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  • Backing up data stored on Amazon S3

    - by Fiver
    I have an EC2 instance running a web server that stores users' uploaded files to S3. The files are written once and never change, but are retrieved occasionally by the users. We will likely accumulate somewhere around 200-500GB of data per year. We would like to ensure this data is safe, particularly from accidental deletions and would like to be able to restore files that were deleted regardless of the reason. I have read about the versioning feature for S3 buckets, but I cannot seem to find if recovery is possible for files with no modification history. See the AWS docs here on versioning: http://docs.aws.amazon.com/AmazonS3/latest/dev/ObjectVersioning.html In those examples, they don't show the scenario where data is uploaded, but never modified, and then deleted. Are files deleted in this scenario recoverable? Then, we thought we may just backup the S3 files to Glacier using object lifecycle management: http://docs.aws.amazon.com/AmazonS3/latest/dev/object-lifecycle-mgmt.html But, it seems this will not work for us, as the file object is not copied to Glacier but moved to Glacier (more accurately it seems it is an object attribute that is changed, but anyway...). So it seems there is no direct way to backup S3 data, and transferring the data from S3 to local servers may be time-consuming and may incur significant transfer costs over time. Finally, we thought we would create a new bucket every month to serve as a monthly full backup, and copy the original bucket's data to the new one on Day 1. Then using something like duplicity (http://duplicity.nongnu.org/) we would synchronize the backup bucket every night. At the end of the month we would put the backup bucket's contents in Glacier storage, and create a new backup bucket using a new, current copy of the original bucket...and repeat this process. This seems like it would work and minimize the storage / transfer costs, but I'm not sure if duplicity allows bucket-to-bucket transfers directly without bringing data down to the controlling client first. So, I guess there are a couple questions here. First, does S3 versioning allow recovery of files that were never modified? Is there some way to "copy" files from S3 to Glacier that I have missed? Can duplicity or any other tool transfer files between S3 buckets directly to avoid transfer costs? Finally, am I way off the mark in my approach to backing up S3 data? Thanks in advance for any insight you could provide!

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  • Time difference between servers after disaster recovery

    - by Sandokan
    We are running an old training system based on Windows Server 2003 and XP-clients. The solution is rather simple with four servers, two of them beeing DC:s. Everything is preconfigured and that goes for backup scheme as well. The backup software is Symantec BackupExec 2010. The scheme is a standard GF-F-S routine with full backups running once a week on Sundays. The other six days run differential backups. Now let's say in a worst case scenario, a server crashes on Saturday and we have to restore it from backup. The last backup will then be six days old and thus it will come online with six days old configurations. Will this pose a problem for the other servers or will the recovered server "get in line" eventually?

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  • ntbackup workalike for adhoc full backups in Windows 7 thats free and preferably open source

    - by Justin Dearing
    On windows 2000 and XP machines I used to be able to do the following: ntbackup backup systemstate c: /f e:\backups\machineName\machineName-full+systemstate_200101206.bkf This gave me a full backup of the system that I could use to do a system restore, after doing a barebones OS install. Windows 7 has a great utility for regular backups with alerting and all that stuff. It does not seem to have command line support. I'd like a backup solution for my Windwos 7 systems that has the following features: Is free Is open source (preferebly) Works while the system is booted and leaves the system functional (clonezilla is great for offline backups, and I use that too) Gives me a backup that is suited for a full system restore or partial system restore (ruling out most imaging software even if they could work while the system is booted via some sort of shadow copy voodoo) Can work via the command line Compression would be nice, the ability to pipe output would be better.

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  • backing up ntfs disk using rsync on ubuntu

    - by user70366
    For a long time I was using windows. I have a separate drive I use to keep copies of my media files, photos etc. on, which I periodically backup to an external drive. In Windows I used SyncToy to do this. After my Windows stopped booting, I decided to switch to Linux (Ubuntu 10.10). That seems to be going fine, but now I want to backup my drive to the external drive like before. Mostly the two drives will be already the same with maybe about 10GB of extra files added. So I try to use rsync to synchronise the two drives like this: rsync --dry-run -rvlt --modify-window=1 /media/Antonio1TB/Backup /media/FREECOM\ HDD/Backup The problem is the dry run indicates that every file on the drive will be copied. Not just the files I have recently added. What is the correct command to synch two NTFS drives under Ubuntu so that files that already exist don't get copied again? Thanks.

