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  • The Arab HEUG is now a reality, and other random thoughts

    - by user9147039
    I just returned from Doha, Qatar where the first of its kind HEUG (Higher Education User Group) meeting for institutions in the Middle East and North Africa was held at Qatar University and jointly hosted by Damman University from Saudi Arabia. Over 80 delegates attended including representation from education institutions in Oman, Saudi Arabia, Lebanon, and Qatar. There are many other regional HEUG organizations in place (in Australia/New Zealand, APAC, EMEA, as well as smaller regional HEUG’s in the Netherlands, South Africa, and in regions of the US), but it was truly an accomplishment to see this Middle East/North Africa group organize and launch their chapter with a meeting of this quality. To be known as the Arab HEUG going forward, I am excited about the prospects for sharing between the institutions and for the growth of Oracle solutions in the region. In particular the hosts for the event (Qatar University) did a masterful job with logistics and organization, and the quality of the event was a testament to their capabilities. Among the more interesting and enlightening presentations I attended were one from Dammam University on the lessons learned from their implementation of Campus Solutions and transition off of Banner, as well as the use by Qatar University E-business Suite for grants management (both pre-and post-award). The most notable fact coming from this latter presentation was the fit (89%) of e-Business Suite Grants to the university’s requirements. In a few weeks time we will be convening the 5th meeting of the Oracle Education & Research Industry Strategy Council in Redwood Shores (5th since my advent into my current role). The main topics of discussion will be around our Higher Education Applications Strategy for the future (including cloud approaches to ERP (HCM, Finance, and Student Information Systems), how some cases studies on the benefits of leveraging delivered functionality and extensibility in the software (versus customization). On the second day of the event we will turn our attention to Oracle in Research and also budgeting and planning in higher education. Both of these sessions will include significant participation from council members in the form of panel discussions. Our EVP’s for Systems (John Fowler) and for Global Cloud Services and North America application sales (Joanne Olson) will join us for the discussion. I recently read a couple of articles that were surprising to me. The first was from Inside Higher Ed on October 15 entitled, “As colleges prepare for major software upgrades, Kuali tries to woo them from corporate vendors.” It continues to disappointment that after all this time we are still debating whether it is better to build enterprise software through open or community source initiatives when fully functional, flexible, supported, and widely adopted options exist in the marketplace. Over a decade or more ago when these solutions were relatively immature and there was a great deal of turnover in the market I could appreciate the initiatives like Kuali. But let’s not kid ourselves – the real objective of this movement is to counter a perceived predatory commercial software industry. Again, when commercial solutions are deployed as written without significant customization, and standard business processes are adopted, the cost of these solutions (relative to the value delivered) is quite low, and certain much lower than the massive investment (and risk) in in-house developers to support a bespoke community source system. In this era of cost pressures in education and the need to refocus resources on teaching, learning, and research, I believe it’s bordering on irresponsible to continue to pursue open-source ERP. Many of the adopter’s total costs are staggering and have little to show for their efforts and expended resources. The second article was recently in the Chronicle of Higher Education and was entitled “’Big Data’ Is Bunk, Obama Campaign’s Tech Guru Tells University Leaders.” This one was so outrageous I almost don’t want to legitimize it by referencing it here. In the article the writer relays statements made by Harper Reed, President Obama’s former CTO for his 2012 re-election campaign, that big data solutions in education have no relevance and are akin to snake oil. He goes on to state that while he’s a fan of data-driven decision making in education, most of the necessary analysis can be accomplished in Excel spreadsheets. Yeah… right. This is exactly what ails education (higher education in particular). Dozens of shadow and siloed systems running on spreadsheets with limited-to-no enterprise wide initiatives to harness the data-rich environment that is a higher ed institution and transform the data into useable information. I’ll grant Mr. Reed that “Big Data” is overused and hackneyed, but imperatives like improving student success in higher education are classic big data problems that data-mining and predictive analytics can address. Further, higher ed need to be producing a massive amount more data scientists and analysts than are currently in the pipeline, to further this discipline and application of these tools to many many other problems across multiple industries.

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  • Security and the Mobile Workforce

    - by tobyehatch
    Now that many organizations are moving to the BYOD philosophy (bring your own devices), security for phones and tablets accessing company sensitive information is of paramount importance. I had the pleasure to interview Brian MacDonald, Principal Product Manager for Oracle Business Intelligence (BI) Mobile Products, about this subject, and he shared some wonderful insight about how the Oracle Mobile Security Tool Kit is addressing mobile security and doing some pretty cool things.  With the rapid proliferation of phones and tablets, there is a perception that mobile devices are a security threat to corporate IT, that mobile operating systems are not secure, and that there are simply too many ways to inadvertently provide access to critical analytic data outside the firewall. Every day, I see employees working on mobile devices at the airport, while waiting for their airplanes, and using public WIFI connections at coffee houses and in restaurants. These methods are not typically secure ways to access confidential company data. I asked Brian to explain why. “The native controls for mobile devices and applications are indeed insufficiently secure for corporate deployments of Business Intelligence and most certainly for businesses where data is extremely critical - such as financial services or defense - although it really applies across the board. The traditional approach for accessing data from outside a firewall is using a VPN connection which is not a viable solution for mobile. The problem is that once you open up a VPN connection on your phone or tablet, you are creating an opening for the whole device, for all the software and installed applications. Often the VPN connection by itself provides insufficient encryption – if any – which means that data can be potentially intercepted.” For this reason, most organizations that deploy Business Intelligence data via mobile devices will only do so with some additional level of control. So, how has the industry responded? What are companies doing to address this very real threat? Brian explained that “Mobile Device Management (MDM) and Mobile Application Management (MAM) software vendors have rapidly created solutions for mobile devices that provide a vast array of services for controlling, managing and establishing enterprise mobile usage policies. On the device front, vendors now support full levels of encryption behind the firewall, encrypted local data storage, credential management such as federated single-sign-on as well as remote wipe, geo-fencing and other risk reducing features (should a device be lost or stolen). More importantly, these software vendors have created methods for providing these capabilities on a per application basis, allowing for complete isolation of the application from the mobile operating system. Finally, there are tools which allow the applications themselves to be distributed through enterprise application stores allowing IT organizations to manage who has access to the apps, when updates to the applications will happen, and revoke access after an employee leaves. So even though an employee may be using a personal device, access to company data can be controlled while on or near the company premises. So do the Oracle BI mobile products integrate with the MDM and MAM vendors? Brian explained that our customers use a wide variety of mobile security vendors and may even have more than one in-house. Therefore, Oracle is ensuring that users have a choice and a mechanism for linking together Oracle’s BI offering with their chosen vendor’s secure technology. The Oracle BI Mobile Security Toolkit, which is a version of the Oracle BI Mobile HD application, delivered through the Oracle Technology Network (OTN) in its component parts, helps Oracle users to build their own version of the Mobile HD application, sign it with their own enterprise development certificates, link with their security vendor of choice, then deploy the combined application through whichever means they feel most appropriate, including enterprise application stores.  Brian further explained that Oracle currently supports most of the major mobile security vendors, has close relationships with each, and maintains strong partnerships enabling both Oracle and the vendors to test, update and release a cooperating solution in lock-step. Oracle also ensures that as new versions of the Oracle HD application are made available on the Apple iTunes store, the same version is also immediately made available through the Security Toolkit on OTN.  Rest assured that as our workforce continues down the mobile path, company sensitive information can be secured.  To listen to the entire podcast, click here. To learn more about the Oracle BI Mobile HD, click  here To learn more about the BI Mobile Security Toolkit, click here 

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  • Columnstore Case Study #1: MSIT SONAR Aggregations

