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  • SQL SERVER – Tricks to Replace SELECT * with Column Names – SQL in Sixty Seconds #017 – Video

    - by pinaldave
    You might have heard many times that one should not use SELECT * as there are many disadvantages to the usage of the SELECT *. I also believe that there are always rare occasion when we need every single column of the query. In most of the cases, we only need a few columns of the query and we should retrieve only those columns. SELECT * has many disadvantages. Let me list a few and remaining you can add as a comment.  Retrieves unnecessary columns and increases network traffic When a new columns are added views needs to be refreshed manually Leads to usage of sub-optimal execution plan Uses clustered index in most of the cases instead of using optimal index It is difficult to debug. There are two quick tricks I have discussed in the video which explains how users can avoid using SELECT * but instead list the column names. 1) Drag the columns folder from SQL Server Management Studio to Query Editor 2) Right Click on Table Name >> Script TAble AS >> SELECT To… >> Select option It is extremely easy to list the column names in the table. In today’s sixty seconds video, you will notice that I was able to demonstrate both the methods very quickly. From now onwards there should be no excuse for not listing ColumnName. Let me ask a question back – is there ever a reason to SELECT *? If yes, would you please share that as a comment. More on SELECT *: SQL SERVER – Solution – Puzzle – SELECT * vs SELECT COUNT(*) SQL SERVER – Puzzle – SELECT * vs SELECT COUNT(*) SQL SERVER – SELECT vs. SET Performance Comparison I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. If we like your idea we promise to share with you educational material. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology, Video

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  • Partition Wise Joins II

    - by jean-pierre.dijcks
    One of the things that I did not talk about in the initial partition wise join post was the effect it has on resource allocation on the database server. When Oracle applies a different join method - e.g. not PWJ - what you will see in SQL Monitor (in Enterprise Manager) or in an Explain Plan is a set of producers and a set of consumers. The producers scan the tables in the the join. If there are two tables the producers first scan one table, then the other. The producers thus provide data to the consumers, and when the consumers have the data from both scans they do the join and give the data to the query coordinator. Now that behavior means that if you choose a degree of parallelism of 4 to run such query with, Oracle will allocate 8 parallel processes. Of these 8 processes 4 are producers and 4 are consumers. The consumers only actually do work once the producers are fully done with scanning both sides of the join. In the plan above you can see that the producers access table SALES [line 11] and then do a PX SEND [line 9]. That is the producer set of processes working. The consumers receive that data [line 8] and twiddle their thumbs while the producers go on and scan CUSTOMERS. The producers send that data to the consumer indicated by PX SEND [line 5]. After receiving that data [line 4] the consumers do the actual join [line 3] and give the data to the QC [line 2]. BTW, the myth that you see twice the number of processes due to the setting PARALLEL_THREADS_PER_CPU=2 is obviously not true. The above is why you will see 2 times the processes of the DOP. In a PWJ plan the consumers are not present. Instead of producing rows and giving those to different processes, a PWJ only uses a single set of processes. Each process reads its piece of the join across the two tables and performs the join. The plan here is notably different from the initial plan. First of all the hash join is done right on top of both table scans [line 8]. This query is a little more complex than the previous so there is a bit of noise above that bit of info, but for this post, lets ignore that (sort stuff). The important piece here is that the PWJ plan typically will be faster and from a PX process number / resources typically cheaper. You may want to look out for those plans and try to get those to appear a lot... CREDITS: credits for the plans and some of the info on the plans go to Maria, as she actually produced these plans and is the expert on plans in general... You can see her talk about explaining the explain plan and other optimizer stuff over here: ODTUG in Washington DC, June 27 - July 1 On the Optimizer blog At OpenWorld in San Francisco, September 19 - 23 Happy joining and hope to see you all at ODTUG and OOW...

