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• Database-as-a-Service on Exadata Cloud

  - by Gagan Chawla

  Note – Oracle Enterprise Manager 12c DBaaS is platform agnostic and is designed to work on Exadata/non-Exadata, physical/virtual, Oracle/non Oracle platforms and it’s not a mandatory requirement to use Exadata as the base platform. Database-as-a-Service (DBaaS) is an important trend these days and the top business drivers motivating customers towards private database cloud model include constant pressure to reduce IT Costs and Complexity, and also to be able to improve Agility and Quality of Service. The first step many enterprises take in their journey towards cloud computing is to move to a consolidated and standardized environment and Exadata being already a proven best-in-class popular consolidation platform, we are seeing now more and more customers starting to evolve from Exadata based platform into an agile self service driven private database cloud using Oracle Enterprise Manager 12c. Together Exadata Database Machine and Enterprise Manager 12c provides industry’s most comprehensive and integrated solution to transform from a typical silo’ed environment into enterprise class database cloud with self service, rapid elasticity and pay-per-use capabilities.   In today’s post, I’ll list down the important steps to enable DBaaS on Exadata using Enterprise Manager 12c. These steps are chalked down based on a recent DBaaS implementation from a real customer engagement - Project Planning - First step involves defining the scope of implementation, mapping functional requirements and objectives to use cases, defining high availability, network, security requirements, and delivering the project plan. In a Cloud project you plan around technology, business and processes all together so ensure you engage your actual end users and stakeholders early on in the project right from the scoping and planning stage. Setup your EM 12c Cloud Control Site – Once the project plan approval and sign off from stakeholders is achieved, refer to EM 12c Install guide and these are some important tips to follow during the site setup phase - Review the new EM 12c Sizing paper before you get started with install Cloud, Chargeback and Trending, Exadata plug ins should be selected to deploy during install Refer to EM 12c Administrator’s guide for High Availability, Security, Network/Firewall best practices and options Your management and managed infrastructure should not be combined i.e. EM 12c repository should not be hosted on same Exadata where target Database Cloud is to be setup Setup Roles and Users – Cloud Administrator (EM_CLOUD_ADMINISTRATOR), Self Service Administrator (EM_SSA_ADMINISTRATOR), Self Service User (EM_SSA_USER) are the important roles required for cloud lifecycle management. Roles and users are managed by Super Administrator via Setup menu –> Security option. For Self Service/SSA users custom role(s) based on EM_SSA_USER should be created and EM_USER, PUBLIC roles should be revoked during SSA user account creation. Configure Software Library – Cloud Administrator logs in and in this step configures software library via Enterprise menu –> provisioning and patching option and the storage location is OMS shared filesystem. Software Library is the centralized repository that stores all software entities and is often termed as ‘local store’. Setup Self Update – Self Update is one of the most innovative and cool new features in EM 12c framework. Self update can be accessed via Setup -> Extensibility option by Super Administrator and is the unified delivery mechanism to get all new and updated entities (Agent software, plug ins, connectors, gold images, provisioning bundles etc) in EM 12c. Deploy Agents on all Compute nodes, and discover Exadata targets – Refer to Exadata discovery cookbook for detailed walkthrough to ensure successful discovery of Exadata targets. Configure Privilege Delegation Settings – This step involves deployment of privilege setting template on all the nodes by Super Administrator via Setup menu -> Security option with the option to define whether to use sudo or powerbroker for all provisioning and patching operations. Provision Grid Infrastructure with RAC Database on Compute Nodes – Software is provisioned in this step via a provisioning profile using EM 12c database provisioning. In case of Exadata, Grid Infrastructure and RAC Database software is already deployed on compute nodes via OneCommand from Oracle, so SSA Administrator just needs to discover Oracle Homes and Listener as EM targets. Databases will be created as and when users request for databases from cloud. Customize Create Database Deployment Procedure – the actual database creation steps are "templatized" in this step by Self Service Administrator and the newly saved deployment procedure will be used during service template creation in next step. This is an important step and make sure you have locked all the required variables marked as locked as ‘Y’ in this table. Setup Self Service Portal – This step involves setting up of zones, user quotas, service templates, chargeback plan. The SSA portal is setup by Self Service Administrator via Setup menu -> Cloud -> Database option and following guided workflow. Refer to DBaaS cookbook for details. You also have an option to customize SSA login page via steps documented in EM 12c Cloud Administrator’s guide Final Checks – Define and document process guidelines for SSA users and administrators. Get your SSA users trained on Self Service Portal features and overall DBaaS model and SSA administrators should be familiar with Self Service Portal setup pieces, EM 12c database lifecycle management capabilities and overall EM 12c monitoring framework. GO LIVE – Announce rollout of Database-as-a-Service to your SSA users. Users can login to the Self Service Portal and request/monitor/view their databases in Exadata based database cloud. Congratulations! You just delivered a successful database cloud implementation project! In future posts, we will cover these additional useful topics around database cloud – DBaaS Implementation tips and tricks – right from setup to self service to managing the cloud lifecycle ‘How to’ enable real production databases copies in DBaaS with rapid provisioning in database cloud Case study of a customer who recently achieved success with their transformational journey from traditional silo’ed environment on to Exadata based database cloud using Enterprise Manager 12c. More Information – Podcast on Database as a Service using Oracle Enterprise Manager 12c Oracle Enterprise Manager 12c Installation and Administration guide, Cloud Administration guide DBaaS Cookbook Exadata Discovery Cookbook Screenwatch: Private Database Cloud: Set Up the Cloud Self-Service Portal Screenwatch: Private Database Cloud: Use the Cloud Self-Service Portal Stay Connected: Twitter |  Face book |  You Tube |  Linked in |  Newsletter

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• Oracle VM RAC template - what it took

  - by wcoekaer

  In my previous posting I introduced the latest Oracle Real Application Cluster / Oracle VM template. I mentioned how easy it is to deploy a complete Oracle RAC cluster with Oracle VM. In fact, you don't need any prior knowledge at all to get a complete production-ready setup going. Here is an example... I built a 4 node RAC cluster, completely configured in just over 40 minutes - starting from import template into Oracle VM, create VMs to fully up and running Oracle RAC. And what was needed? 1 textfile with some hostnames and ip addresses and deploycluster.py. The setup is a 4 node cluster where each VM has 8GB of RAM and 4 vCPUs. The shared ASM storage in this case is 100GB, 5 x 20GB volumes. The VM names are racovm.0-racovm.3. The deploycluster script starts the VMs, verifies the configuration and sends the database cluster configuration info through Oracle VM Manager to the 4 node VMs. Once the VMs are up and running, the first VM starts the actual Oracle RAC setup inside and talks to the 3 other VMs. I did not log into any VM until after everything was completed. In fact, I connected to the database remotely before logging in at all. # ./deploycluster.py -u admin -H localhost --vms racovm.0,racovm.1,racovm.2,racovm.3 --netconfig ./netconfig.ini Oracle RAC OneCommand (v1.1.0) for Oracle VM - deploy cluster - (c) 2011-2012 Oracle Corporation (com: 26700:v1.1.0, lib: 126247:v1.1.0, var: 1100:v1.1.0) - v2.4.3 - wopr8.wimmekes.net (x86_64) Invoked as root at Sat Jun 2 17:31:29 2012 (size: 37500, mtime: Wed May 16 00:13:19 2012) Using: ./deploycluster.py -u admin -H localhost --vms racovm.0,racovm.1,racovm.2,racovm.3 --netconfig ./netconfig.ini INFO: Login password to Oracle VM Manager not supplied on command line or environment (DEPLOYCLUSTER_MGR_PASSWORD), prompting... Password: INFO: Attempting to connect to Oracle VM Manager... INFO: Oracle VM Client (3.1.1.305) protocol (1.8) CONNECTED (tcp) to Oracle VM Manager (3.1.1.336) protocol (1.8) IP (192.168.1.40) UUID (0004fb0000010000cbce8a3181569a3e) INFO: Inspecting /root/rac/deploycluster/netconfig.ini for number of nodes defined... INFO: Detected 4 nodes in: /root/rac/deploycluster/netconfig.ini INFO: Located a total of (4) VMs; 4 VMs with a simple name of: ['racovm.0', 'racovm.1', 'racovm.2', 'racovm.3'] INFO: Verifying all (4) VMs are in Running state INFO: VM with a simple name of "racovm.0" is in a Stopped state, attempting to start it...OK. INFO: VM with a simple name of "racovm.1" is in a Stopped state, attempting to start it...OK. INFO: VM with a simple name of "racovm.2" is in a Stopped state, attempting to start it...OK. INFO: VM with a simple name of "racovm.3" is in a Stopped state, attempting to start it...OK. INFO: Detected that all (4) VMs specified on command have (5) common shared disks between them (ASM_MIN_DISKS=5) INFO: The (4) VMs passed basic sanity checks and in Running state, sending cluster details as follows: netconfig.ini (Network setup): /root/rac/deploycluster/netconfig.ini buildcluster: yes INFO: Starting to send cluster details to all (4) VM(s)....... INFO: Sending to VM with a simple name of "racovm.0".... INFO: Sending to VM with a simple name of "racovm.1"..... INFO: Sending to VM with a simple name of "racovm.2"..... INFO: Sending to VM with a simple name of "racovm.3"...... INFO: Cluster details sent to (4) VMs... Check log (default location /u01/racovm/buildcluster.log) on build VM (racovm.0)... INFO: deploycluster.py completed successfully at 17:32:02 in 33.2 seconds (00m:33s) Logfile at: /root/rac/deploycluster/deploycluster2.log my netconfig.ini # Node specific information NODE1=db11rac1 NODE1VIP=db11rac1-vip NODE1PRIV=db11rac1-priv NODE1IP=192.168.1.56 NODE1VIPIP=192.168.1.65 NODE1PRIVIP=192.168.2.2 NODE2=db11rac2 NODE2VIP=db11rac2-vip NODE2PRIV=db11rac2-priv NODE2IP=192.168.1.58 NODE2VIPIP=192.168.1.66 NODE2PRIVIP=192.168.2.3 NODE3=db11rac3 NODE3VIP=db11rac3-vip NODE3PRIV=db11rac3-priv NODE3IP=192.168.1.173 NODE3VIPIP=192.168.1.174 NODE3PRIVIP=192.168.2.4 NODE4=db11rac4 NODE4VIP=db11rac4-vip NODE4PRIV=db11rac4-priv NODE4IP=192.168.1.175 NODE4VIPIP=192.168.1.176 NODE4PRIVIP=192.168.2.5 # Common data PUBADAP=eth0 PUBMASK=255.255.255.0 PUBGW=192.168.1.1 PRIVADAP=eth1 PRIVMASK=255.255.255.0 RACCLUSTERNAME=raccluster DOMAINNAME=wimmekes.net DNSIP= # Device used to transfer network information to second node # in interview mode NETCONFIG_DEV=/dev/xvdc # 11gR2 specific data SCANNAME=db11vip SCANIP=192.168.1.57 last few lines of the in-VM log file : 2012-06-02 14:01:40:[clusterstate:Time :db11rac1] Completed successfully in 2 seconds (0h:00m:02s) 2012-06-02 14:01:40:[buildcluster:Done :db11rac1] Build 11gR2 RAC Cluster 2012-06-02 14:01:40:[buildcluster:Time :db11rac1] Completed successfully in 1779 seconds (0h:29m:39s) From start_vm to completely configured : 29m:39s. The other 10m was the import template and create 4 VMs from template along with the shared storage configuration. This consists of a complete Oracle 11gR2 RAC database with ASM, CRS and the RDBMS up and running on all 4 nodes. Simply connect and use. Production ready. Oracle on Oracle.