    - by aspiringgeek
    Preamble This is the first in a series of posts documenting big wins encountered using columnstore indexes in SQL Server 2012 & 2014.  Many of these can be found in this deck along with details such as internals, best practices, caveats, etc.  The purpose of sharing the case studies in this context is to provide an easy-to-consume quick-reference alternative. Why Columnstore? If we’re looking for a subset of columns from one or a few rows, given the right indexes, SQL Server can do a superlative job of providing an answer. If we’re asking a question which by design needs to hit lots of rows—DW, reporting, aggregations, grouping, scans, etc., SQL Server has never had a good mechanism—until columnstore. Columnstore indexes were introduced in SQL Server 2012. However, they're still largely unknown. Some adoption blockers existed; yet columnstore was nonetheless a game changer for many apps.  In SQL Server 2014, potential blockers have been largely removed & they're going to profoundly change the way we interact with our data.  The purpose of this series is to share the performance benefits of columnstore & documenting columnstore is a compelling reason to upgrade to SQL Server 2014. App: MSIT SONAR Aggregations At MSIT, performance & configuration data is captured by SCOM. We archive much of the data in a partitioned data warehouse table in SQL Server 2012 for reporting via an application called SONAR.  By definition, this is a primary use case for columnstore—report queries requiring aggregation over large numbers of rows.  New data is refreshed each night by an automated table partitioning mechanism—a best practices scenario for columnstore. The Win Compared to performance using classic indexing which resulted in the expected query plan selection including partition elimination vs. SQL Server 2012 nonclustered columnstore, query performance increased significantly.  Logical reads were reduced by over a factor of 50; both CPU & duration improved by factors of 20 or more.  Other than creating the columnstore index, no special modifications or tweaks to the app or databases schema were necessary to achieve the performance improvements.  Existing nonclustered indexes were rendered superfluous & were deleted, thus mitigating maintenance challenges such as defragging as well as conserving disk capacity. Details The table provides the raw data & summarizes the performance deltas. Logical Reads (8K pages) CPU (ms) Durn (ms) Columnstore 160,323 20,360 9,786 Conventional Table & Indexes 9,053,423 549,608 193,903 ? x56 x27 x20 The charts provide additional perspective of this data.  "Conventional vs. Columnstore Metrics" document the raw data.  Note on this linear display the magnitude of the conventional index performance vs. columnstore.  The “Metrics (?)” chart expresses these values as a ratio. Summary For DW, reports, & other BI workloads, columnstore often provides significant performance enhancements relative to conventional indexing.  I have documented here, the first in a series of reports on columnstore implementations, results from an initial implementation at MSIT in which logical reads were reduced by over a factor of 50; both CPU & duration improved by factors of 20 or more.  Subsequent features in this series document performance enhancements that are even more significant. 

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  • Cloud Backup: Getting the Users' Backs Up

    - by Tony Davis
    On Wednesday last week, Microsoft announced that as of July 1, all data transfers into its Microsoft Azure cloud will be free (though you have to pay for transferring data out). On Thursday last week, SQL Azure in Western Europe went down. It was a relatively short outage, but since SQL Azure currently provides no easy way to take a standard backup of a database and store it locally, many people had no recourse but to wait patiently for their cloud-based app to resume. It seems that Microsoft are very keen encourage developers to move their data onto their cloud, but are developers ready to do it, given that such basic backup capabilities are lacking? Recently on Simple-Talk, Mike Mooney described a perfect use case for the Microsoft Cloud. They had a simple web-based application with a SQL Server backend; they could move the application to Windows Azure, and the data into SQL Azure and in the process free themselves from much of the hassle surrounding management and scaling of the hardware, network and so on. It was a great fit and yet it nearly didn't happen; lack of support for the BACKUP command almost proved a show-stopper. Of course, backups of Azure databases are always and have always been taken automatically, for disaster recovery purposes, but these are strictly on-cloud copies and as of now it is not possible to use them to them to restore a database to a particular point in time. It seems that none of those clever Microsoft people managed to predict the need to perform basic backups of Azure databases so that copies could be stored locally, outside the Azure universe. At the very least, as Mike points out, performing a local backup before a new deployment is more or less mandatory. Microsoft did at least note the sound of gnashing teeth and, as a stop-gap measure, offered SQL Azure Database Copy which basically allows you to create an online clone of your database, but this doesn't allow for storing local archives of the data. To that end MS has provided SQL Azure Import/Export, to package up and export a database and its data, using BACPACs. These BACPACs do not guarantee transactional consistency; for example, if a child table is modified after the parent is copied, then the copied database will be in inconsistent state (meaning, to add to the fun, BACPACs need to be created from a database copy). In any event, widespread problems with BACPAC's evil cousin, the DACPAC have been well-documented, and it seems likely that many will also give BACPAC the bum's rush. Finally, in a TechEd 2011 presentation tagged "SQL Azure Advanced Administration", it was announced that "backup and restore" were coming in the next SQL Azure CTP. And yet this still doesn't mean that we'll get simple backups as DBAs know and love them. What it does mean, at least, is the ability to restore any given database to a point in time within a 2-week window. For the time being, if you want a local copy of your data and don't want to brave the BACPAC, one is left with SSIS or BCP, creative use of schema and data comparison tools, or use of SQL Azure Backup (currently in beta) in order to perform this simple but vital task. Cheers, Tony.

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  • ROracle support for TimesTen In-Memory Database

    - by Sam Drake
    Today's guest post comes from Jason Feldhaus, a Consulting Member of Technical Staff in the TimesTen Database organization at Oracle.  He shares with us a sample session using ROracle with the TimesTen In-Memory database.  Beginning in version 1.1-4, ROracle includes support for the Oracle Times Ten In-Memory Database, version 11.2.2. TimesTen is a relational database providing very fast and high throughput through its memory-centric architecture.  TimesTen is designed for low latency, high-volume data, and event and transaction management. A TimesTen database resides entirely in memory, so no disk I/O is required for transactions and query operations. TimesTen is used in applications requiring very fast and predictable response time, such as real-time financial services trading applications and large web applications. TimesTen can be used as the database of record or as a relational cache database to Oracle Database. ROracle provides an interface between R and the database, providing the rich functionality of the R statistical programming environment using the SQL query language. ROracle uses the OCI libraries to handle database connections, providing much better performance than standard ODBC.The latest ROracle enhancements include: Support for Oracle TimesTen In-Memory Database Support for Date-Time using R's POSIXct/POSIXlt data types RAW, BLOB and BFILE data type support Option to specify number of rows per fetch operation Option to prefetch LOB data Break support using Ctrl-C Statement caching support Times Ten 11.2.2 contains enhanced support for analytics workloads and complex queries: Analytic functions: AVG, SUM, COUNT, MAX, MIN, DENSE_RANK, RANK, ROW_NUMBER, FIRST_VALUE and LAST_VALUE Analytic clauses: OVER PARTITION BY and OVER ORDER BY Multidimensional grouping operators: Grouping clauses: GROUP BY CUBE, GROUP BY ROLLUP, GROUP BY GROUPING SETS Grouping functions: GROUP, GROUPING_ID, GROUP_ID WITH clause, which allows repeated references to a named subquery block Aggregate expressions over DISTINCT expressions General expressions that return a character string in the source or a pattern within the LIKE predicate Ability to order nulls first or last in a sort result (NULLS FIRST or NULLS LAST in the ORDER BY clause) Note: Some functionality is only available with Oracle Exalytics, refer to the TimesTen product licensing document for details. Connecting to TimesTen is easy with ROracle. Simply install and load the ROracle package and load the driver. > install.packages("ROracle") > library(ROracle) Loading required package: DBI > drv <- dbDriver("Oracle") Once the ROracle package is installed, create a database connection object and connect to a TimesTen direct driver DSN as the OS user. > conn <- dbConnect(drv, username ="", password="", dbname = "localhost/SampleDb_1122:timesten_direct") You have the option to report the server type - Oracle or TimesTen? > print (paste ("Server type =", dbGetInfo (conn)$serverType)) [1] "Server type = TimesTen IMDB" To create tables in the database using R data frame objects, use the function dbWriteTable. In the following example we write the built-in iris data frame to TimesTen. The iris data set is a small example data set containing 150 rows and 5 columns. We include it here not to highlight performance, but so users can easily run this example in their R session. > dbWriteTable (conn, "IRIS", iris, overwrite=TRUE, ora.number=FALSE) [1] TRUE Verify that the newly created IRIS table is available in the database. To list the available tables and table columns in the database, use dbListTables and dbListFields, respectively. > dbListTables (conn) [1] "IRIS" > dbListFields (conn, "IRIS") [1] "SEPAL.LENGTH" "SEPAL.WIDTH" "PETAL.LENGTH" "PETAL.WIDTH" "SPECIES" To retrieve a summary of the data from the database we need to save the results to a local object. The following call saves the results of the query as a local R object, iris.summary. The ROracle function dbGetQuery is used to execute an arbitrary SQL statement against the database. When connected to TimesTen, the SQL statement is processed completely within main memory for the fastest response time. > iris.summary <- dbGetQuery(conn, 'SELECT SPECIES, AVG ("SEPAL.LENGTH") AS AVG_SLENGTH, AVG ("SEPAL.WIDTH") AS AVG_SWIDTH, AVG ("PETAL.LENGTH") AS AVG_PLENGTH, AVG ("PETAL.WIDTH") AS AVG_PWIDTH FROM IRIS GROUP BY ROLLUP (SPECIES)') > iris.summary SPECIES AVG_SLENGTH AVG_SWIDTH AVG_PLENGTH AVG_PWIDTH 1 setosa 5.006000 3.428000 1.462 0.246000 2 versicolor 5.936000 2.770000 4.260 1.326000 3 virginica 6.588000 2.974000 5.552 2.026000 4 <NA> 5.843333 3.057333 3.758 1.199333 Finally, disconnect from the TimesTen Database. > dbCommit (conn) [1] TRUE > dbDisconnect (conn) [1] TRUE We encourage you download Oracle software for evaluation from the Oracle Technology Network. See these links for our software: Times Ten In-Memory Database,  ROracle.  As always, we welcome comments and questions on the TimesTen and  Oracle R technical forums.

