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  • MySQL Cluster 7.3: On-Demand Webinar and Q&A Available

    - by Mat Keep
    The on-demand webinar for the MySQL Cluster 7.3 Development Release is now available. You can learn more about the design, implementation and getting started with all of the new MySQL Cluster 7.3 features from the comfort and convenience of your own device, including: - Foreign Key constraints in MySQL Cluster - Node.js NoSQL API  - Auto-installation of higher performance distributed, clusters We received some great questions over the course of the webinar, and I wanted to share those for the benefit of a broader audience. Q. What Foreign Key actions are supported: A. The core referential actions defined in the SQL:2003 standard are implemented: CASCADE RESTRICT NO ACTION SET NULL Q. Where are Foreign Keys implemented, ie data nodes or SQL nodes? A. They are implemented in the data nodes, therefore can be enforced for both the SQL and NoSQL APIs Q. Are they compatible with the InnoDB Foreign Key implementation? A. Yes, with the following exceptions: - InnoDB doesn’t support “No Action” constraints, MySQL Cluster does - You can choose to suspend FK constraint enforcement with InnoDB using the FOREIGN_KEY_CHECKS parameter; at the moment, MySQL Cluster ignores that parameter. - You cannot set up FKs between 2 tables where one is stored using MySQL Cluster and the other InnoDB. - You cannot change primary keys through the NDB API which means that the MySQL Server actually has to simulate such operations by deleting and re-adding the row. If the PK in the parent table has a FK constraint on it then this causes non-ideal behaviour. With Restrict or No Action constraints, the change will result in an error. With Cascaded constraints, you’d want the rows in the child table to be updated with the new FK value but, the implicit delete of the row from the parent table would remove the associated rows from the child table and the subsequent implicit insert into the parent wouldn’t reinstate the child rows. For this reason, an attempt to add an ON UPDATE CASCADE where the parent column is a primary key will be rejected. Q. Does adding or dropping Foreign Keys cause downtime due to a schema change? A. Nope, this is an online operation. MySQL Cluster supports a number of on-line schema changes, ie adding and dropping indexes, adding columns, etc. Q. Where can I see an example of node.js with MySQL Cluster? A. Check out the tutorial and download the code from GitHub Q. Can I use the auto-installer to support remote deployments? How about setting up MySQL Cluster 7.2? A. Yes to both! Q. Can I get a demo Check out the tutorial. You can download the code from http://labs.mysql.com/ Go to Select Build drop-down box Q. What is be minimum internet speen required for Geo distributed cluster with synchronous replication? A. if you're splitting you cluster between sites then we recommend a network latency of 20ms or less. Alternatively, use MySQL asynchronous replication where the latency of your WAN doesn't impact the latency of your reads/writes. Q. Where you can one learn more about the PayPal project with MySQL Cluster? A. Take a look at the following - you'll find press coverage, a video and slides from their keynote presentation  So, if you want to learn more, listen to the new MySQL Cluster 7.3 on-demand webinar  MySQL Cluster 7.3 is still in the development phase, so it would be great to get your feedback on these new features, and things you want to see!

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  • Oracle OpenWorld Update: Oracle GoldenGate for High Availability

    - by Doug Reid
    0 false 18 pt 18 pt 0 0 false false false /* 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-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:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} One of our primary themes this year for the Oracle OpenWorld Sessions featuring Oracle GoldenGate is High Availability. This is a pretty wide theme, but the focus will be on ways of maximizing uptime for critical systems during planned and unplanned events. We have a number of very informative sessions dedicated to exploring this theme in detail; from deep product implementation strategies up to lessons learned by our customers when using Oracle GoldenGate to meet strict SLAs. We kick this track off with our Customer Panel on Zero Downtime Operations on Monday, which I overviewed in my last posting. This is followed by Comcast, who will be hosting a sessions at 1:45PM in Moscone West 3014. Their session will discuss using Oracle GoldenGate to reduce downtime during a database upgrade. Here’s an overview: CON8571 - Oracle Database Upgrade with Oracle GoldenGate: Best Practices from Comcast Does your business demand high availability? In this session, Comcast, among the largest telecom firms in the world, shares tips on how to achieve zero downtime while upgrading to Oracle Database 11g Release 2, using a combination of Oracle technologies: Oracle Real Application Clusters (Oracle RAC), Oracle Database’s Grid Infrastructure and Oracle Recovery Manager (Oracle RMAN) features, Oracle GoldenGate, and Oracle Active Data Guard. This successful upgrade took place on a mission-critical system that handles more than 60 million business requests and service calls a day. You’ll also hear how Comcast leverages Oracle Advanced Customer Support Services, including an Oracle Solution Support Center, to maximize performance and availability of its Oracle technologies. On Tuesday, Joydip Kundu (Director of Software Development) will be presenting “Oracle GoldenGate and Oracle Data Guard: Working Together Seamlessly” at 10:15AM in Moscone South 3005. This session focuses on how both modes of Oracle GoldenGate extract (Classic and Integrated Capture) can be used with Oracle Data Guard for disaster recovery purposes or to offload extract processing. That afternoon at 1:15PM Comcast takes the stage again to discuss firsthand lessons learned implementing Oracle GoldenGate in a heterogeneous, highly available environment. Here’s a rundown of their session: CON8750 - High-Volume OLTP with Oracle GoldenGate: Best Practices from Comcast Does your business demand high availability in a mission-critical environment? In this session, Comcast, one of the largest telecom firms, shares best practices for leveraging Oracle GoldenGate to replicate high-volume online transaction processing data from Tandem NSK SQL/MX to Teradata. Hear critical success factors from Comcast for overall platform and component architectures as well as configuration and tuning techniques. Learn how it met the challenges of replication in a complex heterogeneous environment. You’ll also hear how Comcast leverages Oracle Advanced Customer Support Services, including an Oracle Solution Support Center, to provide mission-critical support for maximized performance and availability of its Oracle environment. The final session on the high availability track will be hosted by Patricia Mcelroy (Distinguished Product Manager) and Stephan Haisly (Principle Member of Technical Staff). Their session (CON8401 - Tuning and Troubleshooting Oracle GoldenGate on Oracle Database) covers techniques for performance tuning and troubleshooting of Oracle GoldenGate on Oracle Database. Using various types of workloads (OLTP, batch, Oracle’s PeopleSoft Enterprise), the presentation steps through the process of monitoring and troubleshooting the configuration to maximize performance and replication throughput within and between Oracle clouds. Join us at our sessions or stop by our demo pods in Moscone south and meet the product management and development teams.

