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• What's wrong with foreign keys?

  - by kronoz

  I remember hearing Joel mention in the podcast that he'd barely ever used a foreign key (if I remember correctly). However, to me they seem pretty vital to avoid duplication and subsequent data integrity problems throughout your database. Do people have some solid reasons as to why (to avoid a discussion in lines with SO principals)? Edit: "I've yet to have a reason to create a foreign key, so this might be my first reason to actually set up one."

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• Object Oriented vs Relational Databases

  - by Dan

  Objects oriented databases seem like a really cool idea to me, no need to worry about mapping your domain model to your database model, no messing around with sql or ORM tools. The way I understand it, relational DBs offer some advantages when there is massive amounts of data, and searching an indexing need to be done. To my mind 99% of websites are not massive, and enterprise issues never need to be thought about, so why arn't OO DBs more widely used?

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• How do I update the members of a MySQL SET Type?

  - by MachinationX

  I have a table of values, with one of the columns being of type SET. If it currently has the members ('a', 'b', 'c', 'd'), how do I add 'e' to the possible values? I realize that using a SET type is a little strange, and I'm unclear why one would use it instead of a foreign key to another table with the values of the set, but I didn't design the database in question, and can't change it that much. Thanks for your help!

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• methods of joining 2 tables without using JOIN or SELECT more than one distinct table in the query

  - by GB_J

  Is there a way of joining results from 2 tables without using JOIN or SELECT from more than one table? The reason being the database im working with requires queries that only contain SELECT, FROM, and WHERE clauses containing only one distinct table. I do, however, need information from other tables for the project i'm working on. More info: the querier returns the query results in a .csv format, is there something we can manipulate there?

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• Oracle/SQL table attribute question

  - by UnceRawr

  I have been given a context schema for a database i need to make for my coursework but some of the attributes (column names) contain letters in brackets at the end of them such as: *x_Number (Adm) *x_Number (A) *x_Number (P) The problem is i have no idea what these letters mean! Can anyone help?

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• Q&A: Oracle's Paul Needham on How to Defend Against Insider Attacks

  - by Troy Kitch

  Source: Database Insider Newsletter: The threat from insider attacks continues to grow. In fact, just since January 1, 2014, insider breaches have been reported by a major consumer bank, a major healthcare organization, and a range of state and local agencies, according to the Privacy Rights Clearinghouse.  We asked Paul Needham, Oracle senior director, product management, to shed light on the nature of these pernicious risks—and how organizations can best defend themselves against the threat from insider risks. Q. First, can you please define the term "insider" in this context? A. According to the CERT Insider Threat Center, a malicious insider is a current or former employee, contractor, or business partner who "has or had authorized access to an organization's network, system, or data and intentionally exceeded or misused that access in a manner that negatively affected the confidentiality, integrity, or availability of the organization's information or information systems."  Q. What has changed with regard to insider risks? A. We are actually seeing the risk of privileged insiders growing. In the latest Independent Oracle Users Group Data Security Survey, the number of organizations that had not taken steps to prevent privileged user access to sensitive information had grown from 37 percent to 42 percent. Additionally, 63 percent of respondents say that insider attacks represent a medium-to-high risk—higher than any other category except human error (by an insider, I might add). Q. What are the dangers of this type of risk? A. Insiders tend to have special insight and access into the kinds of data that are especially sensitive. Breaches can result in long-term legal issues and financial penalties. They can also damage an organization's brand in a way that directly impacts its bottom line. Finally, there is the potential loss of intellectual property, which can have serious long-term consequences because of the loss of market advantage.  Q. How can organizations protect themselves against abuse of privileged access? A. Every organization has privileged users and that will always be the case. The questions are how much access should those users have to application data stored in the database, and how can that default access be controlled? Oracle Database Vault (See image) was designed specifically for this purpose and helps protect application data against unauthorized access.  Oracle Database Vault can be used to block default privileged user access from inside the database, as well as increase security controls on the application itself. Attacks can and do come from inside the organization, and they are just as likely to come from outside as attempts to exploit a privileged account.  Using Oracle Database Vault protection, boundaries can be placed around database schemas, objects, and roles, preventing privileged account access from being exploited by hackers and insiders.  A new Oracle Database Vault capability called privilege analysis identifies privileges and roles used at runtime, which can then be audited or revoked by the security administrators to reduce the attack surface and increase the security of applications overall.  For a more comprehensive look at controlling data access and restricting privileged data in Oracle Database, download Needham's new e-book, Securing Oracle Database 12c: A Technical Primer. 