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  • Oracle GoldenGate 11g Release 2 Launch Webcast Replay Available

    - by Irem Radzik
    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:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman";} For those of you who missed Oracle GoldenGate 11g Release 2 launch webcasts last week, the replay is now available from the following url. Harnessing the Power of the New Release of Oracle GoldenGate 11g I would highly recommend watching the webcast to meet many new features of the new release and hear the product management team respond to the questions from the audience in a nice long Q&A section. In my blog last week I listed the media coverage for this new release. There is a new article published by ITJungle talking about Oracle GoldenGate’s heterogeneity and support for DB2 for iSeries: Oracle Completes DB2/400 Support in Data Replication Tool As mentioned in last week’s blog, we received over 150 questions from the audience and in this blog I'd like to continue to post some of the frequently asked,  questions and their answers: Question: What are the fundamental differences between classic data capture and integrated data capture? Do both use the redo logs in the source database? Answer: Yes, they both use redo logs. Classic capture parses the redo log data directly, whereas the Integrated Capture lets the Oracle database parse the redo log record using an internal API. Question: Does GoldenGate version need to match Oracle Database version? Answer: No, they are not directly linked. Oracle GoldenGate 11g Release 2 supports Oracle Database version 10gR2 as well. For Oracle Database version 10gR1 and Oracle Database version 9i you will need GoldenGate11g Release 1 or lower. And for Oracle Database 8i you need Oracle GoldenGate 10 or earlier versions. Question: If I already use Data Guard, do I need GoldenGate? Answer: Data Guard is designed as the best disaster recovery solution for Oracle Database. If you would like to implement a bidirectional Active-Active replication solution or need to move data between heterogeneous systems, you will need GoldenGate. Question: On Compression and GoldenGate, if the source uses compression, is it required that the target also use compression? Answer: No, the source and target do not need to have the same compression settings. Question: Does GG support Advance Security Option on the Source database? Answer: Yes it does. Question: Can I use GoldenGate to upgrade the Oracle Database to 11g and do OS migration at the same time? Answer: Yes, this is a very common project where GoldenGate can eliminate downtime, give flexibility to test the target as needed, and minimize risks with fail-back option to the old environment. For more information on database upgrades please check out the following white papers: Best Practices for Migrating/Upgrading Oracle Database Using Oracle GoldenGate 11g Zero-Downtime Database Upgrades Using Oracle GoldenGate Question: Does GoldenGate create any trigger in the source database table level or row level to for real-time data integration? Answer: No, GoldenGate does not create triggers. Question: Can transformation be done after insert to destination table or need to be done before? Answer: It can happen in the Capture (Extract) process, in the  Delivery (Replicat) process, or in the target database. For more resources on Oracle GoldenGate 11gR2 please check out our Oracle GoldenGate 11gR2 resource kit as well.

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  • ROracle support for TimesTen In-Memory Database

    - by Sherry LaMonica
    Today's guest post comes from Jason Feldhaus, a Consulting Member of Technical Staff in the TimesTen Database organization at Oracle.  He shares with us a sample session using ROracle with the TimesTen In-Memory database.  Beginning in version 1.1-4, ROracle includes support for the Oracle Times Ten In-Memory Database, version 11.2.2. TimesTen is a relational database providing very fast and high throughput through its memory-centric architecture.  TimesTen is designed for low latency, high-volume data, and event and transaction management. A TimesTen database resides entirely in memory, so no disk I/O is required for transactions and query operations. TimesTen is used in applications requiring very fast and predictable response time, such as real-time financial services trading applications and large web applications. TimesTen can be used as the database of record or as a relational cache database to Oracle Database. ROracle provides an interface between R and the database, providing the rich functionality of the R statistical programming environment using the SQL query language. ROracle uses the OCI libraries to handle database connections, providing much better performance than standard ODBC.The latest ROracle enhancements include: Support for Oracle TimesTen In-Memory Database Support for Date-Time using R's POSIXct/POSIXlt data types RAW, BLOB and BFILE data type support Option to specify number of rows per fetch operation Option to prefetch LOB data Break support using Ctrl-C Statement caching support Times Ten 11.2.2 contains enhanced support for analytics workloads and complex queries: Analytic functions: AVG, SUM, COUNT, MAX, MIN, DENSE_RANK, RANK, ROW_NUMBER, FIRST_VALUE and LAST_VALUE Analytic clauses: OVER PARTITION BY and OVER ORDER BY Multidimensional grouping operators: Grouping clauses: GROUP BY CUBE, GROUP BY ROLLUP, GROUP BY GROUPING SETS Grouping functions: GROUP, GROUPING_ID, GROUP_ID WITH clause, which allows repeated references to a named subquery block Aggregate expressions over DISTINCT expressions General expressions that return a character string in the source or a pattern within the LIKE predicate Ability to order nulls first or last in a sort result (NULLS FIRST or NULLS LAST in the ORDER BY clause) Note: Some functionality is only available with Oracle Exalytics, refer to the TimesTen product licensing document for details. Connecting to TimesTen is easy with ROracle. Simply install and load the ROracle package and load the driver. > install.packages("ROracle") > library(ROracle) Loading required package: DBI > drv <- dbDriver("Oracle") Once the ROracle package is installed, create a database connection object and connect to a TimesTen direct driver DSN as the OS user. > conn <- dbConnect(drv, username ="", password="", dbname = "localhost/SampleDb_1122:timesten_direct") You have the option to report the server type - Oracle or TimesTen? > print (paste ("Server type =", dbGetInfo (conn)$serverType)) [1] "Server type = TimesTen IMDB" To create tables in the database using R data frame objects, use the function dbWriteTable. In the following example we write the built-in iris data frame to TimesTen. The iris data set is a small example data set containing 150 rows and 5 columns. We include it here not to highlight performance, but so users can easily run this example in their R session. > dbWriteTable (conn, "IRIS", iris, overwrite=TRUE, ora.number=FALSE) [1] TRUE Verify that the newly created IRIS table is available in the database. To list the available tables and table columns in the database, use dbListTables and dbListFields, respectively. > dbListTables (conn) [1] "IRIS" > dbListFields (conn, "IRIS") [1] "SEPAL.LENGTH" "SEPAL.WIDTH" "PETAL.LENGTH" "PETAL.WIDTH" "SPECIES" To retrieve a summary of the data from the database we need to save the results to a local object. The following call saves the results of the query as a local R object, iris.summary. The ROracle function dbGetQuery is used to execute an arbitrary SQL statement against the database. When connected to TimesTen, the SQL statement is processed completely within main memory for the fastest response time. > iris.summary <- dbGetQuery(conn, 'SELECT SPECIES, AVG ("SEPAL.LENGTH") AS AVG_SLENGTH, AVG ("SEPAL.WIDTH") AS AVG_SWIDTH, AVG ("PETAL.LENGTH") AS AVG_PLENGTH, AVG ("PETAL.WIDTH") AS AVG_PWIDTH FROM IRIS GROUP BY ROLLUP (SPECIES)') > iris.summary SPECIES AVG_SLENGTH AVG_SWIDTH AVG_PLENGTH AVG_PWIDTH 1 setosa 5.006000 3.428000 1.462 0.246000 2 versicolor 5.936000 2.770000 4.260 1.326000 3 virginica 6.588000 2.974000 5.552 2.026000 4 <NA> 5.843333 3.057333 3.758 1.199333 Finally, disconnect from the TimesTen Database. > dbCommit (conn) [1] TRUE > dbDisconnect (conn) [1] TRUE We encourage you download Oracle software for evaluation from the Oracle Technology Network. See these links for our software: Times Ten In-Memory Database,  ROracle.  As always, we welcome comments and questions on the TimesTen and  Oracle R technical forums.

