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• Database – Beginning with Cloud Database As A Service

  - by Pinal Dave

  I love my weekend projects. Everybody does different activities in their weekend – like traveling, reading or just nothing. Every weekend I try to do something creative and different in the database world. The goal is I learn something new and if I enjoy my learning experience I share with the world. This weekend, I decided to explore Cloud Database As A Service – Morpheus. In my career I have managed many databases in the cloud and I have good experience in managing them. I should highlight that today’s applications use multiple databases from SQL for transactions and analytics, NoSQL for documents, In-Memory for caching to Indexing for search.  Provisioning and deploying these databases often require extensive expertise and time.  Often these databases are also not deployed on the same infrastructure and can create unnecessary latency between the application layer and the databases.  Not to mention the different quality of service based on the infrastructure and the service provider where they are deployed. Moreover, there are additional problems that I have experienced with traditional database setup when hosted in the cloud: Database provisioning & orchestration Slow speed due to hardware issues Poor Monitoring Tools High network latency Now if you have a great software and expert network engineer, you can continuously work on above problems and overcome them. However, not every organization have the luxury to have top notch experts in the field. Now above issues are related to infrastructure, but there are a few more problems which are related to software/application as well. Here are the top three things which can be problems if you do not have application expert: Replication and Clustering Simple provisioning of the hard drive space Automatic Sharding Well, Morpheus looks like a product build by experts who have faced similar situation in the past. The product pretty much addresses all the pain points of developers and database administrators. What is different about Morpheus is that it offers a variety of databases from MySQL, MongoDB, ElasticSearch to Reddis as a service.  Thus users can pick and chose any combination of these databases.  All of them can be provisioned in a matter of minutes with a simple and intuitive point and click user interface.  The Morpheus cloud is built on Solid State Drives (SSD) and is designed for high-speed database transactions.  In addition it offers a direct link to Amazon Web Services to minimize latency between the application layer and the databases. Here are the few steps on how one can get started with Morpheus. Follow along with me.  First go to http://www.gomorpheus.com and register for a new and free account. Step 1: Signup It is very simple to signup for Morpheus. Step 2: Select your database   I use MySQL for my daily routine, so I have selected MySQL. Upon clicking on the big red button to add Instance, it prompted a dialogue of creating a new instance.   Step 3: Create User Now we just have to create a user in our portal which we will use to connect to a database hosted at Morpheus. Click on your database instance and it will bring you to User Screen. Over here you will notice once again a big red button to create a new user. I created a user with my first name.   Step 4: Configure your MySQL client I used MySQL workbench and connected to MySQL instance, which I had created with an IP address and user.   That’s it! You are connecting to MySQL instance. Now you can create your objects just like you would create on your local box. You will have all the features of the Morpheus when you are working with your database. Dashboard While working with Morpheus, I was most impressed with its dashboard. In future blog posts, I will write more about this feature.  Also with Morpheus you use the same process for provisioning and connecting with other databases: MongoDB, ElasticSearch and Reddis. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Next Generation Mobile Clients for Oracle Applications & the role of Oracle Fusion Middleware

  - by Manish Palaparthy

  Oracle Enterprise Applications have been available with modern web browser based interfaces for a while now. The web browsers available in smart phones no longer require special markup language such as WML since the processing power of these handsets is quite near to that of a typical personal computer. Modern Mobile devices such as the IPhone, Android Phones, BlackBerry, Windows 8 devices can now render XHTML & HTML quite well. This means you could potentially use your mobile browser to access your favorite enterprise application. While the Mobile browser would render the UI, you might find it difficult to use it due to the formatting & Presentation of the Native UI. Smart phones offer a lot more than just a powerful web browser, they offer capabilities such as Maps, GPS, Multi touch, pinch zoom, accelerometers, vivid colors, camera with video, support for 3G, 4G networks, cloud storage, NFC, streaming media, tethering, voice based features, multi tasking, messaging, social networking web browsers with support for HTML 5 and many more features.  While the full potential of Enterprise Mobile Apps is yet to be realized, Oracle has published a few of its applications that take advantage of the above capabilities and are available for the IPhone natively. Here are some of them Iphone Apps  Oracle Business Approvals for Managers: Offers a highly intuitive user interface built as a native mobile application to conveniently access pending actions related to expenses, purchase requisitions, HR vacancies and job offers. You can even view BI reports related to the worklist actions. Works with Oracle E-Business Suite Oracle Business Indicators : Real-time secure access to OBI reports. Oracle Business Approvals for Sales Managers: Enables sales executives to review key targeted tasks, access relevant business intelligence reports. Works with Siebel CRM, Siebel Quote & Order Capture. Oracle Mobile Sales Assistant: CRM application that provides real-time, secure access to the information your sales organization needs, complete frequent tasks, collaborate with colleagues and customers. Works with Oracle CRMOracle Mobile Sales Forecast: Designed specifically for the mobile business user to view key opportunities. Works with Oracle CRM on demand Oracle iReceipts : Part of Oracle PeopleSoft Expenses, which allows users to create and submit expense lines for cash transactions in real-time. Works with Oracle PeopleSoft expenses Now, we have seen some mobile Apps that Oracle has published, I am sure you are intrigued as to how develop your own clients for the use-cases that you deem most fit. For that Oracle has ADF Mobile ADF Mobile You could develop Mobile Applications with the SDK available with the smart phone platforms!, but you'd really have to be a mobile ninja developer to develop apps with the rich user experience like the ones above. The challenges really multiply when you have to support multiple mobile devices. ADF Mobile framework is really handy to meet this challenge ADF Mobile can in be used to Develop Apps for the Mobile browser : An application built with ADF Mobile framework installs on a smart device, renders user interface via HTML5, and has access to device services. This means the programming model is primarily web-based, which offers consistency with other enterprise applications as well as easier migration to new platforms. Develop Apps for the Mobile Client (Native Apps): These applications have access to device services, enabling a richer experience for users than a browser alone can offer. ADF mobile enables rapid and declarative development of rich, on-device mobile applications. Developers only need to write an application once and then they can deploy the same application across multiple leading smart phone platforms. Oracle SOA Suite Although the Mobile users are using the smart phone apps, and actual transactions are being executed in the underlying app, there is lot of technical wizardry that is going under the surface. All of this key technical components to make 1. WebService calls 2. Authentication 3. Intercepting Webservice calls and adding security credentials to the request 4. Invoking the services of the enterprise application 5. Integrating with the Enterprise Application via the Adapter is all being implemented at the SOA infrastructure layer.  As you can see from the above diagram. The key pre-requisites to mobile enable an Enterprise application are The core enterprise application Oracle SOA Suite ADF Mobile