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• Applying Test Driven Development to a tightly coupled architecture

  - by Chris D

  Hi all, I've recently been studying TDD, attended a conference and have dabbled in few tests and already I'm 100% sold, I absolutely love it TDD. As a result I've raised this with my seniors and they are prepared to give it a chance, so they have tasked me with coming up with a way to implement TDD in the development of our enterprise product. The problem is our system has evolved since the days of VB6 to .NET and implements alot of legacy technology and some far from best practice development techniques i.e. alot of business logic in the ASP.NET code behind and client script. The largest problem however is how our classes are tightly coupled with database access; properties, methods, constructors - usually has some database access in some form or another. We use an in-house data access code generator tool that creates sqlDataAdapters that gives us all the database access we could ever want, which helps us develop extremely quickly, however, classes in our business layer are very tightly coupled to this data layer - we aren't even close to implementing some form of repository design. This and the issues above have created me all sorts of problems. I have tried to develop some unit tests for some existing classes I've already written but the tests take ALOT longer to run since db access is required, not to mention since we use the MS Enterprise Caching framework I am forced to fake a httpcontext for my tests to run successfully which isn't practical. Also, I can't see how to use TDD to drive the design of any new classes I write since they have to be soo tightly coupled to the database ... help! Because of the architecture of the system it appears I can't implement TDD without some real hack which in my eyes just defeats the aim of TDD and the huge benefits that come with. Does anyone have any suggestions how I could implement TDD with the constraints I'm bound too? or do I need to push the repository design pattern down my seniors throats and tell them we either change our architecture/development methodology or forget about TDD altogether? :) Thanks

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• "[INS-30131] Initial setup required for the execution of installer validations failed." Encountering this error while installing Oracle database 12c. [on hold]

  - by user132992

  I am trying to install Oracle 12c database on my machine running Fedora 20. And I am encountering this problem: "[INS-30131] Initial setup required for the execution of installer validations failed." And when we see the details then it is like this: Cause - Failed to access the temporary location. Action - Ensure that the current user has required permissions to access the temporary location. Additional Information: - Framework setup check failed on all the nodes - Cause: Cause Of Problem Not Available   - Action: User Action Not Available Summary of the failed nodes fedora - Version of exectask could not be retrieved from node "fedora"   - Cause: Cause Of Problem Not Available   - Action: User Action Not Available To eliminate this error I have tried various measures including the change of permission of the tmp folder and restarting the computer but none is working. Plz someone help me out of this. Any kind of help will be appreciated...

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• Use a custom value object or a Guid as an entity identifier in a distributed system?

