Search Results

Search found 1140 results on 46 pages for 'readers contribution'.

Page 6/46 | < Previous Page | 2 3 4 5 6 7 8 9 10 11 12 13  | Next Page >

  • SQL SERVER – Enumerations in Relational Database – Best Practice

    - by pinaldave
    Marko Parkkola This article has been submitted by Marko Parkkola, Data systems designer at Saarionen Oy, Finland. Marko is excellent developer and always thinking at next level. You can read his earlier comment which created very interesting discussion here: SQL SERVER- IF EXISTS(Select null from table) vs IF EXISTS(Select 1 from table). I must express my special thanks to Marko for sending this best practice for Enumerations in Relational Database. He has really wrote excellent piece here and welcome comments here. Enumerations in Relational Database This is a subject which is very basic thing in relational databases but often not very well understood and sometimes badly implemented. There are of course many ways to do this but I concentrate only two cases, one which is “the right way” and one which is definitely wrong way. The concept Let’s say we have table Person in our database. Person has properties/fields like Firstname, Lastname, Birthday and so on. Then there’s a field that tells person’s marital status and let’s name it the same way; MaritalStatus. Now MaritalStatus is an enumeration. In C# I would definitely make it an enumeration with values likes Single, InRelationship, Married, Divorced. Now here comes the problem, SQL doesn’t have enumerations. The wrong way This is, in my opinion, absolutely the wrong way to do this. It has one upside though; you’ll see the enumeration’s description instantly when you do simple SELECT query and you don’t have to deal with mysterious values. There’s plenty of downsides too and one would be database fragmentation. Consider this (I’ve left all indexes and constraints out of the query on purpose). CREATE TABLE [dbo].[Person] ( [Firstname] NVARCHAR(100), [Lastname] NVARCHAR(100), [Birthday] datetime, [MaritalStatus] NVARCHAR(10) ) You have nvarchar(20) field in the table that tells the marital status. Obvious problem with this is that what if you create a new value which doesn’t fit into 20 characters? You’ll have to come and alter the table. There are other problems also but I’ll leave those for the reader to think about. The correct way Here’s how I’ve done this in many projects. This model still has one problem but it can be alleviated in the application layer or with CHECK constraints if you like. First I will create a namespace table which tells the name of the enumeration. I will add one row to it too. I’ll write all the indexes and constraints here too. CREATE TABLE [CodeNamespace] ( [Id] INT IDENTITY(1, 1), [Name] NVARCHAR(100) NOT NULL, CONSTRAINT [PK_CodeNamespace] PRIMARY KEY ([Id]), CONSTRAINT [IXQ_CodeNamespace_Name] UNIQUE NONCLUSTERED ([Name]) ) GO INSERT INTO [CodeNamespace] SELECT 'MaritalStatus' GO Then I create a table that holds the actual values and which reference to namespace table in order to group the values under different namespaces. I’ll add couple of rows here too. CREATE TABLE [CodeValue] ( [CodeNamespaceId] INT NOT NULL, [Value] INT NOT NULL, [Description] NVARCHAR(100) NOT NULL, [OrderBy] INT, CONSTRAINT [PK_CodeValue] PRIMARY KEY CLUSTERED ([CodeNamespaceId], [Value]), CONSTRAINT [FK_CodeValue_CodeNamespace] FOREIGN KEY ([CodeNamespaceId]) REFERENCES [CodeNamespace] ([Id]) ) GO -- 1 is the 'MaritalStatus' namespace INSERT INTO [CodeValue] SELECT 1, 1, 'Single', 1 INSERT INTO [CodeValue] SELECT 1, 2, 'In relationship', 2 INSERT INTO [CodeValue] SELECT 1, 3, 'Married', 3 INSERT INTO [CodeValue] SELECT 1, 4, 'Divorced', 4 GO Now there’s four columns in CodeValue table. CodeNamespaceId tells under which namespace values belongs to. Value tells the enumeration value which is used in Person table (I’ll show how this is done below). Description tells what the value means. You can use this, for example, column in UI’s combo box. OrderBy tells if the values needs to be ordered in some way when displayed in the UI. And here’s the Person table again now with correct columns. I’ll add one row here to show how enumerations are to be used. CREATE TABLE [dbo].[Person] ( [Firstname] NVARCHAR(100), [Lastname] NVARCHAR(100), [Birthday] datetime, [MaritalStatus] INT ) GO INSERT INTO [Person] SELECT 'Marko', 'Parkkola', '1977-03-04', 3 GO Now I said earlier that there is one problem with this. MaritalStatus column doesn’t have any database enforced relationship to the CodeValue table so you can enter any value you like into this field. I’ve solved this problem in the application layer by selecting all the values from the CodeValue table and put them into a combobox / dropdownlist (with Value field as value and Description as text) so the end user can’t enter any illegal values; and of course I’ll check the entered value in data access layer also. I said in the “The wrong way” section that there is one benefit to it. In fact, you can have the same benefit here by using a simple view, which I schema bound so you can even index it if you like. CREATE VIEW [dbo].[Person_v] WITH SCHEMABINDING AS SELECT p.[Firstname], p.[Lastname], p.[BirthDay], c.[Description] MaritalStatus FROM [dbo].[Person] p JOIN [dbo].[CodeValue] c ON p.[MaritalStatus] = c.[Value] JOIN [dbo].[CodeNamespace] n ON n.[Id] = c.[CodeNamespaceId] AND n.[Name] = 'MaritalStatus' GO -- Select from View SELECT * FROM [dbo].[Person_v] GO This is excellent write up byMarko Parkkola. Do you have this kind of design setup at your organization? Let us know your opinion. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Best Practices, Database, DBA, Readers Contribution, Software Development, SQL, SQL Authority, SQL Documentation, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • SQL SERVER – Attach mdf file without ldf file in Database

    - by pinaldave
    Background Story: One of my friends recently called up and asked me if I had spare time to look at his database and give him a performance tuning advice. Because I had some free time to help him out, I said yes. I asked him to send me the details of his database structure and sample data. He said that since his database is in a very early stage and is small as of the moment, so he told me that he would like me to have a complete database. My response to him was “Sure! In that case, take a backup of the database and send it to me. I will restore it into my computer and play with it.” He did send me his database; however, his method made me write this quick note here. Instead of taking a full backup of the database and sending it to me, he sent me only the .mdf (primary database file). In fact, I asked for a complete backup (I wanted to review file groups, files, as well as few other details).  Upon calling my friend,  I found that he was not available. Now,  he left me with only a .mdf file. As I had some extra time, I decided to checkout his database structure and get back to him regarding the full backup, whenever I can get in touch with him again. Technical Talk: If the database is shutdown gracefully and there was no abrupt shutdown (power outrages, pulling plugs to machines, machine crashes or any other reasons), it is possible (there’s no guarantee) to attach .mdf file only to the server. Please note that there can be many more reasons for a database that is not getting attached or restored. In my case, the database had a clean shutdown and there were no complex issues. I was able to recreate a transaction log file and attached the received .mdf file. There are multiple ways of doing this. I am listing all of them here. Before using any of them, please consult the Domain Expert in your company or industry. Also, never attempt this on live/production server without the presence of a Disaster Recovery expert. USE [master] GO -- Method 1: I use this method EXEC sp_attach_single_file_db @dbname='TestDb', @physname=N'C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\TestDb.mdf' GO -- Method 2: CREATE DATABASE TestDb ON (FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\TestDb.mdf') FOR ATTACH_REBUILD_LOG GO Method 2: If one or more log files are missing, they are recreated again. There is one more method which I am demonstrating here but I have not used myself before. According to Book Online, it will work only if there is one log file that is missing. If there are more than one log files involved, all of them are required to undergo the same procedure. -- Method 3: CREATE DATABASE TestDb ON ( FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\TestDb.mdf') FOR ATTACH GO Please read the Book Online in depth and consult DR experts before working on the production server. In my case, the above syntax just worked fine as the database was clean when it was detached. Feel free to write your opinions and experiences for it will help the IT community to learn more from your suggestions and skills. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Backup and Restore, SQL Data Storage, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • SQL SERVER – Guest Post – Architecting Data Warehouse – Niraj Bhatt