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• Modularity through HTTP

  - by Michael Williamson

  As programmers, we strive for modularity in the code we write. We hope that splitting the problem up makes it easier to solve, and allows us to reuse parts of our code in other applications. Object-orientation is the most obvious of many attempts to get us closer to this ideal, and yet one of the most successful approaches is almost accidental: the web. Programming languages provide us with functions and classes, and plenty of other ways to modularize our code. This allows us to take our large problem, split it into small parts, and solve those small parts without having to worry about the whole. It also makes it easier to reason about our code. So far, so good, but now that we’ve written our small, independent module, for example to send out e-mails to my customers, we’d like to reuse it in another application. By creating DLLs, JARs or our platform’s package container of choice, we can do just that – provided our new application is on the same platform. Want to use a Java library from C#? Well, good luck – it might be possible, but it’s not going to be smooth sailing. Even if a library exists, it doesn’t mean that using it going to be a pleasant experience. Say I want to use Java to write out an XML document to an output stream. You’d imagine this would be a simple one-liner. You’d be wrong: import org.w3c.dom.*; import java.io.*; import javax.xml.transform.*; import javax.xml.transform.dom.*; import javax.xml.transform.stream.*; private static final void writeDoc(Document doc, OutputStream out) throws IOException { try { Transformer t = TransformerFactory.newInstance().newTransformer(); t.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, doc.getDoctype().getSystemId()); t.transform(new DOMSource(doc), new StreamResult(out)); } catch (TransformerException e) { throw new AssertionError(e); // Can't happen! } } Most of the time, there is a good chance somebody else has written the code before, but if nobody can understand the interface to that code, nobody’s going to use it. The result is that most of the code we write is just a variation on a theme. Despite our best efforts, we’ve fallen a little short of our ideal, but the web brings us closer. If we want to send e-mails to our customers, we could write an e-mail-sending library. More likely, we’d use an existing one for our language. Even then, we probably wouldn’t have niceties like A/B testing or DKIM signing. Alternatively, we could just fire some HTTP requests at MailChimp, and get a whole slew of features without getting anywhere near the code that implements them. The web is inherently language agnostic. So long as your language can send and receive text over HTTP, and probably parse some JSON, you’re about as well equipped as anybody. Instead of building libraries for a specific language, we can build a service that almost every language can reuse. The text-based nature of HTTP also helps to limit the complexity of the API. As SOAP will attest, you can still make a horrible mess using HTTP, but at least it is an obvious horrible mess. Complex data structures are tedious to marshal to and from text, providing a strong incentive to keep things simple. By contrast, spotting the complexities in a class hierarchy is often not as easy. HTTP doesn’t solve every problem. It probably isn’t such a good idea to use it inside an inner loop that’s executed thousands of times per second. What’s more, the HTTP approach might introduce some new problems. We often need to add a thin shim to each application that we wish to communicate over HTTP. For instance, we might need to write a small plugin in PHP if we want to integrate WordPress into our system. Suddenly, instead of a system written in one language, we’re maintaining a system with several distinct languages and platforms. Even then, we should strive to avoid re-implementing the same old thing. As programmers, we consistently underestimate both the cost of building a system and the ongoing maintenance. If we allow ourselves to integrate existing applications, even if they’re in unfamiliar languages, we save ourselves those development and maintenance costs, as well as being able to pick the best solution for our problem. Thanks to the web, HTTP is often the easiest way to get there.

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• jQuery Templates, Data Link

  - by Renso

  Normal 0 false false false EN-US X-NONE X-NONE /* 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-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Query Templates, Data Link, and Globalization I am sure you must have read Scott Guthrie’s blog post about jQuery support and officially supporting jQuery's templating, data linking and globalization, if not here it is: jQuery Templating Since we are an open source shop and use jQuery and jQuery plugins extensively to say the least, decided to look into the templating a bit and see what data linking is all about. For those not familiar with those terms here is the summary, plenty of material out there on what it is, but here is what in my experience it means: jQuery Templating: A templating engine that allows you to specify a client-side template where you indicate which properties/tags you want dynamically updated. You in a sense specify which parts of the html is dynamic and since it is pluggable you are able to use tools data jQuery data linking and others to let it sync up your template with data. What makes it more powerful is that you can easily work with rows of data, adding and removing rows. Once the template has been generated, which you do dynamically on a client-side event, you then append/inject the resulting template somewhere in your DOM, like for example you would get a JSON object from the database, map it to your template, it populates the template with your data in the indicated places, and then let’s say for example append it to a row in a table. I have not found it that useful for lets say a single record of data since you could easily just get a partial view from the server via an html type ajax call. It really shines when you dynamically add/remove rows from a list in the DOM. I have not found an alternative that meets the functionality of the jQuery template and helps of course that Microsoft officially supports it. In future versions of the jQuery plug-in it may even ship as part of the standard jQuery library and with future versions of Visual Studio. jQuery Data Linking: In short I was fascinated by it initially by how with one line of code I can sync up my JSON object with my form elements. That's where my enthusiasm stopped. It was one-line to let is deal with syncing up your form with your JSON object, but it is not bidirectional as they state and I tried all the work arounds they suggested and none of them work. The problem is that when you update your JSON object it DOES NOT sync it up with your form. In an example, accounts are being edited client side by selecting the account from a list by clicking on the row, it then fetches the entire account JSON object via ajax json-type call and then refreshes the form with the account’s details from the new JSON object. What is the use of syncing up my JSON with the form if I still have to programmatically sync up my new JSON object with each DOM property?! So you may ask: “what is the alternative”? Good question and the same one I was pondering, maybe I can just use it for keeping my from n sync with my JSON object so I can post that JSON object back to the server and update my database. That’s when I discovered Knockout: Knockout It addresses the issues mentioned above and also supports event handling through the observer pattern. Not wanting to go into detail here, Steve Sanderson, the creator of Knockout, has already done a terrific job of that, thanks Steve for a great plug-in! Best of all it integrates perfectly with the jQuery Templating engine as well. I have not found an alternative to this plugin that supports the depth and width of functionality and would recommend it to anyone. The only drawback is the embedded html attributes (data-bind=””) tags that you have to add to the HTML, in my opinion tying your behavior to your HTML, where I like to separate behavior from HTML as well as CSS, so the HTML is purely to define content, not styling or behavior. But there are plusses to this as well and also a nifty work around to this that I will just shortly mention here with an example. Instead of data binding an html tag with knockout event handling like so:  <%=Html.TextBox("PrepayDiscount", String.Empty, new { @class = "number" })%>   Do: <%=Html.DataBoundTextBox("PrepayDiscount", String.Empty, new { @class = "number" })%>   The html extension above then takes care of the internals and you could then swap Knockout for something else if you want to inside the extension and keep the HTML plugin agnostic. Here is what the extension looks like, you can easily build a whole library to support all kinds of data binding options from this:      public static class HtmlExtensions       {         public static MvcHtmlString DataBoundTextBox(this HtmlHelper helper, string name, object value, object htmlAttributes)         {             var dic = new RouteValueDictionary(htmlAttributes);             dic.Add("data-bind", String.Format("value: {0}", name));             return helper.TextBox(name, value, dic);         }       }   Hope this helps in making a decision when and where to consider jQuery templating, data linking and Knockout.

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• ?????????????????!Oracle Database ?????????

  - by Aya Sensui

  ?????????????????????????????????? ?????????????????????????????????????????????? ?????????????????????????????????????????????????? ??????????????????????????????????????????? ?????????????????????????????????? ??????????????????????????????????????????????? ?????????/?????????????????????????????????????????? ?????????????? ????????????????????????????????????????? ???????????????????????????????????? ??????????????????????????????????????????????? ????????????????????????????????????????????????????????? Oracle Database ????????????????? ??????????????????????????? ????????????????????????? ???????????????????????? ????????????????????????????????? ???????????????? ??????????????????????????????????!??????? ??????????????????? TIPS ???????????????? ?????!???????? ???????????????????????????????????????????????? Oracle Database ??????????????????????????????????????????? ??????????????????????????????????????? Oracle Database ????????????????????????????????????? ????????? FAILED_LOGIN_ATTEMPTS    ??????????? PASSWORD_LIFE_TIME       ????????? PASSWORD_REUSE_TIME      ???????????????????? PASSWORD_REUSE_MAX       ????????????????????????????? PASSWORD_LOCK_TIME       ????????????????????????????????????? PASSWORD_GRACE_TIME      ????????????????? PASSWORD_VERIFY_FUNCTION ??????????????????? (*1) (*1)????????????????????????? $ORACLE_HOME/rdbms/admin/utlpwdmg.sql ?????????????????? utlpwdmg.sql ????????? ???????????????????????????  - ?????????????????  - ???????????  - ??????????????  - ?????????????????????  - ???????????????????? ???????????????????????????????????? ???????????????????????????????????? ??????????????????????!?????? ????????????????????????????????????? ??????????????????????????????????? ????????????????????? ???????? SQL*Plus ??????????????????????? ????????????????????????? ???????????????????????????????????? ??????????????????·???????????????? ???Enterprise Edition ?????????????????? Virtual Private Database(VPD) ??????????? ???????????????????????????????????????????????? ?????????????????????????? ???????????????????????????????????????????????? ????????????????????????????? ?????????????????????????????????? ????????????????????????????? ??????????????????????????????????? ???????????????????? ?????????????????????????????? ???????????????????????????????? ????????????????????????????????????????? ??????????????????????????????????????????? ????????????????????????????? Oracle Database ????????????????????Oracle Advanced Security ????????????? ?????????????????????????????? ????DBMS_OBFUSCATION_TOOLKIT ? DBMS_CRYPTO ???????/????? PL/SQL ?????? ?????????????????? ?????????????????????????????????????????????? ?????????????????????????? ????????????!???? Oracle Database ?????????????????????????????????? ????????????????????????DBA ??????????????????? 4 ???? ??????????? Enterprise Edition??????????? ?????DBA ??????????????????????? ?????????????????????? [????] ???????????????????????????????????? ????????????????????  - ????????????  - ?????(SYSOPER, SYSDBA)???????????  - ??????????(??????????) ?????????????????????????????????·?????? ????????????????????????????????? ?????????????????????????????? [DBA ??] ???????????(DBA ??)???????????????????? ??????????????????????????AUDIT_SYS_OPERATIONS ?????? TRUE ????????????? ????? OS ??????????????/????????????????????? ???????????????????????????????????????????????? [????] ???????????????????????????????????? ??AUDIT_TRAIL ??????????????????????????? ???????????  - ???????    ????·????????  - ????????    ??????????????????????????????  - ????    ????????????????  - SQL ???    ????????????? DDL ?????? [??????????] ??????(?????????)??????????????????? Enterprise Edition ?????????? ??????????????????????? ??? Oracle Database ???????????????????????????????????? ??????????????????????????????????????????????? ????????????????????

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• ?Exadata??????DBFS

  - by Liu Maclean(???)

