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• Is there a standard for storing normalized phone numbers in a database?

  - by Eric Z Beard

  What is a good data structure for storing phone numbers in database fields? I'm looking for something that is flexible enough to handle international numbers, and also something that allows the various parts of the number to be queried efficiently. [Edit] Just to clarify the use case here: I currently store numbers in a single varchar field, and I leave them just as the customer entered them. Then, when the number is needed by code, I normalize it. The problem is that if I want to query a few million rows to find matching phone numbers, it involves a function, like where dbo.f_normalizenum(num1) = dbo.f_normalizenum(num2) which is terribly inefficient. Also queries that are looking for things like the area code become extremely tricky when it's just a single varchar field. [Edit] People have made lots of good suggestions here, thanks! As an update, here is what I'm doing now: I still store numbers exactly as they were entered, in a varchar field, but instead of normalizing things at query time, I have a trigger that does all that work as records are inserted or updated. So I have ints or bigints for any parts that I need to query, and those fields are indexed to make queries run faster.

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• How to develop for iphone application about "retrieving database file on web"?

  - by coverboy

  Hi...all experts! I'm a newbie to iphone developer. Well, currently, I'm developing iphone for Location Based Service. That application need to have these functions. 1. hierarchical tree-view on navigation bar. 2. list up page 3. detail page for example, Let's say. I have top category like "Restaurant, Hotel, Gift Shop" Second level "New York, LA, London,....." Third Level displays all Data with 1 photo. Fourth Level displays Detail of that "Restaurant or Hotel, Gift shop, ..." So, My Only Interest is "How to retrieve the data from remote database server. not using iphone local one." Because, that locations, and shops should be updated frequently, (you know some shops closed, new shops opens.) So, till now, I figured out that using XML to retrieve data. However, using XML is the most effective way to implement? Is there any other way to accomplish this work? You know, transferring XML data via 3G Network is really slow. XML file have more bytes than plist file. I'm currently a beginner of iphone development. So, please help me find a right way!! And, one more question, if I use xml way. Is it possible to Paging? (First page 10 lists up, below that more button...) well, you might guess each category have hundreds of shops!!

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• [Database] How to model this one-to-one relation?

  - by pbean

  I have several entities which respresent different types of users who need to be able to log in to a particular system. Additionally, they have different types of information associated with them. For example: a "general user", which has an e-mail address and "admin user", which has a workstation number (note that this a hypothetical case). Both entities also share common properties like first name, surname, address and telephone number. Finally, they naturally need to have a (unique) user name and a password to log in. In the application, the user just has to fill in his user name and password, and the functionality of the application changes slightly according to the type of the user. You can imagine that the username needs to be unique for this work. How should I model this effectively? I can't just create two tables, because then I can't force a unique constaint on the user name. I also can't put them all in just one table, because they have different types of specific information associated to them. I think I might need 3 seperate tables, one for "users" (with user name and password), one for the "general users" and another one for the "admin users", but how would the relations between these work? Or is there another solution? (By the way, the target DBMS is MySQL, so I don't think generalization is supported in the database system itself).

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• Refactoring or Rewriting Monolithic PHP Spaghetti Codebase

  - by nategood

  I've inherited a really poorly designed PHP spaghetti code project. It's been gaining a good bit of traffic recently and is starting to have performance issues on top of the poor monolithic code base. Its maxing out performance on a chunky 16GB dedicated machine when it really shouldn't be. I'm planning on doing some performance tweaks right off the bat to help the performance issue, but this still won't really help the horrible code base. The team is small but expecting to grow very soon. I've read Joel's article on the troubles of doing a complete rewrite and see the concerns. But how bad does the code base have to be before you consider a rewrite? There is PHP handling logic interjected into what one would usually consider a "view". Even worse, in some places SQL statements are in these same files! The only real separation of presentation and logic are a few PHP scripts that serve as function libraries. These scripts do most of the ORM stuff... if you can even call it that. Trying to slowly refractor this seems like a nightmare. Open to your thoughts and opinions... however not interested in hearing, "Run away, Run away!".

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• Question about using an access database as a resource file in Visual Studio.

  - by user354303

  Hi I am trying to embed a Microsoft Access database file into my Class assembly DLL. I want my code to reference the resource file and use it with a ADODB.Connection object. Any body know a simpler way, or an easier way? Or what is wrong with my code, when i added the resource file it added me dataset definitions, but i have no idea what to do with those. The connection string I am trying below is from an automatically generated app.config. I did add the item as a resource... using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; using ConsoleApplication1.Resources;//SPPrinterLicenses using System.Data.OleDb; using ADODB; using System.Configuration; namespace ConsoleApplication1 { class SharePointPrinterManager { public static bool IsValidLicense(string HardwareID) { OleDbDataAdapter da = new OleDbDataAdapter(); DataSet ds = new DataSet(); ADODB.Connection adoCn = new Connection(); ADODB.Recordset adoRs = new Recordset(); //**open command below fails** adoCn.Open( @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Resources\SPPrinterLicenses.accdb;Persist Security Info=True", "", "", 1); adoRs.Open("Select * from AllWorkstationLicenses", adoCn, ADODB.CursorTypeEnum.adOpenForwardOnly, ADODB.LockTypeEnum.adLockReadOnly, 1); da.Fill(ds, adoRs, "AllworkstationLicenses"); adoCn.Close(); DataTable dt = new DataTable(); //ds.Tables. return true; } } }

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• How to show useful error messages from a database error callback in Phonegap?

