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  • Poor performance after reinstalling to a USB drive

    - by anonymous
    I am currently running Ubuntu 11.10 off of a SanDisk 16GB USB. I installed it using a Live USB with the following partition configuration: 6GB Primary /dos FAT32 5GB Logical / ext4 5GB Logical /home ext4 I don't have a hard disk, and don't see myself getting one anytime soon. I rely solely on this 16GB, and two other 4GB USBs, one of which I used as the LiveUSB. I bring the USBs around, and even use the install at work. I previously used an install that used a swap file. It functioned fine for the most part, save for a few slow moments, but I came across this post, and it got me thinking about my USB's life, so I reinstalled with the current config. My problem now is that it is slower. Applications like Firefox would hang more often. In my previous setup (the automatically partitioned setup), Firefox would start hanging if I was running an unzip or install task on the same partition as /. Now however, it would hang if I had another window open i.e. the system settings window. My guess is that it may have something to do with the swap file or the install being on a Logical partition rather than a Primary partition, but I don't know. Any insight as to why it has slowed down?

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  • SQL Server Prefetch and Query Performance

    Prefetching can make a surprising difference to SQL Server query execution times where there is a high incidence of waiting for disk i/o operations, but the benefits come at a cost. Mostly, the Query Optimizer gets it right, but occasionally there are queries that would benefit from tuning. Get smart with SQL Backup ProGet faster, smaller backups with integrated verification.Quickly and easily DBCC CHECKDB your backups. Learn more.

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  • Redefining Search Engine Optimization - Prefer Pay For Performance SEO Over SEO Packages

    There are a lot of business owners who opt for search engine optimization in hope to benefit through this online marketing channel. Most of them sign up with companies offering them fixed SEO packages which is great however it is probably the biggest mistake they are making. Research has shown that in most SEO campaigns you are overpaying because at least for the first few months there is hardly any traffic.

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  • Pay For Performance of Your SEO Experts

    Search Engine Optimization, or SEO as it is popularly known the world over, is now amply discussed topic. What is SEO, is it useful, how is it useful, what are the advantages of SEO, how SEO is done, who does the SEO, what sources are required for SEO, what not to do in SEO - all these questions about SEO have been discussed in detail and supposedly detailed answers have been obtained about each of them.

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  • Async trigger for an update panel refreshes entire page when triggering too much in too short of tim

    - by Matt
    I have a search button tied to an update panel as a trigger like so: <asp:Panel ID="CRM_Search" runat="server"> <p>Search:&nbsp;<asp:TextBox ID="CRM_Search_Box" CssClass="CRM_Search_Box" runat="server"></asp:TextBox> <asp:Button ID="CRM_Search_Button" CssClass="CRM_Search_Button" runat="server" Text="Search" OnClick="SearchLeads" /></p> </asp:Panel> <asp:UpdatePanel ID="UpdatePanel1" runat="server"> <Triggers> <asp:AsyncPostBackTrigger ControlID="CRM_Search_Button" /> </Triggers> <ContentTemplate> /* Content Here */ </ContentTemplate> </asp:UpdatePanel> In my javascript I use jQuery to grab the search box and tie it's keyup to make the search button click: $($(".CRM_Search_Box")[0]).keyup( function () { $($(".CRM_Search_Button")[0]).click(); } ); This works perfectly, except when I start typing too fast. As soon as I type too fast (my guess is if it's any faster than the data actually returns) the entire page refreshes (doing a postback?) instead of just the update panel. I've also found that instead of typing, if I just click the button really fast it starts doing the same thing. Is there any way to prevent it from doing this? Possibly prevent 2nd requests until the first has been completed? If I'm not on the right track then anyone have any other ideas? Thanks, Matt

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  • Refresh page in browser without resubmitting form