  ?Exadata???DBFS ??????? 1. ??fuse RPM  [root@dm01db01 ~]# yum install fuse Loaded plugins: rhnplugin, security This system is not registered with ULN. ULN support will be disabled. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package fuse.x86_64 0:2.7.4-8.0.1.el5 set to be updated --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================  Package                            Arch                                 Version                                         Repository                                Size ======================================================================================================================================================================== Installing:  fuse                               x86_64                               2.7.4-8.0.1.el5                                 el5_latest                                85 k Transaction Summary ======================================================================================================================================================================== Install       1 Package(s) Upgrade       0 Package(s) Total download size: 85 k Is this ok [y/N]: y Downloading Packages: fuse-2.7.4-8.0.1.el5.x86_64.rpm                                                                                                                  |  85 kB     00:00      Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction   Installing     : fuse                                                                                                                                             1/1  Installed:   fuse.x86_64 0:2.7.4-8.0.1.el5                                                                                                                                          [root@dm01db01 ~]# yum install fuse-libs Loaded plugins: rhnplugin, security This system is not registered with ULN. ULN support will be disabled. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package fuse-libs.i386 0:2.7.4-8.0.1.el5 set to be updated ---> Package fuse-libs.x86_64 0:2.7.4-8.0.1.el5 set to be updated --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================  Package                                Arch                                Version                                       Repository                               Size ======================================================================================================================================================================== Installing:  fuse-libs                              i386                                2.7.4-8.0.1.el5                               el5_latest                               71 k  fuse-libs                              x86_64                              2.7.4-8.0.1.el5                               el5_latest                               70 k Transaction Summary ======================================================================================================================================================================== Install       2 Package(s) Upgrade       0 Package(s) Total download size: 141 k Is this ok [y/N]: y Downloading Packages: (1/2): fuse-libs-2.7.4-8.0.1.el5.x86_64.rpm                                                                                                      |  70 kB     00:00      (2/2): fuse-libs-2.7.4-8.0.1.el5.i386.rpm                                                                                                        |  71 kB     00:00      ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Total                                                                                                                                    71 kB/s | 141 kB     00:01      Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction   Installing     : fuse-libs                                                                                                                                        1/2    Installing     : fuse-libs                                                                                                                                        2/2  Installed:   fuse-libs.i386 0:2.7.4-8.0.1.el5                                                  fuse-libs.x86_64 0:2.7.4-8.0.1.el5                                                  Complete! [root@dm01db01 ~]# yum install fuse-devel Loaded plugins: rhnplugin, security This system is not registered with ULN. ULN support will be disabled. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package fuse-devel.i386 0:2.7.4-8.0.1.el5 set to be updated ---> Package fuse-devel.x86_64 0:2.7.4-8.0.1.el5 set to be updated --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================  Package                                 Arch                                Version                                      Repository                               Size ======================================================================================================================================================================== Installing:  fuse-devel                              i386                                2.7.4-8.0.1.el5                              el5_latest                               28 k  fuse-devel                              x86_64                              2.7.4-8.0.1.el5                              el5_latest                               28 k Transaction Summary ======================================================================================================================================================================== Install       2 Package(s) Upgrade       0 Package(s) Total download size: 57 k Is this ok [y/N]: y Downloading Packages: (1/2): fuse-devel-2.7.4-8.0.1.el5.x86_64.rpm                                                                                                     |  28 kB     00:00      (2/2): fuse-devel-2.7.4-8.0.1.el5.i386.rpm                                                                                                       |  28 kB     00:00      ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Total                                                                                                                                    21 kB/s |  57 kB     00:02      Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction   Installing     : fuse-devel                                                                                                                                       1/2    Installing     : fuse-devel                                                                                                                                       2/2  Installed:   fuse-devel.i386 0:2.7.4-8.0.1.el5                                                 fuse-devel.x86_64 0:2.7.4-8.0.1.el5                                                 Complete! 2. ?? DBFS??? ?????? cd $ORACLE_HOME/rdbms/admin sqlplus / as sysdba Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP, Data Mining and Real Application Testing options SQL> @prvtfspi.plb Package body created. No errors. Package body created. No errors. ?????dbms_dbfs_sfs package  SQL> create tablespace dbfstbs datafile size 20g; Tablespace created. SQL> create user maclean_dbfs identified by oracle; User created. SQL> grant dba to maclean_dbfs; Grant succeeded. @@!!! SQL> grant  dbfs_role to maclean_dbfs; Grant succeeded. 3. ??DBFS SQL> conn maclean_dbfs/oracle Connected. SQL> @?/rdbms/admin/dbfs_create_filesystem.sql  dbfstbs mac_dbfs   No errors. -------- CREATE STORE: begin dbms_dbfs_sfs.createFilesystem(store_name => 'FS_MAC_DBFS', tbl_name => 'T_MAC_DBFS', tbl_tbs => 'dbfstbs', lob_tbs => 'dbfstbs', do_partition => false, partition_key => 1, do_compress => false, compression => '', do_dedup => false, do_encrypt => false); end; -------- REGISTER STORE: begin dbms_dbfs_content.registerStore(store_name=> 'FS_MAC_DBFS', provider_name => 'sample1', provider_package => 'dbms_dbfs_sfs'); end; -------- MOUNT STORE: begin dbms_dbfs_content.mountStore(store_name=>'FS_MAC_DBFS', store_mount=>'mac_dbfs'); end; -------- CHMOD STORE: declare m integer; begin m := dbms_fuse.fs_chmod('/mac_dbfs', 16895); end; No errors. 4.  ??mount point  [root@dm01db01 ~]# mkdir /dbfs [root@dm01db01 ~]# chown oracle:oinstall /dbfs 5. ??library path ?OS  # echo "/usr/local/lib" >> /etc/ld.so.conf.d/usr_local_lib.conf 6. ?????? export ORACLE_HOME=/s01/orabase/product/11.2.0/dbhome_1 [root@dm01db01 ~]# ln -s $ORACLE_HOME/lib/libclntsh.so.11.1 /usr/local/lib/libclntsh.so.11.1 [root@dm01db01 ~]#  ln -s $ORACLE_HOME/lib/libnnz11.so /usr/local/lib/libnnz11.so [root@dm01db01 ~]#  ln -s /lib64/libfuse.so.2 /usr/local/lib/libfuse.so.2 7. ??ldconfig  [root@dm01db01 ~]# ldconfig [root@dm01db01 ~]#  8. ??fusermount??????? [root@dm01db01 ~]#  chmod +x /usr/bin/fusermount [root@dm01db01 ~]#  ls -l /usr/bin/fusermount lrwxrwxrwx 1 root root 15 Sep  7 03:06 /usr/bin/fusermount -> /bin/fusermount [root@dm01db01 ~]#  ls -l /bin/fusermount -rwsr-x--x 1 root fuse 27072 Oct 17  2011 /bin/fusermount 9. ???????OS  dbfs_client maclean_dbfs@dm01db01:1521/orcl  /dbfs 10. ????nohup + &?????mount DBFS,???????????? [oracle@dm01db01 ~]$ echo "oracle"  >> dbfs_pw [oracle@dm01db01 ~]$ nohup dbfs_client maclean_dbfs@dm01db01:1521/orcl /dbfs < dbfs_pw & [oracle@dm01db01 ~]$ df -h Filesystem            Size  Used Avail Use% Mounted on /dev/mapper/VGExaDb-LVDbSys1                        30G   15G   14G  53% / /dev/sda1             502M   30M  447M   7% /boot /dev/mapper/VGExaDb-LVDbOra1                        99G   20G   75G  21% /u01 tmpfs                  81G     0   81G   0% /dev/shm dbfs-maclean_dbfs@orcl:/                        20G  120K   20G   1% /dbfs [oracle@dm01db01 ~]$ mount /dev/mapper/VGExaDb-LVDbSys1 on / type ext3 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) /dev/sda1 on /boot type ext3 (rw,nodev) /dev/mapper/VGExaDb-LVDbOra1 on /u01 type ext3 (rw,nodev) tmpfs on /dev/shm type tmpfs (rw,size=82052m) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) dbfs-maclean_dbfs@orcl:/ on /dbfs type fuse (rw,nosuid,nodev,max_read=1048576,default_permissions,user=oracle) [oracle@dm01db01 ~]$ ls -l /dbfs/ total 0 drwxrwxrwx 3 root root 0 Sep 14 05:11 mac_dbfs [oracle@nas ~]$ dbfs_client  --------MOUNT mode: usage: dbfs_client <db_user>@<db_server> [options] <mountpoint>   db_user:              Name of Database user that owns DBFS content repository filesystem(s)   db_server:            A valid connect string for Oracle database server                         (for example, hrdb_host:1521/hrservice)   mountpoint:           Path to mount Database File System(s)                         All the file systems owned by the database user will be seen at the mountpoint. DBFS options:   -o direct_io          Bypass the Linux page cache. Gives much better performance for large files.                         Programs in the file system cannot be executed with this option.                         This option is recommended when DBFS is used as an ETL staging area.   -o wallet             Run dbfs_client in background.                         Wallet must be configured to get credentials.   -o failover           dbfs_client fails over to surviving database instance with no data loss.                         Some performance cost on writes, especially for small files.   -o allow_root         Allows root access to the filesystem.                         This option requires setting 'user_allow_other' parameter in '/etc/fuse.conf'.   -o allow_other        Allows other users access to the file system.                         This option requires setting 'user_allow_other' parameter in '/etc/fuse.conf'.   -o rw                 Mount the filesystem read-write. [Default]   -o ro                 Mount the filesystem read-only. Files cannot be modified.   -o trace_file=STR     Tracing <filename> | 'syslog'   -o trace_level=N      Trace Level: 1->DEBUG, 2->INFO, 3->WARNING, 4->ERROR, 5->CRITICAL [Default: 4]   -h                    help   -V                    version --------COMMAND mode: Usage:     dbfs_client <db_user>@<db_server> --command command [switches] [arguments]             command:          Command to be executed, e.g., ls, cp, mkdir, rm            switches:         Switches are described below for each command.            arguments:        File names or directory names NOTE:      All database pathnames must be absolute and preceded by dbfs:/ Commands   ls            dbfs_client <db_user>@<db_server> --command ls [switches] target      Switches:              -a         Show all files including those starting with '.'            -l         Use a long listing format. In addition to the name of each file                       print the file type, permissions, size, user and group information            -R         List subdirectories recursively cp                     dbfs_client <db_user>@<db_server> --command cp [switches] source destination      Switches:              -r, -R      Copy a directory and its contents recursively into the destination directory rm                     dbfs_client <db_user>@<db_server> --command rm [switches] target      Switches:              -r, -R      Removes a directory and its contents recursively mkdir                  dbfs_client <db_user>@<db_server> --command mkdir directory_name Examples                     dbfs_client ETLUser@DBConnectString --command ls -l -a dbfs:/staging_area/directory1            dbfs_client ETLUser@DBConnectString --command cp -R  /tmp/1-Jan-2009-dump dbfs:/staging_area            dbfs_client ETLUser@DBConnectString --command rm dbfs:/staging_area/hello.txt            dbfs_client ETLUser@DBConnectString --command mkdir dbfs:/staging_area/directory2 [oracle@dm01db01 ~]$ ls -lh /tmp/largefile -rw-r--r-- 1 oracle oinstall 2.0G Sep 14 08:50 /tmp/largefile [oracle@dm01db01 ~]$ time dbfs_client  maclean_dbfs@dm01db01:1521/orcl --command cp /tmp/largefile dbfs:/mac_dbfs Password: /tmp/largefile -> dbfs:/mac_dbfs/largefile real    0m11.802s user    0m0.580s sys     0m2.375s ?Exadata?????2G?????? DBFS???11s => 200MB/s 

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• Guides for PostgreSQL query tuning?

  - by Joe

  I've found a number of resources that talk about tuning the database server, but I haven't found much on the tuning of the individual queries. For instance, in Oracle, I might try adding hints to ignore indexes or to use sort-merge vs. correlated joins, but I can't find much on tuning Postgres other than using explicit joins and recommendations when bulk loading tables. Do any such guides exist so I can focus on tuning the most run and/or underperforming queries, hopefully without adversely affecting the currently well-performing queries? I'd even be happy to find something that compared how certain types of queries performed relative to other databases, so I had a better clue of what sort of things to avoid. update: I should've mentioned, I took all of the Oracle DBA classes along with their data modeling and SQL tuning classes back in the 8i days ... so I know about 'EXPLAIN', but that's more to tell you what's going wrong with the query, not necessarily how to make it better. (eg, are 'while var=1 or var=2' and 'while var in (1,2)' considered the same when generating an execution plan? What if I'm doing it with 10 permutations? When are multi-column indexes used? Are there ways to get the planner to optimize for fastest start vs. fastest finish? What sort of 'gotchas' might I run into when moving from mySQL, Oracle or some other RDBMS?) I could write any complex query dozens if not hundreds of ways, and I'm hoping to not have to try them all and find which one works best through trial and error. I've already found that 'SELECT count(*)' won't use an index, but 'SELECT count(primary_key)' will ... maybe a 'PostgreSQL for experienced SQL users' sort of document that explained sorts of queries to avoid, and how best to re-write them, or how to get the planner to handle them better. update 2: I found a Comparison of different SQL Implementations which covers PostgreSQL, DB2, MS-SQL, mySQL, Oracle and Informix, and explains if, how, and gotchas on things you might try to do, and his references section linked to Oracle / SQL Server / DB2 / Mckoi /MySQL Database Equivalents (which is what its title suggests) and to the wikibook SQL Dialects Reference which covers whatever people contribute (includes some DB2, SQLite, mySQL, PostgreSQL, Firebird, Vituoso, Oracle, MS-SQL, Ingres, and Linter).

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• SubSonic 2.x now supports TVP's - SqlDbType.Structure / DataTables for SQL Server 2008

  - by ElHaix

  For those interested, I have now modified the SubSonic 2.x code to recognize and support DataTable parameter types. You can read more about SQL Server 2008 features here: http://download.microsoft.com/download/4/9/0/4906f81b-eb1a-49c3-bb05-ff3bcbb5d5ae/SQL%20SERVER%202008-RDBMS/T-SQL%20Enhancements%20with%20SQL%20Server%202008%20-%20Praveen%20Srivatsav.pdf What this enhancement will now allow you to do is to create a partial StoredProcedures.cs class, with a method that overrides the stored procedure wrapper method. A bit about good form: My DAL has no direct table access, and my DB only has execute permissions for that user to my sprocs. As such, SubSonic only generates the AllStructs and StoredProcedures classes. The SPROC: ALTER PROCEDURE [dbo].[testInsertToTestTVP] @UserDetails TestTVP READONLY, @Result INT OUT AS BEGIN SET NOCOUNT ON; SET @Result = -1 --SET IDENTITY_INSERT [dbo].[tbl_TestTVP] ON INSERT INTO [dbo].[tbl_TestTVP] ( [GroupInsertID], [FirstName], [LastName] ) SELECT [GroupInsertID], [FirstName], [LastName] FROM @UserDetails IF @@ROWCOUNT > 0 BEGIN SET @Result = 1 SELECT @Result RETURN @Result END --SET IDENTITY_INSERT [dbo].[tbl_TestTVP] OFF END The TVP: CREATE TYPE [dbo].[TestTVP] AS TABLE( [GroupInsertID] [varchar](50) NOT NULL, [FirstName] [varchar](50) NOT NULL, [LastName] [varchar](50) NOT NULL ) GO The the auto gen tool runs, it creates the following erroneous method: /// <summary> /// Creates an object wrapper for the testInsertToTestTVP Procedure /// </summary> public static StoredProcedure TestInsertToTestTVP(string UserDetails, int? Result) { SubSonic.StoredProcedure sp = new SubSonic.StoredProcedure("testInsertToTestTVP", DataService.GetInstance("MyDAL"), "dbo"); sp.Command.AddParameter("@UserDetails", UserDetails, DbType.AnsiString, null, null); sp.Command.AddOutputParameter("@Result", DbType.Int32, 0, 10); return sp; } It sets UserDetails as type string. As it's good form to have two folders for a SubSonic DAL - Custom and Generated, I created a StoredProcedures.cs partial class in Custom that looks like this: /// <summary> /// Creates an object wrapper for the testInsertToTestTVP Procedure /// </summary> public static StoredProcedure TestInsertToTestTVP(DataTable dt, int? Result) { DataSet ds = new DataSet(); SubSonic.StoredProcedure sp = new SubSonic.StoredProcedure("testInsertToTestTVP", DataService.GetInstance("MyDAL"), "dbo"); // TODO: Modify the SubSonic code base in sp.Command.AddParameter to accept // a parameter type of System.Data.SqlDbType.Structured, as it currently only accepts // System.Data.DbType. //sp.Command.AddParameter("@UserDetails", dt, System.Data.SqlDbType.Structured null, null); sp.Command.AddParameter("@UserDetails", dt, SqlDbType.Structured); sp.Command.AddOutputParameter("@Result", DbType.Int32, 0, 10); return sp; } As you can see, the method signature now contains a DataTable, and with my modification to the SubSonic framework, this now works perfectly. I'm wondering if the SubSonic guys can modify the auto-gen to recognize a TVP in a sproc signature, as to avoid having to re-write the warpper? Does SubSonic 3.x support Structured data types? Also, I'm sure many will be interested in using this code, so where can I upload the new code? Thanks.

