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• Myths about Coding Craftsmanship part 2

  - by tom

  Myth 3: The source of all bad code is inept developers and stupid people When you review code is this what you assume?  Shame on you.  You are probably making assumptions in your code if you are assuming so much already.  Bad code can be the result of any number of causes including but not limited to using dated techniques (like boxing when generics are available), not following standards (“look how he does the spacing between arguments!” or “did he really just name that variable ‘bln_Hello_Cats’?”), being redundant, using properties, methods, or objects in a novel way (like switching on button.Text between “Hello World” and “Hello World “ //clever use of space character… sigh), not following the SOLID principals, hacking around assumptions made in earlier iterations / hacking in features that should be worked into the overall design.  The first two issues, while annoying are pretty easy to spot and can be fixed so easily.  If your coding team is made up of experienced professionals who are passionate about staying current then these shouldn’t be happening.  If you work with a variety of skills, backgrounds, and experience then there will be some of this stuff going on.  If you have an opportunity to mentor such a developer who is receptive to constructive criticism don’t be a jerk; help them and the codebase will improve.  A little patience can improve the codebase, your work environment, and even your perspective. The novelty and redundancy I have encountered has often been the use of creativity when language knowledge was perceived as unavailable or too time consuming.  When developers learn on the job you get a lot of this.  Rather than going to MSDN developers will use what they know.  Depending on the constraints of their assignment hacking together what they know may seem quite practical.  This was not stupid though I often wonder how much time is actually “saved” by hacking.  These issues are often harder to untangle if we ever do.  They can also grow out of control as we write hack after hack to make it work and get back to some development that is satisfying. Hacking upon an existing hack is what I call “feeding the monster”.  Code monsters are anti-patterns and hacks gone wild.  The reason code monsters continue to get bigger is that they keep growing in scope, touching more and more of the application.  This is not the result of dumb developers. It is probably the result of avoiding design, not taking the time to understand the problems or anticipate or communicate the vision of the product.  If our developers don’t understand the purpose of a feature or product how do we expect potential customers to do so? Forethought and organization are often what is missing from bad code.  Developers who do not use the SOLID principals should be encouraged to learn these principals and be given guidance on how to apply them.  The time “saved” by giving hackers room to hack will be made up for and then some. Not as technical debt but as shoddy work that if not replaced will be struggled with again and again.  Bad code is not the result of dumb developers (usually) it is the result of trying to do too much without the proper resources and neglecting the right thing that needs doing with the first thoughtless thing that comes into our heads. Object oriented code is all about relationships between objects.  Coders who believe their coworkers are all fools tend to write objects that are difficult to work with, not eager to explain themselves, and perform erratically and irrationally.  If you constantly find you are surrounded by idiots you may want to ask yourself if you are being unreasonable, if you are being closed minded, of if you have chosen the right profession.  Opening your mind up to the idea that you probably work with rational, well-intentioned people will probably make you a better coder and it might even make you less grumpy.  If you are surrounded by jerks who do not engage in the exchange of ideas who do not care about their customers or the durability of the code you are building together then I suggest you find a new place to work.  Myth 4: Customers don’t care about “beautiful” code Craftsmanship is customer focused because it means that the job was done right, the product will withstand the abuse, modifications, and scrutiny of our customers.  Users can appreciate a predictable timeline for a release, a product delivered on time and on budget, a feature set that does not interfere with the task(s) it is supporting, quick turnarounds on exception messages, self healing issues, and less issues.  These are all hindered by skimping on craftsmanship.  When we write data access and when we write reusable code.   What do you think?  Does bad code come primarily from low IQ individuals?  Do customers care about beautiful code?

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• Drive Online Engagement with Intuitive Portals and Websites

  - by kellsey.ruppel

  As more and more business is being conducted via online channels, engaging users and making them more productive and efficient though these online channels is becoming critical. These users could be customers, partners or employees and while the respective channels through which they interact might be different, these users do increasingly interact with your business through the Web, or mobile devices or now through various social mediums.  Businesses need a user engagement strategy and solution that allows them to deliver targeted and personalized content and applications to users through the various online mediums and touch points.  The customer experience today is made up of an ongoing set of interactions with organizations across many channels, online and offline.  The Direct channel (including sales reps, email and mail) is an important point of contact, as is the Contact Center.  Contact Centers rely on the phone as a means of interacting with customers, and also more now than ever, the Web as well.  However, the online organization is often managed separately from the Contact Center organization within a business. In-store is an important channel for retailers, offering Point-of-Service for human interactions, and Kiosks which enable self-service. Kiosks are a Web-enabled touch point but in-store kiosks are often managed by the head of retail operations, rather than the online organization.  And of course, the online channel, including customer interactions with an organization via digital means -- on the website, mobile websites, and social networking sites, has risen to paramount importance in recent years in the customer experience. Historically all of these channels have been managed separately. The result of all of this fragmentation is that the customer touch points with an organization are siloed.  Their interactions online are not known and respected in their dealings in-store.  Their calls to the contact center are not taken as input into what the website offers them when they arrive. Think of how many times you’ve fallen victim to this. Your experience with the company call center is different than the experience in-store. Your experience with the company website on your desktop computer is different than your experience on your iPad. I think you get the point. But the customer isn’t the only one we need to look at here, as employees and the IT organization have challenges as well when it comes to online engagement. There are many common tools and technologies that organizations have been using to try and engage users, whether it’s customers, employees or partners. Some have adopted different blog and wiki technologies (some hosted, some open source, sometimes embedded in platforms), to things like tagging, file sharing and content management, or composite applications for self-service applications and activity streams. Basically, there are so many different tools & technologies that each address different aspects of user engagement. Now, one of the challenges with this, is that if we look at each individual tool, typically just implementing for example a file sharing and basic collaboration solution, may meet the needs of the business user for one aspect of user engagement, but it may not be the best solution to engage with customers and partners, or it may not fit with IT standards such as integrating with their single sign on tools or their corporate website. Often, the scenario is that businesses are having to acquire multiple pieces and parts as well as build custom applications to meet their needs. Leaving customers and partners with a more fragmented way of interacting with the company. Every organization has some sort of enterprise balancing act between the needs of the business user and the needs and restrictions enforced by enterprise IT groups. As we’ve been discussing, we all know that the expectations for online engagement have changed since the days of the static, one-size fits all website. With these changes have come some very difficult organizational challenges as well. Today, as a business user, you want to engage with your customers, and your customers expect you to know who they are. They expect you to recall the details they’ve provided to you on your website, to your CSRs and to your sales people. They expect you to remember their purchases, their preferences and their problems. And they expect you to know who they are, equally well, across channels, including your web presence. This creates a host of challenges for today’s business users. Delivering targeted, relevant content online is now essential for converting prospects into customers and for engendering long term loyalty. Business users need the ability to leverage customer data from different sources to fuel their segmentation and targeting strategies and to easily set-up, manage and optimize online campaigns. Also critical, they need the ability to accomplish these things on-the-fly, at the speed of the marketplace, while making iterative improvements.  These changing expectations put a host of demands on the IT organization as well. The web presence must be able to scale to support the delivery of personalized and targeted content to thousands of site visitors without sacrificing performance. And integration between systems becomes more important as well, as organizations strive to obtain one view of the customer culled from WCM data, CRM data and more. So then, how do you solve these challenges and meet the growing demands of your users?  You need a solution that: Unifies every customer interaction across all channels Personalizes the products and content that interest the customer and to the device Delivers targeted promotions to the right customer Engages and improve employee productivity Provides self-service access to applications Includes embedded in-context social   So how then do you achieve this level of online engagement, complete customer experience and engage your employees? The answer: Oracle WebCenter. If you want to learn how to get there, we encourage you to attend this webcast on Thursday Drive Online Engagement with Intuitive Portals and Websites, where we'll talk about how you are able to transform your portal experience and optimize online engagement -- making your portals more interactive and more engaging across multiple channels. Register today!

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• The Unintended Consequences of Sound Security Policy

  - by Tanu Sood

  v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif"; mso-bidi-font-family:"Times New Roman";} Author: Kevin Moulton, CISSP, CISM Meet the Author: Kevin Moulton, Senior Sales Consulting Manager, Oracle Kevin Moulton, CISSP, CISM, has been in the security space for more than 25 years, and with Oracle for 7 years. He manages the East Enterprise Security Sales Consulting Team. He is also a Distinguished Toastmaster. Follow Kevin on Twitter at twitter.com/kevin_moulton, where he sometimes tweets about security, but might also tweet about running, beer, food, baseball, football, good books, or whatever else grabs his attention. Kevin will be a regular contributor to this blog so stay tuned for more posts from him. When I speak to a room of IT administrators, I like to begin by asking them if they have implemented a complex password policy. Generally, they all nod their heads enthusiastically. I ask them if that password policy requires long passwords. More nodding. I ask if that policy requires upper and lower case letters – faster nodding – numbers – even faster – special characters – enthusiastic nodding all around! I then ask them if their policy also includes a requirement for users to regularly change their passwords. Now we have smiles with the nodding! I ask them if the users have different IDs and passwords on the many systems that they have access to. Of course! I then ask them if, when they walk around the building, they see something like this: Thanks to Jake Ludington for the nice example. Can these administrators be faulted for their policies? Probably not but, in the end, end-users will find a way to get their job done efficiently. Post-It Notes to the rescue! I was visiting a business in New York City one day which was a perfect example of this problem. First I walked up to the security desk and told them where I was headed. They asked me if they should call upstairs to have someone escort me. Is that my call? Is that policy? I said that I knew where I was going, so they let me go. Having the conference room number handy, I wandered around the place in a search of my destination. As I walked around, unescorted, I noticed the post-it note problem in abundance. Had I been so inclined, I could have logged in on almost any machine and into any number of systems. When I reached my intended conference room, I mentioned my post-it note observation to the two gentlemen with whom I was meeting. One of them said, “You mean like this,” and he produced a post it note full of login IDs and passwords from his breast pocket! I gave him kudos for not hanging the list on his monitor. We then talked for the rest of the meeting about the difficulties faced by the employees due to the security policies. These policies, although well-intended, made life very difficult for the end-users. Most users had access to 8 to 12 systems, and the passwords for each expired at a different times. The post-it note solution was understandable. Who could remember even half of them? What could this customer have done differently? I am a fan of using a provisioning system, such as Oracle Identity Manager, to manage all of the target systems. With OIM, and email could be automatically sent to all users when it was time to change their password. The end-users would follow a link to change their password on a web page, and then OIM would propagate that password out to all of the systems that the user had access to, even if the login IDs were different. Another option would be an Enterprise Single-Sign On Solution. With Oracle eSSO, all of a user’s credentials would be stored in a central, encrypted credential store. The end-user would only have to login to their machine each morning and then, as they moved to each new system, Oracle eSSO would supply the credentials. Good-bye post-it notes! 3M may be disappointed, but your end users will thank you. I hear people say that this post-it note problem is not a big deal, because the only people who would see the passwords are fellow employees. Do you really know who is walking around your building? What are the password policies in your business? How do the end-users respond?