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  • General monitoring for SQL Server Analysis Services using Performance Monitor

    - by Testas
    A recent customer engagement required a setup of a monitoring solution for SSAS, due to the time restrictions placed upon this, native Windows Performance Monitor (Perfmon) and SQL Server Profiler Monitoring Tools was used as using a third party tool would have meant the customer providing an additional monitoring server that was not available.I wanted to outline the performance monitoring counters that was used to monitor the system on which SSAS was running. Due to the slow query performance that was occurring during certain scenarios, perfmon was used to establish if any pressure was being placed on the Disk, CPU or Memory subsystem when concurrent connections access the same query, and Profiler to pinpoint how the query was being managed within SSAS, profiler I will leave for another blogThis guide is not designed to provide a definitive list of what should be used when monitoring SSAS, different situations may require the addition or removal of counters as presented by the situation. However I hope that it serves as a good basis for starting your monitoring of SSAS. I would also like to acknowledge Chris Webb’s awesome chapters from “Expert Cube Development” that also helped shape my monitoring strategy:http://cwebbbi.spaces.live.com/blog/cns!7B84B0F2C239489A!6657.entrySimulating ConnectionsTo simulate the additional connections to the SSAS server whilst monitoring, I used ascmd to simulate multiple connections to the typical and worse performing queries that were identified by the customer. A similar sript can be downloaded from codeplex at http://www.codeplex.com/SQLSrvAnalysisSrvcs.     File name: ASCMD_StressTestingScripts.zip. Performance MonitorWithin performance monitor,  a counter log was created that contained the list of counters below. The important point to note when running the counter log is that the RUN AS property within the counter log properties should be changed to an account that has rights to the SSAS instance when monitoring MSAS counters. Failure to do so means that the counter log runs under the system account, no errors or warning are given while running the counter log, and it is not until you need to view the MSAS counters that they will not be displayed if run under the default account that has no right to SSAS. If your connection simulation takes hours, this could prove quite frustrating if not done beforehand JThe counters used……  Object Counter Instance Justification System Processor Queue legnth N/A Indicates how many threads are waiting for execution against the processor. If this counter is consistently higher than around 5 when processor utilization approaches 100%, then this is a good indication that there is more work (active threads) available (ready for execution) than the machine's processors are able to handle. System Context Switches/sec N/A Measures how frequently the processor has to switch from user- to kernel-mode to handle a request from a thread running in user mode. The heavier the workload running on your machine, the higher this counter will generally be, but over long term the value of this counter should remain fairly constant. If this counter suddenly starts increasing however, it may be an indicating of a malfunctioning device, especially if the Processor\Interrupts/sec\(_Total) counter on your machine shows a similar unexplained increase Process % Processor Time sqlservr Definately should be used if Processor\% Processor Time\(_Total) is maxing at 100% to assess the effect of the SQL Server process on the processor Process % Processor Time msmdsrv Definately should be used if Processor\% Processor Time\(_Total) is maxing at 100% to assess the effect of the SQL Server process on the processor Process Working Set sqlservr If the Memory\Available bytes counter is decreaing this counter can be run to indicate if the process is consuming larger and larger amounts of RAM. Process(instance)\Working Set measures the size of the working set for each process, which indicates the number of allocated pages the process can address without generating a page fault. Process Working Set msmdsrv If the Memory\Available bytes counter is decreaing this counter can be run to indicate if the process is consuming larger and larger amounts of RAM. Process(instance)\Working Set measures the size of the working set for each process, which indicates the number of allocated pages the process can address without generating a page fault. Processor % Processor Time _Total and individual cores measures the total utilization of your processor by all running processes. If multi-proc then be mindful only an average is provided Processor % Privileged Time _Total To see how the OS is handling basic IO requests. If kernel mode utilization is high, your machine is likely underpowered as it's too busy handling basic OS housekeeping functions to be able to effectively run other applications. Processor % User Time _Total To see how the applications is interacting from a processor perspective, a high percentage utilisation determine that the server is dealing with too many apps and may require increasing thje hardware or scaling out Processor Interrupts/sec _Total  The average rate, in incidents per second, at which the processor received and serviced hardware interrupts. Shoulr be consistant over time but a sudden unexplained increase could indicate a device malfunction which can be confirmed using the System\Context Switches/sec counter Memory Pages/sec N/A Indicates the rate at which pages are read from or written to disk to resolve hard page faults. This counter is a primary indicator of the kinds of faults that cause system-wide delays, this is the primary counter to watch for indication of possible insufficient RAM to meet your server's needs. A good idea here is to configure a perfmon alert that triggers when the number of pages per second exceeds 50 per paging disk on your system. May also want to see the configuration of the page file on the Server Memory Available Mbytes N/A is the amount of physical memory, in bytes, available to processes running on the computer. if this counter is greater than 10% of the actual RAM in your machine then you probably have more than enough RAM. monitor it regularly to see if any downward trend develops, and set an alert to trigger if it drops below 2% of the installed RAM. Physical Disk Disk Transfers/sec for each physical disk If it goes above 10 disk I/Os per second then you've got poor response time for your disk. Physical Disk Idle Time _total If Disk Transfers/sec is above  25 disk I/Os per second use this counter. which measures the percent time that your hard disk is idle during the measurement interval, and if you see this counter fall below 20% then you've likely got read/write requests queuing up for your disk which is unable to service these requests in a timely fashion. Physical Disk Disk queue legnth For the OLAP and SQL physical disk A value that is consistently less than 2 means that the disk system is handling the IO requests against the physical disk Network Interface Bytes Total/sec For the NIC Should be monitored over a period of time to see if there is anb increase/decrease in network utilisation Network Interface Current Bandwidth For the NIC is an estimate of the current bandwidth of the network interface in bits per second (BPS). MSAS 2005: Memory Memory Limit High KB N/A Shows (as a percentage) the high memory limit configured for SSAS in C:\Program Files\Microsoft SQL Server\MSAS10.MSSQLSERVER\OLAP\Config\msmdsrv.ini MSAS 2005: Memory Memory Limit Low KB N/A Shows (as a percentage) the low memory limit configured for SSAS in C:\Program Files\Microsoft SQL Server\MSAS10.MSSQLSERVER\OLAP\Config\msmdsrv.ini MSAS 2005: Memory Memory Usage KB N/A Displays the memory usage of the server process. MSAS 2005: Memory File Store KB N/A Displays the amount of memory that is reserved for the Cache. Note if total memory limit in the msmdsrv.ini is set to 0, no memory is reserved for the cache MSAS 2005: Storage Engine Query Queries from Cache Direct / sec N/A Displays the rate of queries answered from the cache directly MSAS 2005: Storage Engine Query Queries from Cache Filtered / Sec N/A Displays the Rate of queries answered by filtering existing cache entry. MSAS 2005: Storage Engine Query Queries from File / Sec N/A Displays the Rate of queries answered from files. MSAS 2005: Storage Engine Query Average time /query N/A Displays the average time of a query MSAS 2005: Connection Current connections N/A Displays the number of connections against the SSAS instance MSAS 2005: Connection Requests / sec N/A Displays the rate of query requests per second MSAS 2005: Locks Current Lock Waits N/A Displays thhe number of connections waiting on a lock MSAS 2005: Threads Query Pool job queue Length N/A The number of queries in the job queue MSAS 2005:Proc Aggregations Temp file bytes written/sec N/A Shows the number of bytes of data processed in a temporary file MSAS 2005:Proc Aggregations Temp file rows written/sec N/A Shows the number of bytes of data processed in a temporary file 