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• JPA Entity Manager resource handling

  - by chiragshahkapadia

  Every time I call JPA method its creating entity and binding query. My persistence properties are: <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect"/> <property name="hibernate.cache.provider_class" value="net.sf.ehcache.hibernate.SingletonEhCacheProvider"/> <property name="hibernate.cache.use_second_level_cache" value="true"/> <property name="hibernate.cache.use_query_cache" value="true"/> And I am creating entity manager the way shown below: emf = Persistence.createEntityManagerFactory("pu"); em = emf.createEntityManager(); em = Persistence.createEntityManagerFactory("pu").createEntityManager(); Is there any nice way to manage entity manager resource instead create new every time or any property can set in persistence. Remember it's JPA. See below binding log every time : 15:35:15,527 INFO [AnnotationBinder] Binding entity from annotated class: * 15:35:15,527 INFO [QueryBinder] Binding Named query: * = * 15:35:15,527 INFO [QueryBinder] Binding Named query: * = * 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [EntityBinder] Bind entity com.* on table * 15:35:15,542 INFO [HibernateSearchEventListenerRegister] Unable to find org.hibernate.search.event.FullTextIndexEventListener on the classpath. Hibernate Search is not enabled. 15:35:15,542 INFO [NamingHelper] JNDI InitialContext properties:{} 15:35:15,542 INFO [DatasourceConnectionProvider] Using datasource: 15:35:15,542 INFO [SettingsFactory] RDBMS: and Real Application Testing options 15:35:15,542 INFO [SettingsFactory] JDBC driver: Oracle JDBC driver, version: 9.2.0.1.0 15:35:15,542 INFO [Dialect] Using dialect: org.hibernate.dialect.Oracle10gDialect 15:35:15,542 INFO [TransactionFactoryFactory] Transaction strategy: org.hibernate.transaction.JDBCTransactionFactory 15:35:15,542 INFO [TransactionManagerLookupFactory] No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recomm ended) 15:35:15,542 INFO [SettingsFactory] Automatic flush during beforeCompletion(): disabled 15:35:15,542 INFO [SettingsFactory] Automatic session close at end of transaction: disabled 15:35:15,542 INFO [SettingsFactory] JDBC batch size: 15 15:35:15,542 INFO [SettingsFactory] JDBC batch updates for versioned data: disabled 15:35:15,542 INFO [SettingsFactory] Scrollable result sets: enabled 15:35:15,542 INFO [SettingsFactory] JDBC3 getGeneratedKeys(): disabled 15:35:15,542 INFO [SettingsFactory] Connection release mode: auto 15:35:15,542 INFO [SettingsFactory] Default batch fetch size: 1 15:35:15,542 INFO [SettingsFactory] Generate SQL with comments: disabled 15:35:15,542 INFO [SettingsFactory] Order SQL updates by primary key: disabled 15:35:15,542 INFO [SettingsFactory] Order SQL inserts for batching: disabled 15:35:15,542 INFO [SettingsFactory] Query translator: org.hibernate.hql.ast.ASTQueryTranslatorFactory 15:35:15,542 INFO [ASTQueryTranslatorFactory] Using ASTQueryTranslatorFactory 15:35:15,542 INFO [SettingsFactory] Query language substitutions: {} 15:35:15,542 INFO [SettingsFactory] JPA-QL strict compliance: enabled 15:35:15,542 INFO [SettingsFactory] Second-level cache: enabled 15:35:15,542 INFO [SettingsFactory] Query cache: enabled 15:35:15,542 INFO [SettingsFactory] Cache region factory : org.hibernate.cache.impl.bridge.RegionFactoryCacheProviderBridge 15:35:15,542 INFO [RegionFactoryCacheProviderBridge] Cache provider: net.sf.ehcache.hibernate.SingletonEhCacheProvider 15:35:15,542 INFO [SettingsFactory] Optimize cache for minimal puts: disabled 15:35:15,542 INFO [SettingsFactory] Structured second-level cache entries: disabled 15:35:15,542 INFO [SettingsFactory] Query cache factory: org.hibernate.cache.StandardQueryCacheFactory 15:35:15,542 INFO [SettingsFactory] Statistics: disabled 15:35:15,542 INFO [SettingsFactory] Deleted entity synthetic identifier rollback: disabled 15:35:15,542 INFO [SettingsFactory] Default entity-mode: pojo 15:35:15,542 INFO [SettingsFactory] Named query checking : enabled 15:35:15,542 INFO [SessionFactoryImpl] building session factory 15:35:15,542 INFO [SessionFactoryObjectFactory] Not binding factory to JNDI, no JNDI name configured 15:35:15,542 INFO [UpdateTimestampsCache] starting update timestamps cache at region: org.hibernate.cache.UpdateTimestampsCache 15:35:15,542 INFO [StandardQueryCache] starting query cache at region: org.hibernate.cache.StandardQueryCache

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• Web Services Primer for a WinForms Developer?

  - by Unicorns

  I've been writing client/server applications with Winforms for about six years now, but I have yet to venture into the web space (neither ASP.NET nor web services). Given the direction that the job market has been heading for some time and the fact that I have a basic curiosity, I'd like to get involved with writing web services, but I don't know where to start. I've read about various options (XML/SOAP vs. JSON, REST vs...well, actually I don't know what it's called, etc.), but I'm not sure what sort of criteria are in play when making the determination to use one or the other. Obviously, I'd like to leverage the tools that I have (Visual Studio, the .NET framework, etc.) without hamstringing myself into only targeting a particular audience (i.e. writing the service in such a way as to make it difficult to consume from a Windows Mobile/Android/iPhone client, for example). For the record, my plan--for now--is to use WCF for my web service development, but I'm open to using another .NET approach if that's advisable. I realize that this question is pretty open-ended so it may get closed, but here are some things I'm wondering: What are some things to consider when choosing the type of web service (REST, etc.) I intend to write? Is it possible (and, if so, feasible) to move from one approach to another? Can web services be written in an event-driven way? As I said I'm a Winforms developer, so I'm used to objects raising events for me to react to. For instance, if I have two clients connected to my service, is there a way for me to "push" information to one of them as a result of an action by the other? If this is possible, is this advisable or am I just not thinking about it correctly? What authentication mechanisms seem to work best for public-facing services? What about if I plan to have different types of OS'es and clients connecting to the service? Is there a generally accepted platform-agnostic approach? In the line of authentication, is this something that I should be doing myself (authenticating an managing sessions, etc.) or is this something should be handled at the framework level and I just define exactly how it should work? If that's the case, how do I tell who the requester has authenticated themselves as? I started writing an authentication mechanism (simple username/password combinations stored in the database and a corresponding session table with a GUID key) within my service and just requiring that key to be passed with every operation (other than logging in, of course), but I want to make sure that I'm not reinventing the wheel here. However, I also don't want to clutter up the server with a bunch of machine user accounts just to use Basic authentication. I'm also under the impression that Digest (and of course Windows) authentication requires a machine (or AD) user account.

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• NullPointerException using datanucleus-json with S3

  - by Matt

  I'm using datanucleus 3.2.7 from Maven, trying to use the Amazon S3 JPA provider. I can successfully write data into S3, but querying either by using "SELECT u FROM User u" or "SELECT u FROM User u WHERE id = :id" causes a NullPointerException to be thrown. Using the RDBMS provider, everything works perfectly. Is there something I'm doing wrong? Main.java EntityManagerFactory factory = Persistence.createEntityManagerFactory("MyUnit"); EntityManager entityManager = factory.createEntityManager(); Query query = entityManager.createQuery("SELECT u FROM User u", User.class); List<User> users = query.getResultList(); // Null pointer exception here for(User u:users) System.out.println(u); User.java package test; import javax.persistence.*; @Entity @Table(name = "User") public class User { @Id public String id; public String name; public User(String id, String name) { this.id = id; this.name = name; } public String toString() { return id+" : "+name; } } persistence.xml <?xml version="1.0" encoding="UTF-8" ?> <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"> <persistence-unit name="MyUnit"> <class>test.User</class> <exclude-unlisted-classes /> <properties> <properties> <property name="datanucleus.ConnectionURL" value="amazons3:http://s3.amazonaws.com/" /> <property name="datanucleus.ConnectionUserName" value="xxxxx" /> <property name="datanucleus.ConnectionPassword" value="xxxxx" /> <property name="datanucleus.cloud.storage.bucket" value="my-bucket" /> </properties> <property name="datanucleus.autoCreateSchema" value="true" /> </properties> </persistence-unit> </persistence> Exception java.lang.NullPointerException at org.datanucleus.NucleusContext.isClassWithIdentityCacheable(NucleusContext.java:1840) at org.datanucleus.ExecutionContextImpl.getObjectFromLevel2Cache(ExecutionContextImpl.java:5287) at org.datanucleus.ExecutionContextImpl.getObjectFromCache(ExecutionContextImpl.java:5191) at org.datanucleus.ExecutionContextImpl.findObject(ExecutionContextImpl.java:3137) at org.datanucleus.store.json.CloudStoragePersistenceHandler.getObjectsOfCandidateType(CloudStoragePersistenceHandler.java:367) at org.datanucleus.store.json.query.JPQLQuery.performExecute(JPQLQuery.java:94) at org.datanucleus.store.query.Query.executeQuery(Query.java:1786) at org.datanucleus.store.query.Query.executeWithMap(Query.java:1690) at org.datanucleus.api.jpa.JPAQuery.getResultList(JPAQuery.java:194) at test.Main.main(Main.java:16)

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• Persistent (purely functional) Red-Black trees on disk performance

  - by Waneck

  I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

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• Scalable Database Tagging Schema

  - by Longpoke

  EDIT: To people building tagging systems. Don't read this. It is not what you are looking for. I asked this when I wasn't aware that RDBMS all have their own optimization methods, just use a simple many to many scheme. I have a posting system that has millions of posts. Each post can have an infinite number of tags associated with it. Users can create tags which have notes, date created, owner, etc. A tag is almost like a post itself, because people can post notes about the tag. Each tag association has an owner and date, so we can see who added the tag and when. My question is how can I implement this? It has to be fast searching posts by tag, or tags by post. Also, users can add tags to posts by typing the name into a field, kind of like the google search bar, it has to fill in the rest of the tag name for you. I have 3 solutions at the moment, but not sure which is the best, or if there is a better way. Note that I'm not showing the layout of notes since it will be trivial once I get a proper solution for tags. Method 1. Linked list tagId in post points to a linked list in tag_assoc, the application must traverse the list until flink=0 post: id, content, ownerId, date, tagId, notesId tag_assoc: id, tagId, ownerId, flink tag: id, name, notesId Method 2. Denormalization tags is simply a VARCHAR or TEXT field containing a tab delimited array of tagId:ownerId. It cannot be a fixed size. post: id, content, ownerId, date, tags, notesId tag: id, name, notesId Method 3. Toxi (from: http://www.pui.ch/phred/archives/2005/04/tags-database-schemas.html, also same thing here: http://stackoverflow.com/questions/20856/how-do-you-recommend-implementing-tags-or-tagging) post: id, content, ownerId, date, notesId tag_assoc: ownerId, tagId, postId tag: id, name, notesId Method 3 raises the question, how fast will it be to iterate through every single row in tag_assoc? Methods 1 and 2 should be fast for returning tags by post, but for posts by tag, another lookup table must be made. The last thing I have to worry about is optimizing searching tags by name, I have not worked that out yet. I made an ASCII diagram here: http://pastebin.com/f1c4e0e53

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• Which is the "best" data access framework/approach for C# and .NET?