  - by Magnus Smith

  Using Phonegap you can set a function to be called back if the whole database transaction or the individual SQL statement errors. I'd like to know how to get more information about the error. I have one generic error-handling function, and lots of different SELECTs or INSERTs that may trigger it. How can I tell which one was at fault? It is not always obvious from the error message. My code so far is... function get_rows(tx) { tx.executeSql("SELECT * FROM Blah", [], lovely_success, statement_error); } function add_row(tx) { tx.executeSql("INSERT INTO Blah (1, 2, 3)", [], carry_on, statement_error); } function statement_error(tx, error) { alert(error.code + ' / ' + error.message); } From various examples I see the error callback will be passed a transaction object and an error object. I read that .code can have the following values: UNKNOWN_ERR = 0 DATABASE_ERR = 1 VERSION_ERR = 2 TOO_LARGE_ERR = 3 QUOTA_ERR = 4 SYNTAX_ERR = 5 CONSTRAINT_ERR = 6 TIMEOUT_ERR = 7 Are there any other properties/methods of the error object? What are the properties/methods of the transaction object at this point? I can't seem to find a good online reference for this. Certainly not on the Phonegap website!

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• Database PK-FK design for future-effective-date entries?

  - by Scott Balmos

  Ultimately I'm going to convert this into a Hibernate/JPA design. But I wanted to start out from purely a database perspective. We have various tables containing data that is future-effective-dated. Take an employee table with the following pseudo-definition: employee id INT AUTO_INCREMENT ... data fields ... effectiveFrom DATE effectiveTo DATE employee_reviews id INT AUTO_INCREMENT employee_id INT FK employee.id Very simplistic. But let's say Employee A has id = 1, effectiveFrom = 1/1/2011, effectiveTo = 1/1/2099. That employee is going to be changing jobs in the future, which would in theory create a new row, id = 2 with effectiveFrom = 7/1/2011, effectiveTo = 1/1/2099, and id = 1's effectiveTo updated to 6/30/2011. But now, my program would have to go through any table that has a FK relationship to employee every night, and update those FK to reference the newly-effective employee entry. I have seen various postings in both pure SQL and Hibernate forums that I should have a separate employee_versions table, which is where I would have all effective-dated data stored, resulting in the updated pseudo-definition below: employee id INT AUTO_INCREMENT employee_versions id INT AUTO_INCREMENT employee_id INT FK employee.id ... data fields ... effectiveFrom DATE effectiveTo DATE employee_reviews id INT AUTO_INCREMENT employee_id INT FK employee.id Then to get any actual data, one would have to actually select from employee_versions with the proper employee_id and date range. This feels rather unnatural to have this secondary "versions" table for each versioned entity. Anyone have any opinions, suggestions from your own prior work, etc? Like I said, I'm taking this purely from a general SQL design standpoint first before layering in Hibernate on top. Thanks!

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• How can I integrate advanced computations into a database field?

  - by ciclistadan

  My biological research involves the measurement of a cellular structure as it changes length throughout the course of observation (capturing images every minute for several hours). As my data sets have become larger I am trying to store them in an Access database, from which I would like to perform various queries about their changes in size. I know that the SELECT statement can incorporate some mathematical permutations, but I have been unable to incorporate many of my necessary calculations (probably due to my lack of knowledge). For example, one calculation involves determining the rate of change during specifically defined periods of growth. This calculation is entirely dependent on the raw data saved in the table, therefore I didn't this it would be appropriate to just calculate it in excel prior to entry into the field. So my question is, what would be the most appropriate method of performing this calculation. Should I attempt to string together a huge SELECT calculation in my QUERY, or is there a way to use another language (I know perl?) which can be called to populate the new query field? I'm not looking for someone to write the code, just where is it appropriate to incorporate each step. Also, I am currently using Office Access but would be interested in any mySQL answers as I may be moving to this platform at a later date. Thanks all!

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• Is fetching data from database a get-method thing?

  - by theva

  I have a small class that I call Viewer. This class is supposed to view the proper layout of each page or something like that... I have a method called getFirstPage, when called the user of this method will get a setting value for which page is currently set as the first page. I have some code here, I think it works but I am not really shure that I have done it the right way: class Viewer { private $db; private $user; private $firstPage; function __construct($db, $user) { $this->db = $db; if(isset($user)) { $this->user = $user; } else { $this->user = 'default'; } } function getFistPage() { $std = $db->prepare("SELECT firstPage FROM settings WHERE user = ':user'"); $std->execute(array(':user' => $user)); $result = $std->fetch(); $this->firstPage = $result['firstPage']; return $this->firstPage; } } My get method is fetching the setting from databse (so far so good?). The problem is that then I have to use this get method to set the private variable firstPage. It seems like I should have a set method to do this, but I cannot really have a set method that just fetch some setting from database, right? Because the user of this object should be able to assume that there already is a setting defined in the object... How should I do that?

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• Help! The log file for database 'tempdb' is full. Back up the transaction log for the database to fr

  - by michael.lukatchik

  We're running SQL Server 2000. In our database, we have an "Orders" table with approximately 750,000 rows. We can perform simple SELECT statements on this table. However, when we want to run a query like SELECT TOP 100 * FROM Orders ORDER BY Date_Ordered DESC, we receive the following message: Error: 9002, Severity: 17, State: 6 The log file for database 'tempdb' is full. Back up the transaction log for the database to free up some log space. We have other tables in our database which are similar in size of the amount of records that are in the tables (i.e. 700,000 records). On these tables, we can run any queries we'd like and we never receive a message about 'tempdb being full'. To resolve this, we've backed up our database, shrunk the actual database and also shrunk the database and files in the tempdb system database, but this hasn't resolved the issue. The size of our log file is set to autogrow. We're not sure where to go next. Are there any ideas why we still might be receiving this message? Error: 9002, Severity: 17, State: 6 The log file for database 'tempdb' is full. Back up the transaction log for the database to free up some log space.

