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• Quantum, Nexsan Expand Deduplication Offerings

  EMC partners Quantum and FalconStor have their own data deduplication offerings.

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• Is this proper OO design for C++?

  - by user121917

  I recently took a software processes course and this is my first time attempting OO design on my own. I am trying to follow OO design principles and C++ conventions. I attempted and gave up on MVC for this application, but I am trying to "decouple" my classes such that they can be easily unit-tested and so that I can easily change the GUI library used and/or the target OS. At this time, I have finished designing classes but have not yet started implementing methods. The function of the software is to log all packets sent and received, and display them on the screen (like WireShark, but for one local process only). The software accomplishes this by hooking the send() and recv() functions in winsock32.dll, or some other pair of analogous functions depending on what the intended Target is. The hooks add packets to SendPacketList/RecvPacketList. The GuiLogic class starts a thread which checks for new packets. When new packets are found, it utilizes the PacketFilter class to determine the formatting for the new packet, and then sends it to MainWindow, a native win32 window (with intent to later port to Qt).1 Full size image of UML class diagram Here are my classes in skeleton/header form (this is my actual code): class PacketModel { protected: std::vector<byte> data; int id; public: PacketModel(); PacketModel(byte* data, unsigned int size); PacketModel(int id, byte* data, unsigned int size); int GetLen(); bool IsValid(); //len >= sizeof(opcode_t) opcode_t GetOpcode(); byte* GetData(); //returns &(data[0]) bool GetData(byte* outdata, int maxlen); void SetData(byte* pdata, int len); int GetId(); void SetId(int id); bool ParseData(char* instr); bool StringRepr(char* outstr); byte& operator[] (const int index); }; class SendPacket : public PacketModel { protected: byte* returnAddy; public: byte* GetReturnAddy(); void SetReturnAddy(byte* addy); }; class RecvPacket : public PacketModel { protected: byte* callAddy; public: byte* GetCallAddy(); void SetCallAddy(byte* addy); }; //problem: packets may be added to list at any time by any number of threads //solution: critical section associated with each packet list class Synch { public: void Enter(); void Leave(); }; template<class PacketType> class PacketList { private: static const int MAX_STORED_PACKETS = 1000; public: static const int DEFAULT_SHOWN_PACKETS = 100; private: vector<PacketType> list; Synch synch; //wrapper for critical section public: void AddPacket(PacketType* packet); PacketType* GetPacket(int id); int TotalPackets(); }; class SendPacketList : PacketList<SendPacket> { }; class RecvPacketList : PacketList<RecvPacket> { }; class Target //one socket { bool Send(SendPacket* packet); bool Inject(RecvPacket* packet); bool InitSendHook(SendPacketList* sendList); bool InitRecvHook(RecvPacketList* recvList); }; class FilterModel { private: opcode_t opcode; int colorID; bool bFilter; char name[41]; }; class FilterFile { private: FilterModel filter; public: void Save(); void Load(); FilterModel* GetFilter(opcode_t opcode); }; class PacketFilter { private: FilterFile filters; public: bool IsFiltered(opcode_t opcode); bool GetName(opcode_t opcode, char* namestr); //return false if name does not exist COLORREF GetColor(opcode_t opcode); //return default color if no custom color }; class GuiLogic { private: SendPacketList sendList; RecvPacketList recvList; PacketFilter packetFilter; void GetPacketRepr(PacketModel* packet); void ReadNew(); void AddToWindow(); public: void Refresh(); //called from thread void GetPacketInfo(int id); //called from MainWindow }; I'm looking for a general review of my OO design, use of UML, and use of C++ features. I especially just want to know if I'm doing anything considerably wrong. From what I've read, design review is on-topic for this site (and off-topic for the Code Review site). Any sort of feedback is greatly appreciated. Thanks for reading this.

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• Send arbitrary commands to modem for info

  - by mydoghasworms

  I have a USB 3G data card and modem. According to the supplier, to check the data balance on the account, I must dial a number like *89# (or whatever) from the handset. The device appears as a ppp0 interface in my network devices. How does one go about issuing commands to the modem to send the commands and receive back the information? UPDATE: OK, I found some help here: http://www.linuxquestions.org/questions/linux-hardware-18/sending-at-commands-to-a-sms-modem-372445/, but firstly, there are 3 ttyUSB devices on my system, and I assume that one of them is the 3G modem, but how can I tell? Secondly, trying to echo something to two of them says that the device is busy, which stands to reason, because I am using it to connect to the internet. Some help, please?

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• Subscribable World Cup 2010 Calendar