    - by pinaldave
    Niraj Bhatt works as an Enterprise Architect for a Fortune 500 company and has an innate passion for building / studying software systems. He is a top rated speaker at various technical forums including Tech·Ed, MCT Summit, Developer Summit, and Virtual Tech Days, among others. Having run a successful startup for four years Niraj enjoys working on – IT innovations that can impact an enterprise bottom line, streamlining IT budgets through IT consolidation, architecture and integration of systems, performance tuning, and review of enterprise applications. He has received Microsoft MVP award for ASP.NET, Connected Systems and most recently on Windows Azure. When he is away from his laptop, you will find him taking deep dives in automobiles, pottery, rafting, photography, cooking and financial statements though not necessarily in that order. He is also a manager/speaker at BDOTNET, Asia’s largest .NET user group. Here is the guest post by Niraj Bhatt. As data in your applications grows it’s the database that usually becomes a bottleneck. It’s hard to scale a relational DB and the preferred approach for large scale applications is to create separate databases for writes and reads. These databases are referred as transactional database and reporting database. Though there are tools / techniques which can allow you to create snapshot of your transactional database for reporting purpose, sometimes they don’t quite fit the reporting requirements of an enterprise. These requirements typically are data analytics, effective schema (for an Information worker to self-service herself), historical data, better performance (flat data, no joins) etc. This is where a need for data warehouse or an OLAP system arises. A Key point to remember is a data warehouse is mostly a relational database. It’s built on top of same concepts like Tables, Rows, Columns, Primary keys, Foreign Keys, etc. Before we talk about how data warehouses are typically structured let’s understand key components that can create a data flow between OLTP systems and OLAP systems. There are 3 major areas to it: a) OLTP system should be capable of tracking its changes as all these changes should go back to data warehouse for historical recording. For e.g. if an OLTP transaction moves a customer from silver to gold category, OLTP system needs to ensure that this change is tracked and send to data warehouse for reporting purpose. A report in context could be how many customers divided by geographies moved from sliver to gold category. In data warehouse terminology this process is called Change Data Capture. There are quite a few systems that leverage database triggers to move these changes to corresponding tracking tables. There are also out of box features provided by some databases e.g. SQL Server 2008 offers Change Data Capture and Change Tracking for addressing such requirements. b) After we make the OLTP system capable of tracking its changes we need to provision a batch process that can run periodically and takes these changes from OLTP system and dump them into data warehouse. There are many tools out there that can help you fill this gap – SQL Server Integration Services happens to be one of them. c) So we have an OLTP system that knows how to track its changes, we have jobs that run periodically to move these changes to warehouse. The question though remains is how warehouse will record these changes? This structural change in data warehouse arena is often covered under something called Slowly Changing Dimension (SCD). While we will talk about dimensions in a while, SCD can be applied to pure relational tables too. SCD enables a database structure to capture historical data. This would create multiple records for a given entity in relational database and data warehouses prefer having their own primary key, often known as surrogate key. As I mentioned a data warehouse is just a relational database but industry often attributes a specific schema style to data warehouses. These styles are Star Schema or Snowflake Schema. The motivation behind these styles is to create a flat database structure (as opposed to normalized one), which is easy to understand / use, easy to query and easy to slice / dice. Star schema is a database structure made up of dimensions and facts. Facts are generally the numbers (sales, quantity, etc.) that you want to slice and dice. Fact tables have these numbers and have references (foreign keys) to set of tables that provide context around those facts. E.g. if you have recorded 10,000 USD as sales that number would go in a sales fact table and could have foreign keys attached to it that refers to the sales agent responsible for sale and to time table which contains the dates between which that sale was made. These agent and time tables are called dimensions which provide context to the numbers stored in fact tables. This schema structure of fact being at center surrounded by dimensions is called Star schema. A similar structure with difference of dimension tables being normalized is called a Snowflake schema. This relational structure of facts and dimensions serves as an input for another analysis structure called Cube. Though physically Cube is a special structure supported by commercial databases like SQL Server Analysis Services, logically it’s a multidimensional structure where dimensions define the sides of cube and facts define the content. Facts are often called as Measures inside a cube. Dimensions often tend to form a hierarchy. E.g. Product may be broken into categories and categories in turn to individual items. Category and Items are often referred as Levels and their constituents as Members with their overall structure called as Hierarchy. Measures are rolled up as per dimensional hierarchy. These rolled up measures are called Aggregates. Now this may seem like an overwhelming vocabulary to deal with but don’t worry it will sink in as you start working with Cubes and others. Let’s see few other terms that we would run into while talking about data warehouses. ODS or an Operational Data Store is a frequently misused term. There would be few users in your organization that want to report on most current data and can’t afford to miss a single transaction for their report. Then there is another set of users that typically don’t care how current the data is. Mostly senior level executives who are interesting in trending, mining, forecasting, strategizing, etc. don’t care for that one specific transaction. This is where an ODS can come in handy. ODS can use the same star schema and the OLAP cubes we saw earlier. The only difference is that the data inside an ODS would be short lived, i.e. for few months and ODS would sync with OLTP system every few minutes. Data warehouse can periodically sync with ODS either daily or weekly depending on business drivers. Data marts are another frequently talked about topic in data warehousing. They are subject-specific data warehouse. Data warehouses that try to span over an enterprise are normally too big to scope, build, manage, track, etc. Hence they are often scaled down to something called Data mart that supports a specific segment of business like sales, marketing, or support. Data marts too, are often designed using star schema model discussed earlier. Industry is divided when it comes to use of data marts. Some experts prefer having data marts along with a central data warehouse. Data warehouse here acts as information staging and distribution hub with spokes being data marts connected via data feeds serving summarized data. Others eliminate the need for a centralized data warehouse citing that most users want to report on detailed data. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Best Practices, Business Intelligence, Data Warehousing, Database, Pinal Dave, PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • SQL SERVER – Guest Posts – Feodor Georgiev – The Context of Our Database Environment – Going Beyond the Internal SQL Server Waits – Wait Type – Day 21 of 28