  - by Kazark

  tl;dr I've been told that in domain-driven design, an identifier for an entity could be a custom value object, i.e. something other than Guid, string, int, etc. Can this really be advisable in a distributed system? Long version I will invent an situation analogous to the one I am currently facing. Say I have a distributed system in which a central concept is an egg. The system allows you to order eggs and see spending reports and inventory-centric data such as quantity on hand, usage, valuation and what have you. There area variety of services backing these behaviors. And say there is also another app which allows you to compose recipes that link to a particular egg type. Now egg type is broken down by the species—ostrich, goose, duck, chicken, quail. This is fine and dandy because it means that users don't end up with ostrich eggs when they wanted quail eggs and whatnot. However, we've been getting complaints because jumbo chicken eggs are not even close to equivalent to small ones. The price is different, and they really aren't substitutable in recipes. And here we thought we were doing users a favor by not overwhelming them with too many options. Currently each of the services (say, OrderSubmitter, EggTypeDefiner, SpendingReportsGenerator, InventoryTracker, RecipeCreator, RecipeTracker, or whatever) are identifying egg types with an industry-standard integer representation the species (let's call it speciesCode). We realize we've goofed up because this change could effect every service. There are two basic proposed solutions: Use a predefined identifier type like Guid as the eggTypeID throughout all the services, but make EggTypeDefiner the only service that knows that this maps to a speciesCode and eggSizeCode (and potentially to an isOrganic flag in the future, or whatever). Use an EggTypeID value object which is a combination of speciesCode and eggSizeCode in every service. I've proposed the first solution because I'm hoping it better encapsulates the definition of what an egg type is in the EggTypeDefiner and will be more resilient to changes, say if some people now want to differentiate eggs by whether or not they are "organic". The second solution is being suggested by some people who understand DDD better than I do in the hopes that less enrichment and lookup will be necessary that way, with the justification that in DDD using a value object as an ID is fine. Also, they are saying that EggTypeDefiner is not a domain and EggType is not an entity and as such should not have a Guid for an ID. However, I'm not sure the second solution is viable. This "value object" is going to have to be serialized into JSON and URLs for GET requests and used with a variety of technologies (C#, JavaScript...) which breaks encapsulation and thus removes any behavior of the identifier value object (is either of the fields optional? etc.) Is this a case where we want to avoid something that would normally be fine in DDD because we are trying to do DDD in a distributed fashion? Summary Can it be a good idea to use a custom value object as an identifier in a distributed system (solution #2)?

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• NFS (with Kerberos) mount failing due to "Server not found in Kerberos database" error

  - by Kendall Hopkins

  When running: `sudo mount -t nfs4 -o sec=krb5 sol.domain.com:/ /mnt` I get this error on the client: mount.nfs4: access denied by server while mounting sol.domain.com:/ And on the server syslogs UNKNOWN_SERVER: authtime 0, nfs/[email protected] for nfs/ip-#-#-#-#[email protected], Server not found in Kerberos database UNKNOWN_SERVER: authtime 0, nfs/[email protected] for krbtgt/[email protected], Server not found in Kerberos database UNKNOWN_SERVER: authtime 0, nfs/[email protected] for krbtgt/[email protected], Server not found in Kerberos database UNKNOWN_SERVER: authtime 0, nfs/[email protected] for krbtgt/[email protected], Server not found in Kerberos database UNKNOWN_SERVER: authtime 0, nfs/[email protected] for krbtgt/[email protected], Server not found in Kerberos database UNKNOWN_SERVER: authtime 0, nfs/[email protected] for nfs/ip-#-#-#-#[email protected], Server not found in Kerberos database UNKNOWN_SERVER: authtime 0, nfs/[email protected] for krbtgt/[email protected], Server not found in Kerberos database UNKNOWN_SERVER: authtime 0, nfs/[email protected] for krbtgt/[email protected], Server not found in Kerberos database UNKNOWN_SERVER: authtime 0, nfs/[email protected] for krbtgt/[email protected], Server not found in Kerberos database UNKNOWN_SERVER: authtime 0, nfs/[email protected] for krbtgt/[email protected], Server not found in Kerberos database Server keytab file: ubuntu@sol:~$ sudo klist -e -k /etc/krb5.keytab Keytab name: WRFILE:/etc/krb5.keytab KVNO Principal ---- -------------------------------------------------------------------------- 7 host/[email protected] (aes256-cts-hmac-sha1-96) 7 host/[email protected] (arcfour-hmac) 7 host/[email protected] (des3-cbc-sha1) 7 host/[email protected] (des-cbc-crc) 9 nfs/[email protected] (aes256-cts-hmac-sha1-96) 9 nfs/[email protected] (arcfour-hmac) 9 nfs/[email protected] (des3-cbc-sha1) 9 nfs/[email protected] (des-cbc-crc) Client keytab file: ubuntu@mercury:~$ sudo klist -e -k /etc/krb5.keytab Keytab name: WRFILE:/etc/krb5.keytab KVNO Principal ---- -------------------------------------------------------------------------- 3 host/[email protected] (aes256-cts-hmac-sha1-96) 3 host/[email protected] (arcfour-hmac) 3 host/[email protected] (des3-cbc-sha1) 3 host/[email protected] (des-cbc-crc) 3 nfs/[email protected] (aes256-cts-hmac-sha1-96) 3 nfs/[email protected] (arcfour-hmac) 3 nfs/[email protected] (des3-cbc-sha1) 3 nfs/[email protected] (des-cbc-crc)

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• Database which only holds indexes and last X records in memory?