  - by jamiet

  I bang on quite a lot on this blog about ways in which data can get published over the web and one of the most interesting ways, in my opinion, of publishing data in a structured manner that is well understood is to use the iCalendar specification. There isn’t much information in the world that doesn’t have some concept of “when” so iCalendar is a great way of distributing that information. You have probably used iCalendar at some point without even knowing about it. All files with a .ics suffix are iCalendar format files and that is why you can happily import them into Outlook, Hotmail Calendar, Google Calendar etc… where they can be parsed and have the semantic data (when, where and who) extracted from them. Importing of iCalendar format data is really only half the trick though; in my opinion the real value of iCalendar-formatted calendar is the ability to subscribe to them. Subscribing has a simple benefit over importing but that single benefit is of massive importance: a subscriber to an iCalendar calendar can periodically check to see if any updates have been made and, if they have, automatically update the local copy. The real benefit to the user is the productivity gain – a single update to an iCalendar means that all subscribers are automatically made aware of the change and there is zero effort on the part of the subscriber; as my former colleague Howard van Rooijen is fond of saying, “work smarter not harder” – nowhere is this edict more ably demonstrated than subscribing versus importing of calendars. If you want to read some more thoughts about iCalendar then go and read my past blog post Calendar syndication - My big hope for 2009's breakthrough technology or better still go and seek out Jon Udell who speaks very authoritatively on the issue of iCalendar. With this subject of iCalendar on my mind I was interested to discover (via Steve Clayton’s blog post Download the world cup fixtures) that the BBC had made a .ics file available containing all of the matches in the upcoming World Cup. As you can probably guess this was a file that was made available so that it could be imported into your calendar of choice. It had one obvious downside though, right now nobody knows who is going to be playing in the knock-out stages so the calendar looks like this: with no teams being named after 25th June. How much more useful would this calendar have been if the BBC had made it possible to subscribe to the calendar instead, thus the calendar could be updated with the teams for the knock out stages when they are known and every subscriber would have a permanently up-to-date record of all the fixtures in their calendar. Better still, the calendar could be updated with match results as well or perhaps even post a match report from the BBC sport pages; when calendars are made subscribable a sea of opportunity opens up for distribution of information. So with that in mind I have decided to go one better than the BBC. I have imported their .ics into a brand new Hotmail calendar and made it publicly available at the following URLs: HTML http://cid-dc1ed121af0476be.calendar.live.com/calendar/World+Cup+2010/index.html iCalendar webcal://cid-dc1ed121af0476be.calendar.live.com/calendar/World+Cup+2010/calendar.ics The link you’re really interested in is the second one - click on that and it should open up in your calendar software of choice. Or, if you want to view it in an online calendar such as Hotmail Calendar or Google Calendar, copy and paste that URL into the appropriate place. Some people have told me they’re having trouble with the iCalendar link in which case hit the HTML link and then click “View ICS” at the resultant web page: I shall endeavour to keep the calendar updated throughout the World Cup and even if I don’t you’re no worse off than if you had imported the BBC’s .ics file so why not give it a try? If I do keep it up to date then you will have a permanent record of the 2010 World Cup available in your calendar. Forever. If you have your calendar synced to your smartphone then you’ll be carrying match reports around with you without you having to do a single thing. Surely that’s worth a quick click isn’t it?   If you have any thoughts let me have them in the comments below. Thanks for reading. @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Intel graphics Ubuntu 12.04.3 LTS: does not detect second monitor

  - by user206551

  I have some problems to get the second monitor working on my Ubuntu 12.04.3 LTS. If I click on the detect button it does not work. Info about my system: $uname -a Linux LabTop2 3.8.0-32-generic #47~precise1-Ubuntu SMP Wed Oct 2 16:22:28 UTC 2013 i686 i686 i386 GNU/Linux $cat /etc/*-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=12.04 DISTRIB_CODENAME=precise DISTRIB_DESCRIPTION="Ubuntu 12.04.3 LTS" NAME="Ubuntu" VERSION="12.04.3 LTS, Precise Pangolin" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu precise (12.04.3 LTS)" VERSION_ID="12.04" $lspci |grep VGA 00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09) $lsmod | grep video uvcvideo 72250 0 videobuf2_core 39385 1 uvcvideo videodev 96131 2 uvcvideo,videobuf2_core videobuf2_vmalloc 12920 1 uvcvideo videobuf2_memops 13042 1 videobuf2_vmalloc video 19116 1 i915 $xrandr -q xrandr: Failed to get size of gamma for output default Screen 0: minimum 1366 x 768, current 1368 x 768, maximum 1368 x 768 default connected 1368x768+0+0 0mm x 0mm 1366x768 0.0 1368x768 0.0* Before upgrading the system, xrand -q showed my much more resolution options and the other monitor. I have tried to install intel-linux-graphics-installer but this version of ubuntu is not supported Any help will be apreciated!!

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• AI Game Programming : Bayesian Networks, how to make efficient?

  - by Mahbubur R Aaman

  We know that AI is one of the most important part of Game Programming. Bayesian networks is one of the core part of AI at Game Programming. Bayesian networks are graphs that compactly represent the relationship between random variables for a given problem. These graphs aid in performing reasoning or decision making in the face of uncertainty. Here me, utilizing the monte carlo method and genetic algorithms. But tooks much time and sometimes crashes due to memory. Is there any way to implement efficiently?

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• Thinktecture.IdentityServer RC

  - by Your DisplayName here!