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  • Columnstore Case Study #1: MSIT SONAR Aggregations

    - by aspiringgeek
    Preamble This is the first in a series of posts documenting big wins encountered using columnstore indexes in SQL Server 2012 & 2014.  Many of these can be found in this deck along with details such as internals, best practices, caveats, etc.  The purpose of sharing the case studies in this context is to provide an easy-to-consume quick-reference alternative. Why Columnstore? If we’re looking for a subset of columns from one or a few rows, given the right indexes, SQL Server can do a superlative job of providing an answer. If we’re asking a question which by design needs to hit lots of rows—DW, reporting, aggregations, grouping, scans, etc., SQL Server has never had a good mechanism—until columnstore. Columnstore indexes were introduced in SQL Server 2012. However, they're still largely unknown. Some adoption blockers existed; yet columnstore was nonetheless a game changer for many apps.  In SQL Server 2014, potential blockers have been largely removed & they're going to profoundly change the way we interact with our data.  The purpose of this series is to share the performance benefits of columnstore & documenting columnstore is a compelling reason to upgrade to SQL Server 2014. App: MSIT SONAR Aggregations At MSIT, performance & configuration data is captured by SCOM. We archive much of the data in a partitioned data warehouse table in SQL Server 2012 for reporting via an application called SONAR.  By definition, this is a primary use case for columnstore—report queries requiring aggregation over large numbers of rows.  New data is refreshed each night by an automated table partitioning mechanism—a best practices scenario for columnstore. The Win Compared to performance using classic indexing which resulted in the expected query plan selection including partition elimination vs. SQL Server 2012 nonclustered columnstore, query performance increased significantly.  Logical reads were reduced by over a factor of 50; both CPU & duration improved by factors of 20 or more.  Other than creating the columnstore index, no special modifications or tweaks to the app or databases schema were necessary to achieve the performance improvements.  Existing nonclustered indexes were rendered superfluous & were deleted, thus mitigating maintenance challenges such as defragging as well as conserving disk capacity. Details The table provides the raw data & summarizes the performance deltas. Logical Reads (8K pages) CPU (ms) Durn (ms) Columnstore 160,323 20,360 9,786 Conventional Table & Indexes 9,053,423 549,608 193,903 ? x56 x27 x20 The charts provide additional perspective of this data.  "Conventional vs. Columnstore Metrics" document the raw data.  Note on this linear display the magnitude of the conventional index performance vs. columnstore.  The “Metrics (?)” chart expresses these values as a ratio. Summary For DW, reports, & other BI workloads, columnstore often provides significant performance enhancements relative to conventional indexing.  I have documented here, the first in a series of reports on columnstore implementations, results from an initial implementation at MSIT in which logical reads were reduced by over a factor of 50; both CPU & duration improved by factors of 20 or more.  Subsequent features in this series document performance enhancements that are even more significant. 

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  • Business Case for investing time developing Stubs and BizUnit Tests

    - by charlie.mott
    I was recently in a position where I had to justify why effort should be spent developing Stubbed Integration Tests for BizTalk solutions. These tests are usually developed using the BizUnit framework. I assumed that most seasoned BizTalk developers would consider this best practice. Even though Microsoft suggest use of BizUnit on MSDN, I've not found a single site listing the justifications for investing time writing stubs and BizUnit tests. Stubs Stubs should be developed to isolate your development team from external dependencies. This is described by Michael Stephenson here. Failing to do this can result in the following problems: In contract-first scenarios, the external system interface will have been defined.  But the interface may not have been setup or even developed yet for the BizTalk developers to work with. By the time you open the target location to see the data BizTalk has sent, it may have been swept away. If you are relying on the UI of the target system to see the data BizTalk has sent, what do you do if it fails to arrive? It may take time for the data to be processed or it may be scheduled to be processed later. Learning how to use the source\target systems and investigations into where things go wrong in these systems will slow down the BizTalk development effort. By the time the data is visible in a UI it may have undergone further transformations. In larger development teams working together, do you all use the same source and target instances. How do you know which data was created by whose tests? How do you know which event log error message are whose?  Another developer may have “cleaned up” your data. It is harder to write BizUnit tests that clean up the data\logs after each test run. What if your B2B partners' source or target system cannot support the sort of testing you want to do. They may not even have a development or test instance that you can work with. Their single test instance may be used by the SIT\UAT teams. There may be licencing costs of setting up an instances of the external system. The stubs I like to use are generic stubs that can accept\return any message type.  Usually I need to create one per protocol. They should be driven by BizUnit steps to: validates the data received; and select a response messages (or error response). Once built, they can be re-used for many integration tests and from project to project. I’m not saying that developers should never test against a real instance.  Every so often, you still need to connect to real developer or test instances of the source and target endpoints\services. The interface developers may ask you to send them some data to see if everything still works.  Or you might want some messages sent to BizTalk to get confidence that everything still works beyond BizTalk. Tests Automated “Stubbed Integration Tests” are usually built using the BizUnit framework. These facilitate testing of the entire integration process from source stub to target stub. It will ensure that all of the BizTalk components are configured together correctly to meet all the requirements. More fine grained unit testing of individual BizTalk components is still encouraged.  But BizUnit provides much the easiest way to test some components types (e.g. Orchestrations). Using BizUnit with the Behaviour Driven Development approach described by Mike Stephenson delivers the following benefits: source: http://biztalkbddsample.codeplex.com – Video 1. Requirements can be easily defined using Given/When/Then Requirements are close to the code so easier to manage as features and scenarios Requirements are defined in domain language The feature files can be used as part of the documentation The documentation is accurate to the build of code and can be published with a release The scenarios are effective to document the scenarios and are not over excessive The scenarios are maintained with the code There’s an abstraction between the intention and implementation of tests making them easier to understand The requirements drive the testing These same tests can also be used to drive load testing as described here. If you don't do this ... If you don't follow the above “Stubbed Integration Tests” approach, the developer will need to manually trigger the tests. This has the following risks: Developers are unlikely to check all the scenarios each time and all the expected conditions each time. After the developer leaves, these manual test steps may be lost. What test scenarios are there?  What test messages did they use for each scenario? There is no mechanism to prove adequate test coverage. A test team may attempt to automate integration test scenarios in a test environment through the triggering of tests from a source system UI. If this is a replacement for BizUnit tests, then this carries the following risks: It moves the tests downstream, so problems will be found later in the process. Testers may not check all the expected conditions within the BizTalk infrastructure such as: event logs, suspended messages, etc. These automated tests may also get in the way of manual tests run on these environments.

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  • Managing common code on Windows 7 (.NET) and Windows 8 (WinRT)