  - by Xeoncross

  I'm looking for a data store that is very memory efficient while still allowing many object changes per second and disregarding ACID compliance for the last X records. I need this database for a server with not much memory and I can make a key-value store, document, or SQL database work. The idea is that indexes/keys are the only thing I need in memory and all the actual values/objects/rows can be saved on disk do to the low read rate (I just want index/key lookup to be fast). I also don't want records constantly being flushed to disk, so I would like the last X number of records to be held in memory so that 100 or so of them can all be written at once. I don't care if I lose the last 10 seconds worth of objects/values. I do care if the database as a whole is in danger of becoming corrupt. Is there a data-store like this?

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• Migrating master-slave MySQL database servers to 2 new servers, any tips or suggestions?

  - by mmattax

  I'm setting up 2 new database servers that will be replacing a current master-slave setup. All boxes are running / will be running MySQL on RHEL. Our current naming conventions: db1 - master database db2 - slave (using MySQL replication) db01 - new master db02 - new slave We need to get db01 to be the new master with db02 as the new slave. What is the best way to migrate db1 and db2 to db01 and db02? db1 and db2 are running in a production setting and we need to minimize all downtime; db1 has roughly 30GB of data in the database. Any suggestions or tips on how to migrate to our new servers would be much appreciated.

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• Windows authenticated users have lost access to master (default) database

  - by Rob Nicholson

  Something very strange has occurred on our production SQL database. Users connecting via Windows authentication appear to have lost all access to the master database. By default, all logins have the default database set to master. So when you connect using SQL Server management studio, they get the error: "Cannot open user default database. Login failed error 4064". What's also worrying is that we have a group called "COMPANY - SQL Administrator" which has sysadmin rights and users in this group also get the same error. Worse, they don't appear to be system administrators anymore... If they change their default database to something else, they can connect and then work on the database, it's just the master database that is problematic. I'm not even sure by what mechanism windows authenticated users get access to the master database. Is it something hard coded in or some property that's got changed? Any ideas? Cheers, Rob.

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• Free-space driven log rotation on linux?

  - by kdt

  Someone just asked me 'how long should we keep logs for our application', and my answer was 'until the disk is full' as there's no reason to throw them away other than running out of space. However, standard logrotate wants us to specify a specific period + number of rotations. Is there something similar that would let us say "rotate daily, and keep as much history as you like until there is only 5% space free"? The platform is Redhat Linux.

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• Tool to launch a script driven by modem activity

  - by Will M

  Can anyone suggest a software tool (preferably under Windows XP or later) that would launch an application or script in response to a phone call being received on a landline phone line connected to a data modem on the same PC? or, better, in response to a sequence of touch-tones being played over such a phone line. This would allow, for example, using the telephone to manipulate firewall settings so as to create another layer of security in connection with remote internet access to that computer. I seem to recall seeing tools to do this sort of thing in the days before broadband internet access, when there was more attention to various tips and tricks for the dial-up modem, but a few attempts at Google hasn't turned anything up.

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• Empty mails received from Plesk-driven server

  - by goreSplatter

  From my Plesk managed server I keep receiving emails addressed to the configured administrator (me). Nothing special there. These mails are sent from an empty sender with no body, no subject nor any other relevant headers. I have changed the server administrator's e-mail address to an alternate one which is then the recipient. The mails are sent at irregular intervals. With variations in the timestamp I get an email every 30 minutes. Then there's a break and two and a half hours later I get the same email. I already have turned of crond for more than a day to see if this is the source of the problem. On that server there is no "foreign" software running which would cause that behavior. I have no more guesses as to why this is happening. Any suggestions?

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• Can I convert my database/script to UTF-8 ?