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  • Backups of Exchange 2007 SP3 using VSS are abnormally large

    - by Stew
    I have recently implemented Veeam backup and recovery 6.0, and have noted when backing up my exchange server via incremental updates, it is transferring way more data than expected. Backup is incremental, and setup to use VSS. VSS is stable and healthy, according to vssadmin. Exchange 2007 SP3 running on Windows Server 2008 R2, just last weekend I installed the latest Rollup for Exchange. I thought the nightly incrementals were large, but perhaps my users really are sending that much mail so I tested taking one incremental backup, waiting 10 minutes and taking a second. The second incremental backup transfered 5.8GB of data. We as an organization are absolutely NOT putting 5.8GB of data on the mail server every 10 minutes. Are there any other veeam users who have seen something similar? Is my test faulted? Are there other considerations for VSS?

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  • Backing up a Linux VPS with RSync to Vista

    - by Frank
    I've been working to setup a Linux VPS to host a couple of Wordpress sites and eventually a Mercurial server. I've setup one site and things have gone well. However, before I start moving other things to the VPS, I need to setup a backup solution. My provider, Linode, suggest RSync (among a couple of other options) to do backups. I've seen a few posts on this site that suggests other backup solutions including going to the Amazon Cloud but that costs money and the VPS is all the money I want to spend on this for the time being. So, to help solve that I want to have my backup computer be my home desktop computer. Assuming I'm using RSync, is it possible to use my Vista based home computer to become the destination for the backup? And if it is possible, what type of command or connection would I need to configure on the vista machine? Any insight would be helpful. It's probably obvious, but I've never used RSync.

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  • Creating disk snapshots in Windows 7

    - by Puneet Arora
    Does anyone know of a command or tool to create disk snapshots on Windows 7 (client SKU)? I see vssadmin.exe has a "create shadow" option, but that's available only on server SKUs: http://technet.microsoft.com/en-us/library/cc788055(v=ws.10).aspx I've a backup tool that replicates changes (creations, modifications and deletions to files and directories) since last backup, to my backup volume. Before each time this happens I want to create a persistent snapshot on my backup volume. I could then mount previous snapshots to view previous backups achieving a behavior similar to that of TimeMachine in OS X. This question has been asked before but unfortunately there weren't any good answers: Taking snapshots of filesystem/volume in Windows 7?

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  • BackupPC - are full backups really full when using rsync?

    - by mhost
    Hi, When you run a full backup in backuppc and you use rsync as the transfer method, does it actually transfer the full backup source? Or does it only transfer the changes? The docs seem to imply that it would transfer the full thing and only an incremental would transfer the changes. If this is the case, could I simply use incrementals only, and never do a full backup? The way the backups are stored (using hard links to make each incremental appear full), I would think that this would be the best method. Incrementals will only transfer the changes, yet each backup will appear full. Thanks.

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  • backing up ntfs disk using rsync on ubuntu

    - by user70366
    For a long time I was using windows. I have a separate drive I use to keep copies of my media files, photos etc. on, which I periodically backup to an external drive. In Windows I used SyncToy to do this. After my Windows stopped booting, I decided to switch to Linux (Ubuntu 10.10). That seems to be going fine, but now I want to backup my drive to the external drive like before. Mostly the two drives will be already the same with maybe about 10GB of extra files added. So I try to use rsync to synchronise the two drives like this: rsync --dry-run -rvlt --modify-window=1 /media/Antonio1TB/Backup /media/FREECOM\ HDD/Backup The problem is the dry run indicates that every file on the drive will be copied. Not just the files I have recently added. What is the correct command to synch two NTFS drives under Ubuntu so that files that already exist don't get copied again? Thanks.