    - by ryanabr
    Recent announcements regarding Windows Phone 8 and the fact that it will have the WinRT behind it might make some of this less painful but I  discovered the "XmlDocument" object is in a new location in WinRT and is almost the same as it's brother in .NET System.Xml.XmlDocument (.NET) Windows.Data.Xml.Dom.XmlDocument (WinRT) The problem I am trying to solve is how to work with both types in the code that performs the same task on both Windows Phone 7 and Windows 8 platforms. The first thing I did was define my own XmlNode and XmlNodeList classes that wrap the actual Microsoft objects so that by using the "#if" compiler directive either work with the WinRT version of the type, or the .NET version from the calling code easily. public class XmlNode     { #if WIN8         public Windows.Data.Xml.Dom.IXmlNode Node { get; set; }         public XmlNode(Windows.Data.Xml.Dom.IXmlNode xmlNode)         {             Node = xmlNode;         } #endif #if !WIN8 public System.Xml.XmlNode Node { get; set ; } public XmlNode(System.Xml.XmlNode xmlNode)         {             Node = xmlNode;         } #endif     } public class XmlNodeList     { #if WIN8         public Windows.Data.Xml.Dom.XmlNodeList List { get; set; }         public int Count {get {return (int)List.Count;}}         public XmlNodeList(Windows.Data.Xml.Dom.XmlNodeList list)         {             List = list;         } #endif #if !WIN8 public System.Xml.XmlNodeList List { get; set ; } public int Count { get { return List.Count;}} public XmlNodeList(System.Xml.XmlNodeList list)         {             List = list;        } #endif     } From there I can then use my XmlNode and XmlNodeList in the calling code with out having to clutter the code with all of the additional #if switches. The challenge after this was the code that worked directly with the XMLDocument object needed to be seperate on both platforms since the method for populating the XmlDocument object is completly different on both platforms. To solve this issue. I made partial classes, one partial class for .NET and one for WinRT. Both projects have Links to the Partial Class that contains the code that is the same for the majority of the class, and the partial class contains the code that is unique to the version of the XmlDocument. The files with the little arrow in the lower left corner denotes 'linked files' and are shared in multiple projects but only exist in one location in source control. You can see that the _Win7 partial class is included directly in the project since it include code that is only for the .NET platform, where as it's cousin the _Win8 (not pictured above) has all of the code specific to the _Win8 platform. In the _Win7 partial class is this code: public partial class WUndergroundViewModel     { public static WUndergroundData GetWeatherData( double lat, double lng)         { WUndergroundData data = new WUndergroundData();             System.Net. WebClient c = new System.Net. WebClient(); string req = "http://api.wunderground.com/api/xxx/yesterday/conditions/forecast/q/[LAT],[LNG].xml" ;             req = req.Replace( "[LAT]" , lat.ToString());             req = req.Replace( "[LNG]" , lng.ToString()); XmlDocument doc = new XmlDocument();             doc.Load(c.OpenRead(req)); foreach (XmlNode item in doc.SelectNodes("/response/features/feature" ))             { switch (item.Node.InnerText)                 { case "yesterday" :                         ParseForecast( new FishingControls.XmlNodeList (doc.SelectNodes( "/response/forecast/txt_forecast/forecastdays/forecastday" )), new FishingControls.XmlNodeList (doc.SelectNodes( "/response/forecast/simpleforecast/forecastdays/forecastday" )), data); break ; case "conditions" :                         ParseCurrent( new FishingControls.XmlNode (doc.SelectSingleNode("/response/current_observation" )), data); break ; case "forecast" :                         ParseYesterday( new FishingControls.XmlNodeList (doc.SelectNodes( "/response/history/observations/observation" )),data); break ;                 }             } return data;         }     } in _win8 partial class is this code: public partial class WUndergroundViewModel     { public async static Task< WUndergroundData > GetWeatherData(double lat, double lng)         { WUndergroundData data = new WUndergroundData (); HttpClient c = new HttpClient (); string req = "http://api.wunderground.com/api/xxxx/yesterday/conditions/forecast/q/[LAT],[LNG].xml" ;             req = req.Replace( "[LAT]" , lat.ToString());             req = req.Replace( "[LNG]" , lng.ToString()); HttpResponseMessage msg = await c.GetAsync(req); string stream = await msg.Content.ReadAsStringAsync(); XmlDocument doc = new XmlDocument ();             doc.LoadXml(stream, null); foreach ( IXmlNode item in doc.SelectNodes("/response/features/feature" ))             { switch (item.InnerText)                 { case "yesterday" :                         ParseForecast( new FishingControls.XmlNodeList (doc.SelectNodes( "/response/forecast/txt_forecast/forecastdays/forecastday" )), new FishingControls.XmlNodeList (doc.SelectNodes( "/response/forecast/simpleforecast/forecastdays/forecastday" )), data); break; case "conditions" :                         ParseCurrent( new FishingControls.XmlNode (doc.SelectSingleNode("/response/current_observation" )), data); break; case "forecast" :                         ParseYesterday( new FishingControls.XmlNodeList (doc.SelectNodes( "/response/history/observations/observation")), data); break;                 }             } return data;         }     } Summary: This method allows me to have common 'business' code for both platforms that is pretty clean, and I manage the technology differences separately. Thank you tostringtheory for your suggestion, I was considering that approach.

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  • How much is a subscriber worth?

    - by Tom Lewin
    This year at Red Gate, we’ve started providing a way to back up SQL Azure databases and Azure storage. We decided to sell this as a service, instead of a product, which means customers only pay for what they use. Unfortunately for us, it makes figuring out revenue much trickier. With a product like SQL Compare, a customer pays for it, and it’s theirs for good. Sure, we offer support and upgrades, but, fundamentally, the sale is a simple, upfront transaction: we’ve made this product, you need this product, we swap product for money and everyone is happy. With software as a service, it isn’t that easy. The money and product don’t change hands up front. Instead, we provide a service in exchange for a recurring fee. We know someone buying SQL Compare will pay us $X, but we don’t know how long service customers will stay with us, or how much they will spend. How do we find this out? We use lifetime value analysis. What is lifetime value? Lifetime value, or LTV, is how much a customer is worth to the business. For Entrepreneurs has a brilliant write up that we followed to conduct our analysis. Basically, it all boils down to this equation: LTV = ARPU x ALC To make it a bit less of an alphabet-soup and a bit more understandable, we can write it out in full: The lifetime value of a customer equals the average revenue per customer per month, times the average time a customer spends with the service Simple, right? A customer is worth the average spend times the average stay. If customers pay on average $50/month, and stay on average for ten months, then a new customer will, on average, bring in $500 over the time they are a customer! Average spend is easy to work out; it’s revenue divided by customers. The problem comes when we realise that we don’t know exactly how long a customer will stay with us. How can we figure out the average lifetime of a customer, if we only have six months’ worth of data? The answer lies in the fact that: Average Lifetime of a Customer = 1 / Churn Rate The churn rate is the percentage of customers that cancel in a month. If half of your customers cancel each month, then your average customer lifetime is two months. The problem we faced was that we didn’t have enough data to make an estimate of one month’s cancellations reliable (because barely anybody cancels)! To deal with this data problem, we can take data from the last three months instead. This means we have more data to play with. We can still use the equation above, we just need to multiply the final result by three (as we worked out how many three month periods customers stay for, and we want our answer to be in months). Now these estimates are likely to be fairly unreliable; when there’s not a lot of data it pays to be cautious with inference. That said, the numbers we have look fairly consistent, and it’s super easy to revise our estimates when new data comes in. At the very least, these numbers give us a vague idea of whether a subscription business is viable. As far as Cloud Services goes, the business looks very viable indeed, and the low cancellation rates are much more than just data points in LTV equations; they show that the product is working out great for our customers, which is exactly what we’re looking for!

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  • Application Logging needs work

    Application Logging Application logging is the act of logging events that occur within an application much like how a court report documents what happens in court case. Application logs can be useful for several reasons, but the most common use for logs is to recreate steps to find the root cause of applications errors. Other uses can include the detection of Fraud, verification of user activity, or provide audits on user/data interactions. “Logs can contain different kinds of data. The selection of the data used is normally affected by the motivation leading to the logging. “ (OWASP, 2009) OWASP also stats that logging include applicable debugging information like the event date time, responsible process, and a description of the event. “There are many reasons why a logging system is a necessary part of delivering a distributed application. One of the most important is the ability to track exactly how many users are using the application during different time periods.” (Hatton, 2000) Hatton also states that application logging helps system designers determine whether parts of an application aren't being used as designed. He implies that low usage can be used to identify if users like or do not like aspects of a system based on user usage of the application. This enables application designers to extract why users don't like aspects of an application so that changes can be made to increase its usefulness and effectiveness. “Logging memory usage can also assist you in tuning up the internals of your application. If you're experiencing a randomly occurring problem, being able to match activities performed with the memory status at the time may enable you to discover the cause of the problem. It also gives you a good indication of the health of the distributed server machine at the time any activity is performed. “ (Hatton, 2000) Commonly Logged Application Events (Defined by OWASP) Access of Data Creation of Data Modification of Data in any form Administrative Functions  Configuration Changes Debugging Information(Application Events)  Authorization Attempts  Data Deletion Network Communication  Authentication Events  Errors/Exceptions Application Error Logging The functionality associated with application error logging is actually the combination of proper error handling and applications logging.  If we look back at Figure 4 and Figure 5, these code examples allow developers to handle various types of errors that occur within the life cycle of an application’s execution. Application logging can be applied within the Catch section of the TryCatch statement allowing for the errors to be logged when they occur. By placing the logging within the Catch section specific error details can be accessed that help identify the source of the error, the path to the error, what caused the error and definition of the error that occurred. This can then be logged and reviewed at a later date in order recreate the error that was received based data found in the application log. By allowing applications to log errors developers IT staff can use them to recreate errors that are encountered by end-users or other dependent systems.