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  • SQLAuthority News – New Book Released – SQL Server Interview Questions And Answers

    - by pinaldave
    Two days ago, on birthday of my blog – I asked simple question – Guess! What is in this box? I have received lots of interesting comments on the blog about what is in it. Many of you got it absolutely incorrect and many got it close to the right answer but no one got it 100% correct. Well, no issue at all, I am going to give away the price to whoever has the closest answer first in personal email. Here is the answer to the question about what is in the box? Here it is – the box has my new book. In fact, I should say our new book as I co-authored this book with my very good friend Vinod Kumar. We had real blast writing this book together and had lots of interesting conversation when we were writing this book. This book has one simple goal – “master the basics.” This book is not only for people who are preparing for interview. This book is for every one who wants to revisit the basics and wants to prepare themselves to the technology. One always needs to have practical knowledge to do their duty efficiently. This book talks about more than basics. There are multiple ways to present learning – either we can create simple book or make it interesting. We have decided the learning should be interactive and have opted for Interview Questions and Answer format. Here is quick interview which we have done together. Details of the books are here The core concept of this book will continue to evolve over time. I am sure many of you will come along with us on this journey and submit your suggestions to us to make this book a key reference for anybody who wants to start with SQL server. Today we want to acknowledge the fact that you will help us keep this book alive forever with the latest updates. We want to thank everyone who participates in this journey with us. You can get the books from [Amazon] | [Flipkart]. Read Vinod‘s blog post. Do not forget to wish him happy birthday as today is his birthday and also book release day – two reason to wish him congratulations. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Best Practices, Data Warehousing, Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL Interview Questions and Answers, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Book Review, SQLAuthority News, SQLServer, T SQL, Technology