    - by pinaldave
    This guest post is submitted by Feodor. Feodor Georgiev is a SQL Server database specialist with extensive experience of thinking both within and outside the box. He has wide experience of different systems and solutions in the fields of architecture, scalability, performance, etc. Feodor has experience with SQL Server 2000 and later versions, and is certified in SQL Server 2008. In this article Feodor explains the server-client-server process, and concentrated on the mutual waits between client and SQL Server. This is essential in grasping the concept of waits in a ‘global’ application plan. Recently I was asked to write a blog post about the wait statistics in SQL Server and since I had been thinking about writing it for quite some time now, here it is. It is a wide-spread idea that the wait statistics in SQL Server will tell you everything about your performance. Well, almost. Or should I say – barely. The reason for this is that SQL Server is always a part of a bigger system – there are always other players in the game: whether it is a client application, web service, any other kind of data import/export process and so on. In short, the SQL Server surroundings look like this: This means that SQL Server, aside from its internal waits, also depends on external waits and settings. As we can see in the picture above, SQL Server needs to have an interface in order to communicate with the surrounding clients over the network. For this communication, SQL Server uses protocol interfaces. I will not go into detail about which protocols are best, but you can read this article. Also, review the information about the TDS (Tabular data stream). As we all know, our system is only as fast as its slowest component. This means that when we look at our environment as a whole, the SQL Server might be a victim of external pressure, no matter how well we have tuned our database server performance. Let’s dive into an example: let’s say that we have a web server, hosting a web application which is using data from our SQL Server, hosted on another server. The network card of the web server for some reason is malfunctioning (think of a hardware failure, driver failure, or just improper setup) and does not send/receive data faster than 10Mbs. On the other end, our SQL Server will not be able to send/receive data at a faster rate either. This means that the application users will notify the support team and will say: “My data is coming very slow.” Now, let’s move on to a bit more exciting example: imagine that there is a similar setup as the example above – one web server and one database server, and the application is not using any stored procedure calls, but instead for every user request the application is sending 80kb query over the network to the SQL Server. (I really thought this does not happen in real life until I saw it one day.) So, what happens in this case? To make things worse, let’s say that the 80kb query text is submitted from the application to the SQL Server at least 100 times per minute, and as often as 300 times per minute in peak times. Here is what happens: in order for this query to reach the SQL Server, it will have to be broken into a of number network packets (according to the packet size settings) – and will travel over the network. On the other side, our SQL Server network card will receive the packets, will pass them to our network layer, the packets will get assembled, and eventually SQL Server will start processing the query – parsing, allegorizing, generating the query execution plan and so on. So far, we have already had a serious network overhead by waiting for the packets to reach our Database Engine. There will certainly be some processing overhead – until the database engine deals with the 80kb query and its 20 subqueries. The waits you see in the DMVs are actually collected from the point the query reaches the SQL Server and the packets are assembled. Let’s say that our query is processed and it finally returns 15000 rows. These rows have a certain size as well, depending on the data types returned. This means that the data will have converted to packages (depending on the network size package settings) and will have to reach the application server. There will also be waits, however, this time you will be able to see a wait type in the DMVs called ASYNC_NETWORK_IO. What this wait type indicates is that the client is not consuming the data fast enough and the network buffers are filling up. Recently Pinal Dave posted a blog on Client Statistics. What Client Statistics does is captures the physical flow characteristics of the query between the client(Management Studio, in this case) and the server and back to the client. As you see in the image, there are three categories: Query Profile Statistics, Network Statistics and Time Statistics. Number of server roundtrips–a roundtrip consists of a request sent to the server and a reply from the server to the client. For example, if your query has three select statements, and they are separated by ‘GO’ command, then there will be three different roundtrips. TDS Packets sent from the client – TDS (tabular data stream) is the language which SQL Server speaks, and in order for applications to communicate with SQL Server, they need to pack the requests in TDS packets. TDS Packets sent from the client is the number of packets sent from the client; in case the request is large, then it may need more buffers, and eventually might even need more server roundtrips. TDS packets received from server –is the TDS packets sent by the server to the client during the query execution. Bytes sent from client – is the volume of the data set to our SQL Server, measured in bytes; i.e. how big of a query we have sent to the SQL Server. This is why it is best to use stored procedures, since the reusable code (which already exists as an object in the SQL Server) will only be called as a name of procedure + parameters, and this will minimize the network pressure. Bytes received from server – is the amount of data the SQL Server has sent to the client, measured in bytes. Depending on the number of rows and the datatypes involved, this number will vary. But still, think about the network load when you request data from SQL Server. Client processing time – is the amount of time spent in milliseconds between the first received response packet and the last received response packet by the client. Wait time on server replies – is the time in milliseconds between the last request packet which left the client and the first response packet which came back from the server to the client. Total execution time – is the sum of client processing time and wait time on server replies (the SQL Server internal processing time) Here is an illustration of the Client-server communication model which should help you understand the mutual waits in a client-server environment. Keep in mind that a query with a large ‘wait time on server replies’ means the server took a long time to produce the very first row. This is usual on queries that have operators that need the entire sub-query to evaluate before they proceed (for example, sort and top operators). However, a query with a very short ‘wait time on server replies’ means that the query was able to return the first row fast. However a long ‘client processing time’ does not necessarily imply the client spent a lot of time processing and the server was blocked waiting on the client. It can simply mean that the server continued to return rows from the result and this is how long it took until the very last row was returned. The bottom line is that developers and DBAs should work together and think carefully of the resource utilization in the client-server environment. From experience I can say that so far I have seen only cases when the application developers and the Database developers are on their own and do not ask questions about the other party’s world. I would recommend using the Client Statistics tool during new development to track the performance of the queries, and also to find a synchronous way of utilizing resources between the client – server – client. Here is another example: think about similar setup as above, but add another server to the game. Let’s say that we keep our media on a separate server, and together with the data from our SQL Server we need to display some images on the webpage requested by our user. No matter how simple or complicated the logic to get the images is, if the images are 500kb each our users will get the page slowly and they will still think that there is something wrong with our data. Anyway, I don’t mean to get carried away too far from SQL Server. Instead, what I would like to say is that DBAs should also be aware of ‘the big picture’. I wrote a blog post a while back on this topic, and if you are interested, you can read it here about the big picture. And finally, here are some guidelines for monitoring the network performance and improving it: Run a trace and outline all queries that return more than 1000 rows (in Profiler you can actually filter and sort the captured trace by number of returned rows). This is not a set number; it is more of a guideline. The general thought is that no application user can consume that many rows at once. Ask yourself and your fellow-developers: ‘why?’. Monitor your network counters in Perfmon: Network Interface:Output queue length, Redirector:Network errors/sec, TCPv4: Segments retransmitted/sec and so on. Make sure to establish a good friendship with your network administrator (buy them coffee, for example J ) and get into a conversation about the network settings. Have them explain to you how the network cards are setup – are they standalone, are they ‘teamed’, what are the settings – full duplex and so on. Find some time to read a bit about networking. In this short blog post I hope I have turned your attention to ‘the big picture’ and the fact that there are other factors affecting our SQL Server, aside from its internal workings. As a further reading I would still highly recommend the Wait Stats series on this blog, also I would recommend you have the coffee break conversation with your network admin as soon as possible. This guest post is written by Feodor Georgiev. Read all the post in the Wait Types and Queue series. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL