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  • 65536% Autogrowth!

    - by Tara Kizer
    Twice a year, we move our production systems to our disaster recovery site.  Last Saturday night was one of those days.  There are about 50 SQL Server databases to be moved to the DR site, which is done via database mirroring.  It takes only a few seconds to failover, but some databases have a bit more involved work such as setting up replication.  Everything went relatively smooth, but we encountered a weird bug on our most mission critical system.  After everything was successfully failed over to the DR site, it was noticed that mirroring was in a suspended state on one of the databases.  We thought we had run into a SQL Server 2005 bug that we had been encountering and were working with Microsoft on a fix.  Microsoft did fix it in both SQL Server 2005 service pack 3 cumulative update package 13 and service pack 4 cumulative update package 2, however SP3 CU13 and SP4 both recently failed on this system so we were not patched yet with the bug fix.  As the suspended state was causing us issues with replication, we dropped mirroring.  We then noticed we had 10MB of free disk space on the mount point where the principal’s data files are stored.  I knew something went amiss as this system should have at least 150GB free on that mount point.  I immediately checked the main database’s data file and was shocked to see an autgrowth size of 65536%.  The data file autogrew right before mirroring went into the suspended state. 65536%! I didn’t have a lot of time to research if this autgrowth problem was a known SQL Server bug, so I deferred that research to today.  A quick Google search yielded no results but emphasis on “quick”.  I checked our performance system, which was recently restored with a copy of the affected production database, and found the autogrowth setting to be 512MB.  So this autogrowth bug was encountered sometime in the last two weeks.  On February 26th, we had attempted to install SQL 2005 SP4 on production, however it had failed (PSS case open with Microsoft).  I suspected that the SP4 failure was somehow related to this autgrowth bug although that turned out not to be the case. I then tweeted (@TaraKizer) about this problem to see if the SQL Server community (#sqlhelp) had any insights.  It seems several people have either heard of this bug or encountered it.  Aaron Bertrand (blog|twitter) referred me to this Connect item. Our affected database originated on SQL Server 2000 and was upgraded to SQL Server 2005 in 2007.  Back on SQL Server 2000, we were using the default file growth setting which was a percentage.  Sometime after the 2005 upgrade is when we changed it to 512MB.  Our situation seemed to fit the bug Aaron referred to me, so now the question was whether Microsoft had fixed it yet. I received a reply to my tweet from Amit Banerjee (twitter) that it had been fixed in SP3 CU1 (KB958004).  My affected system is SP3 CU8, so I was initially confused why we had encountered the bug.  Because I don’t read things fully, I had missed that there are additional steps you have to follow after applying the bug fix.  Amit set me straight.  Although you can read this information in the KB article, I will also copy it here in case you are as lazy as me and miss the most important section of it (although if you are as lazy as me, you won’t have read this far down my blog post): This hotfix will prevent only future occurrences of this problem. For example, if you restore a database from SQL Server 2000 to a SQL Server 2005 instance that contains this hotfix, this problem will not occur. However, if you already have a database that is affected by this problem, you must follow these steps to resolve this problem manually: Apply this hotfix. Set the file growth settings for the affected files to percentage settings, and then set the settings back to megabyte settings. Take the database offline, and then bring it back online. Verify that the values of the is_percent_growth column are correct in the sys.database_files system table and in the sys.master_files system table.