  I just uploaded the RC of IdentityServer to Codeplex. This release is feature complete and if I don’t get any bug reports this is also pretty much the final V1. Changes from B1 The configuration data access is now based on EF 4.1 code first. This makes it much easier to use different data stores. For RTM I will also provide a SQL script for SQL Server so you can move the configuration to a separate machine (e.g. for load balancing scenarios). I included the ASP.NET Universal Providers in the download. This adds official support for SQL Azure, SQL Server and SQL Compact for the membership, roles and profile features. Unfortunately the Universal Provider use a different schema than the original ASP.NET providers (that sucks btw!) – so I made them optional. If you want to use them go to web.config and uncomment the new provider. The relying party registration entries now have added fields to add extra data that you want to couple with the RP. One use case could be to give the UI a hint how the login experience should look like per RP. This allows to have a different look and feel for different relying parties. I also included a small helper API that you can use to retrieve the RP record based on the incoming WS-Federation query string. WS-Federation single sign out is now conforming to the spec. Certificate based endpoint identities for SSL endpoints are optional now. Added a initial configuration “wizard”. This sets up the signing certificate, issuer URI and site title on the first run. Installation This is still a “developer” release – that means it ships with source code that you have to build it etc. But from that point it should be a little more straightforward as it used to be: Make sure SSL is configured correctly for IIS Map the WebSite directory to a vdir in IIS Run the web site. This should bring up the initial configuration Make sure the worker process account has access to the signing certificate private key Make sure all your users are in the “IdentityServerUsers” role in your role store. Administrators need the “IdentityServerAdministrators” role That should be it. A proper documentation will be hopefully available soon (any volunteers?). Please provide feedback! thanks!

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• Ubuntu 12.04.1 Setup doesn't detect Windows 7 partition

  - by Dom

  I'm not really that of a linux pro, more of a noob. But i can handle console operations. Well, this is my system: ASUS ZenBook Prime UX31A 256 GB ADATA MX11 SSD Intel Core i5-3317U (Ivy-Bridge) I have a fresh installation of Windows 7 Ultimate (not activated) on a 90 GB NTFS Partition on my SSD, the rest is unassigned. I want to install Ubuntu 12.04.1 from an USB Stick (no CD-Drive...) created with Universal USB Installer 1.9.1.1. However I'm not givven the option 'Install alongside Windows', and when i choose 'other' it shows that 256 GB of 256 GB are unassigned (free) Memory. os-prober gave me: /dev/sda1/:Windows 7 (loader):Windows:chain I also tried: sudo dmraid -rE and: sudo apt-get remove dmraid with no success... How can I install Ubuntu alongside Windows? Thanks very much in advance!

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• Part 1 - 12c Database and WLS - Overview

  - by Steve Felts

  The download of Oracle 12c database became available on June 25, 2013.  There are some big new features in 12c database and WebLogic Server will take advantage of them. Immediately, we will support using 12c database and drivers with WLS 10.3.6 and 12.1.1.  When the next version of WLS ships, additional functionality will be supported (those rows in the table below with all "No" values will get a "Yes).  The following table maps the Oracle 12c Database features supported with various combinations of currently available WLS releases, 11g and 12c Drivers, and 11g and 12c Databases. Feature WebLogic Server 10.3.6/12.1.1 with 11g drivers and 11gR2 DB WebLogic Server 10.3.6/12.1.1 with 11g drivers and 12c DB WebLogic Server 10.3.6/12.1.1 with 12c drivers and 11gR2 DB WebLogic Server 10.3.6/12.1.1 with 12c drivers and 12c DB JDBC replay No No No Yes (Active GridLink only in 10.3.6, add generic in 12.1.1) Multi Tenant Database No Yes (except set container) No Yes (except set container) Dynamic switching between Tenants No No No No Database Resident Connection pooling (DRCP) No No No No Oracle Notification Service (ONS) auto configuration No No No No Global Database Services (GDS) No Yes (Active GridLink only) No Yes (Active GridLink only) JDBC 4.1 (using ojdbc7.jar files & JDK 7) No No Yes Yes  The My Oracle Support (MOS) document covering this is "WebLogic Server 12.1.1 and 10.3.6 Support for Oracle 12c Database [ID 1564509.1]" at the link https://support.oracle.com/epmos/faces/DocumentDisplay?id=1564509.1. The following documents are also key references:12c Oracle Database Developer Guide http://docs.oracle.com/cd/E16655_01/appdev.121/e17620/toc.htm 12c Oracle Database Administrator's Guide http://docs.oracle.com/cd/E16655_01/server.121/e17636/toc.htm . I plan to write some related blog articles not to duplicate existing product documentation but to introduce the features, provide some examples, and tie together some information to make it easier to understand. How do you get started with 12c?  The easiest way is to point your data source at a 12c database.  The only change on the WLS side is to update the URL in your data source (assuming that you are not just upgrading your database).  You can continue to use the 11.2.0.3 driver jar files that shipped with WLS 10.3.6 or 12.1.1.  You shouldn't see any changes in your application.  You can take advantage of enhancements on the database side that don't affect the mid-tier.  On the WLS side, you can take advantage of using Global Data Service or connecting to a tenant in a multi-tenant database transparently. If you want to use the 12c client jar files, it's a bit of work because they aren't shipped with WLS and you can't just drop in ojdbc6.jar as in the old days.  You need to use a matched set of jar files and they need to come before existing jar files in the CLASSPATH.  The MOS article is written from the standpoint that you need to get the jar files directly - download almost 1G and install over 600M footprint to get 15 jar files.  Assuming that you have the database installed and you can get access to the installation (or ask the DBA), you need to copy the 15 jar files to each machine with a WLS installation and get them in your CLASSPATH.  You can play with setting the PRE_CLASSPATH but the more practical approach may be to just update WL_HOME/common/bin/commEnv.sh directly.  There's a change in the transaction completion behavior (read the MOS) so if you think you might run into that, you will want to set -Doracle.jdbc.autoCommitSpecCompliant=false.  Also if you are running with Active GridLink, you must set -Doracle.ucp.PreWLS1212Compatible=true (how's that for telling you that this is fixed in WLS 12.1.2).  Once you get the configuration out of the way, you can start using the new ojdbc7.jar in place of the ojdbc6.jar to get the new JDBC 4.1 API's.  You can also start using Application Continuity.  This feature is also known as JDBC Replay because when a connection fails you get a new one with all JDBC operations up to the failure point automatically replayed.  As you might expect, there are some limitations but it's an interesting feature.  Obviously I'm going to focus on the 12c database features that we can leverage in WLS data source.  You will need to read other sources or the product documentation to get all of the new features.