  - by Frans

  (EDIT: I made it a community wiki as it is more suited to a collaborative format.) There are a plethora of ways to access SQL Server and other databases from .NET. All have their pros and cons and it will never be a simple question of which is "best" - the answer will always be "it depends". However, I am looking for a comparison at a high level of the different approaches and frameworks in the context of different levels of systems. For example, I would imagine that for a quick-and-dirty Web 2.0 application the answer would be very different from an in-house Enterprise-level CRUD application. I am aware that there are numerous questions on Stack Overflow dealing with subsets of this question, but I think it would be useful to try to build a summary comparison. I will endeavour to update the question with corrections and clarifications as we go. So far, this is my understanding at a high level - but I am sure it is wrong... I am primarily focusing on the Microsoft approaches to keep this focused. ADO.NET Entity Framework Database agnostic Good because it allows swapping backends in and out Bad because it can hit performance and database vendors are not too happy about it Seems to be MS's preferred route for the future Complicated to learn (though, see 267357) It is accessed through LINQ to Entities so provides ORM, thus allowing abstraction in your code LINQ to SQL Uncertain future (see Is LINQ to SQL truly dead?) Easy to learn (?) Only works with MS SQL Server See also Pros and cons of LINQ "Standard" ADO.NET No ORM No abstraction so you are back to "roll your own" and play with dynamically generated SQL Direct access, allows potentially better performance This ties in to the age-old debate of whether to focus on objects or relational data, to which the answer of course is "it depends on where the bulk of the work is" and since that is an unanswerable question hopefully we don't have to go in to that too much. IMHO, if your application is primarily manipulating large amounts of data, it does not make sense to abstract it too much into objects in the front-end code, you are better off using stored procedures and dynamic SQL to do as much of the work as possible on the back-end. Whereas, if you primarily have user interaction which causes database interaction at the level of tens or hundreds of rows then ORM makes complete sense. So, I guess my argument for good old-fashioned ADO.NET would be in the case where you manipulate and modify large datasets, in which case you will benefit from the direct access to the backend. Another case, of course, is where you have to access a legacy database that is already guarded by stored procedures. ASP.NET Data Source Controls Are these something altogether different or just a layer over standard ADO.NET? - Would you really use these if you had a DAL or if you implemented LINQ or Entities? NHibernate Seems to be a very powerful and powerful ORM? Open source Some other relevant links; NHibernate or LINQ to SQL Entity Framework vs LINQ to SQL

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• What does Apache need to support both mysqli and PDO?

  - by Nathan Long

  I'm considering changing some PHP code to use PDO for database access instead of mysqli (because the PDO syntax makes more sense to me and is database-agnostic). To do that, I'd need both methods to work while I'm making the changeover. My problem is this: so far, either one or the other method will crash Apache. Right now I'm using XAMPP in Windows XP, and PHP Version 5.2.8. Mysqli works fine, and so does this: $dbc = new PDO("mysql:host=$hostname;dbname=$dbname", $username, $password); echo 'Connected to database'; $sql = "SELECT * FROM `employee`"; But this line makes Apache crash: $dbc->query($sql); I don't want to redo my entire Apache or XAMPP installation, but I'd like for PDO to work. So I tried updating libmysql.dll from here, as oddvibes recommended here. That made my simple PDO query work, but then mysqli queries crashed Apache. (I also tried the suggestion after that one, to update php_pdo_mysql.dll and php_pdo.dll, to no effect.) Test Case I created this test script to compare PDO vs mysqli. With the old copy of libmysql.dll, it crashes if $use_pdo is true and doesn't if it's false. With the new copy of libmysql.dll, it's the opposite. if ($use_pdo){ $dbc = new PDO("mysql:host=$hostname;dbname=$dbname", $username, $password); echo 'Connected to database<br />'; $sql = "SELECT * FROM `employee`"; $dbc->query($sql); foreach ($dbc->query($sql) as $row){ echo $row['firstname'] . ' ' . $row['lastname'] . "<br>\n"; } } else { $dbc = @mysqli_connect($hostname, $username, $password, $dbname) OR die('Could not connect to MySQL: ' . mysqli_connect_error()); $sql = "SELECT * FROM `employee`"; $result = @mysqli_query($dbc, $sql) or die(mysqli_error($dbc)); while ($row = mysqli_fetch_array($result,MYSQLI_ASSOC)) { echo $row['firstname'] . ' ' . $row['lastname'] . "<br>\n"; } } What does Apache need in order to support both methods of database query?

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• How to setup Lucene/Solr for a B2B web app?

  - by Bill Paetzke

  Given: 1 database per client (business customer) 5000 clients Clients have between 2 to 2000 users (avg is ~100 users/client) 100k to 10 million records per database Users need to search those records often (it's the best way to navigate their data) Possibly relevant info: Several new clients each week (any time during business hours) Multiple web servers and database servers (users can login via any web server) Let's stay agnostic of language or sql brand, since Lucene (and Solr) have a breadth of support For Example: Joel Spolsky said in Podcast #11 that his hosted web app product, FogBugz On-Demand, uses Lucene. He has thousands of on-demand clients. And each client gets their own database. They use an index per client and store it in the client's database. I'm not sure on the details. And I'm not sure if this is a serious mod to Lucene. The Question: How would you setup Lucene search so that each client can only search within its database? How would you setup the index(es)? Where do you store the index(es)? Would you need to add a filter to all search queries? If a client cancelled, how would you delete their (part of the) index? (this may be trivial--not sure yet) Possible Solutions: Make an index for each client (database) Pro: Search is faster (than one-index-for-all method). Indices are relative to the size of the client's data. Con: I'm not sure what this entails, nor do I know if this is beyond Lucene's scope. Have a single, gigantic index with a database_name field. Always include database_name as a filter. Pro: Not sure. Maybe good for tech support or billing dept to search all databases for info. Con: Search is slower (than index-per-client method). Flawed security if query filter removed. One last thing: I would also accept an answer that uses Solr (the extension of Lucene). Perhaps it's better suited for this problem. Not sure.

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• Is this a problem typically solved with IOC?

  - by Dirk

  My current application allows users to define custom web forms through a set of admin screens. it's essentially an EAV type application. As such, I can't hard code HTML or ASP.NET markup to render a given page. Instead, the UI requests an instance of a Form object from the service layer, which in turn constructs one using a several RDMBS tables. Form contains the kind of classes you would expect to see in such a context: Form= IEnumerable<FormSections>=IEnumerable<FormFields> Here's what the service layer looks like: public class MyFormService: IFormService{ public Form OpenForm(int formId){ //construct and return a concrete implementation of Form } } Everything works splendidly (for a while). The UI is none the wiser about what sections/fields exist in a given form: It happily renders the Form object it receives into a functional ASP.NET page. A few weeks later, I get a new requirement from the business: When viewing a non-editable (i.e. read-only) versions of a form, certain field values should be merged together and other contrived/calculated fields should are added. No problem I say. Simply amend my service class so that its methods are more explicit: public class MyFormService: IFormService{ public Form OpenFormForEditing(int formId){ //construct and return a concrete implementation of Form } public Form OpenFormForViewing(int formId){ //construct and a concrete implementation of Form //apply additional transformations to the form } } Again everything works great and balance has been restored to the force. The UI continues to be agnostic as to what is in the Form, and our separation of concerns is achieved. Only a few short weeks later, however, the business puts out a new requirement: in certain scenarios, we should apply only some of the form transformations I referenced above. At this point, it feels like the "explicit method" approach has reached a dead end, unless I want to end up with an explosion of methods (OpenFormViewingScenario1, OpenFormViewingScenario2, etc). Instead, I introduce another level of indirection: public interface IFormViewCreator{ void CreateView(Form form); } public class MyFormService: IFormService{ public Form OpenFormForEditing(int formId){ //construct and return a concrete implementation of Form } public Form OpenFormForViewing(int formId, IFormViewCreator formViewCreator){ //construct a concrete implementation of Form //apply transformations to the dynamic field list return formViewCreator.CreateView(form); } } On the surface, this seems like acceptable approach and yet there is a certain smell. Namely, the UI, which had been living in ignorant bliss about the implementation details of OpenFormForViewing, must possess knowledge of and create an instance of IFormViewCreator. My questions are twofold: Is there a better way to achieve the composability I'm after? (perhaps by using an IoC container or a home rolled factory to create the concrete IFormViewCreator)? Did I fundamentally screw up the abstraction here?

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• Pushing DNSSEC updates with offline keys

  - by eggyal

  In a non-professional capacity, I look after the DNS of some 18 domains: mostly personal/vanity domains for immediate family. I outsource the whole shebang to an inexpensive managed hosting provider with a web interface through which I manage the zones; since the provider also offers DNSSEC, I have successfully deployed that too. These domains are so unimportant that an attack targetted against them seems much less likely than a general compromise of my provider's systems, at which point the records of all their customers might be changed to misdirect traffic (perhaps with extremely long TTLs). DNSSEC could protect against such an attack, but only if the zone's private keys are not held by the hosting provider. So, I wonder: how can one keep DNSSEC private keys offline yet still transfer signed zones to an outsourced DNS host? The most obvious answer (to me, at least) is to run one's own shadow/hidden master (from which the provider can slave) and then copy offline-signed zonefiles to the master as required. The problem is that the only machine I (want to*) control is my personal laptop, which usually connects from a typical home ADSL (behind NAT over a dynamically-assigned IP address). Having them slave from that (e.g. with a very long Expiry time on the zone for periods when my laptop is offline/unavailable) would not only require a Dynamic DNS record from which they can slave (if indeed they can slave from a named host rather than a static IP address), but would also involve me running a DNS server on my laptop and opening both it and my home network up to the incoming zone transfer requests: not ideal. I would prefer a much more push-oriented design, whereby my laptop initiates transfer of offline-signed zonefiles/updates to the provider's servers. I looked into whether nsupdate could fit the bill: documentation is a little sketchy, but my testing (with BIND 9.7) suggests it can indeed update DNSSEC zones, but only where the server holds the keys to perform the zone signing; I have not found a way to have it take an update including the relevant RRSIG/NSEC/etc. records and have the server accept them. Is this a supported use-case? If not, I suspect the only solutions which could fit the bill will involve non-DNS-based transfer of the zone updates and would welcome recommendations that are supported by (hopefully inexpensive) hosting providers: SFTP/SCP? rsync? RDBMS replication? Proprietary API? Finally, what would be the practical implications of such a setup? Key rotation is jumping out at me as being an obvious difficulty, especially if my laptop is offline for extended periods. But the zones are extremely stable, so perhaps I could get away with long-lived ZSKs**...? * Whilst I could run a shadow/hidden master on e.g. an outsourced VPS, I dislike the overhead of having to secure / manage / monitor / maintain yet another system; not to mention the additional financial costs of so doing. ** Okay, this would enable a concerted attacker to replay outdated records—but the risk and impact of such are both tolerable in the case of these domains.

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• Parallelism in .NET – Part 15, Making Tasks Run: The TaskScheduler

  - by Reed

  In my introduction to the Task class, I specifically made mention that the Task class does not directly provide it’s own execution.  In addition, I made a strong point that the Task class itself is not directly related to threads or multithreading.  Rather, the Task class is used to implement our decomposition of tasks.  Once we’ve implemented our tasks, we need to execute them.  In the Task Parallel Library, the execution of Tasks is handled via an instance of the TaskScheduler class. The TaskScheduler class is an abstract class which provides a single function: it schedules the tasks and executes them within an appropriate context.  This class is the class which actually runs individual Task instances.  The .NET Framework provides two (internal) implementations of the TaskScheduler class. Since a Task, based on our decomposition, should be a self-contained piece of code, parallel execution makes sense when executing tasks.  The default implementation of the TaskScheduler class, and the one most often used, is based on the ThreadPool.  This can be retrieved via the TaskScheduler.Default property, and is, by default, what is used when we just start a Task instance with Task.Start(). Normally, when a Task is started by the default TaskScheduler, the task will be treated as a single work item, and run on a ThreadPool thread.  This pools tasks, and provides Task instances all of the advantages of the ThreadPool, including thread pooling for reduced resource usage, and an upper cap on the number of work items.  In addition, .NET 4 brings us a much improved thread pool, providing work stealing and reduced locking within the thread pool queues.  By using the default TaskScheduler, our Tasks are run asynchronously on the ThreadPool. There is one notable exception to my above statements when using the default TaskScheduler.  If a Task is created with the TaskCreationOptions set to TaskCreationOptions.LongRunning, the default TaskScheduler will generate a new thread for that Task, at least in the current implementation.  This is useful for Tasks which will persist for most of the lifetime of your application, since it prevents your Task from starving the ThreadPool of one of it’s work threads. The Task Parallel Library provides one other implementation of the TaskScheduler class.  In addition to providing a way to schedule tasks on the ThreadPool, the framework allows you to create a TaskScheduler which works within a specified SynchronizationContext.  This scheduler can be retrieved within a thread that provides a valid SynchronizationContext by calling the TaskScheduler.FromCurrentSynchronizationContext() method. This implementation of TaskScheduler is intended for use with user interface development.  Windows Forms and Windows Presentation Foundation both require any access to user interface controls to occur on the same thread that created the control.  For example, if you want to set the text within a Windows Forms TextBox, and you’re working on a background thread, that UI call must be marshaled back onto the UI thread.  The most common way this is handled depends on the framework being used.  In Windows Forms, Control.Invoke or Control.BeginInvoke is most often used.  In WPF, the equivelent calls are Dispatcher.Invoke or Dispatcher.BeginInvoke. As an example, say we’re working on a background thread, and we want to update a TextBlock in our user interface with a status label.  The code would typically look something like: // Within background thread work... string status = GetUpdatedStatus(); Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action( () => { statusLabel.Text = status; })); // Continue on in background method .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This works fine, but forces your method to take a dependency on WPF or Windows Forms.  There is an alternative option, however.  Both Windows Forms and WPF, when initialized, setup a SynchronizationContext in their thread, which is available on the UI thread via the SynchronizationContext.Current property.  This context is used by classes such as BackgroundWorker to marshal calls back onto the UI thread in a framework-agnostic manner. The Task Parallel Library provides the same functionality via the TaskScheduler.FromCurrentSynchronizationContext() method.  When setting up our Tasks, as long as we’re working on the UI thread, we can construct a TaskScheduler via: TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); We then can use this scheduler on any thread to marshal data back onto the UI thread.  For example, our code above can then be rewritten as: string status = GetUpdatedStatus(); (new Task(() => { statusLabel.Text = status; })) .Start(uiScheduler); // Continue on in background method This is nice since it allows us to write code that isn’t tied to Windows Forms or WPF, but is still fully functional with those technologies.  I’ll discuss even more uses for the SynchronizationContext based TaskScheduler when I demonstrate task continuations, but even without continuations, this is a very useful construct. In addition to the two implementations provided by the Task Parallel Library, it is possible to implement your own TaskScheduler.  The ParallelExtensionsExtras project within the Samples for Parallel Programming provides nine sample TaskScheduler implementations.  These include schedulers which restrict the maximum number of concurrent tasks, run tasks on a single threaded apartment thread, use a new thread per task, and more.