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  • Monitoring Your Servers

    - by Grant Fritchey
    If you are the DBA in a large scale enterprise, you’re probably already monitoring your servers for up-time and performance. But if you work for a medium-sized business, a small shop, or even a one-man operation, chances are pretty good that you’re not doing that sort of monitoring. You know that you’re supposed to be doing it, but other things, more important at-the-moment things, keep getting in the way. After all, which is more important, some monitoring or backup testing?  Backup testing, of course. Monitoring is frequently one of those things that you do when can get around to it.  Well, as you can see at the right, I have your round tuit ready to go. What if I told you that you could get monitoring on your servers for up-time, job completion, performance, all the standard stuff? And what if I told you that you wouldn’t need to install and configure another server in your environment to get it done? And what if I told you that you’d be able to set up and customize your alerts so you could know if your server was offline or a drive was full? Almost nothing for you to do, and you’ll have a full-blown monitoring process. Sounds to good to be true doesn’t it? Well, it’s coming. We’re creating an online, remote, monitoring system here at Red Gate. You’ll be able to use our SQL Monitor tool (which you can see here, monitoring SQL Server Central in real time) to keep track of your systems, but without having to set up a server and a database for storing the information collected. Instead, we’re taking advantage of services available through the internet to enable collection and storage of this information remotely, off your systems. All you have to do is install a piece of software that will communicate between our service and your servers and you’ll be off and running. It’s that easy. Before you get too excited, let me break the news that this is the near future I’m talking about. We’re setting up the program and there’s a sign-up you can use to get in on the initial tests.

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  • SQL SERVER – Validating Spatial Object with IsValidDetailed Function

    - by pinaldave
    What do you prefer – error or warning indicating error may happen with the reason for the error. While writing the previous statement I remember the movie “Minory Report”. This blog post is not about minority report but I will still cover the concept in a single statement “Let us predict the future and prevent the crime which is about to happen in future”. (Please feel free to correct me if I am wrong about the movie concept, I really do not want to hurt your sentiment if you are dedicated fan). Let us switch to the SQL Server world. Spatial data types are interesting concepts. I love writing about spatial data types because it allows me to be creative with shapes (just like toddlers). When working with Spatial Datatypes it is all good when the spatial object works fine. However, when the spatial object has issue or it is created with invalid coordinates it used to give a simple error that there is an issue with the object but did not provide much information. This made it very difficult to debug. If this spatial object was used in the big procedure and while this big procedural error out because of the invalid spatial object, it is indeed very difficult to debug it. I always wished that the more information provided regarding what is the problem with spatial datatype. SQL Server 2012 has introduced the new function IsValidDetailed(). This function has made my life very easy. In simple words this function will check if the spatial object passed is valid or not. If it is valid it will give information that it is valid. If the spatial object is not valid it will return the answer that it is not valid and the reason for the same. This makes it very easy to debug the issue and make the necessary correction. DECLARE @p GEOMETRY = 'Polygon((2 2, 6 6, 4 2, 2 2))' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'Polygon((2 2, 3 3, 4 4, 5 5, 6 6, 2 2))' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'Polygon((2 2, 4 4, 4 2, 2 3, 2 2))' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'CIRCULARSTRING(2 2, 4 4, 0 0)' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'CIRCULARSTRING(2 2, 4 4, 0 0)' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'LINESTRING(2 2, 4 4, 0 0)' SELECT @p.IsValidDetailed() GO Here is the resultset of the above query. You can see any valid query and some invalid query. If the query is invalid it also demonstrates the reason along with the error message. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Spatial Database, SQL Spatial

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  • SQLAuthority News – SQL Server Wait Stats – eBook to Download on Kindle – Answer to FREE PDF Download Request