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• PanelGridLayout - A Layout Revolution

  - by Duncan Mills

  With the most recent 11.1.2 patchset (11.1.2.3) there has been a lot of excitement around ADF Essentials (and rightly so), however, in all the fuss I didn't want an even more significant change to get missed - yes you read that correctly, a more significant change! I'm talking about the new panelGridLayout component, I can confidently say that this one of the most revolutionary components that we've introduced in 11g, even though it sounds rather boring. To be totally accurate, panelGrid was introduced in 11.1.2.2 but without any presence in the component palette or other design time support, so it was largely missed unless you read the release notes. However in this latest patchset it's finally front and center. Its time to explore - we (really) need to talk about layout.  Let's face it,with ADF Faces rich client, layout is a rather arcane pursuit, once you are a layout master, all bow before you, but it's more of an art than a science, and it is often, in fact, way too difficult to achieve what should (apparently) be a pretty simple. Here's a great example, it's a homework assignment I set for folks I'm teaching this stuff to:  The requirements for this layout are: The header is 80px high, the footer is 30px. These are both fixed.  The first section of the header containing the logo is 180px wide The logo is centered within the top left hand corner of the header  The title text is start aligned in the center zone of the header and will wrap if the browser window is narrowed. It should be aligned in the center of the vertical space  The about link is anchored to the right hand side of the browser with a 20px gap and again is center aligned vertically. It will move as the browser window is reduced in width. The footer has a right aligned copyright statement, again middle aligned within a 30px high footer region and with a 20px buffer to the right hand edge. It will move as the browser window is reduced in width. All remaining space is given to a central zone, which, in this case contains a panelSplitter. Expect that at some point in time you'll need a separate messages line in the center of the footer.  In the homework assigment I set I also stipulate that no inlineStyles can be used to control alignment or margins and no use of other taglibs (e.g. JSF HTML or Trinidad HTML). So, if we take this purist approach, that basic page layout (in my stock solution) requires 3 panelStretchLayouts, 5 panelGroupLayouts and 4 spacers - not including the spacer I use for the logo and the contents of the central zone splitter - phew! The point is that even a seemingly simple layout needs a bit of thinking about, particulatly when you consider strechting and browser re-size behavior. In fact, this little sample actually teaches you much of what you need to know to become vaguely competant at layouts in the framework. The underlying result of "the way things are" is that most of us reach for panelStretchLayout before even finishing the first sip of coffee as we embark on a new page design. In fact most pages you will see in any moderately complex ADF page will basically be nested panelStretchLayouts and panelGroupLayouts, sometimes many, many levels deep. So this is a problem, we've known this for some time and now we have a good solution. (I should point out that the oft-used Trinidad trh tags are not a particularly good solution as you're tie-ing yourself to an HTML table based layout in that case with a host of attendent issues in resize and bi-di behavior, but I digress.) So, tadaaa, I give to you panelGridLayout. PanelGrid, as the name suggests takes a grid like (dare I say slightly gridbag-like) approach to layout, dividing your layout into rows and colums with margins, sizing, stretch behaviour, colspans and rowspans all rolled in, all without the use of inlineStyle. As such, it provides for a much more powerful and consise way of defining a layout such as the one above that is actually simpler and much more logical to design. The basic building blocks are the panelGridLayout itself, gridRow and gridCell. Your content sits inside the cells inside the rows, all helpfully allowing both streching, valign and halign definitions without the need to nest further panelGroupLayouts. So much simpler!  If I break down the homework example above my nested comglomorate of 12 containers and spacers can be condensed down into a single panelGrid with 3 rows and 5 cell definitions (39 lines of source reduced to 24 in the case of the sample). What's more, the actual runtime representation in the browser DOM is much, much simpler, and clean, with basically one DIV per cell (Note that just because the panelGridLayout semantics looks like an HTML table does not mean that it's rendered that way!) . Another hidden benefit is the runtime cost. Because we can use a single layout to achieve much more complex geometries the client side layout code inside the browser is having to work a lot less. This will be a real benefit if your application needs to run on lower powered clients such as netbooks or tablets. So, it's time, if you're on 11.1.2.2 or above, to smile warmly at your panelStretchLayouts, wrap the blanket around it's knees and wheel it off to the Sunset Retirement Home for a well deserved rest. There's a new kid on the block and it wants to be your friend. 

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• My error with upgrading 4.0 to 4.2- What NOT to do...

  - by Steve Tunstall

  Last week, I was helping a client upgrade from the 2011.1.4.0 code to the newest 2011.1.4.2 code. We downloaded the 4.2 update from MOS, upload and unpacked it on both controllers, and upgraded one of the controllers in the cluster with no issues at all. As this was a brand-new system with no networking or pools made on it yet, there were not any resources to fail back and forth between the controllers. Each controller had it's own, private, management interface (igb0 and igb1) and that's it. So we took controller 1 as the passive controller and upgraded it first. The first controller came back up with no issues and was now on the 4.2 code. Great. We then did a takeover on controller 1, making it the active head (although there were no resources for it to take), and then proceeded to upgrade controller 2. Upon upgrading the second controller, we ran the health check with no issues. We then ran the update and it ran and rebooted normally. However, something strange then happened. It took longer than normal to come back up, and when it did, we got the "cluster controllers on different code" error message that one gets when the two controllers of a cluster are running different code. But we just upgraded the second controller to 4.2, so they should have been the same, right??? Going into the Maintenance-->System screen of controller 2, we saw something very strange. The "current version" was still on 4.0, and the 4.2 code was there but was in the "previous" state with the rollback icon, as if it was the OLDER code and not the newer code. I have never seen this happen before. I would have thought it was a bad 4.2 code file, but it worked just fine with controller 1, so I don't think that was it. Other than the fact the code did not update, there was nothing else going on with this system. It had no yellow lights, no errors in the Problems section, and no errors in any of the logs. It was just out of the box a few hours ago, and didn't even have a storage pool yet. So.... We deleted the 4.2 code, uploaded it from scratch, ran the health check, and ran the upgrade again. once again, it seemed to go great, rebooted, and came back up to the same issue, where it came to 4.0 instead of 4.2. See the picture below.... HERE IS WHERE I MADE A BIG MISTAKE.... I SHOULD have instantly called support and opened a Sev 2 ticket. They could have done a shared shell and gotten the correct Fishwork engineer to look at the files and the code and determine what file was messed up and fixed it. The system was up and working just fine, it was just on an older code version, not really a huge problem at all. Instead, I went ahead and clicked the "Rollback" icon, thinking that the system would rollback to the 4.2 code.   Ouch... What happened was that the system said, "Fine, I will delete the 4.0 code and boot to your 4.2 code"... Which was stupid on my part because something was wrong with the 4.2 code file here and the 4.0 was just fine.  So now the system could not boot at all, and the 4.0 code was completely missing from the system, and even a high-level Fishworks engineer could not help us. I had messed it up good. We could only get to the ILOM, and I had to re-image the system from scratch using a hard-to-get-and-use FishStick USB drive. These are tightly controlled and difficult to get, almost always handcuffed to an engineer who will drive out to re-image a system. This took another day of my client's time.  So.... If you see a "previous version" of your system code which is actually a version higher than the current version... DO NOT ROLL IT BACK.... It did not upgrade for a very good reason. In my case, after the system was re-imaged to a code level just 3 back, we once again tried the same 4.2 code update and it worked perfectly the first time and is now great and stable.  Lesson learned.  By the way, our buddy Ryan Matthews wanted to point out the best practice and supported way of performing an upgrade of an active/active ZFSSA, where both controllers are doing some of the work. These steps would not have helpped me for the above issue, but it's important to follow the correct proceedure when doing an upgrade. 1) Upload software to both controllers and wait for it to unpack 2) On controller "A" navigate to configuration/cluster and click "takeover" 3) Wait for controller "B" to finish restarting, then login to it, navigate to maintenance/system, and roll forward to the new software. 4) Wait for controller "B" to apply the update and finish rebooting 5) Login to controller "B", navigate to configuration/cluster and click "takeover" 6) Wait for controller "A" to finish restarting, then login to it, navigate to maintenance/system, and roll forward to the new software. 7) Wait for controller "A" to apply the update and finish rebooting 8) Login to controller "B", navigate to configuration/cluster and click "failback"

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• Breaking 1NF to model subset constraints. Does this sound sane?

  - by Chris Travers

  My first question here. Appologize if it is in the wrong forum but this seems pretty conceptual. I am looking at doing something that goes against conventional wisdom and want to get some feedback as to whether this is totally insane or will result in problems, so critique away! I am on PostgreSQL 9.1 but may be moving to 9.2 for this part of this project. To re-iterate: Does it seem sane to break 1NF in this way? I am not looking for debugging code so much as where people see problems that this might lead. The Problem In double entry accounting, financial transactions are journal entries with an arbitrary number of lines. Each line has either a left value (debit) or a right value (credit) which can be modelled as a single value with negatives as debits and positives as credits or vice versa. The sum of all debits and credits must equal zero (so if we go with a single amount field, sum(amount) must equal zero for each financial journal entry). SQL-based databases, pretty much required for this sort of work, have no way to express this sort of constraint natively and so any approach to enforcing it in the database seems rather complex. The Write Model The journal entries are append only. There is a possibility we will add a delete model but it will be subject to a different set of restrictions and so is not applicable here. If and when we allow deletes, we will probably do them using a simple ON DELETE CASCADE designation on the foreign key, and require that deletes go through a dedicated stored procedure which can enforce the other constraints. So inserts and selects have to be accommodated but updates and deletes do not for this task. My Proposed Solution My proposed solution is to break first normal form and model constraints on arrays of tuples, with a trigger that breaks the rows out into another table. CREATE TABLE journal_line ( entry_id bigserial primary key, account_id int not null references account(id), journal_entry_id bigint not null, -- adding references later amount numeric not null ); I would then add "table methods" to extract debits and credits for reporting purposes: CREATE OR REPLACE FUNCTION debits(journal_line) RETURNS numeric LANGUAGE sql IMMUTABLE AS $$ SELECT CASE WHEN $1.amount < 0 THEN $1.amount * -1 ELSE NULL END; $$; CREATE OR REPLACE FUNCTION credits(journal_line) RETURNS numeric LANGUAGE sql IMMUTABLE AS $$ SELECT CASE WHEN $1.amount > 0 THEN $1.amount ELSE NULL END; $$; Then the journal entry table (simplified for this example): CREATE TABLE journal_entry ( entry_id bigserial primary key, -- no natural keys :-( journal_id int not null references journal(id), date_posted date not null, reference text not null, description text not null, journal_lines journal_line[] not null ); Then a table method and and check constraints: CREATE OR REPLACE FUNCTION running_total(journal_entry) returns numeric language sql immutable as $$ SELECT sum(amount) FROM unnest($1.journal_lines); $$; ALTER TABLE journal_entry ADD CONSTRAINT CHECK (((journal_entry.running_total) = 0)); ALTER TABLE journal_line ADD FOREIGN KEY journal_entry_id REFERENCES journal_entry(entry_id); And finally we'd have a breakout trigger: CREATE OR REPLACE FUNCTION je_breakout() RETURNS TRIGGER LANGUAGE PLPGSQL AS $$ BEGIN IF TG_OP = 'INSERT' THEN INSERT INTO journal_line (journal_entry_id, account_id, amount) SELECT NEW.id, account_id, amount FROM unnest(NEW.journal_lines); RETURN NEW; ELSE RAISE EXCEPTION 'Operation Not Allowed'; END IF; END; $$; And finally CREATE TRIGGER AFTER INSERT OR UPDATE OR DELETE ON journal_entry FOR EACH ROW EXECUTE_PROCEDURE je_breaout(); Of course the example above is simplified. There will be a status table that will track approval status allowing for separation of duties, etc. However the goal here is to prevent unbalanced transactions. Any feedback? Does this sound entirely insane? Standard Solutions? In getting to this point I have to say I have looked at four different current ERP solutions to this problems: Represent every line item as a debit and a credit against different accounts. Use of foreign keys against the line item table to enforce an eventual running total of 0 Use of constraint triggers in PostgreSQL Forcing all validation here solely through the app logic. My concerns are that #1 is pretty limiting and very hard to audit internally. It's not programmer transparent and so it strikes me as being difficult to work with in the future. The second strikes me as being very complex and required a series of contraints and foreign keys against self to make work, and therefore it strikes me as complex, hard to sort out at least in my mind, and thus hard to work with. The fourth could be done as we force all access through stored procedures anyway and this is the most common solution (have the app total things up and throw an error otherwise). However, I think proof that a constraint is followed is superior to test cases, and so the question becomes whether this in fact generates insert anomilies rather than solving them. If this is a solved problem it isn't the case that everyone agrees on the solution....