  - by Mohannad Otaibi

  How can I convert a database to support UTF-8 and convert it's old data from what ever encoding they're in to UTF-8 ? Extra Info: I'm running a server which has many websites on it, and one of them is running WHMCS (php script to manage hosting clients). WHMCS has an iPhone application where i can browse it through iPhone, the problem is that this application will only run if everything in my website is in UTF-8 encoding. I was using windows-1256 as encoding in my script's settings, and i tried changing that in some point of time to UTF-8 for a while then changed it back to windows-1256 so, the data in the database are some inserted using UTF standards and most of them are windows-1256 If someone could clear the picture for me, Do I need to convert every database on the server or just one DB ? what should I change? If i had to do that manually, I'll do it but I need some expert advise.

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• DBA Command line options

  - by Anthony Shorten

  There are a number of database utilities supplied with the installation of the Oracle Utilities Application Framework based products. These are typically run in interactive mode where the utility prompts you for the values and then executes the required functionality. Did you know that the utilities also have command line options that allow you to run the utility in silent mode as well? You can assess the command line options by specifying the -h option on the command line. Here is an example of the oragensec command line options: oragensec -d <Owner,OwnerPswd,DbName> -u <Database Users> -r <ReadRole,UserRole> -l <logfile> -h where: -d <Owner,OwnerPswd,DbName> Database connect information for the target database. e.g. spladm,spladm,DB200ODB. -u <Database Users> A comma-separated list of database users where synonyms need to be created. e.g. spluser, splread -r <ReadRole,UserRole> Optional. Names of database roles with read and read-write privileges. Default roles are SPL_READ, SPL_USER. e.g. spl_read,spl_user -l <logfile> Optional. Name of the log file. -h Help The command line options allow the DBA to automate the exeucution either via a script or some utility can than execute utilities. This optin can apply to the majority of DBA utilities supplied with the product. Take a look at others.

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• SQL SERVER – Identify Most Resource Intensive Queries – SQL in Sixty Seconds #029 – Video

  - by pinaldave

  There are a few questions I often get asked. I wonder how interesting is that in our daily life all of us have to often need the same kind of information at the same time. Here is the example of the similar questions: How many user created tables are there in the database? How many non clustered indexes each of the tables in the database have? Is table Heap or has clustered index on it? How many rows each of the tables is contained in the database? I finally wrote down a very quick script (in less than sixty seconds when I originally wrote it) which can answer above questions. I also created a very quick video to explain the results and how to execute the script. Here is the complete script which I have used in the SQL in Sixty Seconds Video. SELECT [schema_name] = s.name, table_name = o.name, MAX(i1.type_desc) ClusteredIndexorHeap, COUNT(i.TYPE) NoOfNonClusteredIndex, p.rows FROM sys.indexes i INNER JOIN sys.objects o ON i.[object_id] = o.[object_id] INNER JOIN sys.schemas s ON o.[schema_id] = s.[schema_id] LEFT JOIN sys.partitions p ON p.OBJECT_ID = o.OBJECT_ID AND p.index_id IN (0,1) LEFT JOIN sys.indexes i1 ON i.OBJECT_ID = i1.OBJECT_ID AND i1.TYPE IN (0,1) WHERE o.TYPE IN ('U') AND i.TYPE = 2 GROUP BY s.name, o.name, p.rows ORDER BY schema_name, table_name Related Tips in SQL in Sixty Seconds: Find Row Count in Table – Find Largest Table in Database Find Row Count in Table – Find Largest Table in Database – T-SQL Identify Numbers of Non Clustered Index on Tables for Entire Database Index Levels, Page Count, Record Count and DMV – sys.dm_db_index_physical_stats Index Levels and Delete Operations – Page Level Observation What would you like to see in the next SQL in Sixty Seconds video? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology, Video Tagged: Excel

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• How to use Nginx to export the mongoDB connection?