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• Run Your Tests With Any NUnit Version

  - by Alois Kraus

  I always thought that the NUnit test runners and the test assemblies need to reference the same NUnit.Framework version. I wanted to be able to run my test assemblies with the newest GUI runner (currently 2.5.3). Ok so all I need to do is to reference both NUnit versions the newest one and the official for the current project. There is a nice article form Kent Bogart online how to reference the same assembly multiple times with different versions. The magic works by referencing one NUnit assembly with an alias which does prefix all types inside it. Then I could decorate my tests with the TestFixture and Test attribute from both NUnit versions and everything worked fine except that this was ugly. After playing a little bit around to make it simpler I found that I did not need to reference both NUnit.Framework assemblies. The test runners do not require the TestFixture and Test attribute in their specific version. That is really neat since the test runners are instructed by attributes what to do in a declarative way there is really no need to tie the runners to a specific version. At its core NUnit has this little method hidden to find matching TestFixtures and Tests   public bool CanBuildFrom(Type type) {     if (!(!type.IsAbstract || type.IsSealed))     {         return false;     }     return (((Reflect.HasAttribute(type,           "NUnit.Framework.TestFixtureAttribute", true) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TestAttribute"       , true)) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TestCaseAttribute"   , true)) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TheoryAttribute"     , true)); } That is versioning and backwards compatibility at its best. I tell NUnit what to do by decorating my tests classes with NUnit Attributes and the runner executes my intent without the need to bind me to a specific version. The contract between NUnit versions is actually a bit more complex (think of AssertExceptions) but this is also handled nicely by using not the concrete type but simply to check for the catched exception type by string. What can we learn from this? Versioning can be easy if the contract is small and the users of your library use it in a declarative way (Attributes). Everything beyond it will force you to reference several versions of the same assembly with all its consequences. Type equality is lost between versions so none of your casts will work. That means that you cannot simply use IBigInterface in two versions. You will need a wrapper to call the correct versioned one. To get out of this mess you can use one (and only one) version agnostic driver to encapsulate your business logic from the concrete versions. This is of course more work but as NUnit shows it can be easy. Simplicity is therefore not a nice thing to have but also requirement number one if you intend to make things more complex in version two and want to support any version (older and newer). Any interaction model above easy will not be maintainable. There are different approached to versioning. Below are my own personal observations how versioning works within the  .NET Framwork and NUnit.   Versioning Models 1. Bug Fixing and New Isolated Features When you only need to fix bugs there is no need to break anything. This is especially true when you have a big API surface. Microsoft did this with the .NET Framework 3.0 which did leave the CLR as is but delivered new assemblies for the features WPF, WCF and Windows Workflow Foundations. Their basic model was that the .NET 2.0 assemblies were declared as red assemblies which must not change (well mostly but each change was carefully reviewed to minimize the risk of breaking changes as much as possible) whereas the new green assemblies of .NET 3,3.5 did not have such obligations since they did implement new unrelated features which did not have any impact on the red assemblies. This is versioning strategy aimed at maximum compatibility and the delivery of new unrelated features. If you have a big API surface you should strive hard to do the same or you will break your customers code with every release. 2. New Breaking Features There are times when really new things need to be added to an existing product. The .NET Framework 4.0 did change the CLR in many ways which caused subtle different behavior although the API´s remained largely unchanged. Sometimes it is possible to simply recompile an application to make it work (e.g. changed method signature void Func() –> bool Func()) but behavioral changes need much more thought and cannot be automated. To minimize the impact .NET 2.0,3.0,3.5 applications will not automatically use the .NET 4.0 runtime when installed but they will keep using the “old” one. What is interesting is that a side by side execution model of both CLR versions (2 and 4) within one process is possible. Key to success was total isolation. You will have 2 GCs, 2 JIT compilers, 2 finalizer threads within one process. The two .NET runtimes cannot talk  (except via the usual IPC mechanisms) to each other. Both runtimes share nothing and run independently within the same process. This enables Explorer plugins written for the CLR 2.0 to work even when a CLR 4 plugin is already running inside the Explorer process. The price for isolation is an increased memory footprint because everything is loaded and running two times.   3. New Non Breaking Features It really depends where you break things. NUnit has evolved and many different Assert, Expect… methods have been added. These changes are all localized in the NUnit.Framework assembly which can be easily extended. As long as the test execution contract (TestFixture, Test, AssertException) remains stable it is possible to write test executors which can run tests written for NUnit 10 because the execution contract has not changed. It is possible to write software which executes other components in a version independent way but this is only feasible if the interaction model is relatively simple.   Versioning software is hard and it looks like it will remain hard since you suddenly work in a severely constrained environment when you try to innovate and to keep everything backwards compatible at the same time. These are contradicting goals and do not play well together. The easiest way out of this is to carefully watch what your customers are doing with your software. Minimizing the impact is much easier when you do not need to guess how many people will be broken when this or that is removed.

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• Listing common SQL Code Smells.

  - by Phil Factor

  Once you’ve done a number of SQL Code-reviews, you’ll know those signs in the code that all might not be well. These ’Code Smells’ are coding styles that don’t directly cause a bug, but are indicators that all is not well with the code. . Kent Beck and Massimo Arnoldi seem to have coined the phrase in the "OnceAndOnlyOnce" page of www.C2.com, where Kent also said that code "wants to be simple". Bad Smells in Code was an essay by Kent Beck and Martin Fowler, published as Chapter 3 of the book ‘Refactoring: Improving the Design of Existing Code’ (ISBN 978-0201485677) Although there are generic code-smells, SQL has its own particular coding habits that will alert the programmer to the need to re-factor what has been written. See Exploring Smelly Code   and Code Deodorants for Code Smells by Nick Harrison for a grounding in Code Smells in C# I’ve always been tempted by the idea of automating a preliminary code-review for SQL. It would be so useful to trawl through code and pick up the various problems, much like the classic ‘Lint’ did for C, and how the Code Metrics plug-in for .NET Reflector by Jonathan 'Peli' de Halleux is used for finding Code Smells in .NET code. The problem is that few of the standard procedural code smells are relevant to SQL, and we need an agreed list of code smells. Merrilll Aldrich made a grand start last year in his blog Top 10 T-SQL Code Smells.However, I'd like to make a start by discovering if there is a general opinion amongst Database developers what the most important SQL Smells are. One can be a bit defensive about code smells. I will cheerfully write very long stored procedures, even though they are frowned on. I’ll use dynamic SQL occasionally. You can only use them as an aid for your own judgment and it is fine to ‘sign them off’ as being appropriate in particular circumstances. Also, whole classes of ‘code smells’ may be irrelevant for a particular database. The use of proprietary SQL, for example, is only a ‘code smell’ if there is a chance that the database will have to be ported to another RDBMS. The use of dynamic SQL is a risk only with certain security models. As the saying goes,  a CodeSmell is a hint of possible bad practice to a pragmatist, but a sure sign of bad practice to a purist. Plamen Ratchev’s wonderful article Ten Common SQL Programming Mistakes lists some of these ‘code smells’ along with out-and-out mistakes, but there are more. The use of nested transactions, for example, isn’t entirely incorrect, even though the database engine ignores all but the outermost: but it does flag up the possibility that the programmer thinks that nested transactions are supported. If anything requires some sort of general agreement, the definition of code smells is one. I’m therefore going to make this Blog ‘dynamic, in that, if anyone twitters a suggestion with a #SQLCodeSmells tag (or sends me a twitter) I’ll update the list here. If you add a comment to the blog with a suggestion of what should be added or removed, I’ll do my best to oblige. In other words, I’ll try to keep this blog up to date. The name against each 'smell' is the name of the person who Twittered me, commented about or who has written about the 'smell'. it does not imply that they were the first ever to think of the smell! Use of deprecated syntax such as *= (Dave Howard) Denormalisation that requires the shredding of the contents of columns. (Merrill Aldrich) Contrived interfaces Use of deprecated datatypes such as TEXT/NTEXT (Dave Howard) Datatype mis-matches in predicates that rely on implicit conversion.(Plamen Ratchev) Using Correlated subqueries instead of a join   (Dave_Levy/ Plamen Ratchev) The use of Hints in queries, especially NOLOCK (Dave Howard /Mike Reigler) Few or No comments. Use of functions in a WHERE clause. (Anil Das) Overuse of scalar UDFs (Dave Howard, Plamen Ratchev) Excessive ‘overloading’ of routines. The use of Exec xp_cmdShell (Merrill Aldrich) Excessive use of brackets. (Dave Levy) Lack of the use of a semicolon to terminate statements Use of non-SARGable functions on indexed columns in predicates (Plamen Ratchev) Duplicated code, or strikingly similar code. Misuse of SELECT * (Plamen Ratchev) Overuse of Cursors (Everyone. Special mention to Dave Levy & Adrian Hills) Overuse of CLR routines when not necessary (Sam Stange) Same column name in different tables with different datatypes. (Ian Stirk) Use of ‘broken’ functions such as ‘ISNUMERIC’ without additional checks. Excessive use of the WHILE loop (Merrill Aldrich) INSERT ... EXEC (Merrill Aldrich) The use of stored procedures where a view is sufficient (Merrill Aldrich) Not using two-part object names (Merrill Aldrich) Using INSERT INTO without specifying the columns and their order (Merrill Aldrich) Full outer joins even when they are not needed. (Plamen Ratchev) Huge stored procedures (hundreds/thousands of lines). Stored procedures that can produce different columns, or order of columns in their results, depending on the inputs. Code that is never used. Complex and nested conditionals WHILE (not done) loops without an error exit. Variable name same as the Datatype Vague identifiers. Storing complex data  or list in a character map, bitmap or XML field User procedures with sp_ prefix (Aaron Bertrand)Views that reference views that reference views that reference views (Aaron Bertrand) Inappropriate use of sql_variant (Neil Hambly) Errors with identity scope using SCOPE_IDENTITY @@IDENTITY or IDENT_CURRENT (Neil Hambly, Aaron Bertrand) Schemas that involve multiple dated copies of the same table instead of partitions (Matt Whitfield-Atlantis UK) Scalar UDFs that do data lookups (poor man's join) (Matt Whitfield-Atlantis UK) Code that allows SQL Injection (Mladen Prajdic) Tables without clustered indexes (Matt Whitfield-Atlantis UK) Use of "SELECT DISTINCT" to mask a join problem (Nick Harrison) Multiple stored procedures with nearly identical implementation. (Nick Harrison) Excessive column aliasing may point to a problem or it could be a mapping implementation. (Nick Harrison) Joining "too many" tables in a query. (Nick Harrison) Stored procedure returning more than one record set. (Nick Harrison) A NOT LIKE condition (Nick Harrison) excessive "OR" conditions. (Nick Harrison) User procedures with sp_ prefix (Aaron Bertrand) Views that reference views that reference views that reference views (Aaron Bertrand) sp_OACreate or anything related to it (Bill Fellows) Prefixing names with tbl_, vw_, fn_, and usp_ ('tibbling') (Jeremiah Peschka) Aliases that go a,b,c,d,e... (Dave Levy/Diane McNurlan) Overweight Queries (e.g. 4 inner joins, 8 left joins, 4 derived tables, 10 subqueries, 8 clustered GUIDs, 2 UDFs, 6 case statements = 1 query) (Robert L Davis) Order by 3,2 (Dave Levy) MultiStatement Table functions which are then filtered 'Sel * from Udf() where Udf.Col = Something' (Dave Ballantyne) running a SQL 2008 system in SQL 2000 compatibility mode(John Stafford)

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• CodePlex Daily Summary for Thursday, April 08, 2010