    Read the article

  • SQL SERVER – Guest Post – Jonathan Kehayias – Wait Type – Day 16 of 28

    - by pinaldave
    Jonathan Kehayias (Blog | Twitter) is a MCITP Database Administrator and Developer, who got started in SQL Server in 2004 as a database developer and report writer in the natural gas industry. After spending two and a half years working in TSQL, in late 2006, he transitioned to the role of SQL Database Administrator. His primary passion is performance tuning, where he frequently rewrites queries for better performance and performs in depth analysis of index implementation and usage. Jonathan blogs regularly on SQLBlog, and was a coauthor of Professional SQL Server 2008 Internals and Troubleshooting. On a personal note, I think Jonathan is extremely positive person. In every conversation with him I have found that he is always eager to help and encourage. Every time he finds something needs to be approved, he has contacted me without hesitation and guided me to improve, change and learn. During all the time, he has not lost his focus to help larger community. I am honored that he has accepted to provide his views on complex subject of Wait Types and Queues. Currently I am reading his series on Extended Events. Here is the guest blog post by Jonathan: SQL Server troubleshooting is all about correlating related pieces of information together to indentify where exactly the root cause of a problem lies. In my daily work as a DBA, I generally get phone calls like, “So and so application is slow, what’s wrong with the SQL Server.” One of the funny things about the letters DBA is that they go so well with Default Blame Acceptor, and I really wish that I knew exactly who the first person was that pointed that out to me, because it really fits at times. A lot of times when I get this call, the problem isn’t related to SQL Server at all, but every now and then in my initial quick checks, something pops up that makes me start looking at things further. The SQL Server is slow, we see a number of tasks waiting on ASYNC_IO_COMPLETION, IO_COMPLETION, or PAGEIOLATCH_* waits in sys.dm_exec_requests and sys.dm_exec_waiting_tasks. These are also some of the highest wait types in sys.dm_os_wait_stats for the server, so it would appear that we have a disk I/O bottleneck on the machine. A quick check of sys.dm_io_virtual_file_stats() and tempdb shows a high write stall rate, while our user databases show high read stall rates on the data files. A quick check of some performance counters and Page Life Expectancy on the server is bouncing up and down in the 50-150 range, the Free Page counter consistently hits zero, and the Free List Stalls/sec counter keeps jumping over 10, but Buffer Cache Hit Ratio is 98-99%. Where exactly is the problem? In this case, which happens to be based on a real scenario I faced a few years back, the problem may not be a disk bottleneck at all; it may very well be a memory pressure issue on the server. A quick check of the system spec’s and it is a dual duo core server with 8GB RAM running SQL Server 2005 SP1 x64 on Windows Server 2003 R2 x64. Max Server memory is configured at 6GB and we think that this should be enough to handle the workload; or is it? This is a unique scenario because there are a couple of things happening inside of this system, and they all relate to what the root cause of the performance problem is on the system. If we were to query sys.dm_exec_query_stats for the TOP 10 queries, by max_physical_reads, max_logical_reads, and max_worker_time, we may be able to find some queries that were using excessive I/O and possibly CPU against the system in their worst single execution. We can also CROSS APPLY to sys.dm_exec_sql_text() and see the statement text, and also CROSS APPLY sys.dm_exec_query_plan() to get the execution plan stored in cache. Ok, quick check, the plans are pretty big, I see some large index seeks, that estimate 2.8GB of data movement between operators, but everything looks like it is optimized the best it can be. Nothing really stands out in the code, and the indexing looks correct, and I should have enough memory to handle this in cache, so it must be a disk I/O problem right? Not exactly! If we were to look at how much memory the plan cache is taking by querying sys.dm_os_memory_clerks for the CACHESTORE_SQLCP and CACHESTORE_OBJCP clerks we might be surprised at what we find. In SQL Server 2005 RTM and SP1, the plan cache was allowed to take up to 75% of the memory under 8GB. I’ll give you a second to go back and read that again. Yes, you read it correctly, it says 75% of the memory under 8GB, but you don’t have to take my word for it, you can validate this by reading Changes in Caching Behavior between SQL Server 2000, SQL Server 2005 RTM and SQL Server 2005 SP2. In this scenario the application uses an entirely adhoc workload against SQL Server and this leads to plan cache bloat, and up to 4.5GB of our 6GB of memory for SQL can be consumed by the plan cache in SQL Server 2005 SP1. This in turn reduces the size of the buffer cache to just 1.5GB, causing our 2.8GB of data movement in this expensive plan to cause complete flushing of the buffer cache, not just once initially, but then another time during the queries execution, resulting in excessive physical I/O from disk. Keep in mind that this is not the only query executing at the time this occurs. Remember the output of sys.dm_io_virtual_file_stats() showed high read stalls on the data files for our user databases versus higher write stalls for tempdb? The memory pressure is also forcing heavier use of tempdb to handle sorting and hashing in the environment as well. The real clue here is the Memory counters for the instance; Page Life Expectancy, Free List Pages, and Free List Stalls/sec. The fact that Page Life Expectancy is fluctuating between 50 and 150 constantly is a sign that the buffer cache is experiencing constant churn of data, once every minute to two and a half minutes. If you add to the Page Life Expectancy counter, the consistent bottoming out of Free List Pages along with Free List Stalls/sec consistently spiking over 10, and you have the perfect memory pressure scenario. All of sudden it may not be that our disk subsystem is the problem, but is instead an innocent bystander and victim. Side Note: The Page Life Expectancy counter dropping briefly and then returning to normal operating values intermittently is not necessarily a sign that the server is under memory pressure. The Books Online and a number of other references will tell you that this counter should remain on average above 300 which is the time in seconds a page will remain in cache before being flushed or aged out. This number, which equates to just five minutes, is incredibly low for modern systems and most published documents pre-date the predominance of 64 bit computing and easy availability to larger amounts of memory in SQL Servers. As food for thought, consider that my personal laptop has more memory in it than most SQL Servers did at the time those numbers were posted. I would argue that today, a system churning the buffer cache every five minutes is in need of some serious tuning or a hardware upgrade. Back to our problem and its investigation: There are two things really wrong with this server; first the plan cache is excessively consuming memory and bloated in size and we need to look at that and second we need to evaluate upgrading the memory to accommodate the workload being performed. In the case of the server I was working on there were a lot of single use plans found in sys.dm_exec_cached_plans (where usecounts=1). Single use plans waste space in the plan cache, especially when they are adhoc plans for statements that had concatenated filter criteria that is not likely to reoccur with any frequency.  SQL Server 2005 doesn’t natively have a way to evict a single plan from cache like SQL Server 2008 does, but MVP Kalen Delaney, showed a hack to evict a single plan by creating a plan guide for the statement and then dropping that plan guide in her blog post Geek City: Clearing a Single Plan from Cache. We could put that hack in place in a job to automate cleaning out all the single use plans periodically, minimizing the size of the plan cache, but a better solution would be to fix the application so that it uses proper parameterized calls to the database. You didn’t write the app, and you can’t change its design? Ok, well you could try to force parameterization to occur by creating and keeping plan guides in place, or we can try forcing parameterization at the database level by using ALTER DATABASE <dbname> SET PARAMETERIZATION FORCED and that might help. If neither of these help, we could periodically dump the plan cache for that database, as discussed as being a problem in Kalen’s blog post referenced above; not an ideal scenario. The other option is to increase the memory on the server to 16GB or 32GB, if the hardware allows it, which will increase the size of the plan cache as well as the buffer cache. In SQL Server 2005 SP1, on a system with 16GB of memory, if we set max server memory to 14GB the plan cache could use at most 9GB  [(8GB*.75)+(6GB*.5)=(6+3)=9GB], leaving 5GB for the buffer cache.  If we went to 32GB of memory and set max server memory to 28GB, the plan cache could use at most 16GB [(8*.75)+(20*.5)=(6+10)=16GB], leaving 12GB for the buffer cache. Thankfully we have SQL Server 2005 Service Pack 2, 3, and 4 these days which include the changes in plan cache sizing discussed in the Changes to Caching Behavior between SQL Server 2000, SQL Server 2005 RTM and SQL Server 2005 SP2 blog post. In real life, when I was troubleshooting this problem, I spent a week trying to chase down the cause of the disk I/O bottleneck with our Server Admin and SAN Admin, and there wasn’t much that could be done immediately there, so I finally asked if we could increase the memory on the server to 16GB, which did fix the problem. It wasn’t until I had this same problem occur on another system that I actually figured out how to really troubleshoot this down to the root cause.  I couldn’t believe the size of the plan cache on the server with 16GB of memory when I actually learned about this and went back to look at it. SQL Server is constantly telling a story to anyone that will listen. As the DBA, you have to sit back and listen to all that it’s telling you and then evaluate the big picture and how all the data you can gather from SQL about performance relate to each other. One of the greatest tools out there is actually a free in the form of Diagnostic Scripts for SQL Server 2005 and 2008, created by MVP Glenn Alan Berry. Glenn’s scripts collect a majority of the information that SQL has to offer for rapid troubleshooting of problems, and he includes a lot of notes about what the outputs of each individual query might be telling you. When I read Pinal’s blog post SQL SERVER – ASYNC_IO_COMPLETION – Wait Type – Day 11 of 28, I noticed that he referenced Checking Memory Related Performance Counters in his post, but there was no real explanation about why checking memory counters is so important when looking at an I/O related wait type. I thought I’d chat with him briefly on Google Talk/Twitter DM and point this out, and offer a couple of other points I noted, so that he could add the information to his blog post if he found it useful.  Instead he asked that I write a guest blog for this. I am honored to be a guest blogger, and to be able to share this kind of information with the community. The information contained in this blog post is a glimpse at how I do troubleshooting almost every day of the week in my own environment. SQL Server provides us with a lot of information about how it is running, and where it may be having problems, it is up to us to play detective and find out how all that information comes together to tell us what’s really the problem. This blog post is written by Jonathan Kehayias (Blog | Twitter). Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: MVP, Pinal Dave, PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

    Read the article

  • SQLAuthority News – Job Interviewing the Right Way (and for the Right Reasons) – Guest Post by Feodor Georgiev

