Why anyone needs to take the database offline?
1. May be user don’t want to use database for time being
2. To restore the database which is used by multiple users. Yes you can restore the database eventhough it is offline
EXEC sp_dboption N'DBName', N'offline', N'true'
OR
ALTER DATABASE [DBName] SET OFFLINE WITH
ROLLBACK IMMEDIATE
You can use the below script to make the database read only so that no user can edit the database.
USE [master]
GO
ALTER DATABASE [DBName] SET READ_ONLY WITH NO_WAIT
OR
GO
ALTER DATABASE [DBName] SET READ_ONLY
GO
Orphan User:
An orphan user is a user in a SQL Server database that is not associated with a SQL Server login.
-- Script to check the orphan user
EXEC sp_change_users_login 'Report'
--Use below code to fix the Orphan User issue
DECLARE @username varchar(25)
DECLARE fixOrphanusers CURSOR
FOR
SELECT UserName = name FROM sysusers
WHERE issqluser = 1 and (sid is not null and sid <> 0x0)
and suser_sname(sid) is null
ORDER BY name
OPEN fixOrphanusers
FETCH NEXT FROM fixOrphanusers
INTO @username
WHILE @@FETCH_STATUS = 0
BEGIN
EXEC sp_change_users_login 'update_one', @username, @username
FETCH NEXT FROM fixOrphanusers
INTO @username
END
CLOSE fixOrphanusers
DEALLOCATE fixOrphanusers
Problem/Error
Could not parse relay log event entry. The possible reasons are: the master’s binary log is corrupted (you can check this by running ‘mysqlbinlog’ on the binary log), the slave’s relay log is corrupted (you can check this by running ‘mysqlbinlog’ on the relay log), a network problem, or a bug in the master’s or slave’s MySQL code. If you want to check the master’s binary log or slave’s relay log, you will be able to know their names by issuing ‘SHOW SLAVE STATUS’ on this slave
Resolution Steps
You have to follow below steps to troubleshoot the error.
Execute the below command
SHOW MASTER STATUS
SHOW SLAVE STATUS
Check the error log for replication and its position.
Ideally there are three sets of file/position coordinates in SHOW SLAVE STATUS to identify the correct file
1) The position, ON THE MASTER, from which the I/O thread is reading: Master_Log_File/Read_Master_Log_Pos.
2) The position, IN THE RELAY LOGS, at which the SQL thread is executing: Relay_Log_File/Relay_Log_Pos
3) The position, ON THE MASTER, at which the SQL thread is executing: Relay_Master_Log_File/Exec_Master_Log_Pos
Next you have to check the error log for the log position to identify the correct binary log file and set the correct log file using below command.
CHANGE MASTER TO MASTER_LOG_FILE=’mysql-bin.000480′
Once the problem is resolved you can use Maatkit tool to sync table to multiple slaves.
mk-table-checksum command is used to check what tables are out of sync and when use mk-table-sync command is used to resync them.
How is the DLL Hell problem solved in .NET? Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly.
How to deploy .Net assembly? An MSI installer, a CAB archive, and XCOPY command.
What is a satellite assembly and what is the use of it? When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
What namespaces are necessary to create a localized application? System.Globalization and System.Resources.
What is the smallest unit of execution in .NET? An Assembly is the smallest unit of execution in .Net
When should you call the garbage collector in .NET? It is recommended that, you should not call the garbage collector. However, you could call the garbage collector when you are done using a large object (or set of objects) to force the garbage collector to dispose of those very large objects from memory.
How do you convert a value-type to a reference-type? Use Boxing
What happens in memory when you Box and Unbox a value-type?
Boxing converts a value-type to a reference-type, thus storing the object on the heap. Unboxing converts a reference-type to a value-type, thus storing the value on the stack