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• JPRT: A Build & Test System

  - by kto

  DRAFT A while back I did a little blogging on a system called JPRT, the hardware used and a summary on my java.net weblog. This is an update on the JPRT system. JPRT ("JDK Putback Reliablity Testing", but ignore what the letters stand for, I change what they mean every day, just to annoy people :\^) is a build and test system for the JDK, or any source base that has been configured for JPRT. As I mentioned in the above blog, JPRT is a major modification to a system called PRT that the HotSpot VM development team has been using for many years, very successfully I might add. Keeping the source base always buildable and reliable is the first step in the 12 steps of dealing with your product quality... or was the 12 steps from Alcoholics Anonymous... oh well, anyway, it's the first of many steps. ;\^) Internally when we make changes to any part of the JDK, there are certain procedures we are required to perform prior to any putback or commit of the changes. The procedures often vary from team to team, depending on many factors, such as whether native code is changed, or if the change could impact other areas of the JDK. But a common requirement is a verification that the source base with the changes (and merged with the very latest source base) will build on many of not all 8 platforms, and a full 'from scratch' build, not an incremental build, which can hide full build problems. The testing needed varies, depending on what has been changed. Anyone that was worked on a project where multiple engineers or groups are submitting changes to a shared source base knows how disruptive a 'bad commit' can be on everyone. How many times have you heard: "So And So made a bunch of changes and now I can't build!". But multiply the number of platforms by 8, and make all the platforms old and antiquated OS versions with bizarre system setup requirements and you have a pretty complicated situation (see http://download.java.net/jdk6/docs/build/README-builds.html). We don't tolerate bad commits, but our enforcement is somewhat lacking, usually it's an 'after the fact' correction. Luckily the Source Code Management system we use (another antique called TeamWare) allows for a tree of repositories and 'bad commits' are usually isolated to a small team. Punishment to date has been pretty drastic, the Queen of Hearts in 'Alice in Wonderland' said 'Off With Their Heads', well trust me, you don't want to be the engineer doing a 'bad commit' to the JDK. With JPRT, hopefully this will become a thing of the past, not that we have had many 'bad commits' to the master source base, in general the teams doing the integrations know how important their jobs are and they rarely make 'bad commits'. So for these JDK integrators, maybe what JPRT does is keep them from chewing their finger nails at night. ;\^) Over the years each of the teams have accumulated sets of machines they use for building, or they use some of the shared machines available to all of us. But the hunt for build machines is just part of the job, or has been. And although the issues with consistency of the build machines hasn't been a horrible problem, often you never know if the Solaris build machine you are using has all the right patches, or if the Linux machine has the right service pack, or if the Windows machine has it's latest updates. Hopefully the JPRT system can solve this problem. When we ship the binary JDK bits, it is SO very important that the build machines are correct, and we know how difficult it is to get them setup. Sure, if you need to debug a JDK problem that only shows up on Windows XP or Solaris 9, you'll still need to hunt down a machine, but not as a regular everyday occurance. I'm a big fan of a regular nightly build and test system, constantly verifying that a source base builds and tests out. There are many examples of automated build/tests, some that trigger on any change to the source base, some that just run every night. Some provide a protection gateway to the 'golden' source base which only gets changes that the nightly process has verified are good. The JPRT (and PRT) system is meant to guard the source base before anything is sent to it, guarding all source bases from the evil developer, well maybe 'evil' isn't the right word, I haven't met many 'evil' developers, more like 'error prone' developers. ;\^) Humm, come to think about it, I may be one from time to time. :\^{ But the point is that by spreading the build up over a set of machines, and getting the turnaround down to under an hour, it becomes realistic to completely build on all platforms and test it, on every putback. We have the technology, we can build and rebuild and rebuild, and it will be better than it was before, ha ha... Anybody remember the Six Million Dollar Man? Man, I gotta get out more often.. Anyway, now the nightly build and test can become a 'fetch the latest JPRT build bits' and start extensive testing (the testing not done by JPRT, or the platforms not tested by JPRT). Is it Open Source? No, not yet. Would you like to be? Let me know. Or is it more important that you have the ability to use such a system for JDK changes? So enough blabbering on about this JPRT system, tell me what you think. And let me know if you want to hear more about it or not. Stay tuned for the next episode, same Bloody Bat time, same Bloody Bat channel. ;\^) -kto

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• Top Questions and Answers for Pluging into Oracle Database as a Service

  - by David Swanger

  Yesterday we hosted a comprehensive online forum that shared a comprehensive path to help your organization design, deploy, and deliver a Database as a Service cloud. If you missed the online forum, you can watch it on demand by registering here. We received numerous questions.  Below are highlights of the most informative: DBaaS requires a lengthy and careful design efforts. What is the minimum requirements of setting up a scaled-down environment and test it out? You should have an OEM 12c environment for DBaaS administration and then a target database deployment platform that has the key characteristics of what your production environment will look like. This could be a single server or it could be a small pool of hosts if your production DBaaS will be larger and you want to test a more robust / real world configuration with Zones and Pools or DR capabilities for example. How does this benefit companies having their own data center? This allows companies to transform their internal IT to a service delivery model for the database. The benefits to the company are significant cost savings, improved business agility and reduced risk. The benefits to the consumers (internal) of services if much fast provisioning, and response to change in business requirements. From a deployment perspective, is DBaaS's job solely DBA's job? The best deployment model enables the DBA (or end-user) to control the entire process. All resources required to deploy the service are pre-provisioned, and there are no external dependencies (on network, storage, sysadmins teams). The service is created either via a self-service portal or by the DBA. The purpose of self service seems to be that the end user does not rely on the DBA. I just need to give him a template. He decides how much AMM he needs. Why shall I set it one by one. That doesn't seem to be the purpose of self service. Most customers we have worked with define a standardized service catalog, with a few (2 to 5) different classes of service. For each of these classes, there is a pre-defined deployment template, and the user has the ability to select from some pre-defined service sizes. The administrator only has to create this catalog once. Each user then simply selects from the options offered in the catalog.  Looking at DBaaS service definition, it seems to be no different from a service definition provided by a well defined DBA team. Why do you attribute it to DBaaS? There are a couple of perspectives. First, some organizations might already be operating with a high level of standardization and a higher level of maturity from an ITIL or Service Management perspective. Their journey to DBaaS could be shorter and their Service Definition will evolve less but they still might need to add capabilities such as Self Service and Metering/Chargeback. Other organizations are still operating in highly siloed environments with little automation and their formal Service Definition (if they have one) will be a lot less mature today. Therefore their future state DBaaS will look a lot different from their current state, as will their Service Definition. How database as a service impact or help with "Click to Compute" or deploying "Database in cloud infrastructure" DBaaS enables Click to Compute. Oracle DBaaS can be implemented using three architecture models: Oracle Multitenant 12c, native consolidation using Oracle Database and consolidation using virtualization in infrastructure cloud. As Deploy session showed, you get higher consolidating density and efficiency using Multitenant and higher isolation using infrastructure cloud. Depending upon your business needs, DBaaS can be implemented using any of these models. How exactly is the DBaaS different from the traditional db? Storage/OS/DB all together to 'transparently' provide service to applications? Will there be across-databases access by application/user. Some key differences are: 1) The services run on a shared platform. 2) The services can be rapidly provisioned (< 15 minutes). 3) The services are dynamic and can be relocated, grown, shrunk as needed to meet business needs without disruption and rapidly. 4) The user is able to provision the services directly from a standardized service catalog.. With 24x7x365 databases its difficult to find off peak hrs to do basic admin tasks such as gathering stats, running backups, batch jobs. How does pluggable database handle this and different needs/patching downtime of apps databases might be serving? You can gather stats in Oracle Multitenant the same way you had been in regular databases. Regarding patching/upgrading, Oracle Multitenant makes patch/upgrade very efficient in that you can pre-provision a new version/patched multitenant db in a different ORACLE_HOME and then unplug a PDB from its CDB and plug it into the newer/patched CDB in seconds.  Thanks for all the great questions!  If you'd like to learn more and missed the online forum, you can watch it on demand here.

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• Rebuilding CoasterBuzz, Part II: Hot data objects

  - by Jeff

  This is the second post, originally from my personal blog, in a series about rebuilding one of my Web sites, which has been around for 12 years. More: Part I: Evolution, and death to WCF After the rush to get moving on stuff, I temporarily lost interest. I went almost two weeks without touching the project, in part because the next thing on my backlog was doing up a bunch of administrative pages. So boring. Unfortunately, because most of the site's content is user-generated, you need some facilities for editing data. CoasterBuzz has a database full of amusement parks and roller coasters. The entities enjoy the relationships that you would expect, though they're further defined by "instances" of a coaster, to define one that has moved between parks as one, with different names and operational dates. And of course, there are pictures and news items, too. It's not horribly complex, except when you have to account for a name change and display just the newest name. In all previous versions, data access was straight SQL. As so much of the old code was rooted in 2003, with some changes in 2008, there wasn't much in the way of ORM frameworks going on then. Let me rephrase that, I mostly wasn't interested in ORM's. Since that time, I used a little LINQ to SQL in some projects, and a whole bunch of nHibernate while at Microsoft. Through all of that experience, I have to admit that these frameworks are often a bigger pain in the ass than not. They're great for basic crud operations, but when you start having all kinds of exotic relationships, they get difficult, and generate all kinds of weird SQL under the covers. The black box can quickly turn into a black hole. Sometimes you end up having to build all kinds of new expertise to do things "right" with a framework. Still, despite my reservations, I used the newer version of Entity Framework, with the "code first" modeling, in a science project and I really liked it. Since it's just a right-click away with NuGet, I figured I'd give it a shot here. My initial effort was spent defining the context class, which requires a bit of work because I deviate quite a bit from the conventions that EF uses, starting with table names. Then throw some partial querying of certain tables (where you'll find image data), and you're splitting tables across several objects (navigation properties). I won't go into the details, because these are all things that are well documented around the Internet, but there was a minor learning curve there. The basics of reading data using EF are fantastic. For example, a roller coaster object has a park associated with it, as well as a number of instances (if it was ever relocated), and there also might be a big banner image for it. This is stupid easy to use because it takes one line of code in your repository class, and by the time you pass it to the view, you have a rich object graph that has everything you need to display stuff. Likewise, editing simple data is also, well, simple. For this goodness, thank the ASP.NET MVC framework. The UpdateModel() method on the controllers is very elegant. Remember the old days of assigning all kinds of properties to objects in your Webforms code-behind? What a time consuming mess that used to be. Even if you're not using an ORM tool, having hydrated objects come off the wire is such a time saver. Not everything is easy, though. When you have to persist a complex graph of objects, particularly if they were composed in the user interface with all kinds of AJAX elements and list boxes, it's not just a simple matter of submitting the form. There were a few instances where I ended up going back to "old-fashioned" SQL just in the interest of time. It's not that I couldn't do what I needed with EF, it's just that the efficiency, both my own and that of the generated SQL, wasn't good. Since EF context objects expose a database connection object, you can use that to do the old school ADO.NET stuff you've done for a decade. Using various extension methods from POP Forums' data project, it was a breeze. You just have to stick to your decision, in this case. When you start messing with SQL directly, you can't go back in the same code to messing with entities because EF doesn't know what you're changing. Not really a big deal. There are a number of take-aways from using EF. The first is that you write a lot less code, which has always been a desired outcome of ORM's. The other lesson, and I particularly learned this the hard way working on the MSDN forums back in the day, is that trying to retrofit an ORM framework into an existing schema isn't fun at all. The CoasterBuzz database isn't bad, but there are design decisions I'd make differently if I were starting from scratch. Now that I have some of this stuff done, I feel like I can start to move on to the more interesting things on the backlog. There's a lot to do, but at least it's fun stuff, and not more forms that will be used infrequently.