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• Top 10 Linked Blogs of 2010

  - by Bill Graziano

  Each week I send out a SQL Server newsletter and include links to interesting blog posts.  I’ve linked to over 500 blog posts so far in 2010.  Late last year I started storing those links in a database so I could do a little reporting.  I tend to link to posts related to the OLTP engine.  I also try to link to the individual blogger in the group blogs.  Unfortunately that wasn’t possible for the SQLCAT and CSS blogs.  I also have a real weakness for posts related to PASS. These are the top 10 blogs that I linked to during the year ordered by the number of posts I linked to. Paul Randal – Paul writes extensively on the internals of the relational engine.  Lots of great posts around transactions, transaction log, disaster recovery, corruption, indexes and DBCC.  I also linked to many of his SQL Server myths posts. Glenn Berry – Glenn writes very interesting posts on how hardware affects SQL Server.  I especially like his posts on the various CPU platforms.  These aren’t necessarily topics that I’m searching for but I really enjoy reading them. The SQLCAT Team – This Microsoft team focuses on the largest and most interesting SQL Server installations.  The regularly publish white papers and best practices. SQL Server CSS Team – These are the top engineers from the Microsoft Customer Service and Support group.  These are the folks you finally talk to after your case has been escalated about 20 times.  They write about the interesting problems they find. Brent Ozar – The posts I linked to mostly focused on the relational engine: CPU, NUMA, SSD drives, performance monitoring, etc.  But Brent writes about a real variety of topics including blogging, social networking, speaking, the MCM, SQL Azure and anything else that seems to strike his fancy.  His posts are always well written and though provoking. Jeremiah Peschka – A number of Jeremiah’s posts weren’t about SQL Server.  He’s very active in the “NoSQL” area and I linked to a number of those posts.  I think it’s important for people to know what other technologies are out there. Brad McGehee – Brad writes about being a DBA including maintenance plans, DBA checklists, compression and audit. Thomas LaRock – I linked to a variety of posts from PBM to networking to 24 Hours of PASS to TDE.  Just a real variety of topics.  Tom always writes with an interesting style usually mixing in a movie theme and/or bacon. Aaron Bertrand – Many of my links this year were Denali features.  He also had a great series on bad habits to kick. Michael J. Swart – This last one surprised me.  There are some well known SQL Server bloggers below Michael on this list.  I linked to posts on indexes, hierarchies, transactions and I/O performance and a variety of other engine related posts.  All are interesting and well thought out.  Many of his non-SQL posts are also very good.  He seems to have an interest in puzzles and other brain teasers.  Michael, I won’t be surprised again!

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• Orchestrating the Virtual Enterprise, Part II

  - by Kathryn Perry

  A guest post by Jon Chorley, Oracle's CSO & Vice President, SCM Product Strategy Almost everyone has ordered from Amazon.com at one time or another. Our orders are as likely to be fulfilled by third parties as they are by Amazon itself. To deliver the order promptly and efficiently, Amazon has to send it to the right fulfillment location and know the availability in that location. It needs to be able to track status of the fulfillment and deal with exceptions. As a virtual enterprise, Amazon's operations, using thousands of trading partners, requires a very different approach to fulfillment than the traditional 'take an order and ship it from your own warehouse' model. Amazon had no choice but to develop a complex, expensive and custom solution to tackle this problem as there used to be no product solution available. Now, other companies who want to follow similar models have a better off-the-shelf choice -- Oracle Distributed Order Orchestration (DOO).  Consider how another of our customers is using our distributed orchestration solution. This major airplane manufacturer has a highly complex business and interacts regularly with the U.S. Government and major airlines. It sits in the middle of an intricate supply chain and needed to improve visibility across its many different entities. Oracle Fusion DOO gives the company an orchestration mechanism so it could improve quality, speed, flexibility, and consistency without requiring an organ transplant of these highly complex legacy systems. Many retailers face the challenge of dealing with brick and mortar, Web, and reseller channels. They all need to be knitted together into a virtual enterprise experience that is consistent for their customers. When a large U.K. grocer with a strong brick and mortar retail operation added an online business, they turned to Oracle Fusion DOO to bring these entities together. Disturbing the Peace with Acquisitions Quite often a company's ERP system is disrupted when it acquires a new company. An acquisition can inject a new set of processes and systems -- or even introduce an entirely new business like Sun's hardware did at Oracle. This challenge has been a driver for some of our DOO customers. A large power management company is using Oracle Fusion DOO to provide the flexibility to rapidly integrate additional products and services into its central fulfillment operation. The Flip Side of Fulfillment Meanwhile, we haven't ignored similar challenges on the supply side of the equation. Specifically, how to manage complex supply in a flexible way when there are multiple trading parties involved? How to manage the supply to suppliers? How to manage critical components that need to merge in a tier two or tier three supply chain? By investing in supply orchestration solutions for the virtual enterprise, we plan to give users better visibility into their network of suppliers to help them drive down costs. We also think this technology and full orchestration process can be applied to the financial side of organizations. An example is transactions that flow through complex internal structures to minimize tax exposure. We can help companies manage those transactions effectively by thinking about the internal organization as a virtual enterprise and bringing the same solution set to this internal challenge.  The Clear Front Runner No other company is investing in solving the virtual enterprise supply chain issues like Oracle is. Oracle is in a unique position to become the gold standard in this market space. We have the infrastructure of Oracle technology. We already have an Oracle Fusion DOO application which embraces the best of what's required in this area. And we're absolutely committed to extending our Fusion solution to other use cases and delivering even more business value. Jon ChorleyChief Sustainability Officer & Vice President, SCM Product StrategyOracle Corporation

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• SQL SERVER – Select the Most Optimal Backup Methods for Server