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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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  • Adopting DBVCS

    - by Wes McClure
    Identify early adopters Pick a small project with a small(ish) team.  This can be a legacy application or a green-field application. Strive to find a team of early adopters that will be eager to try something new. Get the team on board! Research Research the tool(s) that you want to use.  Some tools provide all of the features you would need while some only provide a slice of the pie.  DBVCS requires the ability to manage a set of change scripts that update a database from one version to the next.  Ideally a tool can track database versions and automatically apply updates.  The change script generation process can be manual, but having diff tools available to automatically generate it can really reduce the overhead to adoption.  Finally, an automated tool to generate a script file per database object is an added bonus as your version control system can quickly identify what was changed in a commit (add/del/modify), just like with code changes. Don’t settle on just one tool, identify several.  Then work with the team to evaluate the tools.  Have the team do some tests of the following scenarios with each tool: Baseline an existing database: can the migration tool work with legacy databases?  Caution: most migration platforms do not support baselines or have poor support, especially the fad of fluent APIs. Add/drop tables Add/drop procedures/functions/views Alter tables (rename columns, add columns, remove columns) Massage data – migrations sometimes involve changing data types that cannot be implicitly casted and require you to decide how the data is explicitly cast to the new type.  This is a requirement for a migrations platform.  Think about a case where you might want to combine fields, or move a field from one table to another, you wouldn’t want to lose the data. Run the tool via the command line.  If you cannot automate the tool in Continuous Integration what is the point? Create a copy of a database on demand. Backup/restore databases locally. Let the team give feedback and decide together, what tool they would like to try out. My recommendation at this point would be to include TSqlMigrations and RoundHouse as SQL based migration platforms.  In general I would recommend staying away from the fluent platforms as they often lack baseline capabilities and add overhead to learn a new API when SQL is already a very well known DSL.  Code migrations often get messy with procedures/views/functions as these have to be created with SQL and aren’t cross platform anyways.  IMO stick to SQL based migrations. Reconciling Production If your project is a legacy application, you will need to reconcile the current state of production with your development databases.  Find changes in production and bring them down to development, even if they are old and need to be removed.  Once complete, produce a baseline of either dev or prod as they are now in sync.  Commit this to your VCS of choice. Add whatever schema changes tracking mechanism your tool requires to your development database.  This often requires adding a table to track the schema version of that database.  Your tool should support doing this for you.  You can add this table to production when you do your next release. Script out any changes currently in dev.  Remove production artifacts that you brought down during reconciliation.  Add change scripts for any outstanding changes in dev since the last production release.  Commit these to your repository.   Say No to Shared Dev DBs Simply put, you wouldn’t dream of sharing a code checkout, why would you share a development database?  If you have a shared dev database, back it up, distribute the backups and take the shared version offline (including the dev db server once all projects are using DB VCS).  Doing DB VCS with a shared database is bound to cause problems as people won’t be able to easily script out their own changes from those that others are working on.   First prod release Copy prod to your beta/testing environment.  Add the schema changes table (or mechanism) and do a test run of your changes.  If successful you can schedule this to be run on production.   Evaluation After your first release, evaluate the pain points of the process.  Try to find tools or modifications to existing tools to help fix them.  Don’t leave stones unturned, iteratively evolve your tools and practices to make the process as seamless as possible.  This is why I suggest open source alternatives.  Nothing is set in stone, a good example was adding transactional support to TSqlMigrations.  We ran into situations where an update would break a database, so I added a feature to do transactional updates and rollback on errors!  Another good example is generating change scripts.  We have been manually making these for months now.  I found an open source project called Open DB Diff and integrated this with TSqlMigrations.  These were things we just accepted at the time when we began adopting our tool set.  Once we became comfortable with the base functionality, it was time to start automating more of the process.  Just like anything else with development, never be afraid to try to find tools to make your job easier!   Enjoy -Wes

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  • Sharp HealthCare Reduces Storage Requirements by 50% with Oracle Advanced Compression

    - by [email protected]
    Sharp HealthCare is an award-winning integrated regional health care delivery system based in San Diego, California, with 2,600 physicians and more than 14,000 employees. Sharp HealthCare's data warehouse forms a vital part of the information system's infrastructure and is used to separate business intelligence reporting from time-critical health care transactional systems. Faced with tremendous data growth, Sharp HealthCare decided to replace their existing Microsoft products with a solution based on Oracle Database 11g and to implement Oracle Advanced Compression. Join us to hear directly from the primary DBA for the Data Warehouse Application Team, Kim Nguyen, how the new environment significantly reduced Sharp HealthCare's storage requirements and improved query performance.