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• Is your dream an international experience?

  - by Maria Sandu

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Studying in Poland, having two summer jobs in England, doing one internship in India, working in Thailand for half a year and now working in Prague. Does it seem an adventure? Well it is and I will tell you how I came to have this international experience. Dzien Dobry! My name is Wojciech Jurojc, I am Polish and I am currently a Business Development Consultant within Oracle, based in Prague. I joined Oracle on the 1st of August 2011. I graduated in 2010 and obtained 2 Masters Degrees in Political Science and Economics. I would like to tell you more about my past and how I joined Oracle. In 2005 I began studying at the Faculty of Political Sciences Gdansk University. In 2008, I obtained a Bachelors Degree. During these three years I had the opportunity to go to England twice, where I worked as a Bartender, first in Blackpool and then in Manchester. This allowed me to improve my language skills and become more confident. In the meantime, I joined the International Student Organization-AIESEC, where I was organized conferences and conducted student projects. Also I met a mass of interesting people from around the world. After graduation in 2008, I was able to get an Internship within a big company in Poland. I worked there as an Intern in the Purchase Department. That was my first adventure within a corporate environment. I learnt a lot about purchasing processes and negotiations. In September 2008, I started studying two Masters Faculties: Political Science and Economics. It was very difficult, but it was not impossible. Over the next two years of studying I was able to go on a three month internship to India where I worked as a Marketing Assistant in an NGO. I was travelling around northern India and did presentations to the academic community about green energy and environmental projects. I had the opportunity to visit Nepal and walked in the Himalayas. That was a huge experience as well as a cultural shock. It taught me how to deal with many problems and to appreciate what I have. At the end of 2009 I was working as a Marketing Assistant for a Leasing company, where I learnt useful sales knowledge and improved my objection handling skills. In July 2010, I graduated with a double Masters and found a job in Thailand as Sales Representative in an IT company. I worked in Thailand until the end of January 2011. Besides that, I was working in an International company with interesting people and I had the opportunity to travel around Thailand and visit Cambodia. After this adventure I started looking for jobs in Europe where I could further develop my sales skills. I found Oracle and I don’t regret this decision which I made. I am currently working in Prague in an international Hardware team and I know that is not the end of my adventures. At this moment, I am working in a team of 12 members. Ten of them are based in Prague and 2 others are based in Russia. We come from different countries such as: Czech Republic, Russia, Ukraine, Turkey, Slovakia and Kazakhstan. I am working on the Polish market, cooperating with our Hardware customers and partners. What do I enjoy the most about my job? I enjoy every challenge that I face in my daily activities as there are always new experiences for me and new things that I learn. As part of Oracle, I gain international exposure and therefore more career opportunities to explore. I have planned my next step for the career path I dream of and I am currently working on it. I recommend you check our Career Page if you’re looking for an international career. If you want to find out more about our job opportunities, follow us on https://campus.oracle.com .

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• CPU Usage in Very Large Coherence Clusters

  - by jpurdy

  When sizing Coherence installations, one of the complicating factors is that these installations (by their very nature) tend to be application-specific, with some being large, memory-intensive caches, with others acting as I/O-intensive transaction-processing platforms, and still others performing CPU-intensive calculations across the data grid. Regardless of the primary resource requirements, Coherence sizing calculations are inherently empirical, in that there are so many permutations that a simple spreadsheet approach to sizing is rarely optimal (though it can provide a good starting estimate). So we typically recommend measuring actual resource usage (primarily CPU cycles, network bandwidth and memory) at a given load, and then extrapolating from those measurements. Of course there may be multiple types of load, and these may have varying degrees of correlation -- for example, an increased request rate may drive up the number of objects "pinned" in memory at any point, but the increase may be less than linear if those objects are naturally shared by concurrent requests. But for most reasonably-designed applications, a linear resource model will be reasonably accurate for most levels of scale. However, at extreme scale, sizing becomes a bit more complicated as certain cluster management operations -- while very infrequent -- become increasingly critical. This is because certain operations do not naturally tend to scale out. In a small cluster, sizing is primarily driven by the request rate, required cache size, or other application-driven metrics. In larger clusters (e.g. those with hundreds of cluster members), certain infrastructure tasks become intensive, in particular those related to members joining and leaving the cluster, such as introducing new cluster members to the rest of the cluster, or publishing the location of partitions during rebalancing. These tasks have a strong tendency to require all updates to be routed via a single member for the sake of cluster stability and data integrity. Fortunately that member is dynamically assigned in Coherence, so it is not a single point of failure, but it may still become a single point of bottleneck (until the cluster finishes its reconfiguration, at which point this member will have a similar load to the rest of the members). The most common cause of scaling issues in large clusters is disabling multicast (by configuring well-known addresses, aka WKA). This obviously impacts network usage, but it also has a large impact on CPU usage, primarily since the senior member must directly communicate certain messages with every other cluster member, and this communication requires significant CPU time. In particular, the need to notify the rest of the cluster about membership changes and corresponding partition reassignments adds stress to the senior member. Given that portions of the network stack may tend to be single-threaded (both in Coherence and the underlying OS), this may be even more problematic on servers with poor single-threaded performance. As a result of this, some extremely large clusters may be configured with a smaller number of partitions than ideal. This results in the size of each partition being increased. When a cache server fails, the other servers will use their fractional backups to recover the state of that server (and take over responsibility for their backed-up portion of that state). The finest granularity of this recovery is a single partition, and the single service thread can not accept new requests during this recovery. Ordinarily, recovery is practically instantaneous (it is roughly equivalent to the time required to iterate over a set of backup backing map entries and move them to the primary backing map in the same JVM). But certain factors can increase this duration drastically (to several seconds): large partitions, sufficiently slow single-threaded CPU performance, many or expensive indexes to rebuild, etc. The solution of course is to mitigate each of those factors but in many cases this may be challenging. Larger clusters also lead to the temptation to place more load on the available hardware resources, spreading CPU resources thin. As an example, while we've long been aware of how garbage collection can cause significant pauses, it usually isn't viewed as a major consumer of CPU (in terms of overall system throughput). Typically, the use of a concurrent collector allows greater responsiveness by minimizing pause times, at the cost of reducing system throughput. However, at a recent engagement, we were forced to turn off the concurrent collector and use a traditional parallel "stop the world" collector to reduce CPU usage to an acceptable level. In summary, there are some less obvious factors that may result in excessive CPU consumption in a larger cluster, so it is even more critical to test at full scale, even though allocating sufficient hardware may often be much more difficult for these large clusters.

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• Understanding the 'High Performance' meaning in Extreme Transaction Processing

  - by kyap

  Despite my previous blogs entries on SOA/BPM and Identity Management, the domain where I'm the most passionated is definitely the Extreme Transaction Processing, commonly called XTP.I came across XTP back to 2007 while I was still FMW Product Manager in EMEA. At that time Oracle acquired a company called Tangosol, which owned an unique product called Coherence that we renamed to Oracle Coherence. Beside this innovative renaming of the product, to be honest, I didn't know much about it, except being a "distributed in-memory cache for Extreme Transaction Processing"... not very helpful still.In general when people doesn't fully understand a technology or a concept, they tend to find some shortcuts, either correct or not, to justify their lack-of understanding... and of course I was part of this category of individuals. And the shortcut was "Oracle Coherence Cache helps to improve Performance". Excellent marketing slogan... but not very meaningful still. By chance I was able to get away quickly from that group in July 2007* at Thames Valley Park (UK), after I attended one of the most interesting workshops, in my 10 years career in Oracle, delivered by Brian Oliver. The biggest mistake I made was to assume that performance improvement with Coherence was related to the response time. Which can be considered as legitimus at that time, because after-all caches help to reduce latency on cached data access, hence reduce the response-time. But like all caches, you need to define caching and expiration policies, thinking about the cache-missed strategy, and most of the time you have to re-write partially your application in order to work with the cache. At a result, the expected benefit vanishes... so, not very useful then?The key mistake I made was my perception or obsession on how performance improvement should be driven, but I strongly believe this is still a common problem to most of the developers. In fact we all know the that the performance of a system is generally presented by the Capacity (or Throughput), with the 2 important dimensions Speed (response-time) and Volume (load) :Capacity (TPS) = Volume (T) / Speed (S)To increase the Capacity, we can either reduce the Speed(in terms of response-time), or to increase the Volume. However we tend to only focus on reducing the Speed dimension, perhaps it is more concrete and tangible to measure, and nicer to present to our management because there's a direct impact onto the end-users experience. On the other hand, we assume the Volume can be addressed by the underlying hardware or software stack, so if we need more capacity (scale out), we just add more hardware or software. Unfortunately, the reality proves that IT is never as ideal as we assume...The challenge with Speed improvement approach is that it is generally difficult and costly to make things already fast... faster. And by adding Coherence will not necessarily help either. Even though we manage to do so, the Capacity can not increase forever because... the Speed can be influenced by the Volume. For all system, we always have a performance illustration as follow: In all traditional system, the increase of Volume (Transaction) will also increase the Speed (Response-Time) as some point. The reason is simple: most of the time the Application logics were not designed to scale. As an example, if you have a while-loop in your application, it is natural to conceive that parsing 200 entries will require double execution-time compared to 100 entries. If you need to "Speed-up" the execution, you can only upgrade your hardware (scale-up) with faster CPU and/or network to reduce network latency. It is technically limited and economically inefficient. And this is exactly where XTP and Coherence kick in. The primary objective of XTP is about designing applications which can scale-out for increasing the Volume, by applying coding techniques to keep the execution-time as constant as possible, independently of the number of runtime data being manipulated. It is actually not just about having an application running as fast as possible, but about having a much more predictable system, with constant response-time and linearly scale, so we can easily increase throughput by adding more hardwares in parallel. It is in general combined with the Low Latency Programming model, where we tried to optimize the network usage as much as possible, either from the programmatic angle (less network-hoops to complete a task), and/or from a hardware angle (faster network equipments). In this picture, Oracle Coherence can be considered as software-level XTP enabler, via the Distributed-Cache because it can guarantee: - Constant Data Objects access time, independently from the number of Objects and the Coherence Cluster size - Data Objects Distribution by Affinity for in-memory data grouping - In-place Data Processing for parallel executionTo summarize, Oracle Coherence is indeed useful to improve your application performance, just not in the way we commonly think. It's not about the Speed itself, but about the overall Capacity with Extreme Load while keeping consistant Speed. In the future I will keep adding new blog entries around this topic, with some sample codes experiences sharing that I capture in the last few years. In the meanwhile if you want to know more how Oracle Coherence, I strongly suggest you to start with checking how our worldwide customers are using Oracle Coherence first, then you can start playing with the product through our tutorial.Have Fun !