  - by pinaldave

  Backup and Restore are very interesting concepts and one should be very much with the concept if you are dealing with production database. One never knows when a natural disaster or user error will surface and the first thing everybody wants is to get back on point in time when things were all fine. Well, in this article I have attempted to answer a few of the common questions related to Backup methodology. How to Select a SQL Server Backup Type In order to select a proper SQL Server backup type, a SQL Server administrator needs to understand the difference between the major backup types clearly. Since a picture is worth a thousand words, let me offer it to you below. Select a Recovery Model First The very first question that you should ask yourself is: Can I afford to lose at least a little (15 min, 1 hour, 1 day) worth of data? Resist the temptation to save it all as it comes with the overhead – majority of businesses outside finances can actually afford to lose a bit of data. If your answer is YES, I can afford to lose some data – select a SIMPLE (default) recovery model in the properties of your database, otherwise you need to select a FULL recovery model. The additional advantage of the Full recovery model is that it allows you to restore the data to a specific point in time vs to only last backup time in the Simple recovery model, but it exceeds the scope of this article Backups in SIMPLE Recovery Model In SIMPLE recovery model you can select to do just Full backups or Full + Differential. Full Backup This is the simplest type of backup that contains all information needed to restore the database and should be your first choice. It is often sufficient for small databases, but note that it makes a big impact on the performance of your database Full + Differential Backup After Full, Differential backup picks up all of the changes since the last Full backup. This means if you made Full, Diff, Diff backup – the last Diff backup contains all of the changes and you don’t need the previous Differential backup. Differential backup is obviously smaller and carries less performance overhead Backups in FULL Recovery Model In FULL recovery model you can select Full + Transaction Log or Full + Differential + Transaction Log backup. You have to create Transaction Log backup, because at that time the log is being truncated. Otherwise your Transaction Log will grow uncontrollably. Full + Transaction Log Backup You would always need to perform a Full backup first. Then a series of Transaction log backup. Note that (in contrast to Differential) you need ALL transactions to log since the last Full of Diff backup to properly restore. Transaction log backups have the smallest performance overhead and can be performed often. Full + Differential + Transaction Log Backup If you want to ease the performance overhead on your server, you can replace some of the Full backup in the previous scenario with Differential. You restore scenario would start from Full, then the Last Differential, then all of the remaining transactions log backups Typical backup Scenarios You may say “Well, it is all nice – give me the examples now”. As you may already know, my favorite SQL backup software is SQLBackupAndFTP. If you go to Advanced Backup Schedule form in this program and click “Load a typical backup plan…” link, it will give you these scenarios that I think are quite common – see the image below. The Simplest Way to Schedule SQL Backups I hate to repeat myself, but backup scheduling in SQL agent leaves a lot to be desired. I do not know the simple way to schedule your SQL server backups than in SQLBackupAndFTP – see the image below. The whole backup scheduling with compression, encryption and upload to a Network Folder / HDD / NAS Drive / FTP / Dropbox / Google Drive / Amazon S3 takes just a few minutes – see my previous post for the review. Final Words This post offered an explanation for major backup types only. For more complicated scenarios or to research other options as usually go to MSDN. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• XML DB Content Connector unable to accept binary content due to Invalid argument(s) in call oracle.sql.BLOB.setBinaryStream(0L)

  - by sthieme

  Dear Readers, I am working on implementing a custom Document Management System using the Oracle XML DB Content Connector. See the following documentation link for details Oracle XML DB Developer's Guide 11g Release 2 (11.2)Chapter 31 Using Oracle XML DB Content Connectorhttp://docs.oracle.com/cd/E11882_01/appdev.112/e23094/xdb_jcr.htm especially the following example gave me some trouble to run it successfully Sample Code to Upload Filehttp://docs.oracle.com/cd/E11882_01/appdev.112/e23094/xdb_jcr.htm#ADXDB5627 I had already succeeded to set some of the properties successfully, i.e. jcr:encoding, jcr:mimeType, ojcr:displayName and ojcr:language. However setting the jcr:data property as described in the example failed consistently, both with the documented input FileStream or with a fixed string. contentNode.setProperty("jcr:data", "mystringvalue"); After some research I found the following Support Note which describes the cause for the issue in the JDBC driver version 11.2.0.1. Error "ORA-17068: Invalid argument(s) in call" Using Method setBinaryStream(0L) in JDBC 11.2.0.1 (Doc ID 1234235.1)https://support.oracle.com/epmos/faces/DocContentDisplay?id=1234235.1It can easily be solved by upgrading to JDBC 11.2.0.2 or worked around using the following property setting: java -Doracle.jdbc.LobStreamPosStandardCompliant=false ... Kind regards,Stefan C:\Oracle\Database\product\11.2.0\dbhome_1>java -Doracle.jdbc.LobStreamPosStandardCompliant=false UploadFile jdbc:oracle:oci:@localhost:1522:orcl XDB welcome1 /public MyFile.txt text/plain 19.08.2014 11:50:26 oracle.jcr.impl.OracleRepositoryImpl login INFO: JCR repository descriptors: query.xpath.pos.index = true option.versioning.supported = false jcr.repository.version = 11.1.0.0.0 option.observation.supported = false option.locking.supported = false oracle.jcr.framework.version = 11.1.0.0.0 query.xpath.doc.order = false jcr.specification.version = 1.0 jcr.repository.vendor = Oracle option.query.sql.supported = false jcr.specification.name = Content Repository for Java Technology API level.2.supported = true level.1.supported = true jcr.repository.name = XML DB Content Connector jcr.repository.vendor.url = http://www.oracle.com oracle.jcr.persistenceManagerFactory = oracle.jcr.impl.xdb.XDBPersistenceManagerFactory option.transactions.supported = false 19.08.2014 11:50:26 oracle.jcr.impl.OracleRepositoryImpl login INFO: Session Session-1 connected for user id XDB 19.08.2014 11:50:27 oracle.jcr.impl.OracleSessionImpl logout INFO: Session-1: logout instead of C:\Oracle\Database\product\11.2.0\dbhome_1>java UploadFile jdbc:oracle:oci:@localhost:1522:orcl XDB welcome1 /public MyFile.txt text/plain 19.08.2014 10:56:39 oracle.jcr.impl.OracleRepositoryImpl login INFO: JCR repository descriptors: query.xpath.pos.index = true option.versioning.supported = false jcr.repository.version = 11.1.0.0.0 option.observation.supported = false option.locking.supported = false oracle.jcr.framework.version = 11.1.0.0.0 query.xpath.doc.order = false jcr.specification.version = 1.0 jcr.repository.vendor = Oracle option.query.sql.supported = false jcr.specification.name = Content Repository for Java Technology API level.2.supported = true level.1.supported = true jcr.repository.name = XML DB Content Connector jcr.repository.vendor.url = http://www.oracle.com oracle.jcr.persistenceManagerFactory = oracle.jcr.impl.xdb.XDBPersistenceManagerFactory option.transactions.supported = false 19.08.2014 10:56:39 oracle.jcr.impl.OracleRepositoryImpl login INFO: Session Session-1 connected for user id XDB Exception in thread "main" javax.jcr.RepositoryException: Unable to accept binary content at oracle.jcr.impl.ExceptionFactory.repository(ExceptionFactory.java:142) at oracle.jcr.impl.ExceptionFactory.otherwiseFailed(ExceptionFactory.java:98) at oracle.jcr.impl.xdb.XDBPersistenceManager.acceptBinaryStream(XDBPersistenceManager.java:1421) at oracle.jcr.impl.xdb.XDBResource.setContent(XDBResource.java:898) at oracle.jcr.impl.ContentNode.setProperty(ContentNode.java:472) at oracle.jcr.impl.OracleNode.setProperty(OracleNode.java:1439) at oracle.jcr.impl.OracleNode.setProperty(OracleNode.java:460) at UploadFile.main(UploadFile.java:54) Caused by: java.sql.SQLException: Invalid argument(s) in call at oracle.jdbc.driver.T2CConnection.newOutputStream(T2CConnection.java:2392) at oracle.sql.BLOB.setBinaryStream(BLOB.java:893) at oracle.jcr.impl.xdb.XDBPersistenceManager.acceptBinaryStream(XDBPersistenceManager.java:1393) ... 5 more