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• How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt?

  - by Stu Thompson

  Prelude: I'm a code-monkey that's increasingly taken on SysAdmin duties for my small company. My code is our product, and increasingly we provide the same app as SaaS. About 18 months ago I moved our servers from a premium hosting centric vendor to a barebones rack pusher in a tier IV data center. (Literally across the street.) This ment doing much more ourselves--things like networking, storage and monitoring. As part the big move, to replace our leased direct attached storage from the hosting company, I built a 9TB two-node NAS based on SuperMicro chassises, 3ware RAID cards, Ubuntu 10.04, two dozen SATA disks, DRBD and . It's all lovingly documented in three blog posts: Building up & testing a new 9TB SATA RAID10 NFSv4 NAS: Part I, Part II and Part III. We also setup a Cacit monitoring system. Recently we've been adding more and more data points, like SMART values. I could not have done all this without the awesome boffins at ServerFault. It's been a fun and educational experience. My boss is happy (we saved bucket loads of $$$), our customers are happy (storage costs are down), I'm happy (fun, fun, fun). Until yesterday. Outage & Recovery: Some time after lunch we started getting reports of sluggish performance from our application, an on-demand streaming media CMS. About the same time our Cacti monitoring system sent a blizzard of emails. One of the more telling alerts was a graph of iostat await. Performance became so degraded that Pingdom began sending "server down" notifications. The overall load was moderate, there was not traffic spike. After logging onto the application servers, NFS clients of the NAS, I confirmed that just about everything was experiencing highly intermittent and insanely long IO wait times. And once I hopped onto the primary NAS node itself, the same delays were evident when trying to navigate the problem array's file system. Time to fail over, that went well. Within 20 minuts everything was confirmed to be back up and running perfectly. Post-Mortem: After any and all system failures I perform a post-mortem to determine the cause of the failure. First thing I did was ssh back into the box and start reviewing logs. It was offline, completely. Time for a trip to the data center. Hardware reset, backup an and running. In /var/syslog I found this scary looking entry: Nov 15 06:49:44 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_00], 6 Currently unreadable (pending) sectors Nov 15 06:49:44 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_07], SMART Prefailure Attribute: 1 Raw_Read_Error_Rate changed from 171 to 170 Nov 15 06:49:45 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_10], 16 Currently unreadable (pending) sectors Nov 15 06:49:45 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_10], 4 Offline uncorrectable sectors Nov 15 06:49:45 umbilo smartd[2827]: Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error Nov 15 06:49:45 umbilo smartd[2827]: # 1 Short offline Completed: read failure 90% 6576 3421766910 Nov 15 06:49:45 umbilo smartd[2827]: # 2 Short offline Completed: read failure 90% 6087 3421766910 Nov 15 06:49:45 umbilo smartd[2827]: # 3 Short offline Completed: read failure 10% 5901 656821791 Nov 15 06:49:45 umbilo smartd[2827]: # 4 Short offline Completed: read failure 90% 5818 651637856 Nov 15 06:49:45 umbilo smartd[2827]: So I went to check the Cacti graphs for the disks in the array. Here we see that, yes, disk 7 is slipping away just like syslog says it is. But we also see that disk 8's SMART Read Erros are fluctuating. There are no messages about disk 8 in syslog. More interesting is that the fluctuating values for disk 8 directly correlate to the high IO wait times! My interpretation is that: Disk 8 is experiencing an odd hardware fault that results in intermittent long operation times. Somehow this fault condition on the disk is locking up the entire array Maybe there is a more accurate or correct description, but the net result has been that the one disk is impacting the performance of the whole array. The Question(s) How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt? Am I being naïve to think that the RAID card should have dealt with this? How can I prevent a single misbehaving disk from impacting the entire array? Am I missing something?

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• BNF – how to read syntax?