    - by Michael
    I'm an ASP.NET developer, and I usually find myself leaving the webpage that I'm working on open in my browser (Chrome is my browser of choice, but this question is relevant for any browser). My workflow typically goes like this: I write code, I rebuild my project in Visual Studio, and then I flip back to my browser with Alt-Tab and hit F5 to refresh the page. This is fine and dandy if a form hasn't been submitted since the page was opened. But if I've been clicking around on ASP.NET form controls, the page has posted form data a number of times, so hitting F5 causes the browser to (sensibly) pop up a confirmation message, e.g., "Confirm Form Resubmission: The page that you're looking for used information that you entered...". Sometimes I do want to resubmit the form, but more often than not, I just want to start over with the page (rather than resubmit form data). The way I usually get around this is to simply add some query string data to the URL so that the browser sees it as a fresh page request, e.g.: page.aspx becomes page.aspx? (or vice-versa). My question is: Is there a better way to quickly request a fresh version of a webpage (and not submit form data) in any of the major browsers? It seems like a no-brainer to me for web development, but maybe I'm missing something. What I'd love to see is something like the last item in this list: F5: refresh page Ctrl-F5: refresh page (and force cache refresh) Alt-F5: request fresh copy of the page without resubmitting the form

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  • loading remote page into DOM with javascript

    - by scoobydoo
    I am trying to write a web widget which will allow users to display customized information (from my website) in their own web page. The mechanism I want to use (for creating the web widget) is javascript. So basically, I want to be able to write some javascript code like this (this is what the end user copies into their HTML page, to get my widget displayed in their page) <script type="text/javascript"> /* javascript here to fetch page from remote url and insert into DOM */ </script> I have two questions: how do I write a javascript code to fetch the page from the remote url? Ideally this will be PLAIN javascript (i.e. not using jQuery etc - since I dont want to force the user to get third party scripts jQuery which may conflict with other scripts on their page etc) The page I am fetching contains inline javascript, which gets executed in an body.onLoad event, as well as other functions which are used in response to user actions - my questions are: i). will the body.onLoad event be triggered for the retrieved document?. ii). If the retrieved page is dumped directly into the DOM, then the document will contain two <body> sections, which is no longer valid (X)HTML - however, I need the body.onLoad event to be triggered for the page to be setup correctly, and I also need the other functions in the retrieved page, for the retrieved page to be able to respond to the user interaction. Any suggestions/tips on how I can solve these problems?

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  • SQL SERVER – Update Statistics are Sampled By Default

    - by pinaldave
    After reading my earlier post SQL SERVER – Create Primary Key with Specific Name when Creating Table on Statistics, I have received another question by a blog reader. The question is as follows: Question: Are the statistics sampled by default? Answer: Yes. The sampling rate can be specified by the user and it can be anywhere between a very low value to 100%. Let us do a small experiment to verify if the auto update on statistics is left on. Also, let’s examine a very large table that is created and statistics by default- whether the statistics are sampled or not. USE [AdventureWorks] GO -- Create Table CREATE TABLE [dbo].[StatsTest]( [ID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](100) NULL, [LastName] [varchar](100) NULL, [City] [varchar](100) NULL, CONSTRAINT [PK_StatsTest] PRIMARY KEY CLUSTERED ([ID] ASC) ) ON [PRIMARY] GO -- Insert 1 Million Rows INSERT INTO [dbo].[StatsTest] (FirstName,LastName,City) SELECT TOP 1000000 'Bob', CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Update the statistics UPDATE STATISTICS [dbo].[StatsTest] GO -- Shows the statistics DBCC SHOW_STATISTICS ("StatsTest"PK_StatsTest) GO -- Clean up DROP TABLE [dbo].[StatsTest] GO Now let us observe the result of the DBCC SHOW_STATISTICS. The result shows that Resultset is for sure sampling for a large dataset. The percentage of sampling is based on data distribution as well as the kind of data in the table. Before dropping the table, let us check first the size of the table. The size of the table is 35 MB. Now, let us run the above code with lesser number of the rows. USE [AdventureWorks] GO -- Create Table CREATE TABLE [dbo].[StatsTest]( [ID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](100) NULL, [LastName] [varchar](100) NULL, [City] [varchar](100) NULL, CONSTRAINT [PK_StatsTest] PRIMARY KEY CLUSTERED ([ID] ASC) ) ON [PRIMARY] GO -- Insert 1 Hundred Thousand Rows INSERT INTO [dbo].[StatsTest] (FirstName,LastName,City) SELECT TOP 100000 'Bob', CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Update the statistics UPDATE STATISTICS [dbo].[StatsTest] GO -- Shows the statistics DBCC SHOW_STATISTICS ("StatsTest"PK_StatsTest) GO -- Clean up DROP TABLE [dbo].[StatsTest] GO You can see that Rows Sampled is just the same as Rows of the table. In this case, the sample rate is 100%. Before dropping the table, let us also check the size of the table. The size of the table is less than 4 MB. Let us compare the Result set just for a valid reference. Test 1: Total Rows: 1000000, Rows Sampled: 255420, Size of the Table: 35.516 MB Test 2: Total Rows: 100000, Rows Sampled: 100000, Size of the Table: 3.555 MB The reason behind the sample in the Test1 is that the data space is larger than 8 MB, and therefore it uses more than 1024 data pages. If the data space is smaller than 8 MB and uses less than 1024 data pages, then the sampling does not happen. Sampling aids in reducing excessive data scan; however, sometimes it reduces the accuracy of the data as well. Please note that this is just a sample test and there is no way it can be claimed as a benchmark test. The result can be dissimilar on different machines. There are lots of other information can be included when talking about this subject. I will write detail post covering all the subject very soon. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Statistics