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• Analytics in an Omni-Channel World

  - by David Dorf

  Retail has been around ever since mankind started bartering.  The earliest transactions were very specific to the individuals buying and selling, then someone had the bright idea to open a store.  Those transactions were a little more generic, but the store owner still knew his customers and what they wanted.  As the chains rolled out, customer intimacy was sacrificed for scale, and retailers began to rely on segments and clusters.  But thanks to the widespread availability of data and the technology to convert said data into information, retailers are getting back to details. The retail industry is following a maturity model for analytics that is has progressed through five stages, each delivering more value than the previous. Store Analytics Brick-and-mortar retailers (and pure-play catalogers as well) that collect anonymous basket-level data are able to get some sense of demand to help with allocation decisions.  Promotions and foot-traffic can be measured to understand marketing effectiveness and perhaps focus groups can help test ideas.  But decisions are influenced by the majority, using faceless customer segments and aggregated industry data points.  Loyalty programs help a little, but in many cases the cost outweighs the benefits. Web Analytics The Web made it much easier to collect data on specific, yet still anonymous consumers using cookies to track visits. Clickstreams and product searches are analyzed to understand the purchase journey, gauge demand, and better understand up-selling opportunities.  Personalization begins to allow retailers target market consumers with recommendations. Cross-Channel Analytics This phase is a minor one, but where most retailers probably sit today.  They are able to use information from one channel to bolster activities in another. However, there are technical challenges combining data silos so its not an easy task.  But for those retailers that are able to perform analytics on both sources of data, the pay-off is pretty nice.  Revenue per customer begins to go up as customers have a better brand experience. Mobile & Social Analytics Big data technologies are enabling a 360-degree view of the customer by incorporating psychographic data from social sites alongside traditional demographic data.  Retailers can track individual preferences, opinions, hobbies, etc. in order to understand a consumer's motivations.  Using mobile devices, consumers can interact with brands anywhere, anytime, accessing deep product information and reviews.  Mobile, combined with a loyalty program, presents an opportunity to put shopping into geographic context, understanding paths to the store, patterns within the store, and be an always-on advertising conduit. Omni-Channel Analytics All this data along with the proper technology represents a new paradigm in which the clock is turned back and retail becomes very personal once again.  Rich, individualized data better illuminates demand, allows for highly localized assortments, and helps tailor up-selling.  Interactions with all channels help build an accurate profile of each consumer, and allows retailers to tailor the retail experience to meet the heightened expectations of today's sophisticated shopper.  And of course this culminates in greater customer satisfaction and business profitability.

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• Is there a theory for "transactional" sequences of failing and no-fail actions?

  - by Ross Bencina

  My question is about writing transaction-like functions that execute sequences of actions, some of which may fail. It is related to the general C++ principle "destructors can't throw," no-fail property, and maybe also with multi-phase transactions or exception safety. However, I'm thinking about it in language-neutral terms. My concern is with correctly designing error handling in C++ functions that must be reliable. I would like to know what the concepts below are called so that I can learn more about them. I'm sorry that I can't ask the question more directly. Since I don't know this area I have provided an example to explain my question. The question is at the end. Here goes: Consider a sequence of steps or actions executed sequentially, where actions belong to one of two classes: those that always succeed, and those that may fail. In the examples below: S stands for an action that always succeeds (called "no-fail" in some settings). F stands for an action that may fail (for example, it might fail to allocate memory or do I/O that could fail). Consider a sequences of actions (executed sequentially from left to right): S->S->S->S Since each action in the sequence above succeeds, the whole sequence succeeds. On the other hand, the following sequence may fail because the last action may fail: S->S->S->F So, claim: a sequence has the no-fail (S) property if and only if all of its actions are no-fail. Now, I'm interested in action sequences that form "atomic transactions", with "failure atomicity," i.e. where either the whole sequence completes successfully, or there is no effect. I.e. if some action fails, the earlier ones must be rolled back. This requires that any successfully executed actions prior to a failing action must always be able to be rolled back. Consider the sequence: S->S->S->F S<-S<-S In the example above, the first row is the forward path of the transaction, and the second row are inverse actions (executed from right to left) that can be used to roll back if the final top row actions fails. It seems to me that for a transaction to support failure atomicity, the following invariant must hold: Claim: To support failure atomicity (either completion or complete roll-back on failure) all actions preceding the latest failable (F) action on the forward path (marked * in the example below) must have no-fail (S) inverses. The following is an example of a sequence that supports failure atomicity: * S->F->F->F S<-S<-S Further, if we want the transaction to be able to attempt cancellation mid-way through, but still guarantee either full completion or full rollback then we need the following property: Claim: To support failure atomicity and cancellation mid-way through execution, in the face of errors in the inverse (cancellation) path, all actions following the earliest failable (F) inverse on the reverse path (marked *) must be no-fail (S). F->F->F->S->S S<-S<-F<-F * I believe that these two conditions guarantee that an abortable/cancelable transaction will never get "stuck". My questions are: What is the study and theory of these properties called? are my claims correct? and what else is there to know? UPDATE 1: Updated terminology: what I previously called "robustness" is called atomicity in the database literature. UPDATE 2: Added explicit reference to failure atomicity, which seems to be a thing.