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• Coherence Data Guarantees for Data Reads - Basic Terminology

  - by jpurdy

  When integrating Coherence into applications, each application has its own set of requirements with respect to data integrity guarantees. Developers often describe these requirements using expressions like "avoiding dirty reads" or "making sure that updates are transactional", but we often find that even in a small group of people, there may be a wide range of opinions as to what these terms mean. This may simply be due to a lack of familiarity, but given that Coherence sits at an intersection of several (mostly) unrelated fields, it may be a matter of conflicting vocabularies (e.g. "consistency" is similar but different in transaction processing versus multi-threaded programming). Since almost all data read consistency issues are related to the concept of concurrency, it is helpful to start with a definition of that, or rather what it means for two operations to be concurrent. Rather than implying that they occur "at the same time", concurrency is a slightly weaker statement -- it simply means that it can't be proven that one event precedes (or follows) the other. As an example, in a Coherence application, if two client members mutate two different cache entries sitting on two different cache servers at roughly the same time, it is likely that one update will precede the other by a significant amount of time (say 0.1ms). However, since there is no guarantee that all four members have their clocks perfectly synchronized, and there is no way to precisely measure the time it takes to send a given message between any two members (that have differing clocks), we consider these to be concurrent operations since we can not (easily) prove otherwise. So this leads to a question that we hear quite frequently: "Are the contents of the near cache always synchronized with the underlying distributed cache?". It's easy to see that if an update on a cache server results in a message being sent to each near cache, and then that near cache being updated that there is a window where the contents are different. However, this is irrelevant, since even if the application reads directly from the distributed cache, another thread update the cache before the read is returned to the application. Even if no other member modifies a cache entry prior to the local near cache entry being updated (and subsequently read), the purpose of reading a cache entry is to do something with the result, usually either displaying for consumption by a human, or by updating the entry based on the current state of the entry. In the former case, it's clear that if the data is updated faster than a human can perceive, then there is no problem (and in many cases this can be relaxed even further). For the latter case, the application must assume that the value might potentially be updated before it has a chance to update it. This almost aways the case with read-only caches, and the solution is the traditional optimistic transaction pattern, which requires the application to explicitly state what assumptions it made about the old value of the cache entry. If the application doesn't want to bother stating those assumptions, it is free to lock the cache entry prior to reading it, ensuring that no other threads will mutate the entry, a pessimistic approach. The optimistic approach relies on what is sometimes called a "fuzzy read". In other words, the application assumes that the read should be correct, but it also acknowledges that it might not be. (I use the qualifier "sometimes" because in some writings, "fuzzy read" indicates the situation where the application actually sees an original value and then later sees an updated value within the same transaction -- however, both definitions are roughly equivalent from an application design perspective). If the read is not correct it is called a "stale read". Going back to the definition of concurrency, it may seem difficult to precisely define a stale read, but the practical way of detecting a stale read is that is will cause the encompassing transaction to roll back if it tries to update that value. The pessimistic approach relies on a "coherent read", a guarantee that the value returned is not only the same as the primary copy of that value, but also that it will remain that way. In most cases this can be used interchangeably with "repeatable read" (though that term has additional implications when used in the context of a database system). In none of cases above is it possible for the application to perform a "dirty read". A dirty read occurs when the application reads a piece of data that was never committed. In practice the only way this can occur is with multi-phase updates such as transactions, where a value may be temporarily update but then withdrawn when a transaction is rolled back. If another thread sees that value prior to the rollback, it is a dirty read. If an application uses optimistic transactions, dirty reads will merely result in a lack of forward progress (this is actually one of the main risks of dirty reads -- they can be chained and potentially cause cascading rollbacks). The concepts of dirty reads, fuzzy reads, stale reads and coherent reads are able to describe the vast majority of requirements that we see in the field. However, the important thing is to define the terms used to define requirements. A quick web search for each of the terms in this article will show multiple meanings, so I've selected what are generally the most common variations, but it never hurts to state each definition explicitly if they are critical to the success of a project (many applications have sufficiently loose requirements that precise terminology can be avoided).

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• Building a Repository Pattern against an EF 5 EDMX Model - Part 1

  - by Juan

  I am part of a year long plus project that is re-writing an existing application for a client.  We have decided to develop the project using Visual Studio 2012 and .NET 4.5.  The project will be using a number of technologies and patterns to include Entity Framework 5, WCF Services, and WPF for the client UI.This is my attempt at documenting some of the successes and failures that I will be coming across in the development of the application.In building the data access layer we have to access a database that has already been designed by a dedicated dba. The dba insists on using Stored Procedures which has made the use of EF a little more difficult.  He will not allow direct table access but we did manage to get him to allow us to use Views.  Since EF 5 does not have good support to do Code First with Stored Procedures, my option was to create a model (EDMX) against the existing database views.   I then had to go select each entity and map the Insert/Update/Delete functions to their respective stored procedure. The next step after I had completed mapping the stored procedures to the entities in the EDMX model was to figure out how to build a generic repository that would work well with Entity Framework 5.  After reading the blog posts below, I adopted much of their code with some changes to allow for the use of Ninject for dependency injection.http://www.tcscblog.com/2012/06/22/entity-framework-generic-repository/ http://www.tugberkugurlu.com/archive/generic-repository-pattern-entity-framework-asp-net-mvc-and-unit-testing-triangle IRepository.cs public interface IRepository : IDisposable where T : class { void Add(T entity); void Update(T entity, int id); T GetById(object key); IQueryable Query(Expression> predicate); IQueryable GetAll(); int SaveChanges(); int SaveChanges(bool validateEntities); } GenericRepository.cs public abstract class GenericRepository : IRepository where T : class { public abstract void Add(T entity); public abstract void Update(T entity, int id); public abstract T GetById(object key); public abstract IQueryable Query(Expression> predicate); public abstract IQueryable GetAll(); public int SaveChanges() { return SaveChanges(true); } public abstract int SaveChanges(bool validateEntities); public abstract void Dispose(); } One of the issues I ran into was trying to do an update. I kept receiving errors so I posted a question on Stack Overflow http://stackoverflow.com/questions/12585664/an-object-with-the-same-key-already-exists-in-the-objectstatemanager-the-object and came up with the following hack. If someone has a better way, please let me know. DbContextRepository.cs public class DbContextRepository : GenericRepository where T : class { protected DbContext Context; protected DbSet DbSet; public DbContextRepository(DbContext context) { if (context == null) throw new ArgumentException("context"); Context = context; DbSet = Context.Set(); } public override void Add(T entity) { if (entity == null) throw new ArgumentException("Cannot add a null entity."); DbSet.Add(entity); } public override void Update(T entity, int id) { if (entity == null) throw new ArgumentException("Cannot update a null entity."); var entry = Context.Entry(entity); if (entry.State == EntityState.Detached) { var attachedEntity = DbSet.Find(id); // Need to have access to key if (attachedEntity != null) { var attachedEntry = Context.Entry(attachedEntity); attachedEntry.CurrentValues.SetValues(entity); } else { entry.State = EntityState.Modified; // This should attach entity } } } public override T GetById(object key) { return DbSet.Find(key); } public override IQueryable Query(Expression> predicate) { return DbSet.Where(predicate); } public override IQueryable GetAll() { return Context.Set(); } public override int SaveChanges(bool validateEntities) { Context.Configuration.ValidateOnSaveEnabled = validateEntities; return Context.SaveChanges(); } #region IDisposable implementation public override void Dispose() { if (Context != null) { Context.Dispose(); GC.SuppressFinalize(this); } } #endregion IDisposable implementation } At this point I am able to start creating individual repositories that are needed and add a Unit of Work.  Stay tuned for the next installment in my path to creating a Repository Pattern against EF5.

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• Data Source Security Part 2

  - by Steve Felts

  In Part 1, I introduced the default security behavior and listed the various options available to change that behavior.  One of the key topics to understand is the difference between directly using database user and password values versus mapping from WLS user and password to the associated database values.   The direct use of database credentials is relatively new to WLS, based on customer feedback.  Some of the trade-offs are covered in this article. Credential Mapping vs. Database Credentials Each WLS data source has a credential map that is a mechanism used to map a key, in this case a WLS user, to security credentials (user and password).  By default, when a user and password are specified when getting a connection, they are treated as credentials for a WLS user, validated, and are converted to a database user and password using a credential map associated with the data source.  If a matching entry is not found in the credential map for the data source, then the user and password associated with the data source definition are used.  Because of this defaulting mechanism, you should be careful what permissions are granted to the default user.  Alternatively, you can define an invalid default user to ensure that no one can accidentally get through (in this case, you would need to set the initial capacity for the pool to zero so that the pool is populated only by valid users). To create an entry in the credential map: 1) First create a WLS user.  In the administration console, go to Security realms, select your realm (e.g., myrealm), select Users, and select New.  2) Second, create the mapping.  In the administration console, go to Services, select Data sources, select your data source name, select Security, select Credentials, and select New.  See http://docs.oracle.com/cd/E24329_01/apirefs.1211/e24401/taskhelp/jdbc/jdbc_datasources/ConfigureCredentialMappingForADataSource.html for more information. The advantages of using the credential mapping are that: 1) You don’t hard-code the database user/password into a program or need to prompt for it in addition to the WLS user/password and 2) It provides a layer of abstraction between WLS security and database settings such that many WLS identities can be mapped to a smaller set of DB identities, thereby only requiring middle-tier configuration updates when WLS users are added/removed. You can cut down the number of users that have access to a data source to reduce the user maintenance overhead.  For example, suppose that a servlet has the one pre-defined, special WLS user/password for data source access, hard-wired in its code in a getConnection(user, password) call.  Every WebLogic user can reap the specific DBMS access coded into the servlet, but none has to have general access to the data source.  For instance, there may be a ‘Sales’ DBMS which needs to be protected from unauthorized eyes, but it contains some day-to-day data that everyone needs. The Sales data source is configured with restricted access and a servlet is built that hard-wires the specific data source access credentials in its connection request.  It uses that connection to deliver only the generally needed day-to-day information to any caller. The servlet cannot reveal any other data, and no WebLogic user can get any other access to the data source.  This is the approach that many large applications take and is the reasoning behind the default mapping behavior in WLS. The disadvantages of using the credential map are that: 1) It is difficult to manage (create, update, delete) with a large number of users; it is possible to use WLST scripts or a custom JMX client utility to manage credential map entries. 2) You can’t share a credential map between data sources so they must be duplicated. Some applications prefer not to use the credential map.  Instead, the credentials passed to getConnection(user, password) should be treated as database credentials and used to authenticate with the database for the connection, avoiding going through the credential map.  This is enabled by setting the “use-database-credentials” to true.  See http://docs.oracle.com/cd/E24329_01/apirefs.1211/e24401/taskhelp/jdbc/jdbc_datasources/ConfigureOracleParameters.html "Configure Oracle parameters" in Oracle WebLogic Server Administration Console Help. Use Database Credentials is not currently supported for Multi Data Source configurations.  When enabled, it turns off credential mapping on Generic and Active GridLink data sources for the following attributes: 1. identity-based-connection-pooling-enabled (this interaction is available by patch in 10.3.6.0). 2. oracle-proxy-session (this interaction is first available in 10.3.6.0). 3. set client identifier (this interaction is available by patch in 10.3.6.0).  Note that in the data source schema, the set client identifier feature is poorly named “credential-mapping-enabled”.  The documentation and the console refer to it as Set Client Identifier. To review the behavior of credential mapping and using database credentials: - If using the credential map, there needs to be a mapping for each WLS user to database user for those users that will have access to the database; otherwise the default user for the data source will be used.  If you always specify a user/password when getting a connection, you only need credential map entries for those specific users. - If using database credentials without specifying a user/password, the default user and password in the data source descriptor are always used.  If you specify a user/password when getting a connection, that user will be used for the credentials.  WLS users are not involved at all in the data source connection process.