  - by Piotr Rodak

  A few days ago I read post of Jen McCown (blog) about her idea of blogging about random articles from Books Online. I think this is a great idea, even if Jen says that it’s not exciting or sexy. I noticed that many of the questions that appear on forums and other media arise from pure fact that people asking questions didn’t bother to read and understand the manual – Books Online. Jen came up with a brilliant, concise acronym that describes very well the category of posts about Books Online – RTFM365. I take liberty of tagging this post with the same acronym. I often come across questions of type – ‘Hey, i am trying to create a table, but I am getting an error’. The error often says that the syntax is invalid. 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT DEFAULT Guid_Default NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); 5 The answer is usually(1), ‘Ok, let me check it out.. Ah yes – you have to put name of the DEFAULT constraint before the type of constraint: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); Why many people stumble on syntax errors? Is the syntax poorly documented? No, the issue is, that correct syntax of the CREATE TABLE statement is documented very well in Books Online and is.. intimidating. Many people can be taken aback by the rather complex block of code that describes all intricacies of the statement. However, I don’t know better way of defining syntax of the statement or command. The notation that is used to describe syntax in Books Online is a form of Backus-Naur notatiion, called BNF for short sometimes. This is a notation that was invented around 50 years ago, and some say that even earlier, around 400 BC – would you believe? Originally it was used to define syntax of, rather ancient now, ALGOL programming language (in 1950’s, not in ancient India). If you look closer at the definition of the BNF, it turns out that the principles of this syntax are pretty simple. Here are a few bullet points: italic_text is a placeholder for your identifier <italic_text_in_angle_brackets> is a definition which is described further. [everything in square brackets] is optional {everything in curly brackets} is obligatory everything | separated | by | operator is an alternative ::= “assigns” definition to an identifier Yes, it looks like these six simple points give you the key to understand even the most complicated syntax definitions in Books Online. Books Online contain an article about syntax conventions – have you ever read it? Let’s have a look at fragment of the CREATE TABLE statement: 1 CREATE TABLE 2 [ database_name . [ schema_name ] . | schema_name . ] table_name 3 ( { <column_definition> | <computed_column_definition> 4 | <column_set_definition> } 5 [ <table_constraint> ] [ ,...n ] ) 6 [ ON { partition_scheme_name ( partition_column_name ) | filegroup 7 | "default" } ] 8 [ { TEXTIMAGE_ON { filegroup | "default" } ] 9 [ FILESTREAM_ON { partition_scheme_name | filegroup 10 | "default" } ] 11 [ WITH ( <table_option> [ ,...n ] ) ] 12 [ ; ] Let’s look at line 2 of the above snippet: This line uses rules 3 and 5 from the list. So you know that you can create table which has specified one of the following. just name – table will be created in default user schema schema name and table name – table will be created in specified schema database name, schema name and table name – table will be created in specified database, in specified schema database name, .., table name – table will be created in specified database, in default schema of the user. Note that this single line of the notation describes each of the naming schemes in deterministic way. The ‘optionality’ of the schema_name element is nested within database_name.. section. You can use either database_name and optional schema name, or just schema name – this is specified by the pipe character ‘|’. The error that user gets with execution of the first script fragment in this post is as follows: Msg 156, Level 15, State 1, Line 2 Incorrect syntax near the keyword 'DEFAULT'. Ok, let’s have a look how to find out the correct syntax. Line number 3 of the BNF fragment above contains reference to <column_definition>. Since column_definition is in angle brackets, we know that this is a reference to notion described further in the code. And indeed, the very next fragment of BNF contains syntax of the column definition. 1 <column_definition> ::= 2 column_name <data_type> 3 [ FILESTREAM ] 4 [ COLLATE collation_name ] 5 [ NULL | NOT NULL ] 6 [ 7 [ CONSTRAINT constraint_name ] DEFAULT constant_expression ] 8 | [ IDENTITY [ ( seed ,increment ) ] [ NOT FOR REPLICATION ] 9 ] 10 [ ROWGUIDCOL ] [ <column_constraint> [ ...n ] ] 11 [ SPARSE ] Look at line 7 in the above fragment. It says, that the column can have a DEFAULT constraint which, if you want to name it, has to be prepended with [CONSTRAINT constraint_name] sequence. The name of the constraint is optional, but I strongly recommend you to make the effort of coming up with some meaningful name yourself. So the correct syntax of the CREATE TABLE statement from the beginning of the article is like this: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); That is practically everything you should know about BNF. I encourage you to study the syntax definitions for various statements and commands in Books Online, you can find really interesting things hidden there. Technorati Tags: SQL Server,t-sql,BNF,syntax   (1) No, my answer usually is a question – ‘What error message? What does it say?’. You’d be surprised to know how many people think I can go through time and space and look at their screen at the moment they received the error.

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• I have Oracle SQL Developer Installed, Now What?

  - by thatjeffsmith

  If you’re here because you downloaded a copy of Oracle SQL Developer and now you need help connecting to a database, then you’re in the right place. I’ll show you what you need to get up and going so you can finish your homework, teach yourself Oracle database, or get ready for that job interview. You’ll need about 30 minutes to set everything up…and about 5 years to become proficient with Oracle Oracle Database come with SQL Developer but SQL Developer doesn’t include a database If you install Oracle database, it includes a copy of SQL Developer. If you’re running that copy of SQL Developer, please take a second to upgrade now, as it is WAY out of date. But I’m here to talk to the folks that have downloaded SQL Developer and want to know what to do next. You’ve got it running. You see this ‘Connection’ dialog, and… Where am I connecting to, and who as? You NEED a database Installing SQL Developer does not give you a database. So you’re going to need to install Oracle and create a database, or connect to a database that is already up and running somewhere. Basically you need to know the following: where is this database, what’s it called, and what port is the listener running on? The Default Connection properties in SQL Developer These default settings CAN work, but ONLY if you have installed Oracle Database Express Edition (XE). Localhost is a network alias for 127.0.0.1 which is an IP address that maps to the ‘local’ machine, or the machine you are reading this blog post on. The listener is a service that runs on the server and handles connections for the databases on that machine. You can run a database without a listener and you can run a listener without a database, but you can’t connect to a database on a different server unless both that database and listener are up and running. Each listener ‘listens’ on one or more ports, you need to know the port number for each connection. The default port is 1521, but 1522 is often pretty common. I know all of this sounds very complicated Oracle is a very sophisticated piece of software. It’s not analogous to downloading a mobile phone app and and using it 10 seconds later. It’s not like installing Office/Access either – it requires services, environment setup, kernel tweaks, etc. However. Normally an administrator will setup and install Oracle, create the database, and configure the listener for everyone else to use. They’ll often also setup the connection details for everyone via a ‘TNSNAMES.ORA’ file. This file contains a list of database connection details for folks to browse – kind of like an Oracle database phoneboook. If someone has given you a TNSNAMES.ORA file, or setup your machine to have access to a TNSNAMES file, then you can just switch to the ‘TNS’ connection type, and use the dropdown to select the database you want to connect to. Then you don’t have to worry about the server names, database names, and the port numbers. ORCL – that sounds promising! ORCL is the default SID when creating a new database with the Database Creation Assistant (DBCA). It’s just me, and I need help! No administrator, no database, no nothing. What do you do? You have a few options: Buy a copy of Oracle and download, install, and create a database Download and install XE (FREE!) Download, import, and run our Developer Days Hands-on-Lab (FREE!) If you’re a student (or anyone else) with little to no experience with Oracle, then I recommend the third option. Oracle Technology Network Developer Day: Hands-on Database Application Development Lab The OTN lab runs on a A Virtual Box image which contains: 11gR2 Enterprise Edition copy of Oracle a database and listener running for you to connect to lots of demo data for you to play with SQL Developer installed and ready to connect Some browser based labs you can step through to learn Oracle You download the image, you download and install Virtual Box (also FREE!), then you IMPORT the image you previously downloaded. You then ‘Start’ the image. It will boot a copy of Oracle Enterprise Linux (OEL), start your database, and all that jazz. You can then start up and run SQL Developer inside the image OR you can connect to the database running on the image using the copy of SQL Developer you installed on your host machine. Setup Port Forwarding to Make It Easy to Connect From Your Host When you start the image, it will be assigned an IP address. Depending on what network adapter you select in the image preferences, you may get something that can get out to the internet from your image, something your host machine can see and connect to, or something that kind of just lives out there in a vacuum. You want to avoid the ‘vacuum’ option – unless you’re OK with running SQL Developer inside the Linux image. Open the Virtual Box image properties and go to the Networking options. We’re going to setup port forwarding. This will tell your machine that anything that happens on port 1521 (the default Oracle Listener port), should just go to the image’s port 1521. So I can connect to ‘localhost’ and it will magically get transferred to the image that is running. Oracle Virtual Box Port Forwarding 1521 listener database Now You Just Need a Username and Password The default passwords on this image are all ‘oracle’ – so you can connect as SYS, HR, or whatever – just use ‘oracle’ as the password. The Linux passowrds are all ‘oracle’ too, so you can login as ‘root’ or as ‘oracle’ in the Linux desktop. Connect! Connect as HR to your Oracle database running on the OTN Developer Days Virtual Box image If you’re connecting to someone else’s database, you need to ask the person that manages that environment to create for you an account. Don’t try to ‘guess’ or ‘figure out’ what the username and password is. Introduce yourself, explain your situation, and ask kindly for access. This is your first test – can you connect? I know it’s hard to get started with Oracle. There are however many things we offer to make this easier. You’ll need to do a bit of RTM first though. Once you know what’s required, you will be much more likely to succeed. Of course, if you need help, you know where to find me