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• Concurrent Affairs

  - by Tony Davis

  I once wrote an editorial, multi-core mania, on the conundrum of ever-increasing numbers of processor cores, but without the concurrent programming techniques to get anywhere near exploiting their performance potential. I came to the.controversial.conclusion that, while the problem loomed for all procedural languages, it was not a big issue for the vast majority of programmers. Two years later, I still think most programmers don't concern themselves overly with this issue, but I do think that's a bigger problem than I originally implied. Firstly, is the performance boost from writing code that can fully exploit all available cores worth the cost of the additional programming complexity? Right now, with quad-core processors that, at best, can make our programs four times faster, the answer is still no for many applications. But what happens in a few years, as the number of cores grows to 100 or even 1000? At this point, it becomes very hard to ignore the potential gains from exploiting concurrency. Possibly, I was optimistic to assume that, by the time we have 100-core processors, and most applications really needed to exploit them, some technology would be around to allow us to do so with relative ease. The ideal solution would be one that allows programmers to forget about the problem, in much the same way that garbage collection removed the need to worry too much about memory allocation. From all I can find on the topic, though, there is only a remote likelihood that we'll ever have a compiler that takes a program written in a single-threaded style and "auto-magically" converts it into an efficient, correct, multi-threaded program. At the same time, it seems clear that what is currently the most common solution, multi-threaded programming with shared memory, is unsustainable. As soon as a piece of state can be changed by a different thread of execution, the potential number of execution paths through your program grows exponentially with the number of threads. If you have two threads, each executing n instructions, then there are 2^n possible "interleavings" of those instructions. Of course, many of those interleavings will have identical behavior, but several won't. Not only does this make understanding how a program works an order of magnitude harder, but it will also result in irreproducible, non-deterministic, bugs. And of course, the problem will be many times worse when you have a hundred or a thousand threads. So what is the answer? All of the possible alternatives require a change in the way we write programs and, currently, seem to be plagued by performance issues. Software transactional memory (STM) applies the ideas of database transactions, and optimistic concurrency control, to memory. However, working out how to break down your program into sufficiently small transactions, so as to avoid contention issues, isn't easy. Another approach is concurrency with actors, where instead of having threads share memory, each thread runs in complete isolation, and communicates with others by passing messages. It simplifies concurrent programs but still has performance issues, if the threads need to operate on the same large piece of data. There are doubtless other possible solutions that I haven't mentioned, and I would love to know to what extent you, as a developer, are considering the problem of multi-core concurrency, what solution you currently favor, and why. Cheers, Tony.

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• Webcast On-Demand: Building Java EE Apps That Scale

  - by jeckels

  With some awesome work by one of our architects, Randy Stafford, we recently completed a webcast on scaling Java EE apps efficiently. Did you miss it? No problem. We have a replay available on-demand for you. Just hit the '+' sign drop-down for access.Topics include: Domain object caching Service response caching Session state caching JSR-107 HotCache and more! Further, we had several interesting questions asked by our audience, and we thought we'd share a sampling of those here for you - just in case you had the same queries yourself. Enjoy! What is the largest Coherence deployment out there? We have seen deployments with over 500 JVMs in the Coherence cluster, and deployments with over 1000 JVMs using the Coherence jar file, in one system. On the management side there is an ecosystem of monitoring tools from Oracle and third parties with dashboards graphing values from Coherence's JMX instrumentation. For lifecycle management we have seen a lot of custom scripting over the years, but we've also integrated closely with WebLogic to leverage its management ecosystem for deploying Coherence-based applications and managing process life cycles. That integration introduces a new Java EE archive type, the Grid Archive or GAR, which embeds in an EAR and can be seen by a WAR in WebLogic. That integration also doesn't require any extra WebLogic licensing if Coherence is licensed. How is Coherence different from a NoSQL Database like MongoDB? Coherence can be considered a NoSQL technology. It pre-dates the NoSQL movement, having been first released in 2001 whereas the term "NoSQL" was coined in 2009. Coherence has a key-value data model primarily but can also be used for document data models. Coherence manages data in memory currently, though disk persistence is in a future release currently in beta testing. Where the data is managed yields a few differences from the most well-known NoSQL products: access latency is faster with Coherence, though well-known NoSQL databases can manage more data. Coherence also has features that well-known NoSQL database lack, such as grid computing, eventing, and data source integration. Finally Coherence has had 15 years of maturation and hardening from usage in mission-critical systems across a variety of industries, particularly financial services. Can I use Coherence for local caching? Yes, you get additional features beyond just a java.util.Map: you get expiration capabilities, size-limitation capabilities, eventing capabilites, etc. Are there APIs available for GoldenGate HotCache? It's mostly a black box. You configure it, and it just puts objects into your caches. However you can treat it as a glass box, and use Coherence event interceptors to enhance its behavior - and there are use cases for that. Are Coherence caches updated transactionally? Coherence provides several mechanisms for concurrency control. If a project insists on full-blown JTA / XA distributed transactions, Coherence caches can participate as resources. But nobody does that because it's a performance and scalability anti-pattern. At finer granularity, Coherence guarantees strict ordering of all operations (reads and writes) against a single cache key if the operations are done using Coherence's "EntryProcessor" feature. And Coherence has a unique feature called "partition-level transactions" which guarantees atomic writes of multiple cache entries (even in different caches) without requiring JTA / XA distributed transaction semantics.

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• Getting client denied when accessing a wsgi graphite script

  - by Dr BDO Adams

  I'm trying to set up graphite on my Mac OS X 10.7 lion, i've set up apache to call the python graphite script via WSGI, but when i try to access it, i get a forbiden from apache and in the error log. "client denied by server configuration: /opt/graphite/webapp/graphite.wsgi" I've checked that the scripts location is allowed in httpd.conf, and the permissions of the file, but they seem correct. What do i have to do to get access. Below is the httpd.conf, which is nearly the graphite example. <IfModule !wsgi_module.c> LoadModule wsgi_module modules/mod_wsgi.so </IfModule> WSGISocketPrefix /usr/local/apache/run/wigs <VirtualHost _default_:*> ServerName graphite DocumentRoot "/opt/graphite/webapp" ErrorLog /opt/graphite/storage/log/webapp/error.log CustomLog /opt/graphite/storage/log/webapp/access.log common WSGIDaemonProcess graphite processes=5 threads=5 display-name='%{GROUP}' inactivity-timeout=120 WSGIProcessGroup graphite WSGIApplicationGroup %{GLOBAL} WSGIImportScript /opt/graphite/conf/graphite.wsgi process-group=graphite application-group=%{GLOBAL} # XXX You will need to create this file! There is a graphite.wsgi.example # file in this directory that you can safely use, just copy it to graphite.wgsi WSGIScriptAlias / /opt/graphite/webapp/graphite.wsgi Alias /content/ /opt/graphite/webapp/content/ <Location "/content/"> SetHandler None </Location> # XXX In order for the django admin site media to work you Alias /media/ "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site- packages/django/contrib/admin/media/" <Location "/media/"> SetHandler None </Location> # The graphite.wsgi file has to be accessible by apache. <Directory "/opt/graphite/webapp/"> Options +ExecCGI Order deny,allow Allow from all </Directory> </VirtualHost> Can you help?