    - by pinaldave
    Feodor Georgiev is a SQL Server database specialist with extensive experience of thinking both within and outside the box. He has wide experience of different systems and solutions in the fields of architecture, scalability, performance, etc. Feodor has experience with SQL Server 2000 and later versions, and is certified in SQL Server 2008. Feodor has written excellent article on Job Interviewing the Right Way. Here is his article in his own language. A while back I was thinking to start a blog post series on interviewing and employing IT personnel. At that time I had just read the ‘Smart and gets things done’ book (http://www.joelonsoftware.com/items/2007/06/05.html) and I was hyped up on some debatable topics regarding finding and employing the best people in the branch. I have no problem with hiring the best of the best; it’s just the definition of ‘the best of the best’ that makes things a bit more complicated. One of the fundamental books one can read on the topic of interviewing is the one mentioned above. If you have not read it, then you must do so; not because it contains the ultimate truth, and not because it gives the answers to most questions on the subject, but because the book contains an extensive set of questions about interviewing and employing people. Of course, a big part of these questions have different answers, depending on location, culture, available funds and so on. (What works in the US may not necessarily work in the Nordic countries or India, or it may work in a different way). The only thing that is valid regardless of any external factor is this: curiosity. In my belief there are two kinds of people – curious and not-so-curious; regardless of profession. Think about it – professional success is directly proportional to the individual’s curiosity + time of active experience in the field. (I say ‘active experience’ because vacations and any distractions do not count as experience :)  ) So, curiosity is the factor which will distinguish a good employee from the not-so-good one. But let’s shift our attention to something else for now: a few tips and tricks for successful interviews. Tip and trick #1: get your priorities straight. Your status usually dictates your priorities; for example, if the person looking for a job has just relocated to a new country, they might tend to ignore some of their priorities and overload others. In other words, setting priorities straight means to define the personal criteria by which the interview process is lead. For example, similar to the following questions can help define the criteria for someone looking for a job: How badly do I need a (any) job? Is it more important to work in a clean and quiet environment or is it important to get paid well (or both, if possible)? And so on… Furthermore, before going to the interview, the candidate should have a list of priorities, sorted by the most importance: e.g. I want a quiet environment, x amount of money, great helping boss, a desk next to a window and so on. Also it is a good idea to be prepared and know which factors can be compromised and to what extent. Tip and trick #2: the interview is a two-way street. A job candidate should not forget that the interview process is not a one-way street. What I mean by this is that while the employer is interviewing the potential candidate, the job seeker should not miss the chance to interview the employer. Usually, the employer and the candidate will meet for an interview and talk about a variety of topics. In a quality interview the candidate will be presented to key members of the team and will have the opportunity to ask them questions. By asking the right questions both parties will define their opinion about each other. For example, if the candidate talks to one of the potential bosses during the interview process and they notice that the potential manager has a hard time formulating a question, then it is up to the candidate to decide whether working with such person is a red flag for them. There are as many interview processes out there as there are companies and each one is different. Some bigger companies and corporates can afford pre-selection processes, 3 or even 4 stages of interviews, small companies usually settle with one interview. Some companies even give cognitive tests on the interview. Why not? In his book Joel suggests that a good candidate should be pampered and spoiled beyond belief with a week-long vacation in New York, fancy hotels, food and who knows what. For all I can imagine, an interview might even take place at the top of the Eifel tower (right, Mr. Joel, right?) I doubt, however, that this is the optimal way to capture the attention of a good employee. The ‘curiosity’ topic What I have learned so far in my professional experience is that opinions can be subjective. Plus, opinions on technology subjects can also be subjective. According to Joel, only hiring the best of the best is worth it. If you ask me, there is no such thing as best of the best, simply because human nature (well, aside from some physical limitations, like putting your pants on through your head :) ) has no boundaries. And why would it have boundaries? I have seen many curious and interesting people, naturally good at technology, though uninterested in it as one  can possibly be; I have also seen plenty of people interested in technology, who (in an ideal world) should have stayed far from it. At any rate, all of this sums up at the end to the ‘supply and demand’ factor. The interview process big-bang boils down to this: If there is a mutual benefit for both the employer and the potential employee to work together, then it all sorts out nicely. If there is no benefit, then it is much harder to get to a common place. Tip and trick #3: word-of-mouth is worth a thousand words Here I would just mention that the best thing a job candidate can get during the interview process is access to future team members or other employees of the new company. Nowadays the world has become quite small and everyone knows everyone. Look at LinkedIn, look at other professional networks and you will realize how small the world really is. Knowing people is a good way to become more approachable and to approach them. Tip and trick #4: Be confident. It is true that for some people confidence is as natural as breathing and others have to work hard to express it. Confidence is, however, a key factor in convincing the other side (potential employer or employee) that there is a great chance for success by working together. But it cannot get you very far if it’s not backed up by talent, curiosity and knowledge. Tip and trick #5: The right reasons What really bothers me in Sweden (and I am sure that there are similar situations in other countries) is that there is a tendency to fill quotas and to filter out candidates by criteria different from their skill and knowledge. In job ads I see quite often the phrases ‘positive thinker’, ‘team player’ and many similar hints about personality features. So my guess here is that discrimination has evolved to a new level. Let me clear up the definition of discrimination: ‘unfair treatment of a person or group on the basis of prejudice’. And prejudice is the ‘partiality that prevents objective consideration of an issue or situation’. In other words, there is not much difference whether a job candidate is filtered out by race, gender or by personality features – it is all a bad habit. And in reality, there is no proven correlation between the technology knowledge paired with skills and the personal features (gender, race, age, optimism). It is true that a significantly greater number of Darwin awards were given to men than to women, but I am sure that somewhere there is a paper or theory explaining the genetics behind this. J This topic actually brings to mind one of my favorite work related stories. A while back I was working for a big company with many teams involved in their processes. One of the teams was occupying 2 rooms – one had the team members and was full of light, colorful posters, chit-chats and giggles, whereas the other room was dark, lighted only by a single monitor with a quiet person in front of it. Later on I realized that the ‘dark room’ person was the guru and the ultimate problem-solving-brain who did not like the chats and giggles and hence was in a separate room. In reality, all severe problems which the chatty and cheerful team members could not solve and all emergencies were directed to ‘the dark room’. And thus all worked out well. The moral of the story: Personality has nothing to do with technology knowledge and skills. End of story. Summary: I’d like to stress the fact that there is no ultimately perfect candidate for a job, and there is no such thing as ‘best-of-the-best’. From my personal experience, the main criteria by which I measure people (co-workers and bosses) is the curiosity factor; I know from experience that the more curious and inventive a person is, the better chances there are for great achievements in their field. Related stories: (for extra credit) 1) Get your priorities straight. A while back as a consultant I was working for a few days at a time at different offices and for different clients, and so I was able to compare and analyze the work environments. There were two different places which I compared and recently I asked a friend of mine the following question: “Which one would you prefer as a work environment: a noisy office full of people, or a quiet office full of faulty smells because the office is rarely cleaned?” My friend was puzzled for a while, thought about it and said: “Hmm, you are talking about two different kinds of pollution… I will probably choose the second, since I can clean the workplace myself a bit…” 2) The interview is a two-way street. One time, during a job interview, I met a potential boss that had a hard time phrasing a question. At that particular time it was clear to me that I would not have liked to work under this person. According to my work religion, the properly asked question contains at least half of the answer. And if I work with someone who cannot ask a question… then I’d be doing double or triple work. At another interview, after the technical part with the team leader of the department, I was introduced to one of the team members and we were left alone for 5 minutes. I immediately jumped on the occasion and asked the blunt question: ‘What have you learned here for the past year and how do you like your job?’ The team member looked at me and said ‘Nothing really. I like playing with my cats at home, so I am out of here at 5pm and I don’t have time for much.’ I was disappointed at the time and I did not take the job offer. I wasn’t that shocked a few months later when the company went bankrupt. 3) The right reasons to take a job: personality check. A while back I was asked to serve as a job reference for a coworker. I agreed, and after some weeks I got a phone call from the company where my colleague was applying for a job. The conversation started with the manager’s question about my colleague’s personality and about their social skills. (You can probably guess what my internal reaction was… J ) So, after 30 minutes of pouring common sense into the interviewer’s head, we finally agreed on the fact that a shy or quiet personality has nothing to do with work skills and knowledge. Some years down the road my former colleague is taking the manager’s position as the manager is demoted to a different department. Reference: Feodor Georgiev, Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • Can I implement the readers and writers algorithm in OpenMP by replacing counting semaphores with another feature?

    - by DeveloperDon
    After reading about OpenMP and not finding functions to support semaphores, I did an internet search for OpenMP and the readers and writers problem, but found no suitable matches. Is there a general method for replacing counting semaphores in OpenMP with something that it supports? Or is there just a gap in the environment where it does not permit things that are asymmetrical like the third readers and writers problem shown on the following page? http://en.wikipedia.org/wiki/Readers-writers_problem#The_third_readers-writers_problem

    Read the article

  • Programmer avec les pieds, ça vous tente ? "SoftStep KeyWorx" améliore la productivité en mettant les orteils à contribution

    Programmer avec les pieds, ça vous tente ? "SoftStep KeyWorx" améliore la productivité en mettant à contribution les orteils Alors que les doigts du développeur se déchaînent à longueur de journée sur les centaines de touches de raccourci de son IDE qu'il maîtrise par coeur, ses pieds restent toujours posés sur le sol, inertes, ou même sur un pouf pour les mieux gâtés. Autant d'appendices inutiles sept heures par jour, voire deux fois plus pour beaucoup de geeks et bourreaux de travail ? Pour Keith McMillen Instruments, c'est du passé grâce à SoftStep KeyWorx, un nouveau gadget USB, destiné à mettre à contribution les pieds pour que la programmation devien...