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  • Oracle SALT 11gR1

    - by Maurice Gamanho
    With the 11gR1 release, SALT now supports Web services transactions (WS-TX). In a nutshell, the SALT 11gR1 Web services gateway (GWWS) now supports bi-directional transactional interoperability. What this means is that Tuxedo application services can now be invoked in global transaction context using Web services. This feature is natural to a product like Tuxedo given its history as transaction processing monitor and its significant contribution to the X/Open (now the Open Group) XA specification. We implemented Web Services Coordination (WS-COOR) and Web Services Atomic Transaction (WS-AT). We also tested and certified with WebLogic Server 11gR1 and Microsoft WCF 3.5 (.Net Framework). For more information, please visit the Tuxedo OTN home page, where you can download a document and samples that will help you get started with WS-TX in Tuxedo. You can check the product documentation here.

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  • Logical and Physical Modeling for Analytical Applications

    - by Dejan Sarka
    I am proud to announce that my first course for Pluralsight is released. The course title is Logical and Physical Modeling for Analytical Applications. Here is the description of the course. A bad data model leads to an application that does not perform well. Therefore, when developing an application, you should create a good data model from the start. However, even the best logical model can’t help when the physical implementation is bad. It is also important to know how SQL Server stores and accesses data, and how to optimize the data access. Database optimization starts by splitting transactional and analytical applications. In this course, you learn how to support analytical applications with logical design, get understanding of the problems with data access for queries that deal with large amounts of data, and learn about SQL Server optimizations that help solving these problems. Enjoy the course!

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  • Will LAMP meet the following needs?

    - by Telis Duvoir
    I remember a few years back, when I had a web-site I wanted to develop, that many people recommended I go the LAMP route. Unfortunately, I never got around to studying/practicing that. I'm currently revisiting the web-site idea. The web-site will be dynamic, transactional, and hopefully end up with around 1,000,000 pv/mo and 300,000 members within 18 months. Will LAMP adequately support a site like that (i.e. have you seen it under a site with those specs)?

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  • Improve email Delivery Rates

    - by JMC
    I have a web server that sends legitimate transactional email in high quantities. A reasonable percentage of users report that they never receive the emails. For every message sent, there's also a blind carbon copy going to an unfiltered email box on a different provider that I review to ensure the server actually sent the emails. All of the emails make it to my bcc box, so the server is sending the emails properly. It seems to be a spam filtering problem at other email providers. The hosting provider for the web server indicates a reverse dns lookup has been set at their level linking the emails ip address properly to my server and domain. Question: Is there anything else I can do to improve the rate that 3rd party service providers are filtering the emails I'm sending? Is there anything I can set on the DNS that I control to show that the server sending the emails is legitimate?

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  • Nucleus Research Note: Oracle's Focus on Usability in Fusion Applications

    - by mvaughan
    By Misha Vaughan, Applications User Experience I recently noticed that Nucleus Research Inc. released a research note summarizing their findings on Oracle Fusion Applications. It's always nice when an outside firm is savvy enough to acknowledge the value of a user experience strategy. When it is applied to what Oracle has done with Fusion Applications,  it's even more satisfying.  In the note, Nucleus states: "Based on the demos and testimonials from early adopters Nucleus has reviewed, Oracle has clearly focused on usability with in-application analytics and other smart application features.  "In Oracle Fusion Applications, Oracle has built not just transactional corporate applications where users enter and extract data, but smarter applications that driver user productivity." Read it for yourself here. Read more about the story behind Oracle's Fusion Applications User Experience here.

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  • 11/28 Webinar: How Marketers Are Crafting Customer Experiences

    - by Charles Knapp
    According to recent studies by Sirius Decisions and the CEB, 70% of the consumer buying journey is complete before a salesperson becomes involved. Business customers complete 57% of their buying journey without a salesperson. So, what are savvy marketers doing to stay involved in the customer journey?  Marketers are at the epicenter of turning "big data" into insights that are acted upon by the company and customers. Drawing upon social, transactional, and online behavioral insights, marketers are making customer interactions easier and more rewarding. Marketers are personalizing and innovating customer connections across new channels and devices, especially for interactions that span channels. Learn more about three key innovation strategies in an informative webcast sponsored by the Internet Marketing Association, University of California Irvine Extension, and Oracle on Wednesday, November 28, 11 am to 12 pm Pacific. Register today to learn from these thought leaders.