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• Apache error: could not make child process 25105 exit, attempting to continue anyway

  - by Temnovit

  Hello! I have a web server based on Ubuntu Server 9.10 with this software: apache 2 PHP 5.3 MySQL 5 Python 2.5 Few of my websites are PHP based, few use python/django through mod_wsgi. For month or so, every day my apache server stops responding until I manually restart it. Error logs show: [Fri Mar 05 17:06:47 2010] [error] could not make child process 25059 exit, attempting to continue anyway [Fri Mar 05 17:06:47 2010] [error] could not make child process 25061 exit, attempting to continue anyway [Fri Mar 05 17:06:47 2010] [error] could not make child process 24930 exit, attempting to continue anyway [Fri Mar 05 17:06:47 2010] [error] could not make child process 25084 exit, attempting to continue anyway [Fri Mar 05 17:06:47 2010] [error] could not make child process 25105 exit, attempting to continue anyway and so on. I tried to google this problem but it seems, that I can't find a solution there. How can I determine the cause of this error and how do I fix it? Thank you for your help. UPDATE Updating mod-wsgi to version 3.1 didn't solve the problem Updating PHP to 5.3 also didn't solve it Here is a list of all installed modules: core mod_log_config mod_logio prefork http_core mod_so mod_alias mod_auth_basic mod_authn_file mod_authz_default mod_authz_groupfile mod_authz_host mod_authz_user mod_autoindex mod_cgi mod_deflate mod_dir mod_env mod_mime mod_negotiation mod_php5 mod_rewrite mod_setenvif mod_status mod_wsgi Here's how my virtual host with wsgi looks: <VirtualHost *:80> ServerName example.net DocumentRoot /var/www/example.net #wcgi script that serves all the thing WSGIScriptAlias / /var/www/example.net/index.wsgi WSGIDaemonProcess example user=wsgideamonuser group=root processes=1 threads=10 WSGIProcessGroup example Alias /static /var/www/example.net/static #serving admin files Alias /media/ /usr/local/lib/python2.6/dist-packages/django/contrib/admin/media/ <Location "/static"> SetHandler None </Location> <Location "/media"> SetHandler None </Location> ErrorLog /var/www/example.net/error.log </VirtualHost> Error log now contains two types of errors fallowed one by another: [error] child process 9486 still did not exit, sending a SIGKILL [error] could not make child process 9106 exit, attempting to continue anyway

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• mod_wsgi, .htaccess and rewriterule

  - by hadaraz

  I'm using several django projects running on the same apache instance through mod_wsgi, configured with virtualhost for each site, see the httpd.conf here. For one of the sites I want to use static-cache (staticgenerator), so I set up a directory with .htaccess file which contains: RequestHeader unset X-Forwarded-Host RewriteEngine on RewriteBase / RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_FILENAME}/index.html !-f RewriteRule ^(.*) http://127.0.0.1:3456/$1 [P] where 3456 is the django port on the server. Using this rewrite rule, the request is always forwarded to the mod_wsgi handler, even if the file or directory exists, and if the file index.html exists the request shows as request-path/index.html. I tried another setup: RequestHeader unset X-Forwarded-Host RewriteEngine on RewriteBase / RewriteCond $1 !-d RewriteCond $1index.html !-f RewriteRule ^(.*) http://127.0.0.1:3456/$1 [P] but got almost the same results. All requests are transferred to the mod_wsgi handler, but the request path is now the original one. To sum it up: What is the correct RewriteCond to use here? How do you transfer a request to the mod_wsgi handler? Is it the right way? If that's not the way to do it, then how do you serve static files from a directory when they exist, and when they don't you serve from apache/mode_wsgi? Thanks for your help.

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• sharing a folder between linux and windows over the internet

  - by valya

  Hello Currently my job is to make websites with Django. I use many things like virtualenv, PIL, etc. The problem is, I can't stand Linux on my desktop. I like it on servers, It's greate to use it over the SSH. But for desktop? No way. But for the development Linux is quite essential. Of course almost everything is ported to Windows, but it's not as simple to use as in Linux. For example, Windows shell is awful in comparison with Linux. So I've tried Cygwin, but it's too damn slow. Every time django dev server reloads, it tooks almost 20-30 seconds. In comparison, then using "native" python on Windows or Linux, it reloads instantly. Even worse, Cygwin makes all my system very slow. I've been thinking about it and have thought up a way to go. I can share a folder with my application with some Linux box. The devserver and everything will run on that box, while I'll be happy editing files and running the browser on my Windows 7. SSH shell is much quickier and handy than Cygwin. Currently there are no Linux boxes in my home network (except for my android phone :) but I have several VDS boxes with Debian. So, how do I share a Windows folder with VDS box? I can't rely on my desktop IP but I can rely on the VDS's one. I need sharing to be as quick as possible (well, 2-3 seconds ping is OK) and "native" for both systems, so I could use a folder like a normal folder in both Windows and Linux.

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• How to get nginx to pass HTTP_AUTHORIZATION header to Apache

  - by codeinthehole

  Am using Nginx as a reverse proxy to an Apache server that uses HTTP Auth. For some reason, I can't get the HTTP_AUTHORIZATION header through to Apache, it seems to get filtered out by Nginx. Hence, no requests can authenticate. Note that the Basic auth is dynamic so I don't want to hard-code it in my nginx config. My nginx config is: server { listen 80; server_name example.co.uk ; access_log /var/log/nginx/access.cdk-dev.tangentlabs.co.uk.log; gzip on; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_read_timeout 120; location / { proxy_pass http://localhost:81/; } location ~* \.(jpg|png|gif|jpeg|js|css|mp3|wav|swf|mov|doc|xls|ppt|docx|pptx|xlsx|swf)$ { if (!-f $request_filename) { break; proxy_pass http://localhost:81; } root /var/www/example; } } Anyone know why this is happening? Update - turns out the problem was something I had overlooked in my original question: mod_wsgi. The site in question here is a Django site, and it turns out that Apache does get the auth variables passed through, however mod_wsgi filters them out. The resolution is to use: WSGIPassAuthorization On See http://www.arnebrodowski.de/blog/508-Django,-mod_wsgi-and-HTTP-Authentication.html for more details

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• nginx reverse proxy to apache mod_wsgi doesn't work

  - by user11243

  I'm trying to run a django site with apache mod-wsgi with nginx as the front-end to reverse proxy into apache. In my Apache ports.conf file: NameVirtualHost 192.168.0.1:7000 Listen 192.168.0.1:7000 <VirtualHost 192.168.0.1:7000> DocumentRoot /var/apps/example/ ServerName example.com WSGIDaemonProcess example WSGIProcessGroup example Alias /m/ /var/apps/example/forum/skins/ Alias /upfiles/ /var/apps/example/forum/upfiles/ <Directory /var/apps/example/forum/skins> Order deny,allow Allow from all </Directory> WSGIScriptAlias / /var/apps/example/django.wsgi </VirtualHost> In my nginx config: server { listen 80; server_name example.com; location / { include /usr/local/nginx/conf/proxy.conf; proxy_pass http://192.168.0.1:7000; proxy_redirect default; root /var/apps/example/forum/skins/; } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html error_page 500 502 503 504 /50x.html; location = /50x.html { root html; } } After restarting both apache and nginx, nothing works, example.com simply hangs or serves index.html in my /var/www/ folder. I'd appreciate any advice to point me in the right direction. I've tried several tutorials online to no avail.