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  • Where are my date ranges in Analytics coming from?

    - by Jeffrey McDaniel
    In the P6 Reporting Database there are two main tables to consider when viewing time - W_DAY_D and W_Calendar_FS.  W_DAY_D is populated internally during the ETL process and will provide a row for every day in the given time range. Each row will contain aspects of that day such as calendar year, month, week, quarter, etc. to allow it to be used in the time element when creating requests in Analytics to group data into these time granularities. W_Calendar_FS is used for calculations such as spreads, but is also based on the same set date range. The min and max day_dt (W_DAY_D) and daydate (W_Calendar_FS) will be related to the date range defined, which is a start date and a rolling interval plus a certain range. Generally start date plus 3 years.  In P6 Reporting Database 2.0 this date range was defined in the Configuration utility.  As of P6 Reporting Database 3.0, with the introduction of the Extended Schema this date range is set in the P6 web application. The Extended Schema uses this date range to calculate the data for near real time reporting in P6.  This same date range is validated and used for the P6 Reporting Database.  The rolling date range means if today is April 1, 2010 and the rolling interval is set to three years, the min date will be 1/1/2010 and the max date will be 4/1/2013.  1/1/2010 will be the min date because we always back fill to the beginning of the year. On April 2nd, the Extended schema services are run and the date range is adjusted there to move the max date forward to 4/2/2013.  When the ETL process is run the Reporting Database will pick up this change and also adjust the max date on the W_DAY_D and W_Calendar_FS. There are scenarios where date ranges affecting areas like resource limit may not be adjusted until a change occurs to cause a recalculation, but based on general system usage these dates in these tables will progress forward with the rolling intervals. Choosing a large date range can have an effect on the ETL process for the P6 Reporting Database. The extract portion of the process will pull spread data over into the STAR. The date range defines how long activity and resource assignment spread data is spread out in these tables. If an activity lasts 5 days it will have 5 days of spread data. If a project lasts 5 years, and the date range is 3 years the spread data after that 3 year date range will be bucketed into the last day in the date range. For the overall project and even the activity level you will still see the correct total values.  You just would not be able to see the daily spread 5 years from now. This is an important question when choosing your date range, do you really need to see spread data down to the day 5 years in the future?  Generally this amount of granularity years in the future is not needed. Remember all those values 5, 10, 15, 20 years in the future are still available to report on they would be in more of a summary format on the activity or project.  The data is always there, the level of granularity is the decision.

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  • Local LINQtoSQL Database For Your Windows Phone 7 Application

    - by Tim Murphy
    There aren’t many applications that are of value without having some for of data store.  In Windows Phone development we have a few options.  You can store text directly to isolated storage.  You can also use a number of third party libraries to create or mimic databases in isolated storage.  With Mango we gained the ability to have a native .NET database approach which uses LINQ to SQL.  In this article I will try to bring together the components needed to implement this last type of data store and fill in some of the blanks that I think other articles have left out. Defining A Database The first things you are going to need to do is define classes that represent your tables and a data context class that is used as the overall database definition.  The table class consists of column definitions as you would expect.  They can have relationships and constraints as with any relational DBMS.  Below is an example of a table definition. First you will need to add some assembly references to the code file. using System.ComponentModel;using System.Data.Linq;using System.Data.Linq.Mapping; You can then add the table class and its associated columns.  It needs to implement INotifyPropertyChanged and INotifyPropertyChanging.  Each level of the class needs to be decorated with the attribute appropriate for that part of the definition.  Where the class represents the table the properties represent the columns.  In this example you will see that the column is marked as a primary key and not nullable with a an auto generated value. You will also notice that the in the column property’s set method It uses the NotifyPropertyChanging and NotifyPropertyChanged methods in order to make sure that the proper events are fired. [Table]public class MyTable: INotifyPropertyChanged, INotifyPropertyChanging{ public event PropertyChangedEventHandler PropertyChanged; private void NotifyPropertyChanged(string propertyName) { if(PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } public event PropertyChangingEventHandler PropertyChanging; private void NotifyPropertyChanging(string propertyName) { if(PropertyChanging != null) { PropertyChanging(this, new PropertyChangingEventArgs(propertyName)); } } private int _TableKey; [Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)] public int TableKey { get { return _TableKey; } set { NotifyPropertyChanging("TableKey"); _TableKey = value; NotifyPropertyChanged("TableKey"); } } The last part of the database definition that needs to be created is the data context.  This is a simple class that takes an isolated storage location connection string its constructor and then instantiates tables as public properties. public class MyDataContext: DataContext{ public MyDataContext(string connectionString): base(connectionString) { MyRecords = this.GetTable<MyTable>(); } public Table<MyTable> MyRecords;} Creating A New Database Instance Now that we have a database definition it is time to create an instance of the data context within our Windows Phone app.  When your app fires up it should check if the database already exists and create an instance if it does not.  I would suggest that this be part of the constructor of your ViewModel. db = new MyDataContext(connectionString);if(!db.DatabaseExists()){ db.CreateDatabase();} The next thing you have to know is how the connection string for isolated storage should be constructed.  The main sticking point I have found is that the database cannot be created unless the file mode is read/write.  You may have different connection strings but the initial one needs to be similar to the following. string connString = "Data Source = 'isostore:/MyApp.sdf'; File Mode = read write"; Using you database Now that you have done all the up front work it is time to put the database to use.  To make your life a little easier and keep proper separation between your view and your viewmodel you should add a couple of methods to the viewmodel.  These will do the CRUD work of your application.  What you will notice is that the SubmitChanges method is the secret sauce in all of the methods that change data. private myDataContext myDb;private ObservableCollection<MyTable> _viewRecords;public ObservableCollection<MyTable> ViewRecords{ get { return _viewRecords; } set { _viewRecords = value; NotifyPropertyChanged("ViewRecords"); }}public void LoadMedstarDbData(){ var tempItems = from MyTable myRecord in myDb.LocalScans select myRecord; ViewRecords = new ObservableCollection<MyTable>(tempItems);}public void SaveChangesToDb(){ myDb.SubmitChanges();}public void AddMyTableItem(MyTable newScan){ myDb.LocalScans.InsertOnSubmit(newScan); myDb.SubmitChanges();}public void DeleteMyTableItem(MyTable newScan){ myDb.LocalScans.DeleteOnSubmit(newScan); myDb.SubmitChanges();} Updating existing database What happens when you need to change the structure of your database?  Unfortunately you have to add code to your application that checks the version of the database which over time will create some pollution in your codes base.  On the other hand it does give you control of the update.  In this example you will see the DatabaseSchemaUpdater in action.  Assuming we added a “Notes” field to the MyTable structure, the following code will check if the database is the latest version and add the field if it isn’t. if(!myDb.DatabaseExists()){ myDb.CreateDatabase();}else{ DatabaseSchemaUpdater dbUdater = myDb.CreateDatabaseSchemaUpdater(); if(dbUdater.DatabaseSchemaVersion < 2) { dbUdater.AddColumn<MyTable>("Notes"); dbUdater.DatabaseSchemaVersion = 2; dbUdater.Execute(); }} Summary This approach does take a fairly large amount of work, but I think the end product is robust and very native for .NET developers.  It turns out to be worth the investment. del.icio.us Tags: Windows Phone,Windows Phone 7,LINQ to SQL,LINQ,Database,Isolated Storage

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  • ADSL throughput loss from Reed-Solomon encoding

    - by javano
    I'm reading about ADSL starting here and I am confused by how the Reed-Solomon encoding for ECC is limiting the available transfer rate, as much as it does (nearly half). This pdf on the same subject contains the following; A maximum of 255 sub-carriers can be used to modulate data in the downstream direction. Sub-carrier 256, the downstream Nyquist frequency, and sub-carrier 64, the downstream pilot frequency, are not available for user data, thus limiting the total number of available downstream sub-carriers to 254. Each of these 254 sub-carriers can support the modulation of 0 to 15 bits. Since the ADSL DMT data frame rate is 4000 frames per second, the maximum theoretical downstream data rate of an ADSL system is 15.24Mbps. Due to limitations in system architecture, specifically the maximum allowable Reed-Solomon codeword size (255 bytes), the maximum achievable downstream data rate is 8.16Mbps. How is this nearly halving the throughput? Is all that extra bandwidth overhead of the RS encoding? 15240000 bps (15.24Mbps) - 8160000 bps (8.12Mbps) = 7080000 bps (7.08Mbps). Where has that 7Mbps of throughput gone? EDIT: I tried to read the wiki page on Reed-Soloman but it's all crazy maths and algerbra, which I don't understand. I can understand that data is split into 255 byte codewords, because that maybe the max codeword size whilst still maintaining accuracy during transmission; But I don't understand why that means less data is sent?