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  • SQL SERVER – Puzzle – Statistics are not Updated but are Created Once

    - by pinaldave
    After having excellent response to my quiz – Why SELECT * throws an error but SELECT COUNT(*) does not?I have decided to ask another puzzling question to all of you. I am running this test on SQL Server 2008 R2. Here is the quick scenario about my setup. Create Table Insert 1000 Records Check the Statistics Now insert 10 times more 10,000 indexes Check the Statistics – it will be NOT updated Note: Auto Update Statistics and Auto Create Statistics for database is TRUE Expected Result – Statistics should be updated – SQL SERVER – When are Statistics Updated – What triggers Statistics to Update Now the question is why the statistics are not updated? The common answer is – we can update the statistics ourselves using UPDATE STATISTICS TableName WITH FULLSCAN, ALL However, the solution I am looking is where statistics should be updated automatically based on algorithm mentioned here. Now the solution is to ____________________. Vinod Kumar is not allowed to take participate over here as he is the one who has helped me to build this puzzle. I will publish the solution on next week. Please leave a comment and if your comment consist valid answer, I will publish with due credit. Here is the script to reproduce the scenario which I mentioned. -- Execution Plans Difference -- Create Sample Database CREATE DATABASE SampleDB GO USE SampleDB GO -- Create Table CREATE TABLE ExecTable (ID INT, FirstName VARCHAR(100), LastName VARCHAR(100), City VARCHAR(100)) GO -- Insert One Thousand Records -- INSERT 1 INSERT INTO ExecTable (ID,FirstName,LastName,City) SELECT TOP 1000 ROW_NUMBER() OVER (ORDER BY a.name) RowID, 'Bob', CASE WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%20 = 1 THEN 'New York' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 5 THEN 'San Marino' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 3 THEN 'Los Angeles' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 7 THEN 'La Cinega' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 13 THEN 'San Diego' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 17 THEN 'Las Vegas' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Display statistics of the table - none listed sp_helpstats N'ExecTable', 'ALL' GO -- Select Statement SELECT FirstName, LastName, City FROM ExecTable WHERE City  = 'New York' GO -- Display statistics of the table sp_helpstats N'ExecTable', 'ALL' GO -- Replace your Statistics over here -- NOTE: Replace your _WA_Sys with stats from above query DBCC SHOW_STATISTICS('ExecTable', _WA_Sys_00000004_7D78A4E7); GO -------------------------------------------------------------- -- Round 2 -- Insert Ten Thousand Records -- INSERT 2 INSERT INTO ExecTable (ID,FirstName,LastName,City) SELECT TOP 10000 ROW_NUMBER() OVER (ORDER BY a.name) RowID, 'Bob', CASE WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%20 = 1 THEN 'New York' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 5 THEN 'San Marino' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 3 THEN 'Los Angeles' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 7 THEN 'La Cinega' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 13 THEN 'San Diego' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 17 THEN 'Las Vegas' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Select Statement SELECT FirstName, LastName, City FROM ExecTable WHERE City  = 'New York' GO -- Display statistics of the table sp_helpstats N'ExecTable', 'ALL' GO -- Replace your Statistics over here -- NOTE: Replace your _WA_Sys with stats from above query DBCC SHOW_STATISTICS('ExecTable', _WA_Sys_00000004_7D78A4E7); GO -- You will notice that Statistics are still updated with 1000 rows -- Clean up Database DROP TABLE ExecTable GO USE MASTER GO ALTER DATABASE SampleDB SET SINGLE_USER WITH ROLLBACK IMMEDIATE; GO DROP DATABASE SampleDB GO Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Statistics, Statistics