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  • Visual Studio 2010 Hosting :: Connect to MySQL Database from Visual Studio VS2010

    - by mbridge
    So, in order to connect to a MySql database from VS2010 you need to 1. download the latest version of the MySql Connector/NET from http://www.mysql.com/downloads/connector/net/ 2. install the connector (if you have an older version you need to remove it from Control Panel -> Add / Remove Programs) 3. open Visual Studio 2010 4. open Server Explorer Window (View -> Server Explorer) 5. use Connect to Database button 6. in the Choose Data Source windows select MySql Database and press Continue 7. in the Add Connection window - set server name: 127.0.0.1 or localhost for MySql server running on local machine or an IP address for a remote server - username and password - if the the above data is correct and the connection can be made, you have the possibility to select the database If you want to connect to a MySql database from a C# application (Windows or Web) you can use the next sequence: //define the connection reference and initialize it MySql.Data.MySqlClient.MySqlConnection msqlConnection = null; msqlConnection = new MySql.Data.MySqlClient.MySqlConnection(“server=localhost;user id=UserName;Password=UserPassword;database=DatabaseName;persist security info=False”);     //define the command reference MySql.Data.MySqlClient.MySqlCommand msqlCommand = new MySql.Data.MySqlClient.MySqlCommand();     //define the connection used by the command object msqlCommand.Connection = this.msqlConnection;     //define the command text msqlCommand.CommandText = "SELECT * FROM TestTable;"; try {     //open the connection     this.msqlConnection.Open();     //use a DataReader to process each record     MySql.Data.MySqlClient.MySqlDataReader msqlReader = msqlCommand.ExecuteReader();     while (msqlReader.Read())     {         //do something with each record     } } catch (Exception er) {     //do something with the exception } finally {     //always close the connection     this.msqlConnection.Close(); }.

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  • emca fails with "Database instance is unavailable" though available

    - by Giri Mandalika
    The following example shows the symptoms of failure, and the exact error message. $ emca -repos create ... Password for SYSMAN user: Do you wish to continue? [yes(Y)/no(N)]: Y Nov 19, 2012 10:33:42 AM oracle.sysman.emcp.DatabaseChecks \ checkDbAvailabilityImpl WARNING: ORA-01034: ORACLE not available Nov 19, 2012 10:33:42 AM oracle.sysman.emcp.DatabaseChecks \ throwDBUnavailableException SEVERE: Database instance is unavailable. Fix the ORA error thrown and run EM Configuration Assistant again. Some of the possible reasons may be : 1) Database may not be up. 2) Database is started setting environment variable ORACLE_HOME with trailing '/'. Reset ORACLE_HOME and bounce the database. For eg. Database is started setting environment variable ORACLE_HOME=/scratch/db/ . Reset ORACLE_HOME=/scratch/db and bounce the database. Fix: Ensure that the ORACLE_HOME is pointing to the right location in $ORACLE_HOME/bin/emca file. Rather than installing from scratch, if ORACLE_HOME was copied over from another location, likely it results in wrong location for ORACLE_HOME in several Enterprise Manager (EM) specific scripts and files. It usually happens when the directory structure on the target machine is not identical to the structure on the original/source machine, including the top level directory location where Oracle RDBMS was installed properly using the installer.

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  • Grid Infrastructure Management Repository (GIMR) database now mandatory in Oracle GI 12.1.0.2

    - by Mike Dietrich
    During the installation of Oracle Grid Infrastructure 12.1.0.1 you've had the following option to choose YES/NO to install the Grid Infrastructure Management Repository (GIMR) database MGMTDB: With Oracle Grid Infrastructure 12.1.0.2 this choice has become obsolete and the above screen does not appear anymore. The GIMR database has become mandatory.  What gets stored in the GIMR? See the documentation here See the changes in Oracle Clusterware 12.1.0.2 here: Automatic Installation of Grid Infrastructure Management Repository The Grid Infrastructure Management Repository is automatically installed with Oracle Grid Infrastructure 12c release 1 (12.1.0.2). The Grid Infrastructure Management Repository enables such features as Cluster Health Monitor, Oracle Database QoS Management, and Rapid Home Provisioning, and provides a historical metric repository that simplifies viewing of past performance and diagnosis of issues. This capability is fully integrated into Oracle Enterprise Manager Cloud Control for seamless management. Furthermore what the doc doesn't say explicitly: The -MGMTDB has now become a single-tenant deployment having a CDB with one PDB This will allow the use of a Utility Cluster that can hold the CDB for a collection of GIMR PDBs When you've had already an Oracle 12.1.0.1 GIMR this database will be destroyed and recreated Preserving the CHM/OS data can be acchieved with OCULMON to dump it out into node view The data files associated with it will be created within the same disk group as OCR and VOTING  In a future release there may be an option offered to put in into a separate disk group Some important MOS Notes: MOS Note 1568402.1FAQ: 12c Grid Infrastructure Management Repository, states there's no supported procedure to enable Management Database once the GI stack is configured MOS Note 1589394.1How to Move GI Management Repository to Different Shared Storage(shows how to delete and recreate the MGMTDB) MOS Note 1631336.1Cannot delete Management Database (MGMTDB) in 12.1 -Mike