    - by pinaldave
    Being a book author is a completely new experience for me. I am yet to come across the issues faced by expert book authors. I assume that these interesting issues can be routine ones for expert book authors. One of the biggest requests I am getting for my SQL Server Wait Stats [Amazon] | [Flipkart] | [Kindle] book is my humble attempt to write a book. This is our very first experiment, and the book is beginning of the subject of SQL Server Wait Stats; we will come up with a new version of the book later next year when we have enough information for the SQL Server 2012 version. Following are the top 2 requests that I keep on receiving in emails, on blogs, Twitter, and Facebook. “Please send us FREE PDF of your book so we do not have to purchase it.” “If you can share with us the eBook (free and downloadable) format of your book, we will share it with everybody we know and you will get additional exposure.” Here is my response for the abovementioned requests: If you really need my book and cannot purchase it due to financial trouble, then feel free to let me know and I will purchase it myself and ship it to you. If you are in a country where the print book not available, then you can buy the Kindle book, which is available online in any country, and you can just read it on your computer and mobile devices. You DO NOT have to own a Kindle to read a Kindle format book. You can freely download Kindle software on your desired format and purchase the book online. For next 5 days, the kindle book is available at 3.99 in USA, and in other countries, the price is anywhere between 3.99 and 5.99. The price will go up by USD 2 everywhere across the world after 1st November, 2011. Here is the link to download Kindle Software for free PC, WP7, and in marketplace for various other mobile devices. I thank you for giving warm response to SQL Server Wait Stats book. I am motivated to write the next expanded version of this book. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • How to suggest using an ORM instead of stored procedures?

    - by Wayne M
    I work at a company that only uses stored procedures for all data access, which makes it very annoying to keep our local databases in sync as every commit we have to run new procs. I have used some basic ORMs in the past and I find the experience much better and cleaner. I'd like to suggest to the development manager and rest of the team that we look into using an ORM Of some kind for future development (the rest of the team are only familiar with stored procedures and have never used anything else). The current architecture is .NET 3.5 written like .NET 1.1, with "god classes" that use a strange implementation of ActiveRecord and return untyped DataSets which are looped over in code-behind files - the classes work something like this: class Foo { public bool LoadFoo() { bool blnResult = false; if (this.FooID == 0) { throw new Exception("FooID must be set before calling this method."); } DataSet ds = // ... call to Sproc if (ds.Tables[0].Rows.Count > 0) { foo.FooName = ds.Tables[0].Rows[0]["FooName"].ToString(); // other properties set blnResult = true; } return blnResult; } } // Consumer Foo foo = new Foo(); foo.FooID = 1234; foo.LoadFoo(); // do stuff with foo... There is pretty much no application of any design patterns. There are no tests whatsoever (nobody else knows how to write unit tests, and testing is done through manually loading up the website and poking around). Looking through our database we have: 199 tables, 13 views, a whopping 926 stored procedures and 93 functions. About 30 or so tables are used for batch jobs or external things, the remainder are used in our core application. Is it even worth pursuing a different approach in this scenario? I'm talking about moving forward only since we aren't allowed to refactor the existing code since "it works" so we cannot change the existing classes to use an ORM, but I don't know how often we add brand new modules instead of adding to/fixing current modules so I'm not sure if an ORM is the right approach (too much invested in stored procedures and DataSets). If it is the right choice, how should I present the case for using one? Off the top of my head the only benefits I can think of is having cleaner code (although it might not be, since the current architecture isn't built with ORMs in mind so we would basically be jury-rigging ORMs on to future modules but the old ones would still be using the DataSets) and less hassle to have to remember what procedure scripts have been run and which need to be run, etc. but that's it, and I don't know how compelling an argument that would be. Maintainability is another concern but one that nobody except me seems to be concerned about.

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  • Real-Time Multi-User Gaming Platform