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  • SQL SERVER – How to Ignore Columnstore Index Usage in Query

    - by pinaldave
    Earlier I wrote about SQL SERVER – Fundamentals of Columnstore Index and very first question I received in email was as following. “We are using SQL Server 2012 CTP3 and so far so good. In our data warehouse solution we have created 1 non-clustered columnstore index on our large fact table. We have very unique situation but your article did not cover it. We are running few queries on our fact table which is working very efficiently but there is one query which earlier was running very fine but after creating this non-clustered columnstore index this query is running very slow. We dropped the columnstore index and suddenly this one query is running fast but other queries which were benefited by this columnstore index it is running slow. Any workaround in this situation?” In summary the question in simple words “How can we ignore using columnstore index in selective queries?” Very interesting question – you can use I can understand there may be the cases when columnstore index is not ideal and needs to be ignored the same. You can use the query hint IGNORE_NONCLUSTERED_COLUMNSTORE_INDEX to ignore the columnstore index. SQL Server Engine will use any other index which is best after ignoring the columnstore index. Here is the quick script to prove the same. We will first create sample database and then create columnstore index on the same. Once columnstore index is created we will write simple query. This query will use columnstore index. We will then show the usage of the query hint. USE AdventureWorks GO -- Create New Table CREATE TABLE [dbo].[MySalesOrderDetail]( [SalesOrderID] [int] NOT NULL, [SalesOrderDetailID] [int] NOT NULL, [CarrierTrackingNumber] [nvarchar](25) NULL, [OrderQty] [smallint] NOT NULL, [ProductID] [int] NOT NULL, [SpecialOfferID] [int] NOT NULL, [UnitPrice] [money] NOT NULL, [UnitPriceDiscount] [money] NOT NULL, [LineTotal] [numeric](38, 6) NOT NULL, [rowguid] [uniqueidentifier] NOT NULL, [ModifiedDate] [datetime] NOT NULL ) ON [PRIMARY] GO -- Create clustered index CREATE CLUSTERED INDEX [CL_MySalesOrderDetail] ON [dbo].[MySalesOrderDetail] ( [SalesOrderDetailID]) GO -- Create Sample Data Table -- WARNING: This Query may run upto 2-10 minutes based on your systems resources INSERT INTO [dbo].[MySalesOrderDetail] SELECT S1.* FROM Sales.SalesOrderDetail S1 GO 100 -- Create ColumnStore Index CREATE NONCLUSTERED COLUMNSTORE INDEX [IX_MySalesOrderDetail_ColumnStore] ON [MySalesOrderDetail] (UnitPrice, OrderQty, ProductID) GO Now we have created columnstore index so if we run following query it will use for sure the same index. -- Select Table with regular Index SELECT ProductID, SUM(UnitPrice) SumUnitPrice, AVG(UnitPrice) AvgUnitPrice, SUM(OrderQty) SumOrderQty, AVG(OrderQty) AvgOrderQty FROM [dbo].[MySalesOrderDetail] GROUP BY ProductID ORDER BY ProductID GO We can specify Query Hint IGNORE_NONCLUSTERED_COLUMNSTORE_INDEX as described in following query and it will not use columnstore index. -- Select Table with regular Index SELECT ProductID, SUM(UnitPrice) SumUnitPrice, AVG(UnitPrice) AvgUnitPrice, SUM(OrderQty) SumOrderQty, AVG(OrderQty) AvgOrderQty FROM [dbo].[MySalesOrderDetail] GROUP BY ProductID ORDER BY ProductID OPTION (IGNORE_NONCLUSTERED_COLUMNSTORE_INDEX) GO Let us clean up the database. -- Cleanup DROP INDEX [IX_MySalesOrderDetail_ColumnStore] ON [dbo].[MySalesOrderDetail] GO TRUNCATE TABLE dbo.MySalesOrderDetail GO DROP TABLE dbo.MySalesOrderDetail GO Again, make sure that you use hint sparingly and understanding the proper implication of the same. Make sure that you test it with and without hint and select the best option after review of your administrator. Here is the question for you – have you started to use SQL Server 2012 for your validation and development (not on production)? It will be interesting to know the answer. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • What’s the Difference Between Succession Management and Talent Reviews?