  - by Totty

  I have on my server 2 things: the node.js server and a mongodb database; The node.js server is reachable from myip/server; and now I would like to export the mongodb database to myip/database for example. Now when I use my mongodb viewer (MongoVUE) with "http://myip/database:9000" (the port 9000 is set in nginx and it's also the port that I start mongod). If I go to "http://myip/database:9000" or "http://myip/database" in a browser it look like: "You are trying to access MongoDB on the native driver port. For http diagnostic access, add 1000 to the port number". But in MongoVUE it says: Unable to connect to server 192.168.1.16/database:9000: No such host is known. Type: MongoDB.Driver.MongoConnectionException Stack: at MongoDB.Driver.Internal.DirectConnector.Connect(TimeSpan timeout) at MongoDB.Driver.MongoServer.Connect(TimeSpan timeout, ConnectWaitFor waitFor) at MongoDB.Driver.MongoServer.Connect(TimeSpan timeout) at MongoDB.Driver.MongoServer.Connect() at MangoUI.MMongo.FQlxNlJKqO74gYmXgZR4(Object ) at MangoUI.MMongo.Open(Boolean useSamus) at MangoUI.MMongo.Open() at MangoUI.ComNavTree.wJQdUqApCpjoC39P59n(Object ) at MangoUI.ComNavTree.ExpandMe(MTreeNode expand) at MangoUI.ComNavTree.tree_BeforeExpand(Object sender, TreeViewCancelEventArgs e) No such host is known Type: System.Net.Sockets.SocketException Stack: at System.Net.Dns.GetAddrInfo(String name) at System.Net.Dns.InternalGetHostByName(String hostName, Boolean includeIPv6) at System.Net.Dns.GetHostAddresses(String hostNameOrAddress) at MongoDB.Driver.MongoServerAddress.ToIPEndPoint(AddressFamily addressFamily) at MongoDB.Driver.MongoServerInstance.Connect(Boolean slaveOk) at MongoDB.Driver.Internal.DirectConnector.Connect(TimeSpan timeout)

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• Items cannot be installed or removed

  - by Gyanendra Kumar Gyan

  installArchives() failed: (Reading database ... (Reading database ... 5% (Reading database ... 10% (Reading database ... 15% (Reading database ... 20% (Reading database ... 25% (Reading database ... 30% (Reading database ... 35% (Reading database ... 40% (Reading database ... 45% (Reading database ... 50% (Reading database ... 55% (Reading database ... 60% (Reading database ... 65% (Reading database ... 70% (Reading database ... 75% (Reading database ... 80% (Reading database ... 85% (Reading database ... 90% (Reading database ... 95% (Reading database ... 100% (Reading database ... 136187 files and directories currently installed.) Removing pidgin-ppa ... gpg: key "67265EB522BDD6B1C69E66ED7FB8BEE0A1F196A8" not found: eof gpg: 67265EB522BDD6B1C69E66ED7FB8BEE0A1F196A8: delete key failed: eof dpkg: error processing pidgin-ppa (--remove): subprocess installed post-removal script returned error exit status 2 No apport report written because MaxReports is reached already Processing triggers for ureadahead ... ureadahead will be reprofiled on next reboot Errors were encountered while processing: pidgin-ppa Error in function: SystemError: E:Sub-process /usr/bin/dpkg returned an error code (1)

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• Build vs Buy Webcast: November 8, 2012

  - by TammyBednar

  Date: Thursday, November 8, 2012, 1:00 PM EST You have a choice. Do you build your own database platform or buy a pre-engineered database appliance? Building a high-availability database platform presents unique challenges. Combining servers, storage, networking, OS, firmware, and database is complicated and raises important concerns: Will coordination between multiple SME’s delay deployment? Will it be reliable? Will it scale? Will routine maintenance consume precious IT-staff time? Ultimately, will it work? Enter the Oracle Database Appliance, a complete package of software, server, storage, and networking that’s engineered for simplicity. It saves time and money by simplifying deployment, maintenance, and support of database workloads. Plus, it’s based on Intel Xeon processors to ensure a high level of performance and scalability. Attend this Webcast to hear customer stories and discover how the Oracle Database Appliance: Increases ROI by reducing capital and operational expenses Frees IT staff by reducing deployment and management time from weeks to hours Takes the worry out of supporting mission critical application workloads Register For this WebCast today!

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• ?Oracle DB 11gR2 ??????????????????/????????????????!