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• System Slow After Uprading Ubuntu

  - by Aragon N

  I have an Ubuntu network machine which has release of 10.04.1 LTS Lucid. On this system I have Apache, PostgreSQL and django. For some app. development I have to install PGP and php-curl. Due to being on network, I have exported a VMware machine to the Internet and firstly I have upgraded the system and then installed php5 packages on it. I don't know is it all about django or apache configuration. Maybe some Apache settings had changed. In this case in apache where I have to look at ? After all replacing it with its old place, I see that the new system query is slow according to another. Old system query time : 140 ms New system query time : 9.11 s I have checked /etc/network interface and it seems there is no problem. I have checked /etc/resolv.conf and it seems OK I have checked /etc/nsswitch.conf and only host section is different from old one which old system has hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4 and then I have checked time host -t A services.myapp.com and I got real 0m0.355s user 0m0.010s sys 0m0.020s and I have checked apache2 HostnameLookups : find /etc/apache2/ -type f | xargs grep -i HostnameLookups It returned : /etc/apache2/apache2.conf:# HostnameLookups: Log the names of clients or just their IP addresses /etc/apache2/apache2.conf:HostnameLookups Off and now what can I have to check for boosting my system as before?

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• In solaris, how monitor & auto-respond to critical events

  - by mamcx

  I have a website that randomly fail. Is running in open solaris on joyent. I have a monitoring service that alert me when the site is down, but, I want a way to put a "insider" tool that tell me why that happened. Is because the cpu is too high? Not memory? Which process fail? Is possible to have a backtrace of that? Everything is running on the Solaris Service Management Facility. The webserver is cherokee, the database is mysql and the language is python/django. I want the most simple setup to monitor that & auto-respond , ie: restart the webserver or the django process in case of failure. I prefer a low-overhead tool. I don't need the fancy monitoring that some tools have, no ned graphs or sms alert. Only know what fail, restart it if possible (maybe up to n times), and have a log somewhere when I will check it.

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• Exception "The operation is not valid for the state of the transaction" using TransactionScope

  - by Lanfear

  We have a web service on server #1 and a database on server #2. Web service uses transaction scope to produce distributed transaction. Everything is correct. And we have another database on server #3. We had some problems with this server and we reinstalled operation system and software. We configured MSDTC and tried to use web service from server #1 to communicate with database on this server. And now after first select statement within transaction scope we get: "The operation is not valid for the state of the transaction". This exception falls in every web service request if it is using transaction scope. Server #2 and Server #3 is almost similar. The difference can be only in settings. .NET framework 3.5 SP1 installed and SQL Server SP3 on all servers. Full stacktrace: System.Transactions.TransactionState.EnlistPromotableSinglePhase(InternalTransaction tx, IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Transaction atomicTransaction) ? System.Transactions.Transaction.EnlistPromotableSinglePhase(IPromotableSinglePhaseNotification promotableSinglePhaseNotification) ? System.Data.SqlClient.SqlInternalConnection.EnlistNonNull(Transaction t ? System.Data.SqlClient.SqlInternalConnection.Enlist(Transaction t ? System.Data.SqlClient.SqlInternalConnectionTds.Activate(Transaction transaction) ? System.Data.ProviderBase.DbConnectionInternal.ActivateConnection(Transaction transaction) ? System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) ? System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) ? System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) ? System.Data.SqlClient.SqlConnection.Open() ? NHibernate.Connection.DriverConnectionProvider.GetConnection() ? NHibernate.Impl.SessionFactoryImpl.OpenConnection() I searched this message but didn't found any appropriate solution. So what settings should I check and what exactly should I do to fix it?

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• Windows 7 - Enable Network DTC Access

  - by Russ Clark

  I have a Visual Studio 2010 Windows Forms application in which I start a transaction using the TransactionScope class. I then Receive a message from a Sql Server Broker Services message queue, which works fine. I next try to call a stored procedure from the same database with a call to my data access layer which is a Visual Studio dataset (xsd file). When I make this second call to the database I get the following error message: The MSDTC transaction manager was unable to pull the transaction from the source transaction manager due to communication problems. Possible causes are: a firewall is present and it doesn't have an exception for the MSDTC process, the two machines cannot find each other by their NetBIOS names, or the support for network transactions is not enabled for one of the two transaction managers. (Exception from HRESULT: 0x8004D02B). I've seen several posts on the web that talk about Enabling DTC access through dcomcnfg.exe, and allowing DTC to communicate through Windows Firewall. I've done those things, and am still having this problem. I know our remote database server is setup to Enable DTC access, because we are using similar transactions in other projects built with Visual Studio 2008 on Windows XP and Vista. I think there is something specific about Windows 7 and Visual Studio 2010 causing this problem, but haven't been able to find out what it is. Can anyone help with this problem?

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• SQL Server transaction log backups,

  - by krimerd

  Hi there, I have a question regarding the transaction log backups in sql server 2008. I am currently taking full backups once a week (Sunday) and transaction log backups daily. I put full backup in folder1 on Sunday and then on Monday I also put the 1st transaction log backup in the same folder. On tuesday, before I take the 2nd transaction log backup I move the first transaction log backup from folder1 an put it into folder2 and then I take the 2nd transaction log backup and put it in the folder1. Same thing on Wed, Thurs and so on. Basicaly in folder1 I always have the latest full backup and the latest transaction log backup while the other transaction log backups are in folder2. My questions is, when sql server is about to take, lets say 4th (Thursday) transaction log backup, does it look for the previous transac log backups (1st, 2nd, and 3rd) so that this new backup will only include the transactions from the last backup or it has some other way of knowing whether there are other transac log backups. Basically, I am asking this because all my transaction log backups seem to be about the same size and I thought that their size will depend on the amount of transactions since the last transaction log backup. Can anyone please explain if my assumptions are right? Thanks...