    - by HCM-Oracle
    By Marcie Van Houten Is there a difference or are they pieces of one holistic strategic talent process? And can you have one without the other?  First, let me give a quick definition of each.  Succession planning (or management) is about creating succession slates or talent pools in support of a critical job or position or sets thereof. And then using those plans to help mitigate risk and plan talent needs for the organization.  Talent reviews (known by other names often) are sets of meetings where managers and executives come together to review, discuss and often heatedly debate the merits and potential of their employees, and then place and sometimes calibrate that talent on a performance to potential matrix.  These are some of the most strategic conversations happening in conference rooms across the globe. I speak with a lot of organizations about their practices in this area and the answers to these questions are as varied and nuanced as there are organizations thinking about them.  Some are passionate about their talent review processes and have a very evolved and thoughtful approach.  They really know their people, where their talent is, and the opportunities they plan to offer them.  And to them that is their succession process.  They may never create a slate of named candidates for a job or assign employees to formal talent pools.   On the flip side there are other organizations that create slates and slates and often multiple talent pools to support their strategic positions.  Through these, they are able to mitigate the risk associated with having a key player leave their organization.  And for them, that is their succession process.  Some will start from the lower levels of their organization and roll up their succession plans, while other organizations only cover their top 200 executives and key positions with plans.  And then there are organizations that leverage some of all of these.  Ultimately, the goals are to increase employee engagement, reduce talent-related risk, ensure the right talent is aligned to the strategic initiatives and to drive business value.  The approaches are as unique as the organizations they represent and the business opportunities they are looking to seize upon.   And that's ok.  It's great in fact. Because one thing that is common is the recognition that the need to know your people and align your top talent to the future needs of the organization is mission critical. Sure, there are a set of commonly recognized best practices and guiding principles for all of this.  There is no one right or perfect answer.  And that is what makes this all so much darn fun.  With Talent Review and Succession Management from Oracle HCM Cloud, we’ve blended the ability to support your strategic talent review conversations with both succession plans and talent pools allowing for one very seamless and interactive process. So whether you create a lot of succession plans, only focus on talent pools, have a robust talent review process, or all of the above, Oracle has you covered. I’m looking forward to spending time with our customers at the upcoming OHUG Global Conference 2014 happening June 9-13 in Las Vegas.  It’s an opportunity for me to talk to customers about their business and how they are doing strategic talent processes like talent reviews and succession.  I hope to see you there. Marcie Van Houten brings over 20 years of management consulting, information systems and human capital management experience to her role as director of product strategy at Oracle. Ms. Van Houten has spent the past several years at Oracle working closely with customers to help drive the direction of the company's talent and succession management applications. Additionally, she spent nine years at PeopleSoft as Director of Information Systems leading human capital management implementation projects. Marcie Van Houten lives in Walnut Creek, California, and holds a MBA from Southern Methodist University in Dallas, Texas.  You can follow her on Twitter: @MarcieVH

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  • SQL Server IO handling mechanism can be severely affected by high CPU usage

