSDATE@!-5)Outline Data-------------  /*+      BEGIN_OUTLINE_DATA      IGNORE_OPTIM_EMBEDDED_HINTS      OPTIMIZER_FEATURES_ENABLE('11.2.0.3')      DB_VERSION('11.2.0.3')      ALL_ROWS      OUTLINE_LEAF(@"SEL$2")      OUTLINE_LEAF(@"SEL$3")      OUTLINE_LEAF(@"SEL$1")      OUTLINE_LEAF(@"INS$1")      FULL(@"INS$1" "CC"@"INS$1")      NO_ACCESS(@"SEL$1" "TRT_CELLS"@"SEL$1")      NO_ACCESS(@"SEL$1" "CH_CELLS"@"SEL$1")      LEADING(@"SEL$1" "TRT_CELLS"@"SEL$1" "CH_CELLS"@"SEL$1")      USE_HASH(@"SEL$1" "CH_CELLS"@"SEL$1")      FULL(@"SEL$2" "CH"@"SEL$2")      FULL(@"SEL$2" "DL"@"SEL$2")      LEADING(@"SEL$2" "CH"@"SEL$2" "DL"@"SEL$2")      USE_HASH(@"SEL$2" "DL"@"SEL$2")      USE_HASH_AGGREGATION(@"SEL$2")      FULL(@"SEL$3" "DL"@"SEL$3")      FULL(@"SEL$3" "T"@"SEL$3")      LEADING(@"SEL$3" "DL"@"SEL$3" "T"@"SEL$3")      USE_HASH(@"SEL$3" "T"@"SEL$3")      USE_HASH_AGGREGATION(@"SEL$3")      END_OUTLINE_DATA  */ There is no DISTINCT Placement view and no hint.The 10053 trace shows a new legend "DP: Bypassed: Not SELECT"implying that this is a transformation that it is possible only for SELECTs. GBP/DP: Checking validity of GBP/DP for query block SEL$3 (#4) DP: Checking validity of distinct placement for query block SEL$3 (#4) DP: Bypassed: Not SELECT. GBP/DP: Checking validity of GBP/DP for query block SEL$2 (#3) DP: Checking validity of distinct placement for query block SEL$2 (#3) DP: Bypassed: Not SELECT. In 12.1 (and hopefully in 11.2.0.4 when released) the restriction on applying CBQT to some DMLs and DDLs (like CTAS) is lifted.This is documented in BugTag Note:10013899.8 Allow CBQT for some DML / DDLAnd interestingly enough, it is possible to have a one-off patch in 11.2.0.3. SQL> select DESCRIPTION,OPTIMIZER_FEATURE_ENABLE,IS_DEFAULT     2  from v$system_fix_control where BUGNO='10013899'; DESCRIPTION ---------------------------------------------------------------- OPTIMIZER_FEATURE_ENABLE  IS_DEFAULT ------------------------- ---------- enable some transformations for DDL and DML statements 11.2.0.4                           1

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