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• Windows 8 for productivity?

  - by Charles Young

  At long last I’ve started using Windows 8.  I boot from a VHD on which I have installed Office, Visio, Visual Studio, SQL Server, etc.  For a week, now, I’ve been happily writing code and documents and using Visio and PowerPoint.  I am, very much, a ‘productivity’ user rather than a content consumer.   I spend my days flitting between countless windows and browser tabs displayed across dual monitors.  I need to access a lot of different functionality and information in as fluid a fashion as possible. With that in mind, and like so many others, I was worried about Windows 8.  The Metro interface is primarily about content consumption on touch-enabled screens, and not really geared for people like me sitting in front of an 8-core non-touch laptop and an additional Samsung monitor.  I still use a mouse, not my finger.  And I create more than I consume. Clearly, Windows 8 won’t be viable for people like me unless Metro keeps out of my hair when using productivity and development tools.  With this in mind, I had long expected Microsoft to provide some mechanism for switching Metro off.  There was a registry hack in last year’s Developer Preview, but this capability has been removed.   That’s brave.  So, how have things worked out so far? Well, I am really quite surprised.  When I played with the Developer Preview last year, it was clear that Metro was unfinished and didn’t play well enough with the desktop.  Obviously I expected things to improve, but the context switching from desktop to full-screen seemed a heavy burden to place on users.  That sense of abrupt change hasn’t entirely gone away (how could it), but after a few days, I can’t say that I find it burdensome or irritating.   I’ve got used very quickly to ‘gesturing’ with my mouse at the bottom or top right corners of the screen to move between applications, using the Windows key to toggle the Start screen and generally finding my way around.   I am surprised at how effective the Start screen is, given the rather basic grouping features it provides.  Of course, I had to take control of it and sort things the way I want.  If anything, though, the Start screen provides a better navigation and application launcher tool than the old Start menu. What I didn’t expect was the way that Metro enhances the productivity story.  As I write this, I’ve got my desktop open with a maximised Word window.  However, the desktop extends only across about 85% of the width of my screen.  On the left hand side, I have a column that displays the new Metro email client.  This is currently showing me a list of emails for my main work account.  I can flip easily between different accounts and read my email within that same column.  As I work on documents, I want to be able to monitor my inbox with a quick glance. The desktop, of course, has its own snap feature.  I could run the desktop full screen and bring up Outlook and Word side by side.  However, this doesn’t begin to approach the convenience of snapping the Metro email client.  Consider that when I snap a window on the desktop, it initially takes up 50% of the screen.  Outlook doesn’t really know anything about snap, and doesn’t adjust to make effective use of the limited screen estate.  Even at 50% screen width, it is difficult to use, so forget about trying to use it in a Metro fashion. In any case, I am left with the prospect of having to manually adjust everything to view my email effectively alongside Word.  Worse, there is nothing stopping another window from overlapping and obscuring my email.  It becomes a struggle to keep sight of email as it arrives.  Of course, there is always ‘toast’ to notify me when things arrive, but if Outlook is obscured, this just feels intrusive. The beauty of the Metro snap feature is that my email reader now exists outside of my desktop.   The Metro app has been crafted to work well in the fixed width column as well as in full-screen.  It cannot be obscured by overlapping windows.  I still get notifications if I wish.  More importantly, it is clear that careful attention has been given to how things work when moving between applications when ‘snapped’.  If I decide, say to flick over to the Metro newsreader to catch up with current affairs, my desktop, rather than my email client, obligingly makes way for the reader.  With a simple gesture and click, or alternatively by pressing Windows-Tab, my desktop reappears. Another pleasant surprise is the way Windows 8 handles dual monitors.  It’s not just the fact that both screens now display the desktop task bar.  It’s that I can so easily move between Metro and the desktop on either screen.  I can only have Metro on one screen at a time which makes entire sense given the ‘full-screen’ nature of Metro apps.  Using dual monitors feels smoother and easier than previous versions of Windows. Overall then, I’m enjoying the Windows 8 improvements.  Strangely, for all the hype (“Windows reimagined”, etc.), my perception as a ‘productivity’ user is more one of evolution than revolution.  It all feels very familiar, but just better.

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• Weird networking problem ( Linksys, Windows 7 )

  - by Rohit Nair

  Okay it's a bit tough to figure out where to start from, but here is the basic summary of the issue: During general internet usage, there are times when any attempt to visit a website stalls at "Waiting for somedomain.com". This problem occurs in Firefox, IE and Chrome. No website will load, INCLUDING the router configuration page at 192.168.1.1. Curiously, ping works fine, and other network apps such as MSN Messenger continue to work and I can send and receive messages. Disconnecting and reconnecting to the wireless network seems to fix the problem for a bit, but there are times when it relapses into not loading after every 2-3 http requests. Restarting the router seems to fix the issue, but it can crop up hours or days later. I have a CCNA cert and I know my way around the Windows family of operating systems, so I'm going to list all the things I've tried here. Other computers on the network seem to suffer the same problem, which makes me think it might be a specific problem with something in Win7. The random nature of this issue makes it a bit difficult to confirm, but I can definitely say that I have experienced this on the following systems: Windows 7 64-bit on my desktop Windows Vista 32-bit on my desktop ( the desktop has 2 wireless NICs and the problem existed on both ) Windows Vista 32-bit on my laptop ( both with wireless and wired ) Windows XP SP3 on another laptop ( both wireless and wired ) Using Wireshark to sniff packets seemed to indicate that although HTTP requests were being SENT out, no packets were coming in to respond to the HTTP request. However, other network apps continued to work i.e I would still receive IMs on Windows Live Messenger. Disabling IPV6 had no effect. Updating router firmware to the latest stock firmware by Linksys had no effect. Switching to dd-wrt firmware had no effect. By "no effect" I mean that although the restart required by firmware updates fixed the problem at the time, it still came back. A couple of weeks back, after a LOT of googling and flipping of various options, I figured it might be a case of router slowdown ( http://www.dd-wrt.com/wiki/index.php/Router%5FSlowdown ) caused by the fact that I occasionally run a torrent client. I tried changing the configuration as suggested in that router slowdown link, and restarted the router. However I have not run the torrent client for 12 days now, and yet I still randomly experience this problem. Currently the computer I am using is running Windows 7 64-bit. I would just like to reiterate some of the reasons that I was confused by the issue. Even the router config page at 192.168.1.1 would not load, indicating that it's not a problem with the WAN link, but probably a router issue or a local computer issue. For some reason, disconnecting and reconnecting to the wireless network immediately seems to fix the problem. Updating the router firmware, even switching to open source firmware did nothing. So it seemed to be a computer issue. On the other hand, I have not seen any mass outrage of people having networking problems with Windows 7 and Linksys routers, especially a problem of this sort, and I have tweaked every network setting I could think of. Although HTTP seems to have trouble, ping works fine, DNS lookups work fine, other networking apps work fine. However if I disconnect from Windows Live Messenger and try to reconnect, it fails to reconnect. So although it could receive data over the existing TCP/IP connection, trying to start a new one failed? Does anyone have any further ideas on debugging or fixing this issue? I am reasonably certain there are no viruses or other malicious apps on my network, and I am also reasonably certain that nobody is accessing my router without my consent. Router: Linksys WRT54G2 1.0 running dd-wrt firmware Wireless Card: Alfa AWUS036H OS: Windows 7 64-bit EDIT: I tried switching to a clean wireless channel free from interference, but the problem still persisted. I tried connecting directly with a cable, but the problem still persisted. Signed A very confused and bewildered geek whose knowledge seems to be useless in the face of this frustrating network issue.

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• Windows 7 Boot to VHD using a VHD clone of the system drive

  - by daveh551

  This seems like a not too difficult problem, and, after several hurdles, I'm maddeningly close. But I can't quite get there. I'm running Windows 7 in development shop. I want to start using VS2010 to work on some stuff that won't be released for awhile. My boss said no beta code on the production machine, but I could run VS2010 for this project IF I could do it in an isolated environment, like a virtual PC. Well, I've used the beta and RC of Win7 on VPC's before, and it was painfully slow because of the VPC environment. But everyone has been singing the praises of Windows 7's boot-to-VHD capability, where only the disk is virtualized, and you're actually running on the hardware. Supposed to be little slower, but nowhere near the speed penalty of VPC. I've spent a fair amount of time getting everything installed the way I want it. So I figured, I'll just clone my system drive using Disk2VHD, and boot off of that, and then install VS2010 onto that. (I keep most of my user data, including all my projects, in a separate partition, so that wouldn't have to be duplicated and would still be available.) Well, I had some difficulties with that, owing mainly to the fact that I was using an old version of Disk2VHD - (get the latest if you're going to try it.) But I did finally get it to boot. (Scott Hanselman has a good blog post on boot to VHD). But it wasn't exactly what I was expecting or hoping for. What I expected was that the VHD would become the C: drive, and the original (physical) C: drive would be either hidden or mounted under a different letter, and thus isolated and protected from any changes. What you actually get is that the VHD becomes the D: drive AND you boot from the D: drive, BUT your original C: drive is still there. Which is sort of okay EXCEPT that the Registry on the VHD is a clone of the Registry on C: drive, and includes many hard-coded references to C:. So the result is that some things come from (and modify) D: (the VHD), but some things come from (and modify) C:. (If you open a cmd prompt and do a SET to look at your environment variables, you will see a mixture of D:\ and C:\ paths.) So I don't really have an isolated environment. Most importantly, %ProgramFiles% is still set to C:\Program Files. What I really need is a tool that can access the registry files on the mounted VHD AS FILES, not as registry entries, and do a global search and replace on all the C:\ in strings to D:. I haven't found such a program. (I've tried to do it with a program called Registry Replace, but, even when running as Administrator, there are certain entries that the Registry won't let you change.) Does anyone know of one? Or any other solution to my problem (other than starting from scratch with a clean VHD and installing Win7 and all my programs on it.)?