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• SAN with iSCSI-Target Performance Horrendous

  - by Justin

  We have a poor man's SAN setup in a 1U Ubuntu server running iSCSI-Target with two 300GB drives in RAID-0. We then are using it for block level storage for virtual machines. The hypervisor is connected to the SAN via gigabit on a dedicated VLAN and interfaces. We only have a single virtual machine setup and doing some benchmarks. If we run hdparm -t /dev/sda1 from the virtual machine, we get 'ok' performance of 75MB/s from the virtual machine to the SAN. Then we basically compile a package with ./configure and make. Things start ok, but then all the sudden the load average on the SAN grows to 7+ and things slow down to a crawl. When we SSH into the SAN and run top, sure the load is 7+, but the CPU usage is basically nothing, also the server has 1.5GB of memory available. When we kill the compile on the virtual machine, slowly the LOAD on the SAN goes back to sub 1 figures. What in the world is causing this? How can we diagnosis this further? Here are two screenshot from the SAN during high load. 1> Output of iotop on the SAN: 2> Output of top on the SAN:

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• X11 performance problem after upgrading from Centos3 to Centos5 with an ATI Rage XL

  - by Marcelo Santos

  After upgrading a computer from Centos3 to Centos5 an application that does a lot of scrolling took a very high performance hit. top tells me that X is using a lot of CPU and that was not happening before. The machine has an ATI Rage XL with 8MB and X is using the ati driver as there is no proprietary ATI driver for this board on linux. The xorg.conf: Section "Device" Identifier "Videocard0" Driver "ati" EndSection Section "Screen" Identifier "Screen0" Device "Videocard0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 Modes "1024x768" "800x600" "640x480" EndSubSection EndSection Section "DRI" Group 0 Mode 0666 EndSection A similar machine that still has Centos3 installed is able to start DRI on the X server while this one is not, this is the Xorg.0.log for the Centos5 machine: drmOpenDevice: node name is /dev/dri/card0 drmOpenDevice: open result is -1, (No such device or address) drmOpenDevice: open result is -1, (No such device or address) drmOpenDevice: Open failed drmOpenDevice: node name is /dev/dri/card0 drmOpenDevice: open result is -1, (No such device or address) drmOpenDevice: open result is -1, (No such device or address) drmOpenDevice: Open failed [drm] failed to load kernel module "mach64" (II) ATI(0): [drm] drmOpen failed (EE) ATI(0): [dri] DRIScreenInit Failed (II) ATI(0): Largest offscreen areas (with overlaps): (II) ATI(0): 1024 x 1279 rectangle at 0,768 (II) ATI(0): 768 x 1280 rectangle at 0,768 (II) ATI(0): Using XFree86 Acceleration Architecture (XAA) Screen to screen bit blits Solid filled rectangles 8x8 mono pattern filled rectangles Indirect CPU to Screen color expansion Solid Lines Offscreen Pixmaps Setting up tile and stipple cache: 32 128x128 slots 10 256x256 slots (==) ATI(0): Backing store disabled (==) ATI(0): Silken mouse enabled (II) ATI(0): Direct rendering disabled (==) RandR enabled I also tried using EXA instead of XAA and setting: Option "AccelMethod" "XAA" Option "XAANoOffscreenPixmaps" "true" uname -a Linux sir5.erg.inpe.br 2.6.18-128.7.1.el5 #1 SMP Mon Aug 24 08:20:55 EDT 2009 i686 i686 i386 GNU/Linux rpm -qa | grep xorg-x11-server xorg-x11-server-utils-7.1-4.fc6 xorg-x11-server-sdk-1.1.1-48.52.el5 xorg-x11-server-Xvfb-1.1.1-48.52.el5 xorg-x11-server-Xnest-1.1.1-48.52.el5 xorg-x11-server-Xorg-1.1.1-48.52.el5 The drmOpenDevice error continues when using the suggested Option "AIGLX" "true".