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  • Oracle Unveils Breakthrough Technology: Database In-Memory

    - by Mala Narasimharajan
    Missed Larry Ellison's big announcement this morning? Today, Oracle announced . Oracle Database In-Memory.  Oracle Database In-Memory  transparently extends the power of Oracle Database 12c to enable organizations to discover business insights in real-time while simultaneously increasing transactional performance. Here's why you should care - this new breakthrough technology enables enterprises to get faster answers to business questions ultimately leading to faster business action. Oracle Database In-Memory delivers leading-edge in-memory performance without the need to restrict functionality or accept compromises, complexity and risk. Deploying Oracle Database In-Memory with virtually any existing Oracle Database-compatible application is as easy as flipping a switch--no application changes are required.  For more information on Oracle Database In-Memory go to http://www.oracle.com/us/corporate/press/2215795

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  • TFS Backup Plan Wizard Tool

    - by Enrique Lima
    With the release of the “September – 2010” TFS 2010 Power Tools, came an addition to the Team Foundation Server Administration Console.  This addition is the Team Foundation Backups Tree item.  The tool is used to create backup plans and to work with it you run through a wizard, just like you would in configuring TFS or any of the extensions it has. The areas covered through the tool include: Backup to a Network Backup Path, retention configuration. Under Advanced Options, the extension to be used for the Full and Transactional backups. The capability to include external databases, meaning, include the reporting databases and SharePoint databases as part of the plan. There are further options as you can see, that includes being able to define a task scheduler account, be able to set alerts for notifications on execution of the plans, and last the option to configure the schedule for the plan execution.  All in all a very good tool and great way to safeguard the investment you’ve made.

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  • Using XA Transactions in Coherence-based Applications

    - by jpurdy
    While the costs of XA transactions are well known (e.g. increased data contention, higher latency, significant disk I/O for logging, availability challenges, etc.), in many cases they are the most attractive option for coordinating logical transactions across multiple resources. There are a few common approaches when integrating Coherence into applications via the use of an application server's transaction manager: Use of Coherence as a read-only cache, applying transactions to the underlying database (or any system of record) instead of the cache. Use of TransactionMap interface via the included resource adapter. Use of the new ACID transaction framework, introduced in Coherence 3.6.   Each of these may have significant drawbacks for certain workloads. Using Coherence as a read-only cache is the simplest option. In this approach, the application is responsible for managing both the database and the cache (either within the business logic or via application server hooks). This approach also tends to provide limited benefit for many workloads, particularly those workloads that either have queries (given the complexity of maintaining a fully cached data set in Coherence) or are not read-heavy (where the cost of managing the cache may outweigh the benefits of reading from it). All updates are made synchronously to the database, leaving it as both a source of latency as well as a potential bottleneck. This approach also prevents addressing "hot data" problems (when certain objects are updated by many concurrent transactions) since most database servers offer no facilities for explicitly controlling concurrent updates. Finally, this option tends to be a better fit for key-based access (rather than filter-based access such as queries) since this makes it easier to aggressively invalidate cache entries without worrying about when they will be reloaded. The advantage of this approach is that it allows strong data consistency as long as optimistic concurrency control is used to ensure that database updates are applied correctly regardless of whether the cache contains stale (or even dirty) data. Another benefit of this approach is that it avoids the limitations of Coherence's write-through caching implementation. TransactionMap is generally used when Coherence acts as system of record. TransactionMap is not generally compatible with write-through caching, so it will usually be either used to manage a standalone cache or when the cache is backed by a database via write-behind caching. TransactionMap has some restrictions that may limit its utility, the most significant being: The lock-based concurrency model is relatively inefficient and may introduce significant latency and contention. As an example, in a typical configuration, a transaction that updates 20 cache entries will require roughly 40ms just for lock management (assuming all locks are granted immediately, and excluding validation and writing which will require a similar amount of time). This may be partially mitigated by denormalizing (e.g. combining a parent object and its set of child objects into a single cache entry), at the cost of increasing false contention (e.g. transactions will conflict even when updating different child objects). If the client (application server JVM) fails during the commit phase, locks will be released immediately, and the transaction may be partially committed. In practice, this is usually not as bad as it may sound since the commit phase is usually very short (all locks having been previously acquired). Note that this vulnerability does not exist when a single NamedCache is used and all updates are confined to a single partition (generally implying the use of partition affinity). The unconventional TransactionMap API is cumbersome but manageable. Only a few methods are transactional, primarily get(), put() and remove(). The ACID transactions framework (accessed via the Connection class) provides atomicity guarantees by implementing the NamedCache interface, maintaining its own cache data and transaction logs inside a set of private partitioned caches. This feature may be used as either a local transactional resource or as logging XA resource. However, a lack of database integration precludes the use of this functionality for most applications. A side effect of this is that this feature has not seen significant adoption, meaning that any use of this is subject to the usual headaches associated with being an early adopter (greater chance of bugs and greater risk of hitting an unoptimized code path). As a result, for the moment, we generally recommend against using this feature. In summary, it is possible to use Coherence in XA-oriented applications, and several customers are doing this successfully, but it is not a core usage model for the product, so care should be taken before committing to this path. For most applications, the most robust solution is normally to use Coherence as a read-only cache of the underlying data resources, even if this prevents taking advantage of certain product features.