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• Manage and Monitor Identity Ranges in SQL Server Transactional Replication

  - by Yaniv Etrogi

  Problem When using transactional replication to replicate data in a one way topology from a publisher to a read-only subscriber(s) there is no need to manage identity ranges. However, when using  transactional replication to replicate data in a two way replication topology - between two or more servers there is a need to manage identity ranges in order to prevent a situation where an INSERT commands fails on a PRIMARY KEY violation error  due to the replicated row being inserted having a value for the identity column which already exists at the destination database. Solution There are two ways to address this situation: Assign a range of identity values per each server. Work with parallel identity values. The first method requires some maintenance while the second method does not and so the scripts provided with this article are very useful for anyone using the first method. I will explore this in more detail later in the article. In the first solution set server1 to work in the range of 1 to 1,000,000,000 and server2 to work in the range of 1,000,000,001 to 2,000,000,000.  The ranges are set and defined using the DBCC CHECKIDENT command and when the ranges in this example are well maintained you meet the goal of preventing the INSERT commands to fall due to a PRIMARY KEY violation. The first insert at server1 will get the identity value of 1, the second insert will get the value of 2 and so on while on server2 the first insert will get the identity value of 1000000001, the second insert 1000000002 and so on thus avoiding a conflict. Be aware that when a row is inserted the identity value (seed) is generated as part of the insert command at each server and the inserted row is replicated. The replicated row includes the identity column’s value so the data remains consistent across all servers but you will be able to tell on what server the original insert took place due the range that  the identity value belongs to. In the second solution you do not manage ranges but enforce a situation in which identity values can never get overlapped by setting the first identity value (seed) and the increment property one time only during the CREATE TABLE command of each table. So a table on server1 looks like this: CREATE TABLE T1 (  c1 int NOT NULL IDENTITY(1, 5) PRIMARY KEY CLUSTERED ,c2 int NOT NULL ); And a table on server2 looks like this: CREATE TABLE T1(  c1 int NOT NULL IDENTITY(2, 5) PRIMARY KEY CLUSTERED ,c2 int NOT NULL ); When these two tables are inserted the results of the identity values look like this: Server1:  1, 6, 11, 16, 21, 26… Server2:  2, 7, 12, 17, 22, 27… This assures no identity values conflicts while leaving a room for 3 additional servers to participate in this same environment. You can go up to 9 servers using this method by setting an increment value of 9 instead of 5 as I used in this example. Continues…

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• Table Variables: an empirical approach.