  CodePlex Daily Summary for Thursday, April 08, 2010New ProjectsBackUpAnyWhere: BackUpAnyWhereCustomFormbyEndUser: 在项目开发中，经常遇到不同的用户对同一报表有不同要求的情况，有时甚至用户需要从头生成一个报表，在以前可能使用第三方的开发工具来实现。在SQL Server2005中，通过使用Reporting Services可以使最终用户不通过编码，只要了解数据结构就能自行编辑报表。本例使用Adventur...DbExecutor - linq based database executor: IEnumerable based database reader. (linq like primitive sql executor)DeepZoomRenderingPack: A collection of libraries and plug-ins architecture that turns various files (like PDF, PS, etc.) into a "Visual" representation that the DeepZoom ...DotNetNuke Russian Language packs: DNNRussianLP - DotNetNuke Russian Language pack. F# Refactor: Deisgned to bring Code Refactoring capabilities to the F# Language in Visual Studio 2010. Invocando WebService e Site HTTP dinamicamente com HTTPWebRequest C#: Invocando Site HTTP e WebService dinamicamente com HTTPWebRequest Passando o SoapAction e Envelope XML Escrito em C# www.biztalkbrasil.c...Jitbit WYSWYG BBCode Editor: "Jitbit WYSIWYG-BBCode" is a browser-based JavaScript-powered WYSIWYG BBCode editorMRDS Services for Phidgets: MRDS (Microsoft Robotics Developer Studio) Services for Phidgets provides additional services for Phidgets sensors and controllers that are not inc...MSBuild Addin: This tool is a simple addin for VisualStudio 2008 used in association with Microsoft MSBuild. It allows you to run MSBuild directly inside Visual S...NISHIL-BizTalk Custom Eventlog Functiod: While testing our maps at times when it fails we cant trace it because we don’t know what the output of the functiods are. Normally in a single ma...Northest GNSG: Supinfo B3C Paris Northest University project. Galego, Neveu, Simon, Geissmann.Oily: Composite application project for oil parameters. It's developed in C#Outlook.Utility: The MSDN article Outlook Customization for Integrating with Enterprise Applications at http://msdn.microsoft.com/en-us/library/Aa479345 has quite a...Particle Plot Pivot: Scan select particle physics experiment web sites for plots and generate a Pivot display for easy browsing.project tca: project tca - translating chat application. Satisfyr: A new way of performing assertions on tests so that they remain agnostic to the underlying test framework, and leverage .NET built-in lambda syntax.sejce2008: jce se course wiki and projects linksSGB Controls: SGB Controls is a set of standard .net controls that include a number of enhancements to make life easier for the developer. These controls incl...Syringe: Syringe is a lightweight service container and dependency injection library designed for use with ASP.NET MVC2. Supported features: Dependency inj...topicbox: topicboxUr-Index: Ur-Index makes it a lot easier to create onomastic indexes for books in pdf format.VietGeeks ZohoDocApis: Implement .NET Zoho Document Apis library to help developer can intergrate Zoho Docs easy with their websitesWebometrics Dashboard: Webometrics Dashboardwebpress: It is a WebBased CMS and Blog platform.WPF Ink Canvas Toolbar: WPF Ink Canvas Toolbar makes it easy for WPF developers to use pen input in TabletPC or UMPC applications. The WPF InkCanvas control has drawing, e...WS-TMS: WS GISG HTT TMSNew ReleasesBatterySaver: Version 1.0: Fixed battery increase/decrease events not firing Fixed memory corruption error Added working set trimming (used very sparingly) Fixed poorly rende...Chargify.NET: Chargify.NET 0.65: Added in Transactions, Subscription Re-activation, and finally XML documentation (which has been missing in the previous releases).DbExecutor - linq based database executor: DbExecutor ver.1.0.0.1: renameDotNetNuke Russian Language packs: Russian Language Pack for DotNetNuke 04.09.02: Russian Language Pack for DotNetNuke 04.09.02Encrypted Notes: Encrypted Notes 1.6.3: This is the latest version of Encrypted Notes (1.6.3), with general improvements. It has an installer that will create a directory 'CPascoe' in My ...Invocando WebService e Site HTTP dinamicamente com HTTPWebRequest C#: Código projeto CallSiteHTTP: Código escrito em C#.NET 2.0 - VS2005 Contem: Solution completa(código e executável) XML de configuração - Config.xml ...Jitbit WYSWYG BBCode Editor: Main package: Contains the JS-file, CSS-file and a sample.Live Writer Picasa Plugin: Live Writer Picasa Plugin 1.1.0: Changelog Communication with Picasa Web Albums is done directly via HTTP now (v1.0.0 used Google's GData .NET Libraries) The plugin can search fo...MRDS Services for Phidgets: Phidgets for RDS 2008 R3: First Beta Release This ZIP file contains a web page called Readme_CodePlex.html that explains how to install the RDS Phidgets services for RDS 200...MSBuild Addin: MsBuildAddin-v1.0.0: Initial versionMSBuild Addin: MsBuildAddin-v1.0.0-src.zip: Initial versionOutlook.Utility: Outlook.Utility v1: I have used most of the code in previous projects and seems to be quite stable. Of course the point of open sourcing this is so this project is use...Scrum Dashboard: Scrum Dashboard v3 Alpha 1: Scrum Dashboard v3 is targeting .NET 4, TFS 2010 and the brand new Scrum for Team System v3 process templates. Most of the code has been rewritten ...SharePoint Labs: SPLab4004A-FRA-Level100: SPLab4004A-FRA-Level100 This SharePoint Lab will teach you the 4th best practice you should apply when writing code with the SharePoint API. Lab La...SharePoint Labs: SPLab5012A-FRA-Level100: SPLab5012A-FRA-Level100 This SharePoint Lab will teach you how to provision a new welcome page (how to change and rename the default.aspx page) on ...Shweet: SharePoint 2010 Team Messaging built with Pex: Shweet Source Code: Although the latest version pex and moles used with this project is not available, we thought it would be useful to provide a download to the source.Syringe: Syringe 1.0: Features Dependency injection on properties of services in container Dependency injection on constructors of services in container ASP.Net Mvc ...Text to HTML: 0.4.1.0: Cambios de la versiónOptimización del código de exportación reduciendo el código. Cambio en el icono de exportación. Añadido menú Seleccionar t...VsTortoise - a TortoiseSVN add-in for Microsoft Visual Studio: VsTortoise Build 23: Build 23 Fix: Executing "Blame" through the Solution Explorer on a file opens TortoiseMerge rather than TortoiseBlame. Build 22 (beta) New: Visua...WPF Ink Canvas Toolbar: WPF Ink Canvas Toolbar 1.0: First release - included custom colour selectionMost Popular ProjectsRawrWBFS ManagerMicrosoft SQL Server Product Samples: DatabaseASP.NET Ajax LibrarySilverlight ToolkitAJAX Control ToolkitWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesFacebook Developer ToolkitMost Active ProjectsGraffiti CMSnopCommerce. Open Source online shop e-commerce solution.RawrShweet: SharePoint 2010 Team Messaging built with Pexpatterns & practices – Enterprise LibraryAcadsysAutoPocoIonics Isapi Rewrite FilterNcqrs Framework - The CQRS framework for .NETFarseer Physics Engine

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• Thread placement policies on NUMA systems - update

  - by Dave

  In a prior blog entry I noted that Solaris used a "maximum dispersal" placement policy to assign nascent threads to their initial processors. The general idea is that threads should be placed as far away from each other as possible in the resource topology in order to reduce resource contention between concurrently running threads. This policy assumes that resource contention -- pipelines, memory channel contention, destructive interference in the shared caches, etc -- will likely outweigh (a) any potential communication benefits we might achieve by packing our threads more densely onto a subset of the NUMA nodes, and (b) benefits of NUMA affinity between memory allocated by one thread and accessed by other threads. We want our threads spread widely over the system and not packed together. Conceptually, when placing a new thread, the kernel picks the least loaded node NUMA node (the node with lowest aggregate load average), and then the least loaded core on that node, etc. Furthermore, the kernel places threads onto resources -- sockets, cores, pipelines, etc -- without regard to the thread's process membership. That is, initial placement is process-agnostic. Keep reading, though. This description is incorrect. On Solaris 10 on a SPARC T5440 with 4 x T2+ NUMA nodes, if the system is otherwise unloaded and we launch a process that creates 20 compute-bound concurrent threads, then typically we'll see a perfect balance with 5 threads on each node. We see similar behavior on an 8-node x86 x4800 system, where each node has 8 cores and each core is 2-way hyperthreaded. So far so good; this behavior seems in agreement with the policy I described in the 1st paragraph. I recently tried the same experiment on a 4-node T4-4 running Solaris 11. Both the T5440 and T4-4 are 4-node systems that expose 256 logical thread contexts. To my surprise, all 20 threads were placed onto just one NUMA node while the other 3 nodes remained completely idle. I checked the usual suspects such as processor sets inadvertently left around by colleagues, processors left offline, and power management policies, but the system was configured normally. I then launched multiple concurrent instances of the process, and, interestingly, all the threads from the 1st process landed on one node, all the threads from the 2nd process landed on another node, and so on. This happened even if I interleaved thread creating between the processes, so I was relatively sure the effect didn't related to thread creation time, but rather that placement was a function of process membership. I this point I consulted the Solaris sources and talked with folks in the Solaris group. The new Solaris 11 behavior is intentional. The kernel is no longer using a simple maximum dispersal policy, and thread placement is process membership-aware. Now, even if other nodes are completely unloaded, the kernel will still try to pack new threads onto the home lgroup (socket) of the primordial thread until the load average of that node reaches 50%, after which it will pick the next least loaded node as the process's new favorite node for placement. On the T4-4 we have 64 logical thread contexts (strands) per socket (lgroup), so if we launch 48 concurrent threads we will find 32 placed on one node and 16 on some other node. If we launch 64 threads we'll find 32 and 32. That means we can end up with our threads clustered on a small subset of the nodes in a way that's quite different that what we've seen on Solaris 10. So we have a policy that allows process-aware packing but reverts to spreading threads onto other nodes if a node becomes too saturated. It turns out this policy was enabled in Solaris 10, but certain bugs suppressed the mixed packing/spreading behavior. There are configuration variables in /etc/system that allow us to dial the affinity between nascent threads and their primordial thread up and down: see lgrp_expand_proc_thresh, specifically. In the OpenSolaris source code the key routine is mpo_update_tunables(). This method reads the /etc/system variables and sets up some global variables that will subsequently be used by the dispatcher, which calls lgrp_choose() in lgrp.c to place nascent threads. Lgrp_expand_proc_thresh controls how loaded an lgroup must be before we'll consider homing a process's threads to another lgroup. Tune this value lower to have it spread your process's threads out more. To recap, the 'new' policy is as follows. Threads from the same process are packed onto a subset of the strands of a socket (50% for T-series). Once that socket reaches the 50% threshold the kernel then picks another preferred socket for that process. Threads from unrelated processes are spread across sockets. More precisely, different processes may have different preferred sockets (lgroups). Beware that I've simplified and elided details for the purposes of explication. The truth is in the code. Remarks: It's worth noting that initial thread placement is just that. If there's a gross imbalance between the load on different nodes then the kernel will migrate threads to achieve a better and more even distribution over the set of available nodes. Once a thread runs and gains some affinity for a node, however, it becomes "stickier" under the assumption that the thread has residual cache residency on that node, and that memory allocated by that thread resides on that node given the default "first-touch" page-level NUMA allocation policy. Exactly how the various policies interact and which have precedence under what circumstances could the topic of a future blog entry. The scheduler is work-conserving. The x4800 mentioned above is an interesting system. Each of the 8 sockets houses an Intel 7500-series processor. Each processor has 3 coherent QPI links and the system is arranged as a glueless 8-socket twisted ladder "mobius" topology. Nodes are either 1 or 2 hops distant over the QPI links. As an aside the mapping of logical CPUIDs to physical resources is rather interesting on Solaris/x4800. On SPARC/Solaris the CPUID layout is strictly geographic, with the highest order bits identifying the socket, the next lower bits identifying the core within that socket, following by the pipeline (if present) and finally the logical thread context ("strand") on the core. But on Solaris on the x4800 the CPUID layout is as follows. [6:6] identifies the hyperthread on a core; bits [5:3] identify the socket, or package in Intel terminology; bits [2:0] identify the core within a socket. Such low-level details should be of interest only if you're binding threads -- a bad idea, the kernel typically handles placement best -- or if you're writing NUMA-aware code that's aware of the ambient placement and makes decisions accordingly. Solaris introduced the so-called critical-threads mechanism, which is expressed by putting a thread into the FX scheduling class at priority 60. The critical-threads mechanism applies to placement on cores, not on sockets, however. That is, it's an intra-socket policy, not an inter-socket policy. Solaris 11 introduces the Power Aware Dispatcher (PAD) which packs threads instead of spreading them out in an attempt to be able to keep sockets or cores at lower power levels. Maximum dispersal may be good for performance but is anathema to power management. PAD is off by default, but power management polices constitute yet another confounding factor with respect to scheduling and dispatching. If your threads communicate heavily -- one thread reads cache lines last written by some other thread -- then the new dense packing policy may improve performance by reducing traffic on the coherent interconnect. On the other hand if your threads in your process communicate rarely, then it's possible the new packing policy might result on contention on shared computing resources. Unfortunately there's no simple litmus test that says whether packing or spreading is optimal in a given situation. The answer varies by system load, application, number of threads, and platform hardware characteristics. Currently we don't have the necessary tools and sensoria to decide at runtime, so we're reduced to an empirical approach where we run trials and try to decide on a placement policy. The situation is quite frustrating. Relatedly, it's often hard to determine just the right level of concurrency to optimize throughput. (Understanding constructive vs destructive interference in the shared caches would be a good start. We could augment the lines with a small tag field indicating which strand last installed or accessed a line. Given that, we could augment the CPU with performance counters for misses where a thread evicts a line it installed vs misses where a thread displaces a line installed by some other thread.)