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• Bad Performance when SQL Server hits 99% Memory Usage

  - by user15863

  I've got a server that reports 8 GB of ram used up at 99%. When restart Sql Server, it drops down to about 5% usage, but gradually builds back up to 99% over about 2 hours. When I look at the sqlserver process, its reported as only using 100k ram, and generally never goes up or below that number by very much. In fact, if I add up all the processes in my TaskManager, it's barely scratching the surface of my total available (yet TaskManager still shows 99% memory usage with "All processes shown"). It appears that Sql Server has a huge memory leak going on but it's not reporting it. The server has ran fine for nearly two years, with this only starting to manifest itself in the last 3-4 weeks. Anyone seen this or have any insight into the problem? EDIT When the server hits 99%, performance goes down hill. All queries to the server, apps, etc. come to a crawl. Restarting the service makes things zippy again, until 2 hours has passed and the server hits 99% once again.

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• Performance of Virtual machines on very low end machines

  - by TheLQ

  I am managing a few cheap servers as my user base isn't large enough to get much more powerful servers. I also don't have the money lying around to invest in a server to prepare for the larger user base. So I'm stuck with the old hardware I have. I am toying with the idea of virtualizing all the current OS's with most likely VMware vSphere Hypervisor (AKA ESXi) Xen (ESXi has too strict of an HCL, and my hardware is too old). Big reasons for doing so: Ability to upgrade and scale hardware rapidly - This is most likely what I'll be doing as I distribute services, get a bigger server, centralize (electricity bills are horrible), distribute, get a bigger server, etc... Manually doing this by reinstalling the entire OS would be a big pain Safety from me - I've made many rookie mistakes, like doing lots of risky work on a vital production server. With a VM I can just backup the state, work on my machine, test, and revert if necessary. No worries, and no OS reinstallation Safety from other factors - As I scale servers might go down, and a backup VM can instantly be started. Various other reasons. However the limiting factor here is hardware. And I mean very depressing hardware. The current server's run off of a Pentium 3 and 4, and have 512 MB and 768 MB RAM respectively (RAM can be upgraded soon however). Is the Virtualization layer small enough to run itself and a Linux OS effectively? Will performance be acceptable (50% CPU overhead for every operation isn't acceptable)? Does it leave enough RAM for the Linux OS? Is this even feasible?

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• Hints on diagnosing performance issue in OpenBSD firewall

  - by Tom

  My OpenBSD 4.6 pf firewall has started having really bad performance in the past few weeks. I've isolated the firewall (as opposed to the WAN connection, switch, cable, etc.) as the problem, but need a hint on how to further diagnose or fix the problem. The facts: Normal setup is: DSL Modem - FW Ext. NIC - FW Int. NIC - Switch - Laptop Normal setup described above gives only 25 Kbps! Plugging the laptop straight from the DSL modem gives a 1 MBps connection (full speed, as advertised). Therefore, the DSL connection seems to be OK. Plugging the laptop directly into the firewall's internal NIC (bypassing the switch) also gives only 25 Kbps. Therefore, the switch does not seem to be a problem. I've replaced the ethernet cables, but it didn't help. Here's the weird thing. Reloading the ruleset (/sbin/pfctl -Fa -f /etc/pf.conf) causes the laptop's connection to go up to 1 Mbps (i.e. full speed) for a few minutes before it gradually degrades back down to 25Kbps again. Any ideas on what's wrong or how I could further diagnose the problem?

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• Nginx + uWSGI + Django performance stuck on 100rq/s

  - by dancio

  I have configured Nginx with uWSGI and Django on CentOS 6 x64 (3.06GHz i3 540, 4GB), which should easily handle 2500 rq/s but when I run ab test ( ab -n 1000 -c 100 ) performance stops at 92 - 100 rq/s. Nginx: user nginx; worker_processes 2; events { worker_connections 2048; use epoll; } uWSGI: Emperor /usr/sbin/uwsgi --master --no-orphans --pythonpath /var/python --emperor /var/python/*/uwsgi.ini [uwsgi] socket = 127.0.0.2:3031 master = true processes = 5 env = DJANGO_SETTINGS_MODULE=x.settings env = HTTPS=on module = django.core.handlers.wsgi:WSGIHandler() disable-logging = true catch-exceptions = false post-buffering = 8192 harakiri = 30 harakiri-verbose = true vacuum = true listen = 500 optimize = 2 sysclt changes: # Increase TCP max buffer size setable using setsockopt() net.ipv4.tcp_rmem = 4096 87380 8388608 net.ipv4.tcp_wmem = 4096 87380 8388608 net.core.rmem_max = 8388608 net.core.wmem_max = 8388608 net.core.netdev_max_backlog = 5000 net.ipv4.tcp_max_syn_backlog = 5000 net.ipv4.tcp_window_scaling = 1 net.core.somaxconn = 2048 # Avoid a smurf attack net.ipv4.icmp_echo_ignore_broadcasts = 1 # Optimization for port usefor LBs # Increase system file descriptor limit fs.file-max = 65535 I did sysctl -p to enable changes. Idle server info: top - 13:34:58 up 102 days, 18:35, 1 user, load average: 0.00, 0.00, 0.00 Tasks: 118 total, 1 running, 117 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 3983068k total, 2125088k used, 1857980k free, 262528k buffers Swap: 2104504k total, 0k used, 2104504k free, 606996k cached free -m total used free shared buffers cached Mem: 3889 2075 1814 0 256 592 -/+ buffers/cache: 1226 2663 Swap: 2055 0 2055 **During the test:** top - 13:45:21 up 102 days, 18:46, 1 user, load average: 3.73, 1.51, 0.58 Tasks: 122 total, 8 running, 114 sleeping, 0 stopped, 0 zombie Cpu(s): 93.5%us, 5.2%sy, 0.0%ni, 0.2%id, 0.0%wa, 0.1%hi, 1.1%si, 0.0%st Mem: 3983068k total, 2127564k used, 1855504k free, 262580k buffers Swap: 2104504k total, 0k used, 2104504k free, 608760k cached free -m total used free shared buffers cached Mem: 3889 2125 1763 0 256 595 -/+ buffers/cache: 1274 2615 Swap: 2055 0 2055 iotop 30141 be/4 nginx 0.00 B/s 7.78 K/s 0.00 % 0.00 % nginx: wo~er process Where is the bottleneck ? Or what am I doing wrong ?