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  • Using db4o with multiple application instances under medium trust

    - by Anders Fjeldstad
    I recently stumbled over the object database engine db4o which I think looks really interesting. I would like to use it in an ASP.NET MVC application that will be deployed to a shared hosting environment under medium trust. Because of the trust level, I'm restricted to using db4o in embedded/in-process mode. That in itself should be no problem, but the hosting provider also transparently runs each web application in multiple (load-balanced) server instances with shared storage, which I would say is normally a very nice feature for a $10/month hoster. However, since an instance of a db4o server with write access (whether in-process or networked) locks the underlying database file, having multiple instances of the application using the same file won't work (or at least I can't see how it would). So the question is: is it possible to use db4o in this specific environment? I have considered letting each application have its own database which is synchronized with a master database using replication (dRS), but that approach will most likely end up with very frequent bi-directional replication (read master changes at beginning of each request, write to master after each change) which I don't think will be very efficient. Summary of the web application/environment characteristics: Read-intensive (but not entirely read-only) Some delay (a few seconds) is acceptible between the time that a change is made and the time when the change shows up in all the application instances' data Must run in medium trust No guarantee that the load-balancer uses "sticky sessions" All suggestions are much appreciated!

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  • Setting article properties for a publication using RMO in C# .NET

    - by Pavan Kumar
    I am using transaction replication with push subscription. I am developing a UI for replication using RMO in C#.NET between different instances of the same database within same machine holding similar schema and structure. I am using Single subscriber and multiple publisher topology. During creation of publication i want to set a few article properties such as Keep the existing object unchanged ,allow schema changes at subscriber to false a,copy foriegn key constarint and copy check constraints to true. How do i set the article properties using RMO in C# .NET. I am using Visual Studio 2008 SP1.I also want to know as how we can select all the objects including Tables,Views,Stored Procedures for publishing at one stretch. I could do it for one table but i want to select all the tables at one stretch. This is the code snippet i used for selecting single table for publishing. TransArticle ta = new TransArticle(); ta.Name = "Article_1"; ta.PublicationName = "TransReplication_DB2"; ta.DatabaseName = "DB2"; ta.SourceObjectName = "person"; ta.SourceObjectOwner = "dbo"; ta.ConnectionContext = conn; ta.Create();

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  • Idiomatic Scala way to deal with base vs derived class field names?

    - by Gregor Scheidt
    Consider the following base and derived classes in Scala: abstract class Base( val x : String ) final class Derived( x : String ) extends Base( "Base's " + x ) { override def toString = x } Here, the identifier 'x' of the Derived class parameter overrides the field of the Base class, so invoking toString like this: println( new Derived( "string" ).toString ) returns the Derived value and gives the result "string". So a reference to the 'x' parameter prompts the compiler to automatically generate a field on Derived, which is served up in the call to toString. This is very convenient usually, but leads to a replication of the field (I'm now storing the field on both Base and Derived), which may be undesirable. To avoid this replication, I can rename the Derived class parameter from 'x' to something else, like '_x': abstract class Base( val x : String ) final class Derived( _x : String ) extends Base( "Base's " + _x ) { override def toString = x } Now a call to toString returns "Base's string", which is what I want. Unfortunately, the code now looks somewhat ugly, and using named parameters to initialize the class also becomes less elegant: new Derived( _x = "string" ) There is also a risk of forgetting to give the derived classes' initialization parameters different names and inadvertently referring to the wrong field (undesirable since the Base class might actually hold a different value). Is there a better way? Edit: To clarify, I really only want the Base values; the Derived ones just seem necessary for initializing the Base ones. The example only references them to illustrate the ensuing issues. It might be nice to have a way to suppress automatic field generation if the derived class would otherwise end up hiding a base class field.

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  • DB Strategy for inserting into a high read table (Sql Server)

    - by Tom
    Looking for strategies for a very large table with data maintained for reporting and historical purposes, a very small subset of that data is used in daily operations. Background: We have Visitor and Visits tables which are continuously updated by our consumer facing site. These tables contain information on every visit and visitor, including bots and crawlers, direct traffic that does not result in a conversion, etc. Our back end site allows management of the visitor's (leads) from the front end site. Most of the management occurs on a small subset of our visitors (visitors that become leads). The vast majority of the data in our visitor and visit tables is maintained only for a much smaller subset of user activity (basically reporting type functionality). This is NOT an indexing problem, we have done all we can with indexing and keeping our indexes clean, small, and not fragmented. ps: We do not currently have the budget or expertise for a data warehouse. The problem: We would like the system to be more responsive to our end users when they are querying, for instance, the list of their assigned leads. Currently the query is against a huge data set of mostly irrelevant data. I am pondering a few ideas. One involves new tables and a fairly major re-architecture, I'm not asking for help on that. The other involves creating redundant data, (for instance a Visitor_Archive and a Visitor_Small table) where the larger visitor and visit tables exist for inserts and history/reporting, the smaller visitor1 table would exist for managing leads, sending lead an email, need leads phone number, need my list of leads, etc.. The reason I am reaching out is that I would love opinions on the best way to keep the Visitor_Archive and the Visitor_Small tables in sync... Replication? Can I use replication to replicate only data with a certain column value (FooID = x) Any other strategies?