    - by sqlworkshops
    Are you using SSD or SAN / NAS based storage solution and sporadically observe SQL Server experiencing high IO wait times or from time to time your DAS / HDD becomes very slow according to SQL Server statistics? Read on… I need your help to up vote my connect item – https://connect.microsoft.com/SQLServer/feedback/details/744650/sql-server-io-handling-mechanism-can-be-severely-affected-by-high-cpu-usage. Instead of taking few seconds, queries could take minutes/hours to complete when CPU is busy.In SQL Server when a query / request needs to read data that is not in data cache or when the request has to write to disk, like transaction log records, the request / task will queue up the IO operation and wait for it to complete (task in suspended state, this wait time is the resource wait time). When the IO operation is complete, the task will be queued to run on the CPU. If the CPU is busy executing other tasks, this task will wait (task in runnable state) until other tasks in the queue either complete or get suspended due to waits or exhaust their quantum of 4ms (this is the signal wait time, which along with resource wait time will increase the overall wait time). When the CPU becomes free, the task will finally be run on the CPU (task in running state).The signal wait time can be up to 4ms per runnable task, this is by design. So if a CPU has 5 runnable tasks in the queue, then this query after the resource becomes available might wait up to a maximum of 5 X 4ms = 20ms in the runnable state (normally less as other tasks might not use the full quantum).In case the CPU usage is high, let’s say many CPU intensive queries are running on the instance, there is a possibility that the IO operations that are completed at the Hardware and Operating System level are not yet processed by SQL Server, keeping the task in the resource wait state for longer than necessary. In case of an SSD, the IO operation might even complete in less than a millisecond, but it might take SQL Server 100s of milliseconds, for instance, to process the completed IO operation. For example, let’s say you have a user inserting 500 rows in individual transactions. When the transaction log is on an SSD or battery backed up controller that has write cache enabled, all of these inserts will complete in 100 to 200ms. With a CPU intensive parallel query executing across all CPU cores, the same inserts might take minutes to complete. WRITELOG wait time will be very high in this case (both under sys.dm_io_virtual_file_stats and sys.dm_os_wait_stats). In addition you will notice a large number of WAITELOG waits since log records are written by LOG WRITER and hence very high signal_wait_time_ms leading to more query delays. However, Performance Monitor Counter, PhysicalDisk, Avg. Disk sec/Write will report very low latency times.Such delayed IO handling also occurs to read operations with artificially very high PAGEIOLATCH_SH wait time (with number of PAGEIOLATCH_SH waits remaining the same). This problem will manifest more and more as customers start using SSD based storage for SQL Server, since they drive the CPU usage to the limits with faster IOs. We have a few workarounds for specific scenarios, but we think Microsoft should resolve this issue at the product level. We have a connect item open – https://connect.microsoft.com/SQLServer/feedback/details/744650/sql-server-io-handling-mechanism-can-be-severely-affected-by-high-cpu-usage - (with example scripts) to reproduce this behavior, please up vote the item so the issue will be addressed by the SQL Server product team soon.Thanks for your help and best regards,Ramesh MeyyappanHome: www.sqlworkshops.comLinkedIn: http://at.linkedin.com/in/rmeyyappan

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  • Simple OpenGL program major slow down at high resolution

    - by Grieverheart
    I have created a small OpenGL 3.3 (Core) program using freeglut. The whole geometry is two boxes and one plane with some textures. I can move around like in an FPS and that's it. The problem is I face a big slow down of fps when I make my window large (i.e. above 1920x1080). I have monitors GPU usage when in full-screen and it shows GPU load of nearly 100% and Memory Controller load of ~85%. When at 600x600, these numbers are at about 45%, my CPU is also at full load. I use deferred rendering at the moment but even when forward rendering, the slow down was nearly as severe. I can't imagine my GPU is not powerful enough for something this simple when I play many games at 1080p (I have a GeForce GT 120M btw). Below are my shaders, First Pass #VS #version 330 core uniform mat4 ModelViewMatrix; uniform mat3 NormalMatrix; uniform mat4 MVPMatrix; uniform float scale; layout(location = 0) in vec3 in_Position; layout(location = 1) in vec3 in_Normal; layout(location = 2) in vec2 in_TexCoord; smooth out vec3 pass_Normal; smooth out vec3 pass_Position; smooth out vec2 TexCoord; void main(void){ pass_Position = (ModelViewMatrix * vec4(scale * in_Position, 1.0)).xyz; pass_Normal = NormalMatrix * in_Normal; TexCoord = in_TexCoord; gl_Position = MVPMatrix * vec4(scale * in_Position, 1.0); } #FS #version 330 core uniform sampler2D inSampler; smooth in vec3 pass_Normal; smooth in vec3 pass_Position; smooth in vec2 TexCoord; layout(location = 0) out vec3 outPosition; layout(location = 1) out vec3 outDiffuse; layout(location = 2) out vec3 outNormal; void main(void){ outPosition = pass_Position; outDiffuse = texture(inSampler, TexCoord).xyz; outNormal = pass_Normal; } Second Pass #VS #version 330 core uniform float scale; layout(location = 0) in vec3 in_Position; void main(void){ gl_Position = mat4(1.0) * vec4(scale * in_Position, 1.0); } #FS #version 330 core struct Light{ vec3 direction; }; uniform ivec2 ScreenSize; uniform Light light; uniform sampler2D PositionMap; uniform sampler2D ColorMap; uniform sampler2D NormalMap; out vec4 out_Color; vec2 CalcTexCoord(void){ return gl_FragCoord.xy / ScreenSize; } vec4 CalcLight(vec3 position, vec3 normal){ vec4 DiffuseColor = vec4(0.0); vec4 SpecularColor = vec4(0.0); vec3 light_Direction = -normalize(light.direction); float diffuse = max(0.0, dot(normal, light_Direction)); if(diffuse 0.0){ DiffuseColor = diffuse * vec4(1.0); vec3 camera_Direction = normalize(-position); vec3 half_vector = normalize(camera_Direction + light_Direction); float specular = max(0.0, dot(normal, half_vector)); float fspecular = pow(specular, 128.0); SpecularColor = fspecular * vec4(1.0); } return DiffuseColor + SpecularColor + vec4(0.1); } void main(void){ vec2 TexCoord = CalcTexCoord(); vec3 Position = texture(PositionMap, TexCoord).xyz; vec3 Color = texture(ColorMap, TexCoord).xyz; vec3 Normal = normalize(texture(NormalMap, TexCoord).xyz); out_Color = vec4(Color, 1.0) * CalcLight(Position, Normal); } Is it normal for the GPU to be used that much under the described circumstances? Is it due to poor performance of freeglut? I understand that the problem could be specific to my code, but I can't paste the whole code here, if you need more info, please tell me.