    Read the article

  • A plugin is preventing Eclipse from starting up

    - by Mahmoud Hossam
    It just gives me a blank window, and the splash screen doesn't go away. I tried running it in a terminal, turns out it's a problematic plugin. Is there a way to disable that plugin without the GUI? There's the error log: [org.eclipse.contribution.weaving.jdt] error at org/eclipse/contribution/jdt/IsWovenTester.aj::0 class 'org.eclipse.contribution.jdt.IsWovenTester' is already woven and has not been built in reweavable mode [org.eclipse.contribution.weaving.jdt] error at org/eclipse/contribution/jdt/IsWovenTester.aj::0 class 'org.eclipse.contribution.jdt.IsWovenTester$WeavingMarker' is already woven and has not been built in reweavable mode [org.eclipse.jdt.core] warning at org/eclipse/contribution/jdt/sourceprovider/SourceTransformerAspect.aj:106::0 does not match because declaring type is org.eclipse.jdt.core.IOpenable, if match desired use target(org.eclipse.jdt.core.ICompilationUnit) [Xlint:unmatchedSuperTypeInCall] see also: org/eclipse/jdt/internal/core/SourceRefElement.java:198::0 [org.eclipse.jdt.ui] warning at org/eclipse/contribution/jdt/sourceprovider/SourceTransformerAspect.aj:106::0 does not match because declaring type is org.eclipse.jdt.core.ITypeRoot, if match desired use target(org.eclipse.jdt.core.ICompilationUnit) [Xlint:unmatchedSuperTypeInCall] see also: org/eclipse/jdt/internal/ui/javaeditor/ASTProvider.java:572::0 [org.eclipse.contribution.weaving.jdt] error at org/eclipse/contribution/jdt/sourceprovider/SourceTransformerAspect.aj::0 class 'org.eclipse.contribution.jdt.sourceprovider.SourceTransformerAspect' is already woven and has not been built in reweavable mode [org.eclipse.contribution.weaving.jdt] error at org/eclipse/contribution/jdt/cuprovider/CompilationUnitProviderAspect.aj::0 class 'org.eclipse.contribution.jdt.cuprovider.CompilationUnitProviderAspect' is already woven and has not been built in reweavable mode [ScalaPlugin] [scalaLibBundle] Found 0 bundles: LogFilter.isLoggable threw a non-fatal unchecked exception as follows: java.lang.NullPointerException at org.eclipse.core.internal.runtime.Log.isLoggable(Log.java:101) at org.eclipse.equinox.log.internal.ExtendedLogReaderServiceFactory.safeIsLoggable(ExtendedLogReaderServiceFactory.java:59) at org.eclipse.equinox.log.internal.ExtendedLogReaderServiceFactory.logPrivileged(ExtendedLogReaderServiceFactory.java:164) at org.eclipse.equinox.log.internal.ExtendedLogReaderServiceFactory.log(ExtendedLogReaderServiceFactory.java:150) at org.eclipse.equinox.log.internal.ExtendedLogServiceFactory.log(ExtendedLogServiceFactory.java:65) at org.eclipse.equinox.log.internal.ExtendedLogServiceImpl.log(ExtendedLogServiceImpl.java:87) at org.eclipse.equinox.log.internal.LoggerImpl.log(LoggerImpl.java:54) at org.eclipse.core.internal.runtime.Log.log(Log.java:60) at scala.tools.eclipse.util.DefaultLogger.warning(DefaultLogger.scala:46) at scala.tools.eclipse.ScalaPlugin$$anonfun$3.apply(ScalaPlugin.scala:131) at scala.tools.eclipse.ScalaPlugin$$anonfun$3.apply(ScalaPlugin.scala:130) at scala.Option.getOrElse(Option.scala:108) at scala.tools.eclipse.ScalaPlugin.<init>(ScalaPlugin.scala:130) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:525) at java.lang.Class.newInstance0(Class.java:372) at java.lang.Class.newInstance(Class.java:325) at org.eclipse.osgi.framework.internal.core.AbstractBundle.loadBundleActivator(AbstractBundle.java:166) at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:679) at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381) at org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:299) at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:440) at org.eclipse.osgi.internal.loader.BundleLoader.setLazyTrigger(BundleLoader.java:268) at org.eclipse.core.runtime.internal.adaptor.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107) at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:462) at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:216) at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:400) at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:476) at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:429) at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:417) at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107) at java.lang.ClassLoader.loadClass(ClassLoader.java:356) at org.eclipse.osgi.internal.loader.BundleLoader.loadClass(BundleLoader.java:345) at org.eclipse.osgi.framework.internal.core.BundleHost.loadClass(BundleHost.java:229) at org.eclipse.osgi.framework.internal.core.AbstractBundle.loadClass(AbstractBundle.java:1207) at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:174) at org.eclipse.core.internal.registry.ExtensionRegistry.createExecutableExtension(ExtensionRegistry.java:905) at org.eclipse.core.internal.registry.ConfigurationElement.createExecutableExtension(ConfigurationElement.java:243) at org.eclipse.core.internal.registry.ConfigurationElementHandle.createExecutableExtension(ConfigurationElementHandle.java:55) at org.eclipse.contribution.jdt.cuprovider.CompilationUnitProviderRegistry.registerProviders(CompilationUnitProviderRegistry.java:69) at org.eclipse.contribution.jdt.cuprovider.CompilationUnitProviderRegistry.getProvider(CompilationUnitProviderRegistry.java:46) at org.eclipse.contribution.jdt.cuprovider.CompilationUnitProviderAspect.ajc$inlineAccessMethod$org_eclipse_contribution_jdt_cuprovider_CompilationUnitProviderAspect$org_eclipse_contribution_jdt_cuprovider_CompilationUnitProviderRegistry$getProvider(CompilationUnitProviderAspect.aj:1) at org.eclipse.jdt.internal.core.PackageFragment.init$_aroundBody7$advice(PackageFragment.java:47) at org.eclipse.jdt.internal.core.PackageFragment.getCompilationUnit(PackageFragment.java:216) at org.eclipse.jdt.internal.core.JavaModelManager.createCompilationUnitFrom(JavaModelManager.java:962) at org.eclipse.jdt.internal.core.JavaModelManager.create(JavaModelManager.java:871) at org.eclipse.jdt.core.JavaCore.create(JavaCore.java:2622) at org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitDocumentProvider.createCompilationUnit(CompilationUnitDocumentProvider.java:941) at org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitDocumentProvider.createFileInfo(CompilationUnitDocumentProvider.java:974) at org.eclipse.ui.editors.text.TextFileDocumentProvider.connect(TextFileDocumentProvider.java:478) at org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitDocumentProvider.connect(CompilationUnitDocumentProvider.java:1243) at org.eclipse.ui.texteditor.AbstractTextEditor.doSetInput(AbstractTextEditor.java:4213) at org.eclipse.ui.texteditor.StatusTextEditor.doSetInput(StatusTextEditor.java:237) at org.eclipse.ui.texteditor.AbstractDecoratedTextEditor.doSetInput(AbstractDecoratedTextEditor.java:1451) at org.eclipse.jdt.internal.ui.javaeditor.JavaEditor.internalDoSetInput(JavaEditor.java:2563) at org.eclipse.jdt.internal.ui.javaeditor.JavaEditor.doSetInput(JavaEditor.java:2536) at org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitEditor.doSetInput(CompilationUnitEditor.java:1395) at org.eclipse.ui.texteditor.AbstractTextEditor$19.run(AbstractTextEditor.java:3200) at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:464) at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:372) at org.eclipse.jface.window.ApplicationWindow$1.run(ApplicationWindow.java:759) at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70) at org.eclipse.jface.window.ApplicationWindow.run(ApplicationWindow.java:756) at org.eclipse.ui.internal.WorkbenchWindow.run(WorkbenchWindow.java:2642) at org.eclipse.ui.texteditor.AbstractTextEditor.internalInit(AbstractTextEditor.java:3218) at org.eclipse.ui.texteditor.AbstractTextEditor.init(AbstractTextEditor.java:3245) at org.eclipse.ui.internal.EditorManager.createSite(EditorManager.java:828) at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:647) at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:465) at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595) at org.eclipse.ui.internal.EditorAreaHelper.setVisibleEditor(EditorAreaHelper.java:271) at org.eclipse.ui.internal.EditorManager.setVisibleEditor(EditorManager.java:1459) at org.eclipse.ui.internal.EditorManager$5.runWithException(EditorManager.java:972) at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31) at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135) at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3563) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3212) at org.eclipse.ui.application.WorkbenchAdvisor.openWindows(WorkbenchAdvisor.java:803) at org.eclipse.ui.internal.Workbench$33.runWithException(Workbench.java:1595) at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31) at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135) at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3563) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3212) at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604) at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2494) at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:674) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:667) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149) at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123) at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:601) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577) at org.eclipse.equinox.launcher.Main.run(Main.java:1410) at org.eclipse.equinox.launcher.Main.main(Main.java:1386) [StartupDiagnostics$] startup diagnostics: previous version = 2.0.0.rc01-2_09-201111091447-ce49e0a [StartupDiagnostics$] startup diagnostics: CURRENT version = 2.0.0.rc01-2_09-201111091447-ce49e0a [ScalaPlugin] Scala compiler bundle: reference:file:plugins/org.scala-ide.scala.compiler_2.9.2.r25964-b20111108034957.jar [org.eclipse.jdt.core] warning at org/eclipse/contribution/jdt/sourceprovider/SourceTransformerAspect.aj:106::0 does not match because declaring type is org.eclipse.jdt.core.IOpenable, if match desired use target(org.eclipse.jdt.core.ICompilationUnit) [Xlint:unmatchedSuperTypeInCall] see also: org/eclipse/jdt/internal/core/LocalVariable.java:363::0 [org.eclipse.contribution.weaving.jdt] error at org/eclipse/contribution/jdt/imagedescriptor/ImageDescriptorSelectorAspect.aj::0 class 'org.eclipse.contribution.jdt.imagedescriptor.ImageDescriptorSelectorAspect' is already woven and has not been built in reweavable mode [org.eclipse.jdt.ui] warning at org/eclipse/contribution/jdt/sourceprovider/SourceTransformerAspect.aj:106::0 does not match because declaring type is org.eclipse.jdt.core.IOpenable, if match desired use target(org.eclipse.jdt.core.ICompilationUnit) [Xlint:unmatchedSuperTypeInCall] see also: org/eclipse/jdt/internal/ui/text/java/hover/JavadocHover.java:630::0 [org.eclipse.contribution.weaving.jdt] error at org/eclipse/contribution/jdt/itdawareness/ITDAwarenessAspect.aj::0 class 'org.eclipse.contribution.jdt.itdawareness.ITDAwarenessAspect' is already woven and has not been built in reweavable mode [ScalaPlugin] open Ride.java