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• Curing the Database-Application mismatch

  - by Phil Factor

  If an application requires access to a database, then you have to be able to deploy it so as to be version-compatible with the database, in phase. If you can deploy both together, then the application and database must normally be deployed at the same version in which they, together, passed integration and functional testing.  When a single database supports more than one application, then the problem gets more interesting. I’ll need to be more precise here. It is actually the application-interface definition of the database that needs to be in a compatible ‘version’.  Most databases that get into production have no separate application-interface; in other words they are ‘close-coupled’.  For this vast majority, the whole database is the application-interface, and applications are free to wander through the bowels of the database scot-free.  If you’ve spurned the perceived wisdom of application architects to have a defined application-interface within the database that is based on views and stored procedures, any version-mismatch will be as sensitive as a kitten.  A team that creates an application that makes direct access to base tables in a database will have to put a lot of energy into keeping Database and Application in sync, to say nothing of having to tackle issues such as security and audit. It is not the obvious route to development nirvana. I’ve been in countless tense meetings with application developers who initially bridle instinctively at the apparent restrictions of being ‘banned’ from the base tables or routines of a database.  There is no good technical reason for needing that sort of access that I’ve ever come across.  Everything that the application wants can be delivered via a set of views and procedures, and with far less pain for all concerned: This is the application-interface.  If more than zero developers are creating a database-driven application, then the project will benefit from the loose-coupling that an application interface brings. What is important here is that the database development role is separated from the application development role, even if it is the same developer performing both roles. The idea of an application-interface with a database is as old as I can remember. The big corporate or government databases generally supported several applications, and there was little option. When a new application wanted access to an existing corporate database, the developers, and myself as technical architect, would have to meet with hatchet-faced DBAs and production staff to work out an interface. Sure, they would talk up the effort involved for budgetary reasons, but it was routine work, because it decoupled the database from its supporting applications. We’d be given our own stored procedures. One of them, I still remember, had ninety-two parameters. All database access was encapsulated in one application-module. If you have a stable defined application-interface with the database (Yes, one for each application usually) you need to keep the external definitions of the components of this interface in version control, linked with the application source,  and carefully track and negotiate any changes between database developers and application developers.  Essentially, the application development team owns the interface definition, and the onus is on the Database developers to implement it and maintain it, in conformance.  Internally, the database can then make all sorts of changes and refactoring, as long as source control is maintained.  If the application interface passes all the comprehensive integration and functional tests for the particular version they were designed for, nothing is broken. Your performance-testing can ‘hang’ on the same interface, since databases are judged on the performance of the application, not an ‘internal’ database process. The database developers have responsibility for maintaining the application-interface, but not its definition,  as they refactor the database. This is easily tested on a daily basis since the tests are normally automated. In this setting, the deployment can proceed if the more stable application-interface, rather than the continuously-changing database, passes all tests for the version of the application. Normally, if all goes well, a database with a well-designed application interface can evolve gracefully without changing the external appearance of the interface, and this is confirmed by integration tests that check the interface, and which hopefully don’t need to be altered at all often.  If the application is rapidly changing its ‘domain model’  in the light of an increased understanding of the application domain, then it can change the interface definitions and the database developers need only implement the interface rather than refactor the underlying database.  The test team will also have to redo the functional and integration tests which are, of course ‘written to’ the definition.  The Database developers will find it easier if these tests are done before their re-wiring  job to implement the new interface. If, at the other extreme, an application receives no further development work but survives unchanged, the database can continue to change and develop to keep pace with the requirements of the other applications it supports, and needs only to take care that the application interface is never broken. Testing is easy since your automated scripts to test the interface do not need to change. The database developers will, of course, maintain their own source control for the database, and will be likely to maintain versions for all major releases. However, this will not need to be shared with the applications that the database servers. On the other hand, the definition of the application interfaces should be within the application source. Changes in it have to be subject to change-control procedures, as they will require a chain of tests. Once you allow, instead of an application-interface, an intimate relationship between application and database, we are in the realms of impedance mismatch, over and above the obvious security problems.  Part of this impedance problem is a difference in development practices. Whereas the application has to be regularly built and integrated, this isn’t necessarily the case with the database.  An RDBMS is inherently multi-user and self-integrating. If the developers work together on the database, then a subsequent integration of the database on a staging server doesn’t often bring nasty surprises. A separate database-integration process is only needed if the database is deliberately built in a way that mimics the application development process, but which hampers the normal database-development techniques.  This process is like demanding a official walking with a red flag in front of a motor car.  In order to closely coordinate databases with applications, entire databases have to be ‘versioned’, so that an application version can be matched with a database version to produce a working build without errors.  There is no natural process to ‘version’ databases.  Each development project will have to define a system for maintaining the version level. A curious paradox occurs in development when there is no formal application-interface. When the strains and cracks happen, the extra meetings, bureaucracy, and activity required to maintain accurate deployments looks to IT management like work. They see activity, and it looks good. Work means progress.  Management then smile on the design choices made. In IT, good design work doesn’t necessarily look good, and vice versa.

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• 5 Best Practices - Laying the Foundation for WebCenter Projects

  - by Kellsey Ruppel

  Today’s guest post comes from Oracle WebCenter expert John Brunswick. John specializes in enterprise portal and content management solutions and actively contributes to the enterprise software business community and has authored a series of articles about optimal business involvement in portal, business process management and SOA development, examining ways of helping organizations move away from monolithic application development. We’re happy to have John join us today! Maximizing success with Oracle WebCenter portal requires a strategic understanding of Oracle WebCenter capabilities.  The following best practices enable the creation of portal solutions with minimal resource overhead, while offering the greatest flexibility for progressive elaboration. They are inherently project agnostic, enabling a strong foundation for future growth and an expedient return on your investment in the platform.  If you are able to embrace even only a few of these practices, you will materially improve your deployment capability with WebCenter. 1. Segment Duties Around 3Cs - Content, Collaboration and Contextual Data "Agility" is one of the most common business benefits touted by modern web platforms.  It sounds good - who doesn't want to be Agile, right?  How exactly IT organizations go about supplying agility to their business counterparts often lacks definition - hamstrung by ambiguity. Ultimately, businesses want to benefit from reduced development time to deliver a solution to a particular constituent, which is augmented by as much self-service as possible to develop and manage the solution directly. All done in the absence of direct IT involvement. With Oracle WebCenter's depth in the areas of content management, pallet of native collaborative services, enterprise mashup capability and delegated administration, it is very possible to execute on this business vision at a technical level. To realize the benefits of the platform depth we can think of Oracle WebCenter's segmentation of duties along the lines of the 3 Cs - Content, Collaboration and Contextual Data.  All three of which can have their foundations developed by IT, then provisioned to the business on a per role basis. Content – Oracle WebCenter benefits from an extremely mature content repository.  Work flow, audit, notification, office integration and conversion capabilities for documents (HTML & PDF) make this a haven for business users to take control of content within external and internal portals, custom applications and web sites.  When deploying WebCenter portal take time to think of areas in which IT can provide the "harness" for content to reside, then allow the business to manage any content items within the site, using the content foundation to ensure compliance with business rules and process.  This frees IT to work on more mission critical challenges and allows the business to respond in short order to emerging market needs. Collaboration – Native collaborative services and WebCenter spaces are a perfect match for business users who are looking to enable document sharing, discussions and social networking.  The ability to deploy the services is granular and on the basis of roles scoped to given areas of the system - much like the first C “content”.  This enables business analysts to design the roles required and IT to provision with peace of mind that users leveraging the collaborative services are only able to do so in explicitly designated areas of a site. Bottom line - business will not need to wait for IT, but cannot go outside of the scope that has been defined based on their roles. Contextual Data – Collaborative capabilities are most powerful when included within the context of business data.  The ability to supply business users with decision shaping data that they can include in various parts of a portal or portals, just as they would with content items, is one of the most powerful aspects of Oracle WebCenter.  Imagine a discussion about new store selection for a retail chain that re-purposes existing information from business intelligence services about various potential locations and or custom backend systems - presenting it directly in the context of the discussion.  If there are some data sources that are preexisting in your enterprise take a look at how they can be made into discrete offerings within the portal, then scoped to given business user roles for inclusion within collaborative activities. 2. Think Generically, Execute Specifically Constructs.  Anyone who has spent much time around me knows that I am obsessed with this word.  Why? Because Constructs offer immense power - more than APIs, Web Services or other technical capability. Constructs offer organizations the ability to leverage a platform's native characteristics to offer substantial business functionality - without writing code.  This concept becomes more powerful with the additional understanding of the concepts from the platform that an organization learns over time.  Let's take a look at an example of where an Oracle WebCenter construct can substantially reduce the time to get a subscription-based site out the door and into the hands of the end consumer. Imagine a site that allows members to subscribe to specific disciplines to access information and application data around that various discipline.  A space is a collection of secured pages within Oracle WebCenter.  Spaces are not only secured, but also default content stored within it to be scoped automatically to that space. Taking this a step further, Oracle WebCenter’s Activity Stream surfaces events, discussions and other activities that are scoped to the given user on the basis of their space affiliations.  In order to have a portal that would allow users to "subscribe" to information around various disciplines - spaces could be used out of the box to achieve this capability and without using any APIs or low level technical work to achieve this. 3. Make Governance Work for You Imagine driving down the street without the painted lines on the road.  The rules of the road are so ingrained in our minds, we often do not think about the process, but seemingly mundane lane markers are critical enablers. Lane markers allow us to travel at speeds that would be impossible if not for the agreed upon direction of flow. Additionally and more importantly, it allows people to act autonomously - going where they please at any given time. The return on the investment for mobility is high enough for people to buy into globally agreed up governance processes. In Oracle WebCenter we can use similar enablers to lane markers.  Our goal should be to enable the flow of information and provide end users with the ability to arrive at business solutions as needed, not on the basis of cumbersome processes that cannot meet the business needs in a timely fashion. How do we do this? Just as with "Segmentation of Duties" Oracle WebCenter technologies offer the opportunity to compartmentalize various business initiatives from each other within the system due to constructs and security that are available to use within the platform. For instance, when a WebCenter space is created, any content added within that space by default will be secured to that particular space and inherits meta data that is associated with a folder created for the space. Oracle WebCenter content uses meta data to support a broad range of rich ECM functionality and can automatically impart retention, workflow and other policies automatically on the basis of what has been defaulted for that space. Depending on your business needs, this paradigm will also extend to sub sections of a space, offering some interesting possibilities to enable automated management around content. An example may be press releases within a particular area of an extranet that require a five year retention period and need to the reviewed by marketing and legal before release.  The underlying content system will transparently take care of this process on the basis of the above rules, enabling peace of mind over unstructured data - which could otherwise become overwhelming. 4. Make Your First Project Your Second Imagine if Michael Phelps was competing in a swimming championship, but told right before his race that he had to use a brand new stroke.  There is no doubt that Michael is an outstanding swimmer, but chances are that he would like to have some time to get acquainted with the new stroke. New technologies should not be treated any differently.  Before jumping into the deep end it helps to take time to get to know the new approach - even though you may have been swimming thousands of times before. To quickly get a handle on Oracle WebCenter capabilities it can be helpful to deploy a sandbox for the team to use to share project documents, discussions and announcements in an effort to help the actual deployment get under way, while increasing everyone’s knowledge of the platform and its functionality that may be helpful down the road. Oracle Technology Network has made a pre-configured virtual machine available for download that can be a great starting point for this exercise. 5. Get to Know the Community If you are reading this blog post you have most certainly faced a software decision or challenge that was solved on the basis of a small piece of missing critical information - which took substantial research to discover.  Chances were also good that somewhere, someone had already come across this information and would have been excited to share it. There is no denying the power of passionate, connected users, sharing key tips around technology.  The Oracle WebCenter brand has a rich heritage that includes industry-leading technology and practitioners.  With the new Oracle WebCenter brand, opportunities to connect with these experts has become easier. Oracle WebCenter Blog Oracle Social Enterprise LinkedIn WebCenter Group Oracle WebCenter Twitter Oracle WebCenter Facebook Oracle User Groups Additionally, there are various Oracle WebCenter related blogs by an excellent grouping of services partners.

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