  - by Phil Factor

  It isn’t entirely a pleasant experience to publish an article only to have it described on Twitter as ‘Horrible’, and to have it criticized on the MVP forum. When this happened to me in the aftermath of publishing my article on Temporary tables recently, I was taken aback, because these critics were experts whose views I respect. What was my crime? It was, I think, to suggest that, despite the obvious quirks, it was best to use Table Variables as a first choice, and to use local Temporary Tables if you hit problems due to these quirks, or if you were doing complex joins using a large number of rows. What are these quirks? Well, table variables have advantages if they are used sensibly, but this requires some awareness by the developer about the potential hazards and how to avoid them. You can be hit by a badly-performing join involving a table variable. Table Variables are a compromise, and this compromise doesn’t always work out well. Explicit indexes aren’t allowed on Table Variables, so one cannot use covering indexes or non-unique indexes. The query optimizer has to make assumptions about the data rather than using column distribution statistics when a table variable is involved in a join, because there aren’t any column-based distribution statistics on a table variable. It assumes a reasonably even distribution of data, and is likely to have little idea of the number of rows in the table variables that are involved in queries. However complex the heuristics that are used might be in determining the best way of executing a SQL query, and they most certainly are, the Query Optimizer is likely to fail occasionally with table variables, under certain circumstances, and produce a Query Execution Plan that is frightful. The experienced developer or DBA will be on the lookout for this sort of problem. In this blog, I’ll be expanding on some of the tests I used when writing my article to illustrate the quirks, and include a subsequent example supplied by Kevin Boles. A simplified example. We’ll start out by illustrating a simple example that shows some of these characteristics. We’ll create two tables filled with random numbers and then see how many matches we get between the two tables. We’ll forget indexes altogether for this example, and use heaps. We’ll try the same Join with two table variables, two table variables with OPTION (RECOMPILE) in the JOIN clause, and with two temporary tables. It is all a bit jerky because of the granularity of the timing that isn’t actually happening at the millisecond level (I used DATETIME). However, you’ll see that the table variable is outperforming the local temporary table up to 10,000 rows. Actually, even without a use of the OPTION (RECOMPILE) hint, it is doing well. What happens when your table size increases? The table variable is, from around 30,000 rows, locked into a very bad execution plan unless you use OPTION (RECOMPILE) to provide the Query Analyser with a decent estimation of the size of the table. However, if it has the OPTION (RECOMPILE), then it is smokin’. Well, up to 120,000 rows, at least. It is performing better than a Temporary table, and in a good linear fashion. What about mixed table joins, where you are joining a temporary table to a table variable? You’d probably expect that the query analyzer would throw up its hands and produce a bad execution plan as if it were a table variable. After all, it knows nothing about the statistics in one of the tables so how could it do any better? Well, it behaves as if it were doing a recompile. And an explicit recompile adds no value at all. (we just go up to 45000 rows since we know the bigger picture now)   Now, if you were new to this, you might be tempted to start drawing conclusions. Beware! We’re dealing with a very complex beast: the Query Optimizer. It can come up with surprises What if we change the query very slightly to insert the results into a Table Variable? We change nothing else and just measure the execution time of the statement as before. Suddenly, the table variable isn’t looking so much better, even taking into account the time involved in doing the table insert. OK, if you haven’t used OPTION (RECOMPILE) then you’re toast. Otherwise, there isn’t much in it between the Table variable and the temporary table. The table variable is faster up to 8000 rows and then not much in it up to 100,000 rows. Past the 8000 row mark, we’ve lost the advantage of the table variable’s speed. Any general rule you may be formulating has just gone for a walk. What we can conclude from this experiment is that if you join two table variables, and can’t use constraints, you’re going to need that Option (RECOMPILE) hint. Count Dracula and the Horror Join. These tables of integers provide a rather unreal example, so let’s try a rather different example, and get stuck into some implicit indexing, by using constraints. What unusual words are contained in the book ‘Dracula’ by Bram Stoker? Here we get a table of all the common words in the English language (60,387 of them) and put them in a table. We put them in a Table Variable with the word as a primary key, a Table Variable Heap and a Table Variable with a primary key. We then take all the distinct words used in the book ‘Dracula’ (7,558 of them). We then create a table variable and insert into it all those uncommon words that are in ‘Dracula’. i.e. all the words in Dracula that aren’t matched in the list of common words. To do this we use a left outer join, where the right-hand value is null. The results show a huge variation, between the sublime and the gorblimey. If both tables contain a Primary Key on the columns we join on, and both are Table Variables, it took 33 Ms. If one table contains a Primary Key, and the other is a heap, and both are Table Variables, it took 46 Ms. If both Table Variables use a unique constraint, then the query takes 36 Ms. If neither table contains a Primary Key and both are Table Variables, it took 116383 Ms. Yes, nearly two minutes!! If both tables contain a Primary Key, one is a Table Variables and the other is a temporary table, it took 113 Ms. If one table contains a Primary Key, and both are Temporary Tables, it took 56 Ms.If both tables are temporary tables and both have primary keys, it took 46 Ms. Here we see table variables which are joined on their primary key again enjoying a  slight performance advantage over temporary tables. Where both tables are table variables and both are heaps, the query suddenly takes nearly two minutes! So what if you have two heaps and you use option Recompile? If you take the rogue query and add the hint, then suddenly, the query drops its time down to 76 Ms. If you add unique indexes, then you've done even better, down to half that time. Here are the text execution plans.So where have we got to? Without drilling down into the minutiae of the execution plans we can begin to create a hypothesis. If you are using table variables, and your tables are relatively small, they are faster than temporary tables, but as the number of rows increases you need to do one of two things: either you need to have a primary key on the column you are using to join on, or else you need to use option (RECOMPILE) If you try to execute a query that is a join, and both tables are table variable heaps, you are asking for trouble, well- slow queries, unless you give the table hint once the number of rows has risen past a point (30,000 in our first example, but this varies considerably according to context). Kevin’s Skew In describing the table-size, I used the term ‘relatively small’. Kevin Boles produced an interesting case where a single-row table variable produces a very poor execution plan when joined to a very, very skewed table. In the original, pasted into my article as a comment, a column consisted of 100000 rows in which the key column was one number (1) . To this was added eight rows with sequential numbers up to 9. When this was joined to a single-tow Table Variable with a key of 2 it produced a bad plan. This problem is unlikely to occur in real usage, and the Query Optimiser team probably never set up a test for it. Actually, the skew can be slightly less extreme than Kevin made it. The following test showed that once the table had 54 sequential rows in the table, then it adopted exactly the same execution plan as for the temporary table and then all was well. Undeniably, real data does occasionally cause problems to the performance of joins in Table Variables due to the extreme skew of the distribution. We've all experienced Perfectly Poisonous Table Variables in real live data. As in Kevin’s example, indexes merely make matters worse, and the OPTION (RECOMPILE) trick does nothing to help. In this case, there is no option but to use a temporary table. However, one has to note that once the slight de-skew had taken place, then the plans were identical across a huge range. Conclusions Where you need to hold intermediate results as part of a process, Table Variables offer a good alternative to temporary tables when used wisely. They can perform faster than a temporary table when the number of rows is not great. For some processing with huge tables, they can perform well when only a clustered index is required, and when the nature of the processing makes an index seek very effective. Table Variables are scoped to the batch or procedure and are unlikely to hang about in the TempDB when they are no longer required. They require no explicit cleanup. Where the number of rows in the table is moderate, you can even use them in joins as ‘Heaps’, unindexed. Beware, however, since, as the number of rows increase, joins on Table Variable heaps can easily become saddled by very poor execution plans, and this must be cured either by adding constraints (UNIQUE or PRIMARY KEY) or by adding the OPTION (RECOMPILE) hint if this is impossible. Occasionally, the way that the data is distributed prevents the efficient use of Table Variables, and this will require using a temporary table instead. Tables Variables require some awareness by the developer about the potential hazards and how to avoid them. If you are not prepared to do any performance monitoring of your code or fine-tuning, and just want to pummel out stuff that ‘just runs’ without considering namby-pamby stuff such as indexes, then stick to Temporary tables. If you are likely to slosh about large numbers of rows in temporary tables without considering the niceties of processing just what is required and no more, then temporary tables provide a safer and less fragile means-to-an-end for you.