    Read the article

  • SQLAuthority News – SQL SERVER 2008 R2 Pricing

    - by pinaldave
    I was recently asked question about SQL Server 2008 pricing. I have bookmarked official site here which lists the pricing. Official site: What’s New in SQL Server 2008 R2 Editions Editions Per Processor PricingRetail Per Server Plus CAL PricingRetail Parallel Data Warehouse $57,498 Not offered via Server CAL Datacenter $57,498 Not offered via Server CAL Enterprise $28,749 $13,969 with 25 CALs Standard $7,499 $1,849 with 5 CALs However, I have [...]

    Read the article

  • What You Said: What’s on Your Geeky Christmas List

    - by Jason Fitzpatrick
    Earlier this week we asked you to share what’s on your geeky Christmas list; you responded and we’re back to share your longed for tech goodies. The most requested item was this year’s hot introduction to the project board market: the Raspberry Pi. Dave writes: A Rapsberry Pi to tinker with, especially to see if I can get it up and running with OpenElec/Raspbmc and a torrent client for a low power media centre/htpc We just finished setting up a batch of new 512MB Raspberry Pi systems running the newest release of Rasbmbc and can’t recommend it enough–new refinements in Raspbmc and the extra 256MB of RAM really improve the media center experience. All John wants is a real keyboard so he can escape the torture of using a touch screen: How to Factory Reset Your Android Phone or Tablet When It Won’t Boot Our Geek Trivia App for Windows 8 is Now Available Everywhere How To Boot Your Android Phone or Tablet Into Safe Mode

    Read the article

  • Congratulations 2010 Microsoft MVP, woo hoo 5th time now

    - by ssqa.net
    Well, its April 01st again and a big day for me 2 important events to note (daughter's birthday and MVP renewal notification). After a long travel from London to Hyderabad after speaking at UK AIC 2010 conference, I was able to make it by half day here for my daughter's birthday, phew. Then next one awaiting official confirmation about MVP renewal (April - Mar cycle), woo hooo here is one.... Dear Satya Jayanty, Congratulations! We are pleased to present you with the 2010 Microsoft® MVP Award...(read more)

    Read the article

  • What You Said: Do You Use the Command Line?

    - by Jason Fitzpatrick
    Earlier this week we asked you to sound off with your love (or lack there of) for the command line. You sounded off in force and now we’re back with a comment roundup. It turns out you all pretty much love the command line with that love ranging from not even liking Graphic User Interfaces (GUIs) to using the command line to get serious work done but having a long standing affair with your OS’s GUI. Many of you lamented the poor command line implementation in Windows—especially after you’d had experience with other operation systems. Mike writes: Of course. Some things are easier that was. Like ping and ipconfig. With a strong Unix background I still write and use batch files. It would be nice is the command line included more nice things like grep, sleep, touch. Maybe, someday, Windows will mature into a full OS. What is a Histogram, and How Can I Use it to Improve My Photos?How To Easily Access Your Home Network From Anywhere With DDNSHow To Recover After Your Email Password Is Compromised

    Read the article

  • Author has inserted copyright into code with gnu public license notice - implications?

    - by Nicholas Pickering
    I've found a project on Github that I'm interested in contributing to which claims to be open source and has a GPL license included with it. But the original author has added a copyright notification to each source file. I'm not sure why but I don't feel right contributing to a project that's always going to have someone else's name on it. It really breaks the community-created feel, and makes me uneasy about what the author might choose to do with the project next. What are the implications of copyrighting open source GPL code as so? What power does this give the original author over a contributor? # Copyright (C) 2012, 2013 __AUTHORNAME__ # This file is part of __PROJECTNAME__. # # __PROJECTNAME__ is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # __PROJECTNAME__ is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License

    Read the article

  • What You Said: Your Tech Spring Cleaning Routines

    - by Jason Fitzpatrick
    Earlier this week we asked you to share your tech spring cleaning routine; now we’re back to highlight your tips, tricks, and techniques. What tools rule the spring cleaning roost? Compressed air and microfiber cloths are the tools of choice by a wide margin. D^Angelo highlights the software and physicals tools he uses: Backup all the important stuff just to be safe (c:/, my documents, desktop, drivers) Cleaning the dust with some office depot compressed air, avoiding spinning the fans. Use a brush for that small places (fans, memory, capacitors, etc). Use some dielectric spray on the motherboard. If the pc turned on without problems its time to use ccleaner, Check if there is a toolbar installed or another unusual software that I don’t want. Run my antivirus software or malwarebytes; some defraggler maybe. Make Your Own Windows 8 Start Button with Zero Memory Usage Reader Request: How To Repair Blurry Photos HTG Explains: What Can You Find in an Email Header?

    Read the article

  • Reader Poll: Are You Going to Buy the New iPad 2?