    - by Victor Engel
    I asked this question at Stack Overflow but was told it's more appropriate here, so I'm posting it again here. I'm considering developing a real-time multi-user game, and I want to gather some information about possibilities before I do some real development. I've thought about how best to ask the question, and for simplicity, the best way that occurred to me was to make an analogy to the field (or playground) game darebase. In the field game of darebase, there are two or more bases. To start, there is one team on each base. The game is a fancy game of tag. When two people meet out in the field, the person who left his base most recently timewise captures the other person. They then return to that person's base. Play continues until everyone is part of the same team. So, analogizing this to an online computer game, let's suppose there are an indefinite number of bases. When a person starts up the game, he has a team that is located at, for example, his current GPS coordinates. It could be a virtual world, but for sake of argument, let's suppose the virtual world corresponds to the player's actual GPS coordinates. The game software then consults the database to see where the closest other base is that is online, and the two teams play their game of virtual tag. Note that the user of the other base could have a different base than the one run by the current user as the closest base to him, in which case, he would be in two simultaneous battles, one with each base. When they go offline, the state of their players is saved on a server somewhere. Game logic calls for the players to have some automaton-logic of some sort, so they can fend for themselves in a limited way using basic rules, until their user goes online again. The user doesn't control the players' movements directly, but issues general directives that influence the players' movement logic. I think this analogy is good enough to frame my question. What sort of platforms are available to develop this sort of game? I've been looking at smartfoxserver, but I'm not convinced yet that it is the best option or even that it will work at all. One possibility, of course, would be to roll out my own web server, but I'd rather not do that if there is an existing service out there already that I could tap into. I will be developing for iOS devices at first. So any suggestions would be greatly appreciated. I think I need to establish the architecture first before proceeding with this project. Note that darbase is not the game I intend to implement, but, upon reflection, that might not be a bad idea either.

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  • Assessing Relative Maintainability

    - by João Bragança
    We (a contractor, actually) are implementing an off the shelf system to replace a legacy homegrown system for the core domain of the company (designing widgets). Unfortunately both systems will have to run concurrently for some time, as the product just isn't ready yet. Also, the decision was made to only migrate some of the widgets from the legacy system, based on date of last sale activity. Later on a new requirement came down: certain people in the company, most of them outside of the widget development context, want to search all widgets. The search results screen has 3 pieces of data: a GUID, a human readable id that is searchable, and a brief description (may need to be searchable in the future). In the widget details, there will be multiple screens. These screens align very well along SOA / bounded context lines - a screen for marketing data, a screen for sales history, etc. UML ahead! I am probably using the wrong kind of arrows here so please forgive me. The current solution - which is not in production yet - is something like the following: Both systems will be queried and the controller will merge the results. The new system has its own proprietary query language (we've alleviated this a bit with a LINQ provider). It also puts a lot of data on the wire. 15 search results typically run about 60k of unintelligible SOAP-wrapped xml. So I would prefer to avoid querying this system directly. These two systems publish events to help us integrate with other systems, mainly an ERP system. One of these events contains all the data necessary for the search screen. I proposed the following alternative: However I am being told that 'adding another database' will create more maintenance down the road. However, I believe this to be false, as I had to add a relatively simple feature that took several hours longer than anticipated because of this merging code. I want to get a feel for which system is more maintainable in the long run. I personally have not had the burden of maintaining any large system. I want something more than my gut. Specifically I'd like to know if having more, specialized physical databases is more or less maintainable than having less larger physical databases.

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  • How to make my Oracle update/insert action through Java faster?

    - by gunbuster363
    I am facing a problem in my company that is - our program's speed is not fast enough. To be more specific, we are telecommunication company and this program handle call/internet serfing transaction made by every mobile phone users in our city. Because the amount of download content made by the iphone users is just too much, our program cannot handle them fast enough. The situation is, the amount of transaction made by users are double of the transaction processed by our program. Most of the running time of the program are dominated by DB transactions. I've search through the internet and browsed some sites ( for example: http://www.javaperformancetuning.com/tips/rawtips.shtml ) talking about Java performace in DB, but I cannot find a suggestion suitable for us. These advices are not applicable/already used, for instance: 1. Use prepared statements. Use parameterized SQL Already used prepared statement. Each time will use different parameter by clear parameters and set parameters. 2. Tune the SQL to minimize the data returned (e.g. not 'SELECT *'). Sure, already used. 3. Use connection pooling. We hold a single connection during the program's execution. And I doubt that pooling cannot solve the problem because our program act as 1 user, so there are no problem for concurrent access to DB. If anyone of you think pooling is good, please tell me why. Thanks. 4. Try to combine queries and batch updates. Cannot do it. Every query/insert/update is depend on the database's information. For example, we look up the DB for the client's information, if we cannot find his usage, we insert the usage into DB, otherwise we do update. 5. Close resources (Connections, Statements, ResultSets) when finished Sure. 6. Select the fastest JDBC driver. I don't know. I've search on the internet about the type of driver available and I am very confused. We use oracle.jdbc.driver.OracleDriver and we use thin instead of oci, that's all I know. In addition, our program is a two-tier way ( java <- oracle ) 7. Turn off auto-commit already done that. Looking forwards to any help.