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• New Exadata, Exalogic, Exalytics Public References

  - by Javier Puerta

  CUSTOMER SUCCESS STORIES & SPOTLIGHTS AmerisourceBergen (US) Oracle Exadata, Oracle Advanced Compression, Oracle Advanced Customer Support Services, Oracle Active Data Guard Published: July 31, 2014 Guangzhou Municipal Human Resources and Social Security Bureau (China) Exalogic, Enterprise Mgr Published: July 31, 2014 Norfolk Southern Corp. (US) Oracle Exadata, Oracle Exalytics, Oracle Business Intelligence Suite, Enterprise Edition Published: July 30, 2014 TDC (Denmark) Oracle Exadata, Oracle ZFS Storage Appliance, SPARC T4-4, SPARC T4-1, Oracle Solaris, Oracle Consulting, Oracle Advanced Customer Support Services Published: July 30, 2014 Chosun Ilbo (Korea) Oracle Exadata, Oracle GoldenGate Published: July 29, 2014 GIA (Gemological Institute of America) (US), Exalogic, Exadata Published: July 25, 2014 City of Lakeland (US) Oracle Exadata, Oracle Active Data Guard, Oracle Partitioning, Oracle Tuning Pack, Oracle Enterprise Manager, Oracle Diagnostics Pack, Oracle Enterprise Service Bus, Oracle Advanced Customer Support Services, Oracle Platinum Services Published: July 15, 2014 Tech Mahindra (India) Oracle Exadata, SPARC T5-4, Oracle Solaris 11, PeopleSoft Human Resources, Oracle Advanced Customer Support Services Published: July 01, 2014

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• Oracle ADF Mobile - Develop iOS and Android Mobile Applications with Oracle ADF

  - by Shay Shmeltzer

  We are very happy to announce the release of Oracle ADF Mobile.  The new Oracle ADF Mobile enables developers to build applications that run on iOS and Android devices. Several unique aspects to Oracle ADF Mobile solution: Develop once run on many - same code base used for both iOS and Android applicaitons Uses Java - no need to learn device specific languages Leverage ADF - same concepts you are familiar with (component based UI construction, taskflow, data controls) Leverage JDeveloper - same development environment you know, same declarative and visual style. Create native looking applications - HTML 5 based UI components (that you can also skin) Use device services - Leverage the camera, SMS, location, contact etc without learning device specific APIs Create Hybrid applications - run on the device and able to consume remote data and UI if needed Here is the 3 minute introduction Oracle ADF Mobile is available as an extension to Oracle JDeveloper 11.1.2.3 - use the help->check for updates to install it. Then head over to the Oracle ADF Mobile page for all the resources you need. If you are an Oracle ADF developer, it's time to update your resume - you are now a mobile device developer too :-)

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• Class Design -- Multiple Calls from One Method or One Call from Multiple Methods?

  - by Andrew

  I've been working on some code recently that interfaces with a CMS we use and it's presented me with a question on class design that I think is applicable in a number of situations. Essentially, what I am doing is extracting information from the CMS and transforming this information into objects that I can use programatically for other purposes. This consists of two steps: Retrieve the data from the CMS (we have a DAL that I use, so this is essentially just specifying what data from the CMS I want--no connection logic or anything like that) Map the parsed data to my own [C#] objects There are basically two ways I can approach this: One call from multiple methods public void MainMethodWhereIDoStuff() { IEnumerable<MyObject> myObjects = GetMyObjects(); // Do other stuff with myObjects } private static IEnumerable<MyObject> GetMyObjects() { IEnumerable<CmsDataItem> cmsDataItems = GetCmsDataItems(); List<MyObject> mappedObjects = new List<MyObject>(); // do stuff to map the CmsDataItems to MyObjects return mappedObjects; } private static IEnumerable<CmsDataItem> GetCmsDataItems() { List<CmsDataItem> cmsDataItems = new List<CmsDataItem>(); // do stuff to get the CmsDataItems I want return cmsDataItems; } Multiple calls from one method public void MainMethodWhereIDoStuff() { IEnumerable<CmsDataItem> cmsDataItems = GetCmsDataItems(); IEnumerable<MyObject> myObjects = GetMyObjects(cmsDataItems); // do stuff with myObjects } private static IEnumerable<MyObject> GetMyObjects(IEnumerable<CmsDataItem> itemsToMap) { // ... } private static IEnumerable<CmsDataItem> GetCmsDataItems() { // ... } I am tempted to say that the latter is better than the former, as GetMyObjects does not depend on GetCmsDataItems, and it is explicit in the calling method the steps that are executed to retrieve the objects (I'm concerned that the first approach is kind of an object-oriented version of spaghetti code). On the other hand, the two helper methods are never going to be used outside of the class, so I'm not sure if it really matters whether one depends on the other. Furthermore, I like the fact that in the first approach the objects can be retrieved from one line-- most likely anyone working with the main method doesn't care how the objects are retrieved, they just need to retrieve the objects, and the "daisy chained" helper methods hide the exact steps needed to retrieve them (in practice, I actually have a few more methods but am still able to retrieve the object collection I want in one line). Is one of these methods right and the other wrong? Or is it simply a matter of preference or context dependent?