    - by Jason Fitzpatrick
    Steve Jobs announced the iPad 2 moments ago which will touch off a flurry of new purchases, upgrades, and general Apple-centric muttering and fist shaking. Will you be buying an iPad 2? Photo courtesy of Endgadget’s liveblog coverage of the iPad 2 launch. The first iPad sales exceeded everyones expectations, Apple fans and detractors alike, with a crazy 15 million units moved last year. The new iPad rocks a dual-core processor, a front and rear-facing camera, improved graphics, and a razor thinness (33% thinner than the current model), among other improvements. Are the improvements enough to entice you into buying one? Hit up the poll below to log your vote and then fill in the details in the comments. How-To Geek Polls require Javascript. Please Click Here to View the Poll. Latest Features How-To Geek ETC Learn To Adjust Contrast Like a Pro in Photoshop, GIMP, and Paint.NET Have You Ever Wondered How Your Operating System Got Its Name? Should You Delete Windows 7 Service Pack Backup Files to Save Space? What Can Super Mario Teach Us About Graphics Technology? Windows 7 Service Pack 1 is Released: But Should You Install It? How To Make Hundreds of Complex Photo Edits in Seconds With Photoshop Actions Add a “Textmate Style” Lightweight Text Editor with Dropbox Syncing to Chrome and Iron Is the Forcefield Really On or Not? [Star Wars Parody Video] Google Updates Picasa Web Albums; Emphasis on Sharing and Showcasing Uwall.tv Turns YouTube into a Video Jukebox Early Morning Sunrise at the Beach Wallpaper Data Networks Visualized via Light Paintings [Video]

    Read the article

  • What You Said: Your Favorite Windows Customization Tricks

    - by Jason Fitzpatrick
    Earlier this week we asked you to share your favorite Windows customization tricks and now we’re back to highlight some of the tips, tricks, and tweaks you shared. Your customization tips ranged from cosmetic to behind the scenes tweaks and offered a wide variety of ways to customize the Windows experience. Ted Lilley’s favorite must-have tweak involves Windows Explorer: The most fundamental change I make to Windows 7 is to immediately add tabs to Explorer via the QTTabbar add-on. I also add the good old cut/copy/paste/delete/new folder buttons alongside the tabs by installing Classic Shell (I skip Classic Start). Robin sets up virtual desktops: How to Use an Xbox 360 Controller On Your Windows PC Download the Official How-To Geek Trivia App for Windows 8 How to Banish Duplicate Photos with VisiPic

    Read the article

  • What You Said: How You Organize Your Apps

    - by Jason Fitzpatrick
    Earlier this week we asked you to share your tips and tricks for keeping your apps organized and accessible; now we’re back to showcase some great reader tips to help you manage your mountain of apps. One of the trends was striving for consistency across environments. Henrique highlights how this plays out on a dual OS setup: On my windows desktop I use the taskbar and to keep my day to day applications (basically firefox, itunes, office, adobe, evernote and wunderkit), and whenever I need something else, I use windows built in search, which is quite fast, despite needing a few more clicks than spotlight would. On my macbook the dock is basically mirrors my taskbar, and I use spotlight for other applications, but launchpad is wining my heart a bit more every day. It’s faster then than accessing the applications folder and the windows start menu, and possibly even than spotlight, at least for apps How To Properly Scan a Photograph (And Get An Even Better Image) The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage

    Read the article

  • What You Said: How You Customize Your Computer

    - by Jason Fitzpatrick
    Earlier this week we asked you to share the ways you customize your computing experience. You sounded off in the comments and we rounded up your tips and tricks to share. Read on to see how your fellow personalize their computers. It would seem the first stop on just about everyone’s customization route is stripping away the bloat/crapware. Lisa Wang writes: Depending on how much time I have when I receive my new machine,I might do the following in a few batches, starting with the simplest one. Usually, my list goes like this:1.Remove all bloatware and pretty much unneeded stuffs.2.Change my wallpaper,login screen,themes, and sound.3.Installing my ‘must-have’ softwares-starting with fences and rocketdock+stacks plugin4.Setting taskbar to autohide, pinning some apps there5.Installing additional languages6.Tweaking all settings and keyboard shortcuts to my preferance7.Changing the icons(either manual or with TuneUp Styler) Interface tweaks like the aforementioned Fences and Rocket Dock made quite a few appearances, as did Rainmeter. Graphalfkor writes: How to Stress Test the Hard Drives in Your PC or Server How To Customize Your Android Lock Screen with WidgetLocker The Best Free Portable Apps for Your Flash Drive Toolkit

    Read the article

  • What makes a person contribute to opensource? [duplicate]

    - by Jibin
    This question already has an answer here: Why develop free, open source programs? [closed] 14 answers I know this is controversial, but.. There are many great projects like Apache Webserver or Hadoop provided by the OpenSource Community. I often feel that the people that actually benefit (financially), from these projects are developers like me, sitting in India, working for MNCs, who has never contributed anything to any opensource project so far, but earn handsomely due to my basic googling skills & the community provided documentation. Is it fair ? I mean no other industry in the world face such dilemma.Those who work get paid. I mean I almost am starting to feel guilty of taking such advantage of some thing that I contribute nothing to. I had to do projects every semester in college (we could choose projects) & I used to enjoy coding then. I want to contribute. But contributing to opensource is not a task [unlike college or office work]. And life is so busy .. Are all these opensource contributors really jobless ?[just kidding..] Could someone please share some personal experiences on how you guys started contributing or any advice on why I should contribute or what attitude in life makes you keep aside time or is it that you just crazly love writing code or is it that you just love to see your name in the contributors list or do you have a local coding group you hang out with ? Do you feel I am destined to do this ? This is my part of contributing back to the world ? Whats that basic mentality that make you guys want to contribute, while I just want to finish my work and go home. What makes you guys tick ?

    Read the article

  • What You Said: How You Monitor Your Computer

    - by Jason Fitzpatrick
    Earlier this week we asked you to share your computer monitoring tips and tricks, now we’re back to share the wealth. Read on to see how your fellow reader monitor their gear. One of the more popular monitoring tools, thanks in part to the amount of things beyond just hardware it can monitor, in the comments was Rainmeter. Lee writes: I don’t really monitor my computer constantly, only when something is hanging up and I need to see what’s causing it. That being said, I do have Rainmeter so I can quickly see how much RAM or CPU is being used. For anything more detailed, I just go into the task manager and sort by RAM or CPU. Shinigamibob uses a wider range of tools to get a more in-depth look at difference aspects of his computer: 7 Ways To Free Up Hard Disk Space On Windows HTG Explains: How System Restore Works in Windows HTG Explains: How Antivirus Software Works

    Read the article

  • Do you think asking to sign contributor license agreement for a open source project creates a resistance for contributors?

    - by Appu
    I am working on a open-source project which is backed by an organization. Organization pays a team to make this open-source project. This project will be licensed with GPLv3. We are debating on having a CLA for contributors. Do you think mandating a CLA will reduce the number of contributors? I have observed that people have no issues in signing a CLA when the project is really popular. So do you think CLA will create a resistance to contribute?

    Read the article

  • What You Said: Cutting the Cable Cord

    - by Jason Fitzpatrick
    Earlier this week we asked you if you’d cut the cable and switched to alternate media sources to get your movie and TV fix. You responded and we’re back with a What You Said roundup. One of the recurrent themes in reader comments and one, we must admit, we didn’t expect to see with such prevalence, was the number of people who had ditched cable for over-the-air HD broadcasts. Fantasm writes: I have a triple HD antenna array, mounted on an old tv tower, each antenna facing out from a different side of the triangular tower. On tope of the tower are two 20+ year old antennas… I’m 60 miles from toronto and get 35 channels, most in brilliant HD… Anything else, comes from the Internet… Never want cable or sat again… Grant uses a combination of streaming services and, like Fantasm, manages to pull in HD content with a nice antenna setup: We use Netflix, Hulu Plus, Amazon Prime, Crackle, and others on a Roku as well as OTA on a Tivo Premier. The Tivo is simply the best DVR interface I have ever used. The Tivo Netflix application, though, is terrible, and it does not support Amazon Prime. Having both boxes makes it easy to use all of the services. 6 Ways Windows 8 Is More Secure Than Windows 7 HTG Explains: Why It’s Good That Your Computer’s RAM Is Full 10 Awesome Improvements For Desktop Users in Windows 8

    Read the article

< Previous Page | 2 3 4 5 6 7 8 9 10 11 12 13  | Next Page >