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  • mysql: Bind on unix socket: Permission denied

    - by Alex
    Can't start mysql with: sudo /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 120222 13:40:48 mysqld_safe Starting mysqld daemon with databases from /srv/mysql/myDB 120222 13:40:54 mysqld_safe mysqld from pid file /srv/mysql/pids/mysqld-myDB.pid ended /srv/mysql/logs/mysqld-myDB.log: 120222 13:43:53 mysqld_safe Starting mysqld daemon with databases from /srv/mysql/myDB 120222 13:43:53 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld: Table 'plugin' is read only 120222 13:43:53 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 120222 13:43:53 InnoDB: Completed initialization of buffer pool 120222 13:43:53 InnoDB: Started; log sequence number 32 4232720908 120222 13:43:53 [ERROR] Can't start server : Bind on unix socket: Permission denied 120222 13:43:53 [ERROR] Do you already have another mysqld server running on socket: /srv/mysql/sockets/mysql-myDB.sock ? 120222 13:43:53 [ERROR] Aborting 120222 13:43:53 InnoDB: Starting shutdown... One instance mysqld is running: $ ps aux | grep mysql mysql 1093 0.0 0.2 169972 18700 ? Ssl 11:50 0:02 /usr/sbin/mysqld $ Port 3700 is available: $ netstat -a | grep 3700 $ Directory with sockets is empty: $ ls /srv/mysql/sockets/ $ There are all permissions: $ ls -l /srv/mysql/ total 20 drwxrwxrwx 2 mysql mysql 4096 2012-02-22 13:28 logs drwxrwxrwx 13 mysql mysql 4096 2012-02-22 13:44 myDB drwxrwxrwx 2 mysql mysql 4096 2012-02-22 12:55 pids drwxrwxrwx 2 mysql mysql 4096 2012-02-22 12:55 sockets drwxrwxrwx 2 mysql mysql 4096 2012-02-22 13:25 version Apparmor config: $cat /etc/apparmor.d/usr.sbin.mysqld # vim:syntax=apparmor # Last Modified: Tue Jun 19 17:37:30 2007 #include <tunables/global> /usr/sbin/mysqld flags=(complain) { #include <abstractions/base> #include <abstractions/nameservice> #include <abstractions/user-tmp> #include <abstractions/mysql> #include <abstractions/winbind> capability dac_override, capability sys_resource, capability setgid, capability setuid, network tcp, /etc/hosts.allow r, /etc/hosts.deny r, /etc/mysql/*.pem r, /etc/mysql/conf.d/ r, /etc/mysql/conf.d/* r, /etc/mysql/*.cnf r, /usr/lib/mysql/plugin/ r, /usr/lib/mysql/plugin/*.so* mr, /usr/sbin/mysqld mr, /usr/share/mysql/** r, /var/log/mysql.log rw, /var/log/mysql.err rw, /var/lib/mysql/ r, /var/lib/mysql/** rwk, /var/log/mysql/ r, /var/log/mysql/* rw, /{,var/}run/mysqld/mysqld.pid w, /{,var/}run/mysqld/mysqld.sock w, /srv/mysql/ r, /srv/mysql/** rwk, /sys/devices/system/cpu/ r, # Site-specific additions and overrides. See local/README for details. #include <local/usr.sbin.mysqld> } Any suggestions? UPD1: $ touch /srv/mysql/sockets/mysql-myDB.sock $ sudo chown mysql:mysql /srv/mysql/sockets/mysql-myDB.sock $ ls -l /srv/mysql/sockets/mysql-myDB.sock -rw-rw-r-- 1 mysql mysql 0 2012-02-22 14:29 /srv/mysql/sockets/mysql-myDB.sock $ sudo /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 120222 14:30:18 mysqld_safe Can't log to error log and syslog at the same time. Remove all --log-error configuration options for --syslog to take effect. 120222 14:30:18 mysqld_safe Logging to '/srv/mysql/logs/mysqld-myDB.log'. 120222 14:30:18 mysqld_safe Starting mysqld daemon with databases from /srv/mysqlmyDB 120222 14:30:24 mysqld_safe mysqld from pid file /srv/mysql/pids/mysqld-myDB.pid ended $ ls -l /srv/mysql/sockets/mysql-myDB.sock ls: cannot access /srv/mysql/sockets/mysql-myDB.sock: No such file or directory $ UPD2: $ sudo netstat -lnp | grep mysql tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 1093/mysqld unix 2 [ ACC ] STREAM LISTENING 5912 1093/mysqld /var/run/mysqld/mysqld.sock $ sudo lsof | grep /srv/mysql/sockets/mysql-myDB.sock lsof: WARNING: can't stat() fuse.gvfs-fuse-daemon file system /home/sears/.gvfs Output information may be incomplete. UPD3: $ cat /etc/mysql/my.cnf # # The MySQL database server configuration file. # # You can copy this to one of: # - "/etc/mysql/my.cnf" to set global options, # - "~/.my.cnf" to set user-specific options. # # One can use all long options that the program supports. # Run program with --help to get a list of available options and with # --print-defaults to see which it would actually understand and use. # # For explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # This will be passed to all mysql clients # It has been reported that passwords should be enclosed with ticks/quotes # escpecially if they contain "#" chars... # Remember to edit /etc/mysql/debian.cnf when changing the socket location. [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. Both versions are currently parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] # # * Basic Settings # # # * IMPORTANT # If you make changes to these settings and your system uses apparmor, you may # also need to also adjust /etc/apparmor.d/usr.sbin.mysqld. # user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. #bind-address = 127.0.0.1 # # * Fine Tuning # key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #max_connections = 100 #table_cache = 64 #thread_concurrency = 10 # # * Query Cache Configuration # query_cache_limit = 1M query_cache_size = 16M # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. # As of 5.1 you can enable the log at runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 log_error = /var/log/mysql/error.log # Here you can see queries with especially long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log expire_logs_days = 10 max_binlog_size = 100M #binlog_do_db = include_database_name #binlog_ignore_db = include_database_name # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 16M # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/