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  • Reducing Deadlocks - not a DBA issue ?

    - by steveh99999
     As a DBA, I'm involved on an almost daily basis troubleshooting 'SQL Server' performance issues. Often, this troubleshooting soon veers away from a 'its a SQL Server issue' to instead become a wider application/database design/coding issue.One common perception with SQL Server is that deadlocking is an application design issue - and is fixed by recoding...  I see this reinforced by MCP-type questions/scenarios where the answer to prevent deadlocking is simply to change the order in code in which tables are accessed....Whilst this is correct, I do think this has led to a situation where many 'operational' or 'production support' DBAs, when faced with a deadlock, are happy to throw the issue over to developers without analysing the issue further....A couple of 'war stories' on deadlocks which I think are interesting :- Case One , I had an issue recently on a third-party application that I support on SQL 2008.  This particular third-party application has an unusual support agreement where the customer is allowed to change the index design on the third-party provided database.  However, we are not allowed to alter application code or modify table structure..This third-party application is also known to encounter occasional deadlocks – indeed, I have documentation from the vendor that up to 50 deadlocks per day is not unusual !So, as a DBA I have to support an application which in my opinion has too many deadlocks - but, I cannot influence the design of the tables or stored procedures for the application. This should be the classic - blame the third-party developers scenario, and hope this issue gets addressed in a future application release - ie we could wait years for this to be resolved and implemented in our production environment...But, as DBAs  can change the index layout, is there anything I could do still to reduce the deadlocks in the application ?I initially used SQL traceflag 1222 to write deadlock detection output to the SQL Errorlog – using this I was able to identify one table heavily involved in the deadlocks.When I examined the table definition, I was surprised to see it was a heap – ie no clustered index existed on the table.Using SQL profiler to see locking behaviour and plan for the query involved in the deadlock, I was able to confirm a table scan was being performed.By creating an appropriate clustered index - it was possible to produce a more efficient plan and locking behaviour.So, less locks, held for less time = less possibility of deadlocks. I'm still unhappy about the overall number of deadlocks on this system - but that's something to be discussed further with the vendor.Case Two,  a system which hadn't changed for months suddenly started seeing deadlocks on a regular basis. I love the 'nothing's changed' scenario, as it gives me the opportunity to appear wise and say 'nothings changed on this system, except the data'.. This particular deadlock occurred on a table which had been growing rapidly. By using DBCC SHOW_STATISTICS - the DBA team were able to see that the deadlocks seemed to be occurring shortly after auto-update stats had regenerated the table statistics using it's default sampling behaviour.As a quick fix, we were able to schedule a nightly UPDATE STATISTICS WITH FULLSCAN on the table involved in the deadlock - thus, greatly reducing the potential for stats to be updated via auto_update_stats, consequently reducing the potential for a bad plan to be generated based on an unrepresentative sample of the data. This reduced the possibility of a deadlock occurring.  Not a perfect solution by any means, but quick, easy to implement, and needed no application code changes. This fix gave us some 'breathing space'  to properly fix the code during the next scheduled application release.   The moral of this post - don't dismiss deadlocks as issues that can only be fixed by developers...

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