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• Managing access to multiple linux system

  - by Swartz

  A searched for answers but have found nothing on here... Long story short: a non-profit organization is in dire need of modernizing its infrastructure. First thing is to find an alternatives to managing user accounts on a number of Linux hosts. We have 12 servers (both physical and virtual) and about 50 workstations. We have 500 potential users for these systems. The individual who built and maintained the systems over the years has retired. He wrote his own scripts to manage it all. It still works. No complaints there. However, a lot of the stuff is very manual and error-prone. Code is messy and after updates often needs to be tweaked. Worst part is there is little to no docs written. There are just a few ReadMe's and random notes which may or may not be relevant anymore. So maintenance has become a difficult task. Currently accounts are managed via /etc/passwd on each system. Updates are distributed via cron scripts to correct systems as accounts are added on the "main" server. Some users have to have access to all systems (like a sysadmin account), others need access to shared servers, while others may need access to workstations or only a subset of those. Is there a tool that can help us manage accounts that meets the following requirements? Preferably open source (i.e. free as budget is VERY limited) mainstream (i.e. maintained) preferably has LDAP integration or could be made to interface with LDAP or AD service for user authentication (will be needed in the near future to integrate accounts with other offices) user management (adding, expiring, removing, lockout, etc) allows to manage what systems (or group of systems) each user has access to - not all users are allowed on all systems support for user accounts that could have different homedirs and mounts available depending on what system they are logged into. For example sysadmin logged into "main" server has main://home/sysadmin/ as homedir and has all shared mounts sysadmin logged into staff workstations would have nas://user/s/sysadmin as homedir(different from above) and potentially limited set of mounts, a logged in client would have his/her homedir at different location and no shared mounts. If there is an easy management interface that would be awesome. And if this tool is cross-platform (Linux / MacOS / *nix), that will be a miracle! I have searched the web and so have found nothing suitable. We are open to any suggestions. Thank you. EDIT: This question has been incorrectly marked as a duplicate. The linked to answer only talks about having same homedirs on all systems, whereas we need to have different homedirs based on what system user is currently logged into(MULTIPLE homedirs). Also access needs to be granted only to some machinees not the whole lot. Mods, please understand the full extent of the problem instead of merely marking it as duplicate for points...

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• Integrating HP Systems Insight Manager into an existing environment

  - by ewwhite

  I'm working with an environment that spans multiple data centers/sites and consists primarily of HP ProLiant servers (G5-G7) running Linux. The mix is 30% RHEL/CentOS, the rest are Gentoo :(. I also have a few dozen virtual machines running back-office and Windows servers on VMWare ESX hosts. I run OpenNMS to pull SNMP data from the various server nodes and networking devices. While OpenNMS works wonderfully for up/down, thresholds and notifications, it's native handling of traps is a little rough and the graphs are not particularly pretty. I use Orca/RRD graphs for performance trending and nice graphs. I'm tasked with inventorying the environment and wanted to come up with a clean way to organize server information. Since my environment is mostly HP, I've been playing with HP Systems Insight Manager as a way to extract server data and to deploy HP health/monitoring packages and firmware. The Gentoo systems eventually have to be converted to CentOS, so getting a quick assessment of what hardware is where would be great. Although I've read through a few hundred pages of HP manuals, I'm having a difficult time understanding how to get HP SIM to do what I want, though. My main problems are: I have about 40 subnets to deal with; 98% connected with private lines to facilities across the globe. I don't want to initiate an HP SIM discovery only to pull back every piece of intermediate networking hardware and equipment from all of the locations. I'd like this to focus on the servers. I have OpenNMS configured to accept traps. I don't want HP SIM to duplicate that effort. It seems like the built-in software deployment tool wants to overwrite the trapsink parameters for the systems it encounters during discovery. I have about 10 administrative username/password combinations in use across this infrastructure. Is there a more efficient way to get HP SIM to do the discovery or break discovery into manageable chunks? In terms of general workflow, do people typically install the HP Management Agents during the initial OS deployment (e.g. kickstart post script) or afterwards from HP SIM? Is HP SIM too thick/fat to be an inventory tool? I can't tell if it's meant to be used standalone or alongside other monitoring products. Since the majority of the systems I'm trying to track are those running Gentoo (in order to plan the move to CentOS), is there any way for HP SIM to extract system model information from them ( like dmidecode)? I have systems here where I may have an SSH key established, but not direct user or login access. Is there a way for me to import an SSH private/public key pair into HP SIM to reach out to the servers that can't accept standard credentials? There are a handful of sites where I have inconsistent access or have a double-NAT situation. I may be able to poke a server, but it may not be able to find its way back to the management system. Is there a workaround for this? The certificate configuration for HP SIM seems complicated. What is the preferred setup for trust between systems? I'd also appreciate any notes or recommendations to using this product. Or if there's a better way to do this, I'd like to know.

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• Cannot join Win7 workstations to Win2k8 domain

  - by wfaulk

  I am trying to connect a Windows 7 Ultimate machine to a Windows 2k8 domain and it's not working. I get this error: Note: This information is intended for a network administrator. If you are not your network's administrator, notify the administrator that you received this information, which has been recorded in the file C:\Windows\debug\dcdiag.txt. DNS was successfully queried for the service location (SRV) resource record used to locate a domain controller for domain "example.local": The query was for the SRV record for _ldap._tcp.dc._msdcs.example.local The following domain controllers were identified by the query: dc1.example.local dc2.example.local However no domain controllers could be contacted. Common causes of this error include: Host (A) or (AAAA) records that map the names of the domain controllers to their IP addresses are missing or contain incorrect addresses. Domain controllers registered in DNS are not connected to the network or are not running. The client is in an office connected remotely via MPLS to the data center where our domain controllers exist. I don't seem to have anything blocking connectivity to the DCs, but I don't have total control over the MPLS circuit, so it's possible that there's something blocking connectivity. I have tried multiple clients (Win7 Ultimate and WinXP SP3) in the one office and get the same symptoms on all of them. I have no trouble connecting to either of the domain controllers, though I have, admittedly, not tried every possible port. ICMP, LDAP, DNS, and SMB connections all work fine. Client DNS is pointing to the DCs, and "example.local" resolves to the two IP addresses of the DCs. I get this output from the NetLogon Test command line utility: C:\Windows\System32>nltest /dsgetdc:example.local Getting DC name failed: Status = 1355 0x54b ERROR_NO_SUCH_DOMAIN I have also created a separate network to emulate that office's configuration that's connected to the DC network via LAN-to-LAN VPN instead of MPLS. Joining Windows 7 computers from that remote network works fine. The only difference I can find between the two environments is the intermediate connectivity, but I'm out of ideas as to what to test or how to do it. What further steps should I take? (Note that this isn't actually my client workstation and I have no direct access to it; I'm forced to do remote hands access to it, which makes some of the obvious troubleshooting methods, like packet sniffing, more difficult. If I could just set up a system there that I could remote into, I would, but requests to that effect have gone unanswered.) 2011-08-25 update: I had DCDIAG.EXE run on a client attempting to join the domain: C:\Windows\System32>dcdiag /u:example\adminuser /p:********* /s:dc2.example.local Directory Server Diagnosis Performing initial setup: Ldap search capabality attribute search failed on server dc2.example.local, return value = 81 This sounds like it was able to connect via LDAP, but the thing that it was trying to do failed. But I don't quite follow what it was trying to do, much less how to reproduce it or resolve it. 2011-08-26 update: Using LDP.EXE to try and make an LDAP connection directly to the DCs results in these errors: ld = ldap_open("10.0.0.1", 389); Error <0x51: Fail to connect to 10.0.0.1. ld = ldap_open("10.0.0.2", 389); Error <0x51: Fail to connect to 10.0.0.2. ld = ldap_open("10.0.0.1", 3268); Error <0x51: Fail to connect to 10.0.0.1. ld = ldap_open("10.0.0.2", 3268); Error <0x51: Fail to connect to 10.0.0.2. This would seem to point fingers at LDAP connections being blocked somewhere. (And 0x51 == 81, which was the error from DCDIAG.EXE from yesterday's update.) I could swear I tested this using TELNET.EXE weeks ago, but now I'm thinking that I may have assumed that its clearing of the screen was telling me that it was waiting and not that it had connected. I'm tracking down LDAP connectivity problems now. This update may become an answer.

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• Windows 7 .NET 3.5.1 - 2.0 Slightly Corrupted, How to Repair?

  - by Quinxy von Besiex

  My Windows 7 included .NET installation (3.5 to 2.0) appears very slightly and particularly corrupted and I am trying to fix it without reinstalling Windows or trying to revert to backups. Everything was working and then my hard drive started corrupting a few files and checkdisk found bad clusters so I imaged the drive to a new one. As soon as I booted on the new drive everything worked except programs which call the System.Net.NetworkInformation methods within .NET 3.5 to 2.0 (like Ping() and IsNetworkAvailable()), which immediately crash the app in which the calls are (those calls in .NET 4.0 works fine). Those methods are found inside System.dll, and I assume call native methods which I believe are inside winnsi.dll or iphlpapi.dll or something else (I've not found this yet); I assume it calls native methods because the exception which causes the crash is Fatal Execution Engine Error which people mention is usually related to calling native methods and marshaling data between them. A huge clue about the culprit is likely found in the fact that when I launch the exact same crashing application through a code profiler (which executes the exe and captures stats on which methods took the longest) the app works fine, no crash at all! How could running it within the profiler work and running it outside not work? That seems the key to the mystery. I've used procmon to catch all the registry, filesystem, and network events from the crashing execution and the profiler-run successful execution and compared the two outputs but didn't learn much (I see the moment at which the non-profiled app crashes, but up until then they behave the same, loaded the same modules, ). The only big difference seems to be that at the moment before the app crash the profiler-executed code creates 4-6 new threads and the directly executed code only creates 1-2. I have diffed the files/directories which seemed most relevant (the .NET stuff under Windows and Program Files) pre- and post- disk trouble and seen no changes where I didn't expect any (no obvious file corruption). I have diffed the software and system registry hives pre- and post- disk trouble and seen no changes which seemed relevant. I have created a new user account and cleaned up any environment variables in case environment was related. No change. I did "sfc /scannow" and it found no integrity problems. I tried "ngen update" to regenerate pre-compiled code in case I missed something that might be damaged and nothing changed. I assume I need to repair my .NET installation but because Windows 7 included .NET 3.5 - 2.0 you can't just re-run a .NET installer to redo it. I do not have access to the Windows disks to try to re-install Windows over itself (the computer has a recovery partition but it is unusable); also the drive uses a whole-disk encryption solution and re-installing would be difficult. I absolutely do not want to start from scratch here and install a fresh Windows, reinstall dozens of software packages, try and remember dozens of development-related customizations/etc. Given all that... does anyone have any helpful advice? I need .NET 3.5 - 2.0 working as I am a developer and need to build and test against it. Thanks! Quinxy

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• Logging to MySQL without empty rows/skipped records?