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• New Options for MySQL High Availability

  - by Mat Keep

  Data is the currency of today’s web, mobile, social, enterprise and cloud applications. Ensuring data is always available is a top priority for any organization – minutes of downtime will result in significant loss of revenue and reputation. There is not a “one size fits all” approach to delivering High Availability (HA). Unique application attributes, business requirements, operational capabilities and legacy infrastructure can all influence HA technology selection. And then technology is only one element in delivering HA – “People and Processes” are just as critical as the technology itself. For this reason, MySQL Enterprise Edition is available supporting a range of HA solutions, fully certified and supported by Oracle. MySQL Enterprise HA is not some expensive add-on, but included within the core Enterprise Edition offering, along with the management tools, consulting and 24x7 support needed to deliver true HA. At the recent MySQL Connect conference, we announced new HA options for MySQL users running on both Linux and Solaris: - DRBD for MySQL - Oracle Solaris Clustering for MySQL DRBD (Distributed Replicated Block Device) is an open source Linux kernel module which leverages synchronous replication to deliver high availability database applications across local storage. DRBD synchronizes database changes by mirroring data from an active node to a standby node and supports automatic failover and recovery. Linux, DRBD, Corosync and Pacemaker, provide an integrated stack of mature and proven open source technologies. DRBD Stack: Providing Synchronous Replication for the MySQL Database with InnoDB Download the DRBD for MySQL whitepaper to learn more, including step-by-step instructions to install, configure and provision DRBD with MySQL Oracle Solaris Cluster provides high availability and load balancing to mission-critical applications and services in physical or virtualized environments. With Oracle Solaris Cluster, organizations have a scalable and flexible solution that is suited equally to small clusters in local datacenters or larger multi-site, multi-cluster deployments that are part of enterprise disaster recovery implementations. The Oracle Solaris Cluster MySQL agent integrates seamlessly with MySQL offering a selection of configuration options in the various Oracle Solaris Cluster topologies. Putting it All Together When you add MySQL Replication and MySQL Cluster into the HA mix, along with 3rd party solutions, users have extensive choice (and decisions to make) to deliver HA services built on MySQL To make the decision process simpler, we have also published a new MySQL HA Solutions Guide. Exploring beyond just the technology, the guide presents a methodology to select the best HA solution for your new web, cloud and mobile services, while also discussing the importance of people and process in ensuring service continuity. This is subject recently presented at Oracle Open World, and the slides are available here. Whatever your uptime requirements, you can be sure MySQL has an HA solution for your needs Please don't hesitate to let us know of your HA requirements in the comments section of this blog. You can also contact MySQL consulting to learn more about their HA Jumpstart offering which will help you scope out your scaling and HA requirements.

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• When should I make the first commit to source control?

  - by Kendall Frey

  I'm never sure when a project is far enough along to first commit to source control. I tend to put off committing until the project is 'framework-complete' and primarily commit features from then on. (I haven't done any personal projects large enough to have a core framework too big for this.) I have a feeling this isn't best practice, though I'm not sure what all could go wrong. Let's say, for example, I have a project which consists of a single code file. It will take about 10 lines of boilerplate code, and 100 lines to get the project working with extremely basic functionality (1 or 2 features). Should I first check in: The empty file? The boilerplate code? The first features? At some other point? Also, what are the reasons to check in at a specific point?

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• SharePoint Content Database Sizing

  - by Sahil Malik

  SharePoint, WCF and Azure Trainings: more information SharePoint stores majority of its content in SQL Server databases. Many of these databases are concerned with the overall configuration of the system, or managed services support. However, a majority of these databases are those that accept uploaded content, or collaborative content. These databases need to be sized with various factors in mind, such as, Ability to backup/restore the content quickly, thereby allowing for quicker SLAs and isolation in event of database failure. SharePoint as a system avoids SQL transactions in many instances. It does so to avoid locks, but does so at the cost of resultant orphan data or possible data corruption. Larger databases are known to have more orphan items than smaller ones. Also smaller databases keep the problems isolated. As a result, it is very important for any project to estimate content database base sizing estimation. This is especially important in collaborative document centric projects. Not doing this upfront planning can Read full article ....

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• YouSendIt Alternative?

  - by WuckaChucka

  Looking for a reasonably priced alternative to YouSendIt's exorbitant pricing for an embedded, unbranded (i.e. no "Uploads by SomeCompany" or at the very least, discrete, subtle co-branding) file upload solution for my client's print shop Website. To do what we want to do with YouSendIt, we're looking at a corporate account of $995 USD plus $29.99 USD monthly fee, that is only sold pro-rated, so you have to buy the entire year's worth. To me, this is just unacceptable considering the commodity pricing of storage and bandwidth nowadays. For data, we're looking at roughly 10MB per upload, with perhaps 250-1000 uploads per month, with transient data storage of no more than 30 days (and more than likely 1-2 business days) for a total of 10 GB transfer (upload) and 10 GB transfer (download, to the print shop) at the very max each month. Any ideas? Everything I've found through searching seems to be geared more towards personal file sharing and not for embedding into Websites. Thanks

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• Do I need to know servlets and JSP to learn spring or hibernate or any other java web frameworks?