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  • Storing a looong lookup table

    - by inquisitive
    Background The product i am working on has a very long lookup-table. the table contains static data and cannot be auto generated. there are about 500 rows and 10 columns. columns have mostly integers and strings. to complicate the matters, there are actually two such tables. every row in table-1 maps to zero-or-more rows in table-2. we use an SQLite database with two tables. the product installer places the SQLite file in the installation directory. the application is written in dot-net and we use ADO to load the data once on startup. now, the lookup table grows. in each release a month, we add about 10 new entries existing entries are adjusted. every release we fine tune existing entries. The problem a team of (10) developers work on the lookup table. Code goes in the SVN, but the little devil the SQLite does not. this prevents multiple developers to work on it. we do take regular backups of the file, but proper versioning is not possible. we never know who did the breaking change. the worse thing is we dont know if there is any change at all. diff'ing databases is tedious if not impossible. the tables are expected to grow quite large in years to come and we would need developers to work in parallel on it. the data is business critical. we need to be able to audit changes made to it. Question What would be a solution for the problems outlines above? one idea was to transform the whole thing to XML and treat it like just another source file. that way SVN can do the versioning and we can work in parallel. but the data shows relational behavior. with XML we loose the unique and foreign-key constraints. also we cant query it with sql like ease. any help here will be appreciated.

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  • [JAVA]How to make my Oracle update/insert action through JAVA faster?

    - by gunbuster363
    [JAVA]How to make my Oracle update/insert action through JAVA faster? Hi everyone, I am facing a problem in my company that is - our program's speed is not fast enough. To be more specific, we are telecommunication company and this program handle call/internet serfing transaction made by every mobile phone users in our city. Because the amount of download content made by the iphone users is just too much, our program cannot handle them fast enough. The situation is, the amount of transaction made by users are double of the transaction processed by our program. Most of the running time of the program are dominated by DB transactions. I've search through the internet and browsed some sites ( for example: http://www.javaperformancetuning.com/tips/rawtips.shtml ) talking about java performace in DB, but I cannot find a suggestion suitable for us. these advices are not applicable/already used, for instance: 1)Use prepared statements. Use parametrized SQL Already used prepared statement. Each time will use different parameter by clear parameters and set parameters. 2)Tune the SQL to minimize the data returned (e.g. not 'SELECT *'). Sure, already used. 3)Use connection pooling. We hold a single connection during the program's execution. And I doubt that pooling cannot solve the problem because our program act as 1 user, so there are no problem for concurrent access to DB. If anyone of you think pooling is good, please tell me why. Thanks. 4)Try to combine queries and batch updates. Cannot do it. Every query/insert/update is depend on the database's information. For example, we look up the DB for the client's information, if we cannot find his usage, we insert the usage into DB, otherwise we do update. 5)Close resources (Connections, Statements, ResultSets) when finished Sure. 6)Select the fastest JDBC driver. I don't know. I've search on the internet about the type of driver available and I am very confused. We use oracle.jdbc.driver.OracleDriver and we use thin instead of oci, that's all I know. In addition, our program is a two-tier way ( java <- oracle ) 7)turn off auto-commit already done that. Looking forwards to any helps, thank you very much.

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  • Running MS Access Programs

    - by fredhappier
    I have an old program developed in MS Access and would like to convert it to Kexi somehow. The program on Windows is launched with Access. Is there any way that Kexi can launch this program? I know my way around Ubuntu and the terminal, but not well versed on databases. Once you make something in Kexi how do you "run" it or "view" what you've made? So far I am able to import the MDB file into Kexi and see all of the database data, but that is as far I have gone. The program was made by a relative years ago for my dad. I myself am an Ubuntu only user for 6+ years now and have no intentions to touch Windows and am looking for a linux solution. My dad is also an Ubuntu user, hence why Im looking for a solution. If Kexi cannot launch and run an MDB file, what else can I try? Anything browser based? Any tips or direction would be extremely helpful. I spoke to my brother who originally made the program. I told him about Kexi and here is what he said. Does any of this make sense? Thanks. This is how I would try to get them to work: Stand alone setup - after import, look for an option where you designate which form object you want to open upon startup. It might be in the tools tab in the picture below. After you save that change, it re-start it and it should work. Front end/back end setup - Do what I suggested for the stand alone setup to the "front-end" MDB file. After you do that, put the other file (table MDB file) where you want it to reside on the network. Now, open back up the "front end" file and look for an option that will allow you to "connect" to those tables in the other file. It looks like it could be in the "External data" tab in the picture below. For this setup, you may need to do these two tasks in the reverse order I just mentioned. Thanks! Fred

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  • Memory leak with Microsoft.JScript.Eval.JScriptEvaluate?

