Understanding Public Clouds: IaaS, PaaS, & SaaS

Excellent article can be found at: http://www.keithpij.com/Home/tabid/36/EntryID/27/Default.aspx

IIS7 - static content is not displayed

Use Case

On fresh Win7 Professional box, static content (images, css, js) is not displayed.

Solution

By default, Static Content Service is turned off in IIS7 installation. Make sure, that you have that service enabled at: Turn Windows Features On and Off > Internet Information Service > World Wide Web Services > Common Http Features > Static Content.

For more information, refer to http://weblogs.asp.net/anasghanem/archive/2008/05/23/don-t-forget-to-check-quot-static-content-service-quot-in-iis7-installation.aspx

System.Transactions with ODP.NET. System.AccessViolationException: “Attempted to read or write protected memory. Data provider internal error(-3000).

Use Case

Oracle 10g
Oracle Data Provider for .NET 2.0 11.2.0.1.2

VS 2008, C#

When trying to open connection to Oracle database inside Distributed Transactions, weird exception appears:

System.AccessViolationException: “Attempted to read or write protected memory. This is often an indication that other memory is corrupt.”

another people reported following exception:

Data provider internal error(-3000) [System.String]

Steps to reproduce.

1. Use explicit CommittableTransaction

            var factory = DbProviderFactories.GetFactory("Oracle.DataAccess.Client");
            string constr = 'my connection string';

            using (var transaction = new CommittableTransaction())
            {
                using (var conn = factory.CreateConnection())
                {
                    conn.ConnectionString = constr;
                    conn.Open();
                    conn.EnlistTransaction(transaction); <- Exception thrown here
                }
            }

2. Use implicit TransactionScope

            var factory = DbProviderFactories.GetFactory("Oracle.DataAccess.Client");

            string constr = 'my connection string';

            using (var scope = new TransactionScope())

            {

                using (var conn = factory.CreateConnection())

                {

                    conn.ConnectionString = constr;

                    conn.Open(); <-- Exception thrown here

                }

            }

Solution

After some time spent to reading documentation and googling, following things became apparent.

First of all, distributed transactions are handled by Distributed Transaction Coordinator service, so, MS DTC service must be running (in major configuration it's start mode is Manual)

Second, behaviour of odp.net depends on exact version of Oracle server and client versions and .net framework version. Recipe shown here wasn't checked on all possible combinations.

Third, there are some special connection string parameters needs to be considered.

As follows from http://download.oracle.com/docs/cd/E11882_01/win.112/e12249/featADO20.htm#CJAEBFEB, when first connection is opened to Oracle Database 10g (or higher), a local transaction is created. When a second connection is opened, the transaction is automatically promoted to a distributed transaction.

Connections, created from transaction context, must have "Promotable Transaction" setting set to "promotable".

Also, if application use System.Transactions, it is required that the "enlist" connection string attribute is set to either "true" (default) or "dynamic".

So, in my case, all what I had to do is just make sure that correct Promotable Transaction and Enlist settings are set.

Simplest way to create user in oracle

Use Case

You need to create new user in Oracle database with ability to connect and manage data objects

Solution

The simplest form is:

create user ecxtenant102 identified by ecxtenant102_secret

where ecxtenant102_secret is user's password

For more comprehensive explanation, please refer to http://www.stanford.edu/dept/itss/docs/oracle/10g/server.101/b10759/statements_8003.htm

I also had to assign two roles to that user.

grant connect, resource to ecxtenant102

Oracle Sql Developer migrate connectons

Use Case

You've reinstalled OS from a scratch and need to import your Oracle Sql Developer settings

Solution
Copy file "I:\Users\xxx\AppData\Roaming\SQL Developer\system1.5.4.59.40\o.jdeveloper.db.connection.11.1.1.0.22.49.48\connections.xml" to appriate location on your system drive

where I: - your backup disk drive, xxx - your username

More information can be found at: http://www.webxpert.ro/andrei/2008/06/12/oracle-sql-developer-import-connections/

Outlook 2010 gmail imap synchonization issue

Use Case

After adding Gmail account via IMAP, Outlook starts Synchronization process which never ends.

Solution

Easiest solition I've found at: http://social.technet.microsoft.com/Forums/en-US/officesetupdeploy/thread/603cd05f-4f0c-4c39-ab77-6789cfac0577

1. File > Options > Advanced > Send / Receive
2. For IMAP accounts set "Download headers for subscribed folders" (under "Receive mail items" checkbox)

Prevent termination of shell command executing during logoff

Use Case

You've started a process that will take a long time, and didn't specify nohup in front of it, and don't want your command to be terminated on logoff.

Solution

Press Ctrl + Z - this will suspend the job
Enter disown -h %xxx, where xxx is the job number you get after suspending the job
Execute bg to put the job in the background
Disconnect from the shell

More information about bash commands can be found here: http://linux.about.com/library/cmd/blcmdl1_disown.htm