  - by Yuichi.Hayashi

  ?????????????????????????????40~60%????????????? ??????????????????????????????????????????????????????????????????????????????????... ????????????????????????????????????????TCO(Total Cost of Ownership)???????????? ??????????????????????????????????????????????????????????????????????????? ???????1?1???????????????????????????????????1??????????????????????????????????????·????????????? ??????????????????·???·????????????????TCO????????????? ????????????????Grid(????)????????????????????????????·???? = Oracle Real Application Clusters(RAC)???????·???? = Oracle Automatic Storage Management(ASM)????????????????????????????????????? Oracle Database???????11g R2?????????????????????????/???????????????????????(????????????????)?????????????????????????????! SCAN Single Client Access Name(SCAN)??Oracle Real Application Clusters(RAC)11g R2??????? SCAN??????????????????????????????????????????????????RAC?????????????????????????·????????????????????SCAN?????????????????????VIP?????????????RAC????????????????????????????????!???????????????? ???????????????????????????????????????SCAN?????????????????????????????TCO?????????????????(????????????)???????????????????????????????!????????????? SCAN?????????????????????? ??????Oracle Database 11gR2 Real Application Clusters(?????????) ??????Oracle Real Application Clusters 11g Release 2 SCAN??? ACFS ASM Cluster File System(ACFS)??Automatic Storage Management(ASM)11g R2??????? ASM??S.A.M.E.(Stripe And Mirror Everything)????????????????????????????????????????????????????????·???????·??????????????????10g????????????????·??????????·???????????????ASM????????????·??????????????????????????????????????????·?????????????????????????????????????????????? 11g R2??????ACFS?????????????????(????????????????????????????????????????????????????????)????ASM???????????????????????????????????????????????????????·??????????????ACFS????! · ??????????????????? · ????????????/???? · ??????????????????????(?????)??? · ????????????? ?2???????????????????????????? · ???????????? ??????????????????????·??????????·?????????????????????!???????????????????????????????????????? ACFS??????????????????? ??????Oracle Database 11gR2 Automatic Storage Management ??????Oracle Database 11g Release 2 Automatic Storage Management???????????????? ??????·????? ??????·???????Oracle Database Resource Manager(????·?????)11g R2??????? ????·????????????·???????????????????????????????Oracle Database???Oracle RAC????????????????????????????????????????????????????????????????????????????????????????????????????1????????????? ????????????·?????????????????????????????????????????????????????????????????? CPU ???????????????????????????????????????????????????·??????????????????????????? 11g R2??????????·???????????????? CPU_COUNT ?????????????? CPU ???????????????????????????·??????? CPU ?????????????????????????????????????????????? ????????·???????????????????????????????????????????Oracle ??????????????????????·??????? CPU ??????????????????????????????·???????????????!???????????????? ??????·???????????????????????? ??????Oracle Database 11gR2 ????????????? ?????????? ? ??????????????????????????????????!? ? ???????????????????????????????????!?

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• BizTalk host throttling &ndash; Singleton pattern and High database size

  - by S.E.R.