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• How to detach a sql server 2008 database that is not in database list?

  - by Amir

  I installed SQL Server 2008 on Windows 7. Then I created a database. After 2 days I reinstalled Windows and SQL Server. Now I am trying to attach my database file, but I have encountered the error below. I think that the files are like an attached file and I can't attach them. What is difference between an attached file and a non-attached file? How can I attach this file? Please Help Me. Error Text: TITLE: Microsoft SQL Server Management Studio Attach database failed for Server 'AMIR-PC'. (Microsoft.SqlServer.Smo) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=10.50.1600.1+((KJ_RTM).100402-1540+)&EvtSrc=Microsoft.SqlServer.Management.Smo.ExceptionTemplates.FailedOperationExceptionText&EvtID=Attach+database+Server&LinkId=20476 ------------------------------ ADDITIONAL INFORMATION: An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo) Unable to open the physical file "F:\Company.mdf". Operating system error 5: "5(Access is denied.)". (Microsoft SQL Server, Error: 5120) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=10.50.1600&EvtSrc=MSSQLServer&EvtID=5120&LinkId=20476

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• X11 performance problem after upgrading from Centos3 to Centos5 with an ATI Rage XL

  - by Marcelo Santos

  After upgrading a computer from Centos3 to Centos5 an application that does a lot of scrolling took a very high performance hit. top tells me that X is using a lot of CPU and that was not happening before. The machine has an ATI Rage XL with 8MB and X is using the ati driver as there is no proprietary ATI driver for this board on linux. The xorg.conf: Section "Device" Identifier "Videocard0" Driver "ati" EndSection Section "Screen" Identifier "Screen0" Device "Videocard0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 Modes "1024x768" "800x600" "640x480" EndSubSection EndSection Section "DRI" Group 0 Mode 0666 EndSection A similar machine that still has Centos3 installed is able to start DRI on the X server while this one is not, this is the Xorg.0.log for the Centos5 machine: drmOpenDevice: node name is /dev/dri/card0 drmOpenDevice: open result is -1, (No such device or address) drmOpenDevice: open result is -1, (No such device or address) drmOpenDevice: Open failed drmOpenDevice: node name is /dev/dri/card0 drmOpenDevice: open result is -1, (No such device or address) drmOpenDevice: open result is -1, (No such device or address) drmOpenDevice: Open failed [drm] failed to load kernel module "mach64" (II) ATI(0): [drm] drmOpen failed (EE) ATI(0): [dri] DRIScreenInit Failed (II) ATI(0): Largest offscreen areas (with overlaps): (II) ATI(0): 1024 x 1279 rectangle at 0,768 (II) ATI(0): 768 x 1280 rectangle at 0,768 (II) ATI(0): Using XFree86 Acceleration Architecture (XAA) Screen to screen bit blits Solid filled rectangles 8x8 mono pattern filled rectangles Indirect CPU to Screen color expansion Solid Lines Offscreen Pixmaps Setting up tile and stipple cache: 32 128x128 slots 10 256x256 slots (==) ATI(0): Backing store disabled (==) ATI(0): Silken mouse enabled (II) ATI(0): Direct rendering disabled (==) RandR enabled I also tried using EXA instead of XAA and setting: Option "AccelMethod" "XAA" Option "XAANoOffscreenPixmaps" "true" uname -a Linux sir5.erg.inpe.br 2.6.18-128.7.1.el5 #1 SMP Mon Aug 24 08:20:55 EDT 2009 i686 i686 i386 GNU/Linux rpm -qa | grep xorg-x11-server xorg-x11-server-utils-7.1-4.fc6 xorg-x11-server-sdk-1.1.1-48.52.el5 xorg-x11-server-Xvfb-1.1.1-48.52.el5 xorg-x11-server-Xnest-1.1.1-48.52.el5 xorg-x11-server-Xorg-1.1.1-48.52.el5 The drmOpenDevice error continues when using the suggested Option "AIGLX" "true".