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  • Remote Access to MSSQL Database From 1&1 Hosting [duplicate]

    - by Zerkey
    This question already has an answer here: How to find web hosting that meets my requirements? 5 answers I just paid ($6 /month) for shared Windows hosting through 1&1 hosting. I was having trouble connecting to my database from home, so I sent an email to support. I received the following response: As we checked your concern here in our end, please be advised that due to limitation of Shared Hosting services, there is no option to connect the database to your SQL Management Studio or through Visual Studio. It is only possible for Dedicated Server package. You may only access the database using MyLittleAdmin at the Control Panel. A dedicated server is like $200 per month! What is the point of having database access only through a web console? I feel I am missing something here, or maybe the support agent is. Is there a way to access my MS SQL database on their servers through Visual Studio or SQL Management Studio from my machine? If not, is there a web host who allows this for less than $200 a month? EDIT: Marked as duplicate... I'm not asking for a list of web hosts, I'm asking how to remotely connect to my MSSQL database through 1&1's services.

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  • SQL SERVER – Validating Unique Columnname Across Whole Database

    - by pinaldave
    I sometimes come across very strange requirements and often I do not receive a proper explanation of the same. Here is the one of those examples. Asker: “Our business requirement is when we add new column we want it unique across current database.” Pinal: “Why do you have such requirement?” Asker: “Do you know the solution?” Pinal: “Sure I can come up with the answer but it will help me to come up with an optimal answer if I know the business need.” Asker: “Thanks – what will be the answer in that case.” Pinal: “Honestly I am just curious about the reason why you need your column name to be unique across database.” (Silence) Pinal: “Alright – here is the answer – I guess you do not want to tell me reason.” Option 1: Check if Column Exists in Current Database IF EXISTS (  SELECT * FROM sys.columns WHERE Name = N'NameofColumn') BEGIN SELECT 'Column Exists' -- add other logic END ELSE BEGIN SELECT 'Column Does NOT Exists' -- add other logic END Option 2: Check if Column Exists in Current Database in Specific Table IF EXISTS (  SELECT * FROM sys.columns WHERE Name = N'NameofColumn' AND OBJECT_ID = OBJECT_ID(N'tableName')) BEGIN SELECT 'Column Exists' -- add other logic END ELSE BEGIN SELECT 'Column Does NOT Exists' -- add other logic END I guess user did not want to share the reason why he had a unique requirement of having column name unique across databases. Here is my question back to you – have you faced a similar situation ever where you needed unique column name across a database. If not, can you guess what could be the reason for this kind of requirement?  Additional Reference: SQL SERVER – Query to Find Column From All Tables of Database Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL System Table, SQL Tips and Tricks, T SQL, Technology

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  • Migration a database from 32bit to 64bit