  - by KyelJmD

  I've been asking a lot of people where to start learning java web development, I already know core java (Threading,Generics,Collections, a little experience with (JDBC)) but I do not know JSPs and servlets. I did my fair share of development with several web based applications using PHP for server-side and HTML,CSS,Javascript,HTML5 for client side. Most people that I asked told me to jump right ahead to Hibernate while some told me that I do not need to learn servlets and jsps and I should immediately study the Spring framework. Is this true? do I not need to learn servlets and JSPs to learn hibernate or Spring? All of their answers confused me and now I am completely lost what to learn or study. I feel that if I skipped learning JSP and servlets I would missed a lot of important concepts that will surely help me in the future. So the question, do I need to have foundation/know servlets and JSP to learn spring or hibernate or any other java web frameworks.?

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• How to stop programs on starting from returning to log in screen?

  - by Bruce McKean

  I'm not a computer nerd but have been able to fix Ubuntu/Linux problems in the pass two years with a Google search but this on has me stumped. I upgraded to 12.04 about thirty days ago and all was well except that every time I tried to load KeePassX it would go to the login screen. I installed KeePass2 and all seemed to work. Last week I tried to load Bibble5 (Raw photo editor) and it would try to load and then back to the login screen. After a few days I gave up and downloaded Corel After Shot Pro (Corel's now owns Bibble5) and it has the same problem. Could someone please head me into the steps I need to follow to find out what is the cause. I'm interested in learning more about the Linux system how to correct any future problems thanks in advance – Bruce -Computer- Processor : 8x Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz Memory : 8155MB (1092MB used) Operating System : Ubuntu 12.04 LTS OpenGL Renderer : GeForce GT 520/PCIe/SSE2

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• Graphics Driver problem, ATI Radeon HD 3200, small screen size and slows everything down.

  - by Arvind Jangid

  Regards. I am using a: 2009 Compaq Presario CQ40-415AU Notebook AMD Athlon X2 Dual core Processor 2.1 GHz 1024 MB L2 cache 3GB DDR2 RAM ATI Radeon + HD 3200 Graphics 256 MB, screen is 14 inch widescreen with resolution of 1280*800. I installed Ubuntu 12.04 LTS 32bit on my laptop. It works brilliantly until I installed graphics driver. When I installed the driver, the graphics became slow. Everything slowed down. Even the splash screen resolution changed to something like 640*480. I have liked Ubuntu since 9.10 and for the freedom it provides and its versatility, but graphics problem remains the same. I even installed Ubuntu on a 50 GB partition with 6 GB swap partition. My HDD is 320 GB. Please tell me what is wrong.

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• What I do in year to get software oriented job [on hold]

  - by Rohit patil

  I am Rohit patil, studing in 4th year Electronics & telecommunications engineering. I have interest in programming language. I completed c, c++, core java course & get basic knowledge. I have 2 choices to do career in web design or mobile applications, I am confused in which is select. I have one year period for preparing for it. So please give me advice about field is better for me & what I do to get command in that field. Thank you.

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• Problems detecting android tablet IView 788TPC with mtp-tools

  - by Elder Geek

  I installed mtp-tools on 14.04 "Trusty" through Software Center. No problems with install. Issuing `mtp-detect' results in 'Unable to open ~/.mtpz-data for reading, MTPZ disabled.libmtp version: 1.1.6 Listing raw device(s) No raw devices found.' I did some research and found that mtpfs might be required. so installed that with :~$ sudo apt-get install mtpfs I still get the following result :~$ mtp-detect Unable to open ~/.mtpz-data for reading, MTPZ disabled.libmtp version: 1.1.6 Listing raw device(s) No raw devices found. My research indicates that the mtp-tools package is still under development. source: http://libmtp.sourceforge.net/ and the documentation is not comprehensive. source man mtp-tools as well as mtp-detect -h I tried adding the PPA from Are there any plans to improve mtp support on future Ubuntu releases? but it seems this is already worked into trusty 14.04 and won't resolve the problem. Can anyone provide a recommended course of action to resolve this problem?

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• Permissions & File Structure w/ nginx & multiple sites

  - by Michael

  I am using nginx for the first time as a long time Apache user. I setup a Linode to test everything and to eventually port over my websites. Previously I had /home/user/www (wwwroot) I am looking at doing something similar with /srv/www/domain/www (wwwroot) Rather than using /srv/domain (wwwroot), the reason is many of the sites are WordPress and one of the things I do for security is to move the config file one level above wwwroot and can't have multiple configuration files from multiple domains in the same top level folder. Since I own all the sites, I wasn't going to create a user for each domain. My user is a member of www-data and was going to use 2770 for www and have domain/www for each new domain. www would be owned by group www-data. Is this the best way to handle this?

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• Scrum: How to work on one story at a time

  - by Juergen

  I was nominated as scrum master in a new formed scrum team. We have already done some sprints. In the beginning I tried to make my team to work on one story at a time. But it didn't work. My team had difficulties to distribute the tasks in a way that they can work simultaneously on one story. Maybe we are doing something wrong? For example: we have a story to create a new dialog. We create the following tasks: Create Model classes Read model data from database Connect model classes with view Implement dialog handling Save data on close Test Documentation Solution Description Can theses tasks be done by more than one person at a time? The tasks - more or less - build upon each other. Or do we design the tasks in a wrong way?

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