    - by Dmi
    I'm evaluating some javascript with Microsoft.JScript.Eval.JScriptEvaluate() and I noticed from my memory profiler that there are a large number of System.String left allocated by Microsoft.JScript.HashtableEntry. Microsoft.JScript.Eval is a static class, does anyone know what class is holding these instances and how I can clear them?

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  • Memory management for NSURLConnection

    - by eman
    Sorry if this has been asked before, but I'm wondering what the best memory management practice is for NSURLConnection. Apple's sample code uses -[NSURLConnection initWithRequest:delegate:] in one method and then releases in connection:didFailWithError: or connectionDidFinishLoading:, but this spits out a bunch of analyzer warnings and seems sort of dangerous (what if neither of those methods is called?). I've been autoreleasing (using +[NSURLConnection connectionWithRequest:delegate:]), which seems cleaner, but I'm wondering--in this case, is it at ever possible for the NSURLConnection to be released before the connection has closed?

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  • SyncFramework upgrade from 1.0 to 2.0 Sql Server CE database change tracking issue

    - by Andronicus
    I'm trying to upgrade an application that uses Sync Framework 1.0 to synchronise a SqlServerCe database with SqlServer 2005. On the client, the existing database already has change tracking enabled, but when the sync is initiated SyncFramework 2.0 fails to find the last Sync Received anchor and then tries to re=initialize the Change tracking, which fails. I get the exception... {System.Exception} = {"The specified change tracking operation is not supported. To carry out this operation on the table, disable the change tracking on the table, and enable the change tracking."} It seems like all I can do is delete the local database and recreate it. Which is not a great solution for us, since some of the data in the clients database is not synced with the server, and our users would prefer not to loose this data in the upgrade. Is there any reason why SyncFramework 2.0 cannot locate the existing Last received sync anchor?

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  • Missing processor/memory counters in the Windows XP Performance Monitor application (perfmon)

    - by Jader Dias
    Perfmon is a Windows utility that helps the developer to find bottlenecks in his applications, by measuring system counters. I was reading a perfmon tutorial and from this list of essential counters I have found the following ones on my machine: PhysicalDisk\Bytes/sec_Total Network Interface\Bytes Total/Sec\nic name But I haven't found the following counters nowhere: Processor\% Processor Time_Total Process\Working Set_Total Memory\Available MBytes Where do I find them? Note that my Windows is pt-BR (instead of en-US). Where do I find language specific documentation for windows tools like PerfMon?

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  • Microsoft Sync Framework with Mutliple Client and Server Database

    - by David Osborn
    I'm working on changes to an application to have a local data store instead of connecting directly to the database server. The client app will then sync changes both ways between the server database and its local data store. I'm trying to implement the syncing solution using Microsoft Sync Framework. To be clear there is no server application, only the database server, but there are multiple clients. I have started implementing two classes that implement FullEnumerationSimpleSyncProvider, one called LocalSyncProvider and one called ServerSyncProvider. The LocalSyncProvider knows how to enumerate, insert, update, delete items from the local data store, and the ServerSyncProvider knows how to enumerate, insert, update, delete items from the database server. They each use the provided SqlMetadataStore and store the two metadata stores (one for the local and one for the server) on the local drive of the client. This means that each client will have its own metadata store for its local data store and its own metadata store for the server database. Is this actually going to work, does there need to exists only one server metadata store, or do I need to be using the Sync Framework differently?

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  • Using C# and Repository Factory and the error: The requested database is not defined in configurati

    - by odiseh
    hi I am using Repository factory for visual studio 2008 for a personal project. It generated a class called ProductRepository which inherits from Repository. The ProductRepository has a constructor which gets a database name as string and passes it to its base (I mean Repository ). So when I try to debug my project step by step, I pass my database name to ProductRepository but it raises the following error: The requested database is not defined in configuration. What's wrong?

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