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  • nginx + wordpress in /wordpress subdir

    - by nkr1pt
    I installed nginx and would like to setup wordpress as a final step. I followed many howtos but am unable to get it working. The setup is fairly straightforward, the root dir of the webserver is /data/Sites/nkr1pt.homelinux.net. In that root dir I created a symlink to the wordpress folder in /usr/local/wordpress, so in fact all wordpress files can be accessed at /data/Sites/nkr1pt.homelinux.net/wordpress. Permissions are ok. The plan is to get wordpress working at http://sirius/wordpress, the server's name is sirius. spawn-fcgi is running and listening on port 7777. Here you can see the relevant config: server { listen 80; listen 8080; server_name sirius; root /data/Sites/nkr1pt.homelinux.net; passenger_enabled on; passenger_base_uri /redmine; #charset koi8-r; #access_log logs/access.log main; location ^~ /data { root /data/Sites/nkr1pt.homelinux.net; autoindex on; auth_basic "Restricted"; auth_basic_user_file htpasswd; } location ^~ /dump { root /data/Sites/nkr1pt.homelinux.net; autoindex on; } location ^~ /wordpress { try_files $uri $uri/ /wordpress/index.php; } # pass the PHP scripts to FastCGI server listening on 127.0.0.1:7777 location ~ \.php$ { #fastcgi_split_path_info ^(/wordpress)(/.*)$; fastcgi_pass localhost:7777; #fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; #index index.php; } please note that redmine, and the locations dump and data are working perfectly, it is only wordpress that I cannot get to work. Can you please help me to the correct wordpress configuration in nginx? All help is much appreciated!

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  • Why does Mysql Xampp restart only when i run the mysqld.exe file manually?

    - by Ranjit Kumar
    I am using mysql-xampp v3.0.2 version. while restarting the mysql server first it show me the running status and after 2or3s it stops running automatically. So as of now i got a temporary solution like going into xampp installation folder Xampp-mysql-bin-running the msqld.exe file. i dont know whether it is the correct solution or is there any alternate solution to be made !! please suggest me errorlog 120629 15:29:59 [Note] Plugin 'FEDERATED' is disabled. 120629 15:29:59 InnoDB: The InnoDB memory heap is disabled 120629 15:29:59 InnoDB: Mutexes and rw_locks use Windows interlocked functions 120629 15:29:59 InnoDB: Compressed tables use zlib 1.2.3 120629 15:29:59 InnoDB: Initializing buffer pool, size = 16.0M 120629 15:29:59 InnoDB: Completed initialization of buffer pool InnoDB: The first specified data file D:\xampp\xampp\mysql\data\ibdata1 did not exist: InnoDB: a new database to be created! 120629 15:29:59 InnoDB: Setting file D:\xampp\xampp\mysql\data\ibdata1 size to 10 MB InnoDB: Database physically writes the file full: wait... 120629 15:29:59 InnoDB: Log file D:\xampp\xampp\mysql\data\ib_logfile0 did not exist: new to be created InnoDB: Setting log file D:\xampp\xampp\mysql\data\ib_logfile0 size to 5 MB InnoDB: Database physically writes the file full: wait... 120629 15:30:00 InnoDB: Log file D:\xampp\xampp\mysql\data\ib_logfile1 did not exist: new to be created InnoDB: Setting log file D:\xampp\xampp\mysql\data\ib_logfile1 size to 5 MB InnoDB: Database physically writes the file full: wait... InnoDB: Doublewrite buffer not found: creating new InnoDB: Doublewrite buffer created InnoDB: 127 rollback segment(s) active. InnoDB: Creating foreign key constraint system tables InnoDB: Foreign key constraint system tables created 120629 15:30:02 InnoDB: Waiting for the background threads to start

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  • PostgreSQL failover cluster on Windows Server

    - by user36997
    We are looking for advice on how to setup a basic failover cluster for our application: We will be using 4 machines running Microsoft Windows Server (most probably 2003). All four will always run our application, which is essentially a web service. Load balancing is "outsourced" - somebody else handles the distribution of the web requests among the servers. Only one of the servers will be running the PostgreSQL server actively at any given time. Another server (of the four) also has the DB installed, but is on standby/passive. The DB data is stored on shared storage. No copying data between servers. Reads are done very frequently by many end-users, and in rather small chunks of data. Writes are done much less frequently, by less users, and in very large bulks of data. Now, how can one configure Microsoft Cluster Service to keep only one instance of the DB server and 4 instances (1 per server) of our application at all times? And does PostgreSQL integrate neatly with MSCS at all? Update: Instead of keeping the data on shared storage, I also consider using log shipping to replicate data on a couple of DB servers. There are two issues with this option: Log shipping only makes sure that I have a second server that gets all of the data and is ready to take over. How do I implement the actual failure detection and failover switch? Switching back: Suppose the master fails and the system automatically fails over to the slave, and later the master comes back online. I understand that with WAL shipping this will require to reconfigure the log shipping once again, and that switching back is far from seamless. Is that so?

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  • OpenVPN bad source address from client

    - by Bogdan
    I have one problem with OpenVPN. There are a lot drops records in the openvpn log file on the server: Mon Oct 22 10:14:41 2012 us=726541 laptop/???:1194 MULTI: bad source address from client [192.168.1.107], packet dropped grep -E "^[a-z]" server.conf ----- port 1194 proto udp dev tun ca data/ca.crt cert data/server.crt key data/server.key dh data/dh1024.pem tls-server tls-auth data/ta.key 0 remote-cert-tls client cipher AES-256-CBC tun-mtu 1200 server 10.10.10.0 255.255.255.0 ifconfig-pool-persist ipp.txt push "redirect-gateway def1 bypass-dhcp" push "dhcp-option DNS 8.8.8.8" client-to-client client-config-dir /etc/openvpn/ccd route 10.10.10.0 255.255.255.0 keepalive 10 120 comp-lzo persist-key persist-tun max-clients 5 status /var/log/status-openvpn.log log /var/log/openvpn.log verb 4 auth-user-pass-verify /etc/openvpn/verify.sh via-file tmp-dir /tmp script-security 2 ----- cat ccd/laptop ----- iroute 10.10.10.0 255.255.255.0 ----- cat client.conf ----- remote server ip 1194 client dev tun ping 10 comp-lzo proto udp tls-client tls-auth data/ta.key 1 pkcs12 data/vpn.laptop.p12 remote-cert-tls server #ns-cert-type server persist-key persist-tun cipher AES-256-CBC verb 3 pull auth-user-pass /home/user/.openvpn/users.db ----- According to "Jan Just Keijser - OpenVPN 2 Cookbook" root of the problem is incorrect config options.see the screenshot But, as you see, my config has such options. Could you please help me to solve this problem. @week Verb leverl=6; client log. Mon Oct 22 16:06:02 2012 do_ifconfig, tt->ipv6=0, tt->did_ifconfig_ipv6_setup=0 Mon Oct 22 16:06:02 2012 /sbin/ifconfig tun0 10.10.10.3 pointopoint 10.10.10.5 mtu 1500 Mon Oct 22 16:06:02 2012 /sbin/route add -net xxxx netmask 255.255.255.255 gw 192.168.1.1 Mon Oct 22 16:06:02 2012 /sbin/route add -net 0.0.0.0 netmask 128.0.0.0 gw 10.10.10.5 Mon Oct 22 16:06:02 2012 /sbin/route add -net 128.0.0.0 netmask 128.0.0.0 gw 10.10.10.5 Mon Oct 22 16:06:02 2012 Initialization Sequence Completed cat ccd/latop iroute 10.10.10.0 255.255.255.0 ifconfig-push 10.10.10.3 10.10.10.5

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  • How do I solve this error: ssh_exchange_identification: Connection closed by remote host