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• apache performance timing out

  - by Mike

  Im running a webserver where I'm hosting about 6-7 websites. Most of these websites get their content from MySQL which is hosted on the same server. Traffic average per day is about 500-600 unique visitors, about 150K hits per week. But for some reason sometimes websites send a timeout, OR sometimes websites dont load all images. I know that I should perhaps separate static content from dynamic content, but for now I think that's not a possibility. I would appreciate any suggestions on how could I improve the performance of apache, so it doesn't keep timing out. Server is running on Sempron LE 1300; 2.3GHz,512K Cache 2GB RAM 10Mbps/1Mbps Services: MySQL, ProFTPD, Apache. Private + Shared = RAM used Program ---------------------------------------------------- 1.2 MiB + 54.0 KiB = 1.2 MiB proftpd 4.1 MiB + 23.0 KiB = 4.1 MiB munin-node 20.8 MiB + 120.5 KiB = 20.9 MiB mysqld 47.3 MiB + 9.9 MiB = 57.3 MiB apache2 (22) top: Mem: 2075356k total, 1826196k used, 249160k free, Timeout 35 KeepAlive On MaxKeepAliveRequests 300 KeepAliveTimeout 5 <IfModule mpm_prefork_module> StartServers 10 MinSpareServers 20 MaxSpareServers 20 MaxClients 60 MaxRequestsPerChild 1000 </IfModule> <IfModule mpm_worker_module> StartServers 2 MaxClients 150 MinSpareThreads 25 MaxSpareThreads 75 ThreadsPerChild 25 MaxRequestsPerChild 0 </IfModule>

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• VMWare converter performance

  - by bellocarico

  Hello, I have a question about my test lab. It's more to understand the concept more than apply this into production: I have an ESXi with few VMs linux/windows configured and I'd like to use VMWare converter to create backups. To speedup the process I decided to create a Windows VM on the same ESXi host where I've installed Windows 7 and VMWare Converter. The Host has a gigabit card but it's currently connected to a 100Mb FD port. Windows 7 sees a 1gb card connected. When I do the backup using VMWare converter I specify the host IP as source and destination, so I thought the copy could be faster then use my laptop across the network. Well, to cut a long sotry short: I get dreadful performance (4Mb/sec). I'm a buit confused on this because despite the fact that the host is running 100Mb communication between VMs and hosts shouldn't (correct me if I'm wrong) have any limitation instead. I did tweak windows 7 to optimise network performane but I got just a little improvement. i still need 4 hours to back up a 50Gb (thin) VM. Additionally I wanted to ask: Would jumbo frame help in this? I know that jumbo frame have to be supported end to end, and the network switch where the host is currently connected doesn't support this, but I was wondering: 1) Does ESXi host support jumbo frames at all? 2) Can I enable it somehow? 3) If I do so, I guess bulk transfert between VMs and host would improve, but would this affect the communication going through the real switch as this doesn't do jumbo? Thanks for reading

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• Setting up MongoDB in High Performance Computing LSF linux cluster

  - by Dnaiel

  I am trying to run mongo in a LSF cluster computing environment where I have no admin control. Our sysadmin installed mongodb, but it is not running. Any ideas on what should I ask the server admin to do for it to run? Or if I could run it locally? [node1382]allelix> mongod --dbpath /users/dnaiel/ma/mongodb/ Tue Oct 2 21:33:48 [initandlisten] MongoDB starting : pid=22436 port=27017 dbpath=/seq/epigenome01/allelix/ma/mongodb/ 64-bit host=node1382 Tue Oct 2 21:33:48 [initandlisten] Tue Oct 2 21:33:48 [initandlisten] ** WARNING: You are running on a NUMA machine. Tue Oct 2 21:33:48 [initandlisten] ** We suggest launching mongod like this to avoid performance problems: Tue Oct 2 21:33:48 [initandlisten] ** numactl --interleave=all mongod [other options] Tue Oct 2 21:33:48 [initandlisten] Tue Oct 2 21:33:48 [initandlisten] db version v2.2.0, pdfile version 4.5 Tue Oct 2 21:33:48 [initandlisten] git version: f5e83eae9cfbec7fb7a071321928f00d1b0c5207 Tue Oct 2 21:33:48 [initandlisten] build info: Linux ip-10-2-29-40 2.6.21.7-2.ec2.v1.2.fc8xen #1 SMP Fri Nov 20 17:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_49 Tue Oct 2 21:33:48 [initandlisten] options: { dbpath: "/users/dnaiel/ma/mongodb/" } Tue Oct 2 21:33:48 [initandlisten] journal dir=users/dnaiel/ma/mongodb/journal Tue Oct 2 21:33:48 [initandlisten] recover begin Tue Oct 2 21:33:48 [initandlisten] info no lsn file in journal/ directory Tue Oct 2 21:33:48 [initandlisten] recover lsn: 0 Tue Oct 2 21:33:48 [initandlisten] recover /seq/epigenome01/allelix/ma/mongodb/journal/j._0 Tue Oct 2 21:33:48 [initandlisten] recover cleaning up Tue Oct 2 21:33:48 [initandlisten] removeJournalFiles Tue Oct 2 21:33:48 [initandlisten] recover done Tue Oct 2 21:33:48 [websvr] admin web console waiting for connections on port 28017 Tue Oct 2 21:33:48 [initandlisten] waiting for connections on port 27017 It basically waits forever and cannot start mongodb. These servers are not webservers but they do have network access, it's a cloud computing LSF environment system. Any advice would be welcome, thanks in advance.

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• Site resolves fine without "www", "www" creates database error

  - by PatrickS

  Working with BOA ( Barracuda / Octopus / Aegir ) , I've installed a few Drupal sites without any problems and following the same process for all. BOA is running on Nginx. All sites are going thru Cloudflare's network , where I set the same DNS settings. A example.com points to IPADDRESS A www points to IPADDRESS the nameservers of each domain are pointing to Cloudflare's respective nameservers. It all works , except for one site that works perfectly without "www" , but with "www" returns the typical database error if Drupal can't find the site's database. Site off-line The site is currently not available due to technical problems. Please try again later. Thank you for your understanding. If you are the maintainer of this site, please check your database settings in the settings.php file and ensure that your hosting provider's database server is running. For more help, see the handbook, or contact your hosting provider. In BOA, all sites have the same alias, basically a symlink, redirecting like this... www.example.com - example.com

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