When you are installing PostgreSQL first time, the default port is 5432.

But when you install another PostgreSQL server on the same server, for this another installation port will be change.

In open forums, I found this kind of questions like If we have multiple PostgreSQL Servers, how to differentiate PostgreSQL Server of a single Linux/Windows server.
The answer is straightforward which is PostgreSQL Port number.

If you want to change your default port number, you can modify the value of “port” parameter in postgresql.conf.

After this change, PostgreSQL service requires to restart.
Now next question, If we installed multiple PostgreSQL servers, how to connect a particular PostgreSQL Server.

You can connect a particular PostgreSQL Server by specifying Port number.

psql -l -p port_number -d database_name

How to check server side configuration?

SELECT * FROM sys.configurations;

How to check the current location of data and log files for the system databases?

SELECT name, physical_name AS current_file_location
FROM sys.master_files
WHERE database_id IN (DB_ID('master'), DB_ID('model'), DB_ID('msdb'), DB_ID('tempdb'));

What are the types of CHECKSUM?

SQL Server supports three types of checksums: a checksum on pages, a checksum in log blocks, and a backup checksum.

What is a SQL Server Credential?

A SQL Server credential is an object that is used to store authentication information required to connect to a resource outside of SQL Server.

How to remove all SQL Job related history from the related system tables?

Using this system stored procedure – sp_purge_jobhistory .

What are Database Maintenance Plans?

Database Maintenance Plans allow us to automate many database administration tasks in Microsoft SQL Server. Maintenance plans create a workflow of the tasks required to make sure that our database is optimized, regularly backed up, and free of inconsistencies.

What all options we have in a Database maintenance plans which helps a DBA to keep the database healthy?

• Check Database Integrity
• Shrink Database
• Reorganize Index
• Rebuild Index
• Update Statistics
• Clean Up History
• Execute SQL Server agent job
• All type of Database Backup
• Maintenance clean up task

In which Database all the Maintenance Plans are stored?

MSDB database contains information about all the Database Maintenance plans.

Can we execute TSQL Statement using Database Maintenance Tasks?

Yes, we can run TSQL Statement in a Database Maintenance Plan.

Can we run a SQL Server Agent job using Database Maintenance Tasks?

Yes, we run a SQL Server Agent job in a Database Maintenance Plan.

Is it possible to mark Primary File Group as Read only?

No it’s not possible to make Primary File Group read only.

How to make the File Group read only?

ALTER DATABASE AdvantureWorks2012 MODIFY FILEGROUP SecondaryFile Read_Only;

What are the benefits of Read only file groups?

• Can be compressed (using NTFS compression)
• During recovery you don’t need to apply logs to recover a read-only file group
• Protection of data from accidental modifications

What are the important dynamic management views to find different type of fragmentations?

• dm_db_index_operational_stats
• dm_db_index_physical_stats
• dm_db_partition_stats
• dm_db_index_usage_stats

What are the important dynamic management views to find space usage related information?

• dm_db_file_space_usage
• dm_db_task_space_usage
• dm_db_session_space_usage

What is the Query Hints option?

Query hints override the default behavior of the query optimizer for the duration of the query statement.

You can use query hints to specify a locking method on the affected tables, one or more indexes, a query processing operation such as a table scan or index seek, or other options. Query hints are applied to the entire query.

What is BCP? When does it used?

BulkCopy is a tool used to copy huge amount of data from tables and views. BCP does not copy the structures same as source to destination. BULK INSERT command helps to import a data file into a database table or view in a user-specified format.

Can we add CPU to sql server?

Yes: Adding CPUs can occur physically by adding new hardware, logically by online hardware partitioning, or virtually through a virtualization layer.

What are the most common ports of SQL Server?

• MSSQL Server: 1433
• HTTP TCP: 80
• HTTPS TCP: 443

In this post, I am sharing an important list of ports which are used by the Cassandra for a different purpose.

Cassandra developer has to know about these ports because it is very important while they are configuring the firewall for Cassandra server.

9160: Cassandra Thrift client API
9042: Cassandra native client port

7000: Cassandra Internode cluster communication (not used if TLS enabled)
7001: Cassandra SSL Internode cluster communication.
7199 / 8080: JMX monitoring port

61620: Cassandra OpsCenter monitoring port
61621: Cassandra OpsCenter agent port

8888: OpsCenter browser http request