Default Port and its Assignments (http,https,LDAP,Telnet,SSH,FTP etc)

Operating System reserves first 1024 ports for its internal usage and each port within 1024 port has been assigned for different protocols. When I say reserved it means that only Root/Administrator user can change the preferences. Here are the list of ports and their default assignments.

Port	Usage
21	FTP
22	SSH
23	Telnet
80	HTTP
66	Oracle SQL
443	HTTPS
389	LDAP/OID
115	SFTP
143	IMAP
513	RAW/Rlogin
1521	Database Listener
8000	Oracle Applications http port
8100	Oracle Application PLS port
9000	Oracle Applications forms server port

More default ports to come.... Keep watching......

Comments

SQL Interview Questions on Subqueries

SUB Queries:
1. List the employees working in research department 2. List employees who are located in New York and Chicago
3. Display the department name in which ANALYSTS are working
4. Display