    - by bernie
    data@server01:~$ ssh [email protected] -vvv OpenSSH_5.5p1 Debian-6, OpenSSL 0.9.8o 01 Jun 2010 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to 10.7.4.1 [10.7.4.1] port 22. debug1: Connection established. debug3: Not a RSA1 key file /home/data/.ssh/id_rsa. debug2: key_type_from_name: unknown key type '-----BEGIN' debug3: key_read: missing keytype debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug2: key_type_from_name: unknown key type '-----END' debug3: key_read: missing keytype debug1: identity file /home/data/.ssh/id_rsa type 1 debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048 debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048 debug1: identity file /home/data/.ssh/id_rsa-cert type -1 debug1: identity file /home/data/.ssh/id_dsa type -1 debug1: identity file /home/data/.ssh/id_dsa-cert type -1 ssh_exchange_identification: Connection closed by remote host

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  • Linux commands shows different results

    - by ClydeFrog
    I'm really having a hard time to process these results on my Ubuntu server. I have a major problem with my JBoss server where I get FileNotFoundExceptions along with "No space left on device" errors. And I thought "maybe I'm out of disk space", and used df command to figure out how much I have left: root@ubuntu1:/# df -h Filsystem Storlek Anvnt Tillg Anv% Monterat på /dev/mapper/ubuntu1-root 36G 13G 21G 38% / none 2,0G 192K 2,0G 1% /dev none 2,0G 0 2,0G 0% /dev/shm none 2,0G 64K 2,0G 1% /var/run none 2,0G 0 2,0G 0% /var/lock /dev/sda1 228M 23M 193M 11% /boot /dev/mapper/vgdata-lvdata 79G 9,2G 66G 13% /data And as you can see, I have plenty of space left. And I also checked if I'm out of i-nodes: root@ubuntu1:/# df -i Filsystem Inoder IAnv IFria IAnv% Monterat på /dev/mapper/ubuntu1-root 2346512 61992 2284520 3% / none 505380 773 504607 1% /dev none 507383 1 507382 1% /dev/shm none 507383 30 507353 1% /var/run none 507383 2 507381 1% /var/lock /dev/sda1 124496 230 124266 1% /boot /dev/mapper/vgdata-lvdata 10486784 233945 10252839 3% /data But then i used du: root@ubuntu1:/# du -s -h /* 7,5M /bin 23M /boot 19G /data 192K /dev 11G /eniro 5,3M /etc 112K /home 0 /initrd.img 183M /lib 0 /lib64 16K /lost+found 12K /media 4,0K /mnt 4,0K /opt du: kan inte komma åt "/proc/20452/task/20452/fd/3": Filen eller katalogen finns inte du: kan inte komma åt "/proc/20452/task/20452/fdinfo/3": Filen eller katalogen finns inte du: kan inte komma åt "/proc/20452/fd/3": Filen eller katalogen finns inte du: kan inte komma åt "/proc/20452/fdinfo/3": Filen eller katalogen finns inte 0 /proc 18M /root 8,2M /sbin 4,0K /selinux 8,0K /srv 0 /sys 40K /tmp 691M /usr 1,2G /var 0 /vmlinuz Notice that /data and /eniro are 30G combined! How is it possible? Do I have a memory leak somewhere? Or is it something else? ----- EDIT 1 ----- Ok, I figured out that /data has its own mount so it's not possible to combine /data and /eniro because they aren't on the same mount. But how come it says 9,2G on the first command when it says 19G on the third on directory /data?

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  • Copy one db diagram from one db to another on different servers? (Same db)

    - by sah302
    I used the copy database wizard to copy my database from our test server to our production server, the database copied everything fine except for the diagram. Okay no problem, first I make sure the target database on production has the support objects created to use database diagraming. Then I select to import data from the other database and chose the dbo.sysdiagrams.Go through with the rest of the import data wizard, but then I get the following error: Validating (Error) Messages Error 0xc0202049: Data Flow Task: Failure inserting into the read-only column "diagram_id". (SQL Server Import and Export Wizard) Error 0xc0202045: Data Flow Task: Column metadata validation failed. (SQL Server Import and Export Wizard) Error 0xc004706b: Data Flow Task: "component "Destination - sysdiagrams" (31)" failed validation and returned validation status "VS_ISBROKEN". (SQL Server Import and Export Wizard) Error 0xc004700c: Data Flow Task: One or more component failed validation. (SQL Server Import and Export Wizard) Error 0xc0024107: Data Flow Task: There were errors during task validation. (SQL Server Import and Export Wizard) So apparently it didn't like that. What's the problem? I am pretty beginner in SQL Server and only do stuff via the GUI usually so am not sure what to do at this point. The databases are the same, but on different servers. Thanks!

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  • How do I collect SNMP readings from intermittently-connected sites?

    - by Luke404
    I am collecting SNMP data on-site for a number of systems, currently using Cacti. These systems are spread on a number of sites that aren't always connected to internet, but I also need to centralize the data on a single system (datacenter housed server) and get graphs out of it. If I directly poll remote systems with a centralized Cacti I'd loose data when a site is not connected to internet. I should record data on-site (I have a server at each site and I can run whatever I want on it) and then 'sync' everything to the central system. One hack could be a cacti or directly an rrdtool on site and then periodically rsync RRD data to the central Cacti system, but that doesn't sound like a 'clean' solution: every RRD would have to be defined at both places and rsync scripts setup with the specific file names. Can you suggest a better solution? Cacti is not a requirement but I'd like to use something like that on the central system. On-site systems need only to collect data I don't need to graph it there or manage users rights to view data and stuff like that, users will only access the centralized system.

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  • How to access previous VHD versions of system backup?

    - by feklee
    Quote from the 31 Oct 2009 TechNet article "Learn more about system image backup": During the first backup, the backup engine scans the source drive and copies only blocks that contain data into a .vhd file stored on the target, creating a compact view of the source drive. The next time a system image is created, only new and changed data is written to the .vhd file, and old data on the same block is moved out of the VHD and into the shadow copy storage area. Volume Shadow Copy Service is used to compute the changed data between backups, as well as to handle the process of moving the old data out to the shadow copy area on the target. This approach makes the backup fast (since only changed blocks are backed up) and efficient (since data is stored in a compact manner). When restoring the image, blocks will be restored to their original locations on the source disk. If you want to restore from an older backup, the engine reads from the shadow copy area and restores the appropriate blocks. For the last days, a daily system backup of drive C: to drive E: has been scheduled and run by Windows 7 Backup and Restore. Drive C: currently holds 233 GB of data, which fits comfortably on drive E:, a 1 TB drive, with 727 GB of free space remaining. How do I access the previous version of a VHD? I right clicked on files and folders in E:\WindowsImageBackup, and I looked for Previous Versions but always: There are no previous versions available

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  • How to import a text file into powershell and email it, formatted as HTML

    - by Don
    I'm trying to get a list of all Exchange accounts, format them in descending order from largest mailbox and put that data into an email in HTML format to email to myself. So far I can get the data, push it to a text file as well as create an email and send to myself. I just can't seem to get it all put together. I've been trying to use ConvertTo-Html but it just seems to return data via email like "pageFooterEntry" and "Microsoft.PowerShell.Commands.Internal.Format.AutosizeInfo" versus the actual data. I can get it to send me the right data if i don't tell it to ConvertTo-Html, just have it pipe the data to a text file and pull from it, but it's all ran together with no formatting. I don't need to save the file, i'd just like to run the command, get the data, put it in HTML and mail it to myself. Here's what I have currently: #Connects to Database and returns information on all users, organized by Total Item Size, User $body = Get-MailboxStatistics -database "Mailbox Database 0846468905" | where {$_.ObjectClass -eq “Mailbox”} | Sort-Object TotalItemSize -Descending | ft @{label=”User”;expression={$_.DisplayName}},@{label=”Total Size (MB)”;expression={$_.TotalItemSize.Value.ToMB()}} -auto | ConvertTo-Html #Pause for 5 seconds for Exchange write-host -foregroundcolor Green "Pausing for 5 seconds for Exchange" Start-Sleep -s 5 $toemail = "[email protected]" # Emails report to this address. $fromemail = "[email protected]" #Emails from this address. $server = "Exchange.company.com" #Exchange server - SMTP. #Email the report. $email = New-Object System.Net.Mail.MailMessage $email.IsBodyHtml = $True $email.To.Add($toemail) $email.From = $fromemail $email.Subject = "Exchange Mailbox Sizes" $email.Body = $body $client = New-Object System.Net.Mail.SmtpClient $server $client.UseDefaultCredentials = $true $client.Send($email) Any thoughts would be helpful, thanks!

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