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• JDBC connection for a background thread being closed accessing in Websphere

  - by ferrari fan

  Hi, I have an application running in Websphere Portal Server inside of Websphere Application Server 6.0 (WAS). In this application for one particular functionality that takes a long time to complete, I am firing a new thread that performs this action. This new thread opens a new Session from Hibernate and starts performing DB transactions with it. Sometimes (haven't been able to see a pattern), the transactions inside the thread work fine and the process completes successfully. Other times however I get the errors below: org.hibernate.exception.GenericJDBCException: could not load an entity: [OBJECT NAME#218294] ... Caused by: com.ibm.websphere.ce.cm.ObjectClosedException: DSRA9110E: Connection is closed. Method cleanup failed while trying to execute method cleanup on ManagedConnection WSRdbManagedConnectionImpl@642aa0d8 from resource jdbc/MyJDBCDataSource. Caught exception: com.ibm.ws.exception.WsException: DSRA0080E: An exception was received by the Data Store Adapter. See original exception message: Cannot call 'cleanup' on a ManagedConnection while it is still in a transaction.. How can I stop this from happening? Why does it seem that WAS wants to kill my connections even though they're not done. Is there a way I can stop WAS from attempting to close this particular connection? Thanks

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• Guice, JDBC and managing database connections

  - by pledge

  I'm looking to create a sample project while learning Guice which uses JDBC to read/write to a SQL database. However, after years of using Spring and letting it abstract away connection handling and transactions I'm struggling to work it our conceptually. I'd like to have a service which starts and stops a transaction and calls numerous repositories which reuse the same connection and participate in the same transaction. My questions are: Where do I create my Datasource? How do I give the repositories access to the connection? (ThreadLocal?) Best way to manage the transaction (Creating an Interceptor for an annotation?) The code below shows how I would do this in Spring. The JdbcOperations injected into each repository would have access to the connection associated with the active transaction. I haven't been able to find many tutorials which cover this, beyond ones which show creating interceptors for transactions. I am happy with continuing to use Spring as it is working very well in my projects, but I'd like to know how to do this in pure Guice and JBBC (No JPA/Hibernate/Warp/Reusing Spring) @Service public class MyService implements MyInterface { @Autowired private RepositoryA repositoryA; @Autowired private RepositoryB repositoryB; @Autowired private RepositoryC repositoryC; @Override @Transactional public void doSomeWork() { this.repositoryA.someInsert(); this.repositoryB.someUpdate(); this.repositoryC.someSelect(); } } @Repository public class MyRepositoryA implements RepositoryA { @Autowired private JdbcOperations jdbcOperations; @Override public void someInsert() { //use jdbcOperations to perform an insert } } @Repository public class MyRepositoryB implements RepositoryB { @Autowired private JdbcOperations jdbcOperations; @Override public void someUpdate() { //use jdbcOperations to perform an update } } @Repository public class MyRepositoryC implements RepositoryC { @Autowired private JdbcOperations jdbcOperations; @Override public String someSelect() { //use jdbcOperations to perform a select and use a RowMapper to produce results return "select result"; } }

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• Making Spring Data JPA work with DataNucleus (GAE) (Spring Boot)

  - by xybrek

  There are several hints that Spring Data works with Google App Engine like: http://tommysiu.blogspot.com/2014/01/spring-data-on-gae-part-1.html http://blog.eisele.net/2009/07/spring-300m3-on-google-appengine-with.html Much of the examples are not "Spring Boot" so I've been trying to retrofit things with it. However, I've been stuck with this error for days and days: [INFO] Caused by: java.lang.NullPointerException [INFO] at org.datanucleus.api.jpa.metamodel.SingularAttributeImpl.isVersion(SingularAttributeImpl.java:79) [INFO] at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.findVersionAttribute(JpaMetamodelEntityInformation.java:102) [INFO] at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.<init>(JpaMetamodelEntityInformation.java:79) [INFO] at org.springframework.data.jpa.repository.support.JpaEntityInformationSupport.getMetadata(JpaEntityInformationSupport.java:65) [INFO] at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getEntityInformation(JpaRepositoryFactory.java:149) [INFO] at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:88) [INFO] at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:68) [INFO] at org.springframework.data.repository.core.support.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:158) [INFO] at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.initAndReturn(RepositoryFactoryBeanSupport.java:224) [INFO] at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.afterPropertiesSet(RepositoryFactoryBeanSupport.java:210) [INFO] at org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean.afterPropertiesSet(JpaRepositoryFactoryBean.java:92) [INFO] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$6.run(AbstractAutowireCapableBeanFactory.java:1602) [INFO] at java.security.AccessController.doPrivileged(Native Method) [INFO] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1599) [INFO] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1549) [INFO] ... 40 more Where, I'm trying to use Spring Data JPA with DataNucleus/AppEngine: @Configuration @ComponentScan @EnableJpaRepositories @EnableTransactionManagement class JpaApplicationConfig { private static final Logger logger = Logger .getLogger(JpaApplicationConfig.class.getName()); @Bean public EntityManagerFactory entityManagerFactory() { logger.info("Loading Entity Manager..."); return Persistence .createEntityManagerFactory("transactions-optional"); } @Bean public PlatformTransactionManager transactionManager() { logger.info("Loading Transaction Manager..."); final JpaTransactionManager txManager = new JpaTransactionManager(); txManager.setEntityManagerFactory(entityManagerFactory()); return txManager; } } I've tested Persistence.createEntityManagerFactory("transactions-optional"); to see if the app can persist using this EMF, well, it does, so I am sure that this EMF works fine. The problem is the "wiring" up with the Spring Data JPA, can anybody help?

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• Doing large updates against indexed view

  - by user217136

  We have an indexed view that runs across three large tables. Two of these tables (A & B) are constantly getting updated with user transactions and the other table (C) contains data product info that is needs to be updated once a week. This product table contains over 6 million records. We need this view across these three tables for our core business process and unfortunately we cannot change this aspect. We even had a sql server MVP come in to help test under load to make sure we have the most efficient configuration. There is one column in the product table that gets utilized in the view and has to be updated each week. The problem we are now encountering is that as volume is increasing on our transactions against tables A & B, the update to Table C is causing deadlocks. I have tried several different methods to no avail: 1) I was hoping that we could change the view so that table C could be a dirty read "WITH (NOLOCK)" but apparently that functionality is not available with indexes views. 2) I thought about updating a new column in Table C and then just renaming it when the process is done but you cannot do that due to the dependency in the view. 3) I also entertained the idea of writing this value to a temporary product table, and then running an ALTER statement against the view to have it point to my new table. however when i did that the indexes on my view were dropped and it took quite a bit of time to recreate them. 4) we tried to do the weekly update in small chunks (as small as 100 records at a time) but we still run into dead locks. questions: a) we are using sql server 2005. Does sql server 2008 have a new functionality with their indexed views that would help us? Is there now a way to do dirty reads w/ an indexed view? b) a better approach to altering an existing view to point to a new table? thanks!

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