    - by Mike Dietrich
    Database migrations from an 32bit environment to an 64bit environment keeping the same platform architecture (e.g. moving an Oracle 10.2.0.5 database from MS Windows XP 32bit to MS Windows Server 2003 64bit) does not happen that often anymore. But still we see them getting done. And there are a few things to note when doing such a move. First of all the important question is:Will you upgrade your database as part of this move - Yes or No? If you say "Yes" then you are almost done with that topic as we will take care of that bitnes move during the upgrade. The only thing you have to take care is OLAP in case you are using OLAP Option with Analytic Workspaces (AW) by yourself. Those store data in Binary LOBs - and in order to move AWs from 32bit to 64bit you have to export your AWs prior to the move - and import them later on. People who don't use OLAP don't have to take care on this. But if you say "No" (meaning: no upgrade actions involved - you keep your database version) then you have to make sure to invalidate all packages and stored code in the database before you shutdown your database in the 32bit environment and prior to moving it over. And the same rule as above for OLAP applies once you use the OLAP Option. In the source environment: startup upgrade;    -- [or startup migrate; -- for Oracle 9i] @?/rdbms/admin/utlirp.sqlshutdown immediate In the destination environment: startup upgrade @?/olap/admin/xumuts.plb --Only if OLAP Option is installed@?/rdbms/admin/utlrp.sql The script utlirp.sql will invalidate all packages and stored code, utlrp.sql will recompile - and xumuts.plb will rebuild the OLAP Analytic Workspaces in case you have the OLAP Option installed.

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  • Storing info in a PostgreSQl database issue

    - by MrEnder
    Ok I am making a registry for my website. First page asks for some personal info if($error==false) { $query = pg_query("INSERT INTO chatterlogins(firstName, lastName, gender, password, ageMonth, ageDay, ageYear, email, createDate) VALUES('$firstNameSignup', '$lastNameSignup', '$genderSignup', md5('$passwordSignup'), $monthSignup, $daySignup, $yearSignup, '$emailSignup', now());"); $query = pg_query("INSERT INTO chatterprofileinfo(email, lastLogin) VALUES('$emailSignup', now());"); $userNameSet = $emailSignup; $_SESSION['$userNameSet'] = $userNameSet; header('Location: signup_step2.php'.$rdruri); } The first query works. The second query works but doesn't save the email... the session doesn't work but the header works and sends me to the next page I get no errors even if I comment out header next page @session_start(); $conn = pg_connect("host=localhost dbname=brittains_db user=brittains password=XXXX" ); $signinCheck = false; $checkForm = ""; if(isset($_SESSION['$userName'])) { $userName = $_SESSION['$userName']; $signinCheck = true; $query = pg_query("UPDATE chatterprofileinfo SET lastLogin='now()' WHERE email='$userName'"); } if(isset($_SESSION['$userNameSet'])) { $userName = $_SESSION['$userNameSet']; $signinCheck = true; $query = pg_query("UPDATE chatterprofileinfo SET lastLogin='now()' WHERE email='$userName'"); } This is the top starting the session depending on if your logged in or not. then if I enter in the info here and put it through this if($error==false) { $query = pg_query("UPDATE chatterprofileinfo SET aboutSelf='$aboutSelf', hobbies='$hobbies', music='$music', tv='$tv', sports='$sports', lastLogin='now()' WHERE email='$userName'") or exit(pg_last_error()); //header('Location: signup_step3.php'.$rdruri); } nothing shows up for on my database from this. I have no idea where I went wrong the website is http://opentech.durhamcollege.ca/~intn2201/brittains/chatter/

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  • The Date type and the Android database

    - by cdonner
    I understand that SQLite stores dates as long integers. When I read rows into a cursor using the standard method (i.e. using the query() method that reads data into a cursor), the result is a date string that includes the time. If I want a different format, I have to parse the string back into a date - possible, but a bit backwards. By using a ViewBinder (as suggested in this question), I can pretty much do anything I want, but the date is already a string at the time the method executes. The accepted answer to the above question also suggests that storing dates as longs would help avoid this problem. I don't want to do that, just in case I want to interpret my data with something else than this application. Maybe I want to expose it via a provider. Is there a way to handle this in the database adapter instead, i.e. controlling the date format that the cursor contains, so that I don't have to change the schema, and don't have to parse the default output back into a Date type?

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  • Is Berkeley DB XML a viable database backend?