  Originally posted on: http://geekswithblogs.net/SERivas/archive/2013/06/30/biztalk-host-throttling-ndash-singleton-pattern-and-high-database-size.aspxI have worked for some days around the singleton pattern (for those unfamiliar with it, read this post by Victor Fehlberg) and have come across a few very interesting posts, among which one dealt with performance issues (here, also by Victor Fehlberg). Simply put: if you have an orchestration which implements the singleton pattern, then performances will continuously decrease as the orchestration receives and consumes messages, and that behavior is more obvious when the orchestration never ends (ie : it keeps looping and never terminates or completes). As I experienced the same kind of problem (actually I was alerted by SCOM, which told me that the host was being throttled because of High database size), I thought it would be a good idea to dig a little bit a see what happens deep inside BizTalk and thus understand the reasons for this behavior. NOTE: in this article, I will focus on this High database size throttling condition. I will try and work on the other conditions in some not too distant future… Test conditions The singleton orchestration For the purpose of this study, I have created the following orchestration, which is a very basic implementation of a singleton that piles up incoming messages, then does something else when a certain timeout has been reached without receiving another message: Throttling settings I have two distinct hosts : one that hosts the receive port (basic FILE port) : Ports_ReceiveHostone that hosts the orchestration : ProcessingHost In order to emphasize the throttling mechanism, I have modified the throttling settings for each of these hosts are as follows (all other parameters are set to the default value): [Throttling thresholds] Message count in database: 500 (default value : 50000) Evolution of performance counters when submitting messages Since we are investigating the High database size throttling condition, here are the performance counter that we should take a look at (all of them are in the BizTalk:Message Agent performance object): Database sizeHigh database sizeMessage delivery throttling stateMessage publishing throttling stateMessage delivery delay (ms)Message publishing delay (ms)Message delivery throttling state durationMessage publishing throttling state duration (If you are not used to Perfmon, I strongly recommend that you start using it right now: it is a wonderful tool that allows you to open the hood and see what is going on inside BizTalk – and other systems) Database size It is quite obvious that we will start by watching the database size and high database size counters, just to see when the first reaches the configured threshold (500) and when the second rings the alarm. NOTE : During this test I submitted 600 messages, one message at a time every 10ms to see the evolution of the counters we have previously selected. It might not show very well on this screenshot, but here is what happened: From 15:46:50 to 15:47:50, the database size for the Ports_ReceiveHost host (blue line) kept growing until it reached a maximum of 504.At 15:47:50, the high database size alert fires At first I was surprised by this result: why is it the database size of the receiving host that keeps growing since it is the processing host that piles up messages? Actually, it makes total sense. This counter measures the size of the database queue that is being filled by the host, not consumed. Therefore, the high database size alert is raised on the host that fills the queue: Ports_ReceiveHost. More information is available on the Public MPWiki page. Now, looking at the Message publishing throttling state for the receiving host (green line), we can see that a throttling condition has been reached at 15:47:50: We can also see that the Message publishing delay(ms) (blue line) has begun growing slowly from this point. All of this explains why performances keep decreasing when a singleton keeps processing new messages: the database size grows and when it has exceeded the Message count in database threshold, the host is throttled and the publishing delay keeps increasing. Digging further So, what happens to the database queue then? Is it flushed some day or does it keep growing and growing indefinitely? The real question being: will the host be throttled forever because of this singleton? To answer this question, I set the Message count in database threshold to 20 (this value is very low in order not to wait for too long, otherwise I certainly would have fallen asleep in front of my screen) and I submitted 30 messages. The test was started at 18:26. At 18:56 (ie : exactly 30min later) the throttling was stopped and the database size was divided by 2. 30 min later again, the database size had dropped to almost zero: I guess I’ll have to find some documentation and do some more testing before I sort this out! My guess is that some maintenance job is at work here, though I cannot tell which one Digging even further If we take a look at the Message delivery throttling state counter for the processing host, we can see that this host was also throttled during the submission of the 600 documents: The value for the counter was 1, meaning that Message delivery incoming rate for the host instance exceeds the Message delivery outgoing rate * the specified Rate overdrive factor (percent) value. We will see this another day… :) A last word Let’s end this article with a warning: DO NOT CHANGE THE THROTTLING SETTINGS LIGHTLY! The temptation can be great to just bypass throttling by setting very high values for each parameter (or zero in some cases, which simply disables throttling). Nevertheless, always keep in mind that this mechanism is here for a very good reason: prevent your BizTalk infrastructure from exploding!! So whatever you do with those settings, do a lot of testing and benchmarking!

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• Where do we put "asking the world" code when we separate computation from side effects?

  - by Alexey

  According to Command-Query Separation principle, as well as Thinking in Data and DDD with Clojure presentations one should separate side effects (modifying the world) from computations and decisions, so that it would be easier to understand and test both parts. This leaves an unanswered question: where relatively to the boundary should we put "asking the world"? On the one hand, requesting data from external systems (like database, extental services' APIs etc) is not referentially transparent and thus should not sit together with pure computational and decision making code. On the other hand, it's problematic, or maybe impossible to tease them apart from computational part and pass it as an argument as because we may not know in advance which data we may need to request.

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