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  • windows 2003 server : can't find a primary authoritative dns server for the name srv.domain1.local [

    - by phill
    I originally tried to rejoin a computer to a network which led to a "cannot find domain" error. The username/password box don't even come up. some tests i ran: I can ping the server, however I can't ping the domain name domain1.local. nslookup can't find the domain either. It looks to the isp's dns instead of my own to resolve the local machines. So i go to the dns and run netdiag.exe and gives me this error. DNS test . . . . . . . . . . . . . : Failed [WARNING] Cannot find a primary authoritative DNS server for the name 'stmartinsrv.stmartin.local.'. [RCODE_SERVER_FAILURE] The name 'srv.domain1.local.' may not be registered in DNS. [WARNING] The DNS entries for this DC are not registered correctly on DNS se rver '68.94.156.1'. Please wait for 30 minutes for DNS server replication. [WARNING] The DNS entries for this DC are not registered correctly on DNS se rver '68.94.157.1'. Please wait for 30 minutes for DNS server replication. [FATAL] No DNS servers have the DNS records for this DC registered. Redir and Browser test . . . . . . : Passed List of NetBt transports currently bound to the Redir NetBT_Tcpip_{04BB0F6B-06AE-4D60-80C8-2A7A24C1D87B} The redir is bound to 1 NetBt transport. List of NetBt transports currently bound to the browser NetBT_Tcpip_{04BB0F6B-06AE-4D60-80C8-2A7A24C1D87B} The browser is bound to 1 NetBt transport. from previous postings, I've tried adding the domain suffix to the nic ip properties to both the client machine and the dc server which didn't help. any ideas? thanks in advance

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  • Binary Log Format in MySQL

    - by amritansu
    Reference manual for MySQL 5.6 states that " Some changes, however, still use the statement-based format. Examples include all DDL (data definition language) statements such as CREATE TABLE, ALTER TABLE, or DROP TABLE. " Does this statement means that even if we have ROW format for binary logs all DDLs will be logged in binary log as statement based? How does this affect replication? Kindly help me to understand this.

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  • How much time do I have to remove a domain controller that was lost using metadata cleanup?

    - by dasko
    I am wondering how long after a Domain Controller has been permanently lost, from the domain due to it dying from hardware perspective, do I have before I have to clean up references of it using meta data cleanup? Planning on doing it soon but not sure if there is anything I should be concerned about. This dead or lost domain controller had no roles other than being a Domain Controller and having integrated Active Directory DNS. As well it held NO FSMO roles, it was just an older replication Domain Controller.

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  • What is the standard system architecture for MongoDB

    - by learner
    I know this question is too vague, so I would like to add some key numbers to give insights about what the scenario is Each Document size - 360KB Total Documents - 1.5 million Document created/day - 2k read intensive - YES Availability requirement - HIGH With these requirements in mind, here is what I believe should be the architecture, but not too sure, please share your experiences and point me to right directions 2 Linux Box(Ubuntu 11 would do)(on a different rack setup for availability) 64-bit Mongo Database 1-master(for read/wr1te) and 1-slave(read-only with replication ON) Sharding not needed at this point in time Thank you in advance

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  • drbd block device as storage for kvm virtual machine

    - by facha
    Hi, everyone I've setup a drbd replication between two machines and used a drbd block device as storage for a kvm machine. Everything is running well. However I'm in doubt if this setup is ok to use. From what I've read so far on the internet, people tend to use drbd-ospf-qcow2_file as storage for their virtual machines.

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