    - by w00t
    Apparently, BDB-XML has been around since at least 2003 but I only recently stumbled upon it on Oracle's website: Berkeley DB XML. Here's the blurb: Oracle Berkeley DB XML is an open source, embeddable XML database with XQuery-based access to documents stored in containers and indexed based on their content. Oracle Berkeley DB XML is built on top of Oracle Berkeley DB and inherits its rich features and attributes. Like Oracle Berkeley DB, it runs in process with the application with no need for human administration. Oracle Berkeley DB XML adds a document parser, XML indexer and XQuery engine on top of Oracle Berkeley DB to enable the fastest, most efficient retrieval of data. To me it seems that the underlying ideas are technically sound and probably more mature than the newer document-based DBs like CouchDB or MongoDB. It has support for C, C++, Ruby and Perl, as far as I can determine. It even has HA-capabilities like automatic replication using a master/slave model with automatic election. However, I can't seem to find any projects that use it. Is there something fundamentally wrong with it? Is the license too onerous? Is it too complicated? Why is it not being used?

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  • Guice, JDBC and managing database connections

    - by pledge
    I'm looking to create a sample project while learning Guice which uses JDBC to read/write to a SQL database. However, after years of using Spring and letting it abstract away connection handling and transactions I'm struggling to work it our conceptually. I'd like to have a service which starts and stops a transaction and calls numerous repositories which reuse the same connection and participate in the same transaction. My questions are: Where do I create my Datasource? How do I give the repositories access to the connection? (ThreadLocal?) Best way to manage the transaction (Creating an Interceptor for an annotation?) The code below shows how I would do this in Spring. The JdbcOperations injected into each repository would have access to the connection associated with the active transaction. I haven't been able to find many tutorials which cover this, beyond ones which show creating interceptors for transactions. I am happy with continuing to use Spring as it is working very well in my projects, but I'd like to know how to do this in pure Guice and JBBC (No JPA/Hibernate/Warp/Reusing Spring) @Service public class MyService implements MyInterface { @Autowired private RepositoryA repositoryA; @Autowired private RepositoryB repositoryB; @Autowired private RepositoryC repositoryC; @Override @Transactional public void doSomeWork() { this.repositoryA.someInsert(); this.repositoryB.someUpdate(); this.repositoryC.someSelect(); } } @Repository public class MyRepositoryA implements RepositoryA { @Autowired private JdbcOperations jdbcOperations; @Override public void someInsert() { //use jdbcOperations to perform an insert } } @Repository public class MyRepositoryB implements RepositoryB { @Autowired private JdbcOperations jdbcOperations; @Override public void someUpdate() { //use jdbcOperations to perform an update } } @Repository public class MyRepositoryC implements RepositoryC { @Autowired private JdbcOperations jdbcOperations; @Override public String someSelect() { //use jdbcOperations to perform a select and use a RowMapper to produce results return "select result"; } }

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  • Using Oracle hint "FIRST_ROWS" to improve Oracle database performances

    - by bobetko
    I have a statement that runs on Oracle database server. The statement has about 5 joins and there is nothing unusual there. It looks pretty much like below: SELECT field1, field2, field3, ... FROM table1, table2, table3, table4, table5 WHERE table1.id = table2.id AND table2.id = table3.id AND ... table5.userid = 1 The problem (and what is interesting) is that statement for userid = 1 takes 1 second to return 590 records. Statement for userid = 2 takes around 30 seconds to return 70 records. I don't understand why is difference so big. It seems that different execution plan is chosen for statement with userid = 1 and different for userid = 2. After I implemented Oracle Hint FIRST_ROW, performance become significantly better. Both statements (for both ids 1 and 2) produce return in under 1 second. SELECT /*+ FIRST_ROWS */ field1, field2, field3, ... FROM table1, table2, table3, table4, table5 WHERE table1.id = table2.id AND table2.id = table3.id AND ... table5.userid = 1 Questions: 1) What are possible reasons for bad performance when userid = 2 (when hint is not used)? 2) Why would execution plan be different for one vs another statement (when hint is not used)? 3) Is there anything that I should be careful about when deciding to add this hint to my queries? Thanks

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  • NHibernate Legacy Database Mappings Impossible?