  - by Lee Ward

  I'm trying to figure out how to make Squid proxy log to MySQL. I know ACL order is pretty important but I'm not sure if I understand exactly what ACLs are or do, it's difficult to explain, but hopefully you'll see where I'm going with this as you read! I have created the lines to make Squid interact with a helper in squid.conf as follows: external_acl_type mysql_log %LOGIN %SRC %PROTO %URI php /etc/squid3/custom/mysql_lg.php acl ex_log external mysql_log http_access allow ex_log The external ACL helper (mysql_lg.php) is a PHP script and is as follows: error_reporting(0); if (! defined(STDIN)) { define("STDIN", fopen("php://stdin", "r")); } $res = mysql_connect('localhost', 'squid', 'testsquidpw'); $dbres = mysql_select_db('squid', $res); while (!feof(STDIN)) { $line = trim(fgets(STDIN)); $fields = explode(' ', $line); $user = rawurldecode($fields[0]); $cli_ip = rawurldecode($fields[1]); $protocol = rawurldecode($fields[2]); $uri = rawurldecode($fields[3]); $q = "INSERT INTO logs (id, user, cli_ip, protocol, url) VALUES ('', '".$user."', '".$cli_ip."', '".$protocol."', '".$uri."');"; mysql_query($q) or die (mysql_error()); if ($fault) { fwrite(STDOUT, "ERR\n"); }; fwrite(STDOUT, "OK\n"); } The configuration I have right now looks like this: ## Authentication Handler auth_param ntlm program /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp auth_param ntlm children 30 auth_param negotiate program /usr/bin/ntlm_auth --helper-protocol=squid-2.5-basic auth_param negotiate children 5 # Allow squid to update log external_acl_type mysql_log %LOGIN %SRC %PROTO %URI php /etc/squid3/custom/mysql_lg.php acl ex_log external mysql_log http_access allow ex_log acl localnet src 172.16.45.0/24 acl AuthorizedUsers proxy_auth REQUIRED acl SSL_ports port 443 acl Safe_ports port 80 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl CONNECT method CONNECT acl blockeddomain url_regex "/etc/squid3/bl.acl" http_access deny blockeddomain deny_info ERR_BAD_GENERAL blockeddomain # Deny requests to certain unsafe ports http_access deny !Safe_ports # Deny CONNECT to other than secure SSL ports http_access deny CONNECT !SSL_ports # Allow the internal network access to this proxy http_access allow localnet # Allow authorized users access to this proxy http_access allow AuthorizedUsers # FINAL RULE - Deny all other access to this proxy http_access deny all From testing, the closer to the bottom I place the logging lines the less it logs. Oftentimes, it even places empty rows in to the MySQL table. The file-based logs in /var/log/squid3/access.log are correct but many of the rows in the access logs are missing from the MySQL logs. I can't help but think it's down to the order I'm putting lines in because I want to log everything to MySQL, unauthenticated requests, blocked requests, which category blocked a specific request. The reason I want this in MySQL is because I'm trying to have everything managed via a custom web-based frontend and want to avoid using any shell commands and access to system log files if I can help it. The end result is to make it as easy as possible to maintain without keeping staff waiting on the phone whilst I add a new rule and reload the server! Hopefully someone can help me out here because this is very much a learning experience for me and I'm pretty stumped. Many thanks in advance for any help!

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• What Apache/PHP configurations do you know and how good are they?

  - by FractalizeR

  Hello. I wanted to ask you about PHP/Apache configuration methods you know, their pros and cons. I will start myself: ---------------- PHP as Apache module---------------- Pros: good speed since you don't need to start exe every time especially in mpm-worker mode. You can also use various PHP accelerators in this mode like APC or eAccelerator. Cons: if you are running apache in mpm-worker mode, you may face stability issues because every glitch in any php script will lead to unstability to the whole thread pool of that apache process. Also in this mode all scripts are executed on behalf of apache user. This is bad for security. mpm-worker configuration requires PHP compiled in thread-safe mode. At least CentOS and RedHat default repositories doesn't have thread-safe PHP version so on these OSes you need to compile at least PHP yourself (there is a way to activate worker mpm on Apache). The use of thread-safe PHP binaries is considered experimental and unstable. Plus, many PHP extensions does not support thread-safe mode or were not well-tested in thread-safe mode. ---------------- PHP as CGI ---------------- This seems to be the slowest default configuration which seems to be a "con" itself ;) ---------------- PHP as CGI via mod_suphp ---------------- Pros: suphp allows you to execute php scipts on behalf of the script file owner. This way you can securely separate different sites on the same machine. Also, suphp allows to use different php.ini files per virtual host. Cons: PHP in CGI mode means less performance. In this mode you can't use php accelerators like APC because each time new process is spawned to handle script rendering the cache of previous process useless. BTW, do you know the way to apply some accelerator in this config? I heard something about using shm for php bytecode cache. Also, you cannot configure PHP via .htaccess files in this mode. You will need to install PECL htscanner for this if you need to set various per-script options via .htaccess (php_value / php_flag directives) ---------------- PHP as CGI via suexec ---------------- This configuration looks the same as with suphp, but I heard, that it's slower and less safe. Almost same pros and cons apply. ---------------- PHP as FastCGI ---------------- Pros: FastCGI standard allows single php process to handle several scripts before php process is killed. This way you gain performance since no need to spin up new php process for each script. You can also use PHP accelerators in this configuration (see cons section for comment). Also, FCGI almost like suphp also allows php processes to be executed on behalf of some user. mod_fcgid seems to have the most complete fcgi support and flexibility for apache. Cons: The use of php accelerator in fastcgi mode will lead to high memory consumption because each PHP process will have his own bytecode cache (unless there is some accelerator that can use shared memory for bytecode cache. Is there such?). FastCGI is also a little bit complex to configure. You need to create various configuration files and make some configuration modifications. It seems, that fastcgi is the most stable, secure, fast and flexible PHP configuration, however, a bit difficult to be configured. But, may be, I missed something? Comments are welcome!

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• Troubleshooting inconsistent ODBC connectivity

  - by Chris

  I'm attempting to integrate UPS WorldShip with a SQL Server 2008 R2 database but the connection is very inconsistent. UPS claims this is a DSN/Windows problem and I have not been able to convince them otherwise. The integration is quite simple: my shipping guy clicks a button which opens a form where he enters an order #. After pressing enter the shipping information will be pulled from the database for that order #. The problem is that WorldShip often times thinks the DSN does not exist. However, I am able to open WorldShip's customization tool and browse all the tables and fields in the database my DSN is connected to which means at the very least my DSN does, in fact, exist. The reason this has been so difficult to troubleshoot is because there is no consistency to the problem and I'm not able to reliably repeat any behavior. That is to say that rebooting the PC doesn't cause the connection to break and opening the integration tool and viewing the tables and fields doesn't cause the integration button to work. Is there some way for me to monitor this connection from the SQL server or get any clues as to why it fails? As requested by TallTed here is a sample of the trace file I created. After a mere 5 hours the trace file was over 130MB so there's no way I could provide it in its entirety. WorldShipTD d94-690 EXIT SQLSetStmtAttrW with return code -1 (SQL_ERROR) SQLHSTMT 0x0C6632A0 SQLINTEGER 1227 <unknown> SQLPOINTER [Unknown attribute 1227] SQLINTEGER -5 DIAG [IM006] [Microsoft][ODBC Driver Manager] Driver's SQLSetConnectAttr failed (0) WorldShipTD d94-690 ENTER SQLAllocHandle SQLSMALLINT 3 <SQL_HANDLE_STMT> SQLHANDLE 0x0C662FC0 SQLHANDLE * 0x03EBCE38 WorldShipTD d94-690 EXIT SQLAllocHandle with return code 0 (SQL_SUCCESS) SQLSMALLINT 3 <SQL_HANDLE_STMT> SQLHANDLE 0x0C662FC0 SQLHANDLE * 0x03EBCE38 ( 0x0C6632A0) WorldShipTD d94-690 ENTER SQLSetStmtAttrW SQLHSTMT 0x0C6632A0 SQLINTEGER 0 <SQL_ATTR_QUERY_TIMEOUT> SQLPOINTER 30 SQLINTEGER -5 WorldShipTD d94-690 EXIT SQLSetStmtAttrW with return code -1 (SQL_ERROR) SQLHSTMT 0x0C6632A0 SQLINTEGER 0 <SQL_ATTR_QUERY_TIMEOUT> SQLPOINTER 30 SQLINTEGER -5 DIAG [HYC00] [Microsoft][ODBC Microsoft Access Driver]Optional feature not implemented (106) WorldShipTD d94-690 ENTER SQLGetDiagFieldW SQLSMALLINT 3 SQLHANDLE 0x0C6632A0 SQLSMALLINT 1 SQLSMALLINT 4 SQLPOINTER 0x00520708 SQLSMALLINT 12 SQLSMALLINT * 0x0028E2A8 WorldShipTD d94-690 EXIT SQLGetDiagFieldW with return code 0 (SQL_SUCCESS) SQLSMALLINT 3 SQLHANDLE 0x0C6632A0 SQLSMALLINT 1 SQLSMALLINT 4 SQLPOINTER 0x00520708 SQLSMALLINT 12 SQLSMALLINT * 0x0028E2A8 (10) WorldShipTD d94-690 ENTER SQLGetInfoW HDBC 0x0C662FC0 UWORD 77 <SQL_DRIVER_ODBC_VER> PTR 0x03EBCEDC SWORD 100 SWORD * 0x0028E290 WorldShipTD d94-690 EXIT SQLGetInfoW with return code 0 (SQL_SUCCESS) HDBC 0x0C662FC0 UWORD 77 <SQL_DRIVER_ODBC_VER> PTR 0x03EBCEDC [ 10] "03.51" SWORD 100 SWORD * 0x0028E290 (10) WorldShipTD d94-690 ENTER SQLSetStmtAttrW SQLHSTMT 0x0C6632A0 SQLINTEGER 1228 <unknown> SQLPOINTER [Unknown attribute 1228] SQLINTEGER -5 WorldShipTD d94-690 EXIT SQLSetStmtAttrW with return code -1 (SQL_ERROR) SQLHSTMT 0x0C6632A0 SQLINTEGER 1228 <unknown> SQLPOINTER [Unknown attribute 1228] SQLINTEGER -5 DIAG [HY092] [Microsoft][ODBC Microsoft Access Driver]Invalid attribute/option identifier (86) WorldShipTD d94-690 ENTER SQLGetDiagFieldW SQLSMALLINT 3 SQLHANDLE 0x0C6632A0 SQLSMALLINT 1 SQLSMALLINT 4 SQLPOINTER 0x00520708 SQLSMALLINT 12 SQLSMALLINT * 0x0028E2A8 WorldShipTD d94-690 EXIT SQLGetDiagFieldW with return code 0 (SQL_SUCCESS) SQLSMALLINT 3 SQLHANDLE 0x0C6632A0 SQLSMALLINT 1 SQLSMALLINT 4 SQLPOINTER 0x00520708 SQLSMALLINT 12 SQLSMALLINT * 0x0028E2A8 (10) WorldShipTD d94-690 ENTER SQLSetStmtAttrW SQLHSTMT 0x0C6632A0 SQLINTEGER 1227 <unknown> SQLPOINTER [Unknown attribute 1227] SQLINTEGER -5 WorldShipTD d94-690 EXIT SQLSetStmtAttrW with return code -1 (SQL_ERROR) SQLHSTMT 0x0C6632A0 SQLINTEGER 1227 <unknown> SQLPOINTER [Unknown attribute 1227] SQLINTEGER -5 DIAG [HY092] [Microsoft][ODBC Microsoft Access Driver]Invalid attribute/option identifier (86) WorldShipTD d94-690 ENTER SQLGetDiagFieldW SQLSMALLINT 3 SQLHANDLE 0x0C6632A0 SQLSMALLINT 1 SQLSMALLINT 4 SQLPOINTER 0x00520708 SQLSMALLINT 12 SQLSMALLINT * 0x0028E2A8 WorldShipTD d94-690 EXIT SQLGetDiagFieldW with return code 0 (SQL_SUCCESS) SQLSMALLINT 3 SQLHANDLE 0x0C6632A0 SQLSMALLINT 1 SQLSMALLINT 4 SQLPOINTER 0x00520708 SQLSMALLINT 12 SQLSMALLINT * 0x0028E2A8 (10)

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