    - by Corey Coogan
    I'm hoping someone can help me with mapping a legacy database. The problem I'm describing here has plagued others, yet I was unable to find a real good solution around the web. DISCLAIMER: this is a legacy DB. I have no control over the composite keys. They suck and can't be changed no matter much you tell me they suck. I have 2 tables, both with composite keys. One of the keys from one table is used as part of the key to get a collection from the other table. In short, the keys don't fully match between the table. ClassB is used everywhere I would like to avoid adding properties for the sake of this mapping if possible. public class ClassA { //[PK] public string SsoUid; //[PK] public string PolicyNumber; public IList<ClassB> Others; //more properties.... } public class ClassB { //[PK] public string PolicyNumber; //[PK] public string PolicyDateTime; //more properties } I want to get an instance of ClassA and get all ClassB rows that match PolicyNumber. I am trying to get something going with a one-to-many, but I realize that this may technically be a many-to-many that I am just treating as one-to-many. I've tried using an association class but didn't get far enough to see if it works. I'm new to these more complex mappings and am looking for advice. I'm open to pretty much any ideas. Thanks, Corey

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  • Non-Relational Database Design

    - by Ian Varley
    I'm interested in hearing about design strategies you have used with non-relational "nosql" databases - that is, the (mostly new) class of data stores that don't use traditional relational design or SQL (such as Hypertable, CouchDB, SimpleDB, Google App Engine datastore, Voldemort, Cassandra, SQL Data Services, etc.). They're also often referred to as "key/value stores", and at base they act like giant distributed persistent hash tables. Specifically, I want to learn about the differences in conceptual data design with these new databases. What's easier, what's harder, what can't be done at all? Have you come up with alternate designs that work much better in the non-relational world? Have you hit your head against anything that seems impossible? Have you bridged the gap with any design patterns, e.g. to translate from one to the other? Do you even do explicit data models at all now (e.g. in UML) or have you chucked them entirely in favor of semi-structured / document-oriented data blobs? Do you miss any of the major extra services that RDBMSes provide, like relational integrity, arbitrarily complex transaction support, triggers, etc? I come from a SQL relational DB background, so normalization is in my blood. That said, I get the advantages of non-relational databases for simplicity and scaling, and my gut tells me that there has to be a richer overlap of design capabilities. What have you done? FYI, there have been StackOverflow discussions on similar topics here: the next generation of databases changing schemas to work with Google App Engine choosing a document-oriented database

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  • GAE python database object design for simple list of values

    - by Joey
    I'm really new to database object design so please forgive any weirdness in my question. Basically, I am use Google AppEngine (Python) and contructing an object to track user info. One of these pieces of data is 40 Achievement scores. Do I make a list of ints in the User object for this? Or do I make a separate entity with my user id, the achievement index (0-39) and the score and then do a query to grab these 40 items every time I want to get the user data in total? The latter approach seems more object oriented to me, and certainly better if I extend it to have more than just scores for these 40 achievements. However, considering that I might not extend it, should I even consider just doing a simple list of 40 ints in my user data? I would then forgo doing a query, getting the sorted list of achievements, reading the score from each one just to process a response etc. Is doing this latter approach just such a common practice and hand-waved as not even worth batting an eyelash at in terms of thinking it might be more costly or complex processing wise?

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  • SEO on a Database Driven Website

    - by Ryan Giglio
    I have a question about a site I'm developing. It is a database driven directory site where people can make a profile and list themselves in one or many area codes and in one or many fields of work. When someone is looking for a person to hire, they enter one or more area codes to look in (or select them with checkboxes) and when the form submits, it saves these as a cookie so the site remembers what location you were searching in. You then narrow down your search by category and field (which are links) and get a listing of all the profiles that match your search. What I am concerned about is this: because a search engine can't type in or select area codes to search in, how is it going to find and index any of the profile pages? It doesn't allow the user to search for people without first selecting an area code, because there's no practical purpose to do so. There would also be no practical purpose from a user experience/usability standpoint of simply having a list of each area code as a link to the categories page, but as far as I know, isn't that the only way for search engines to see every person? How does a site like Facebook accomplish this? There isn't some sort of master directory with a link to ever single Facebook user's profile page, and yet they're often the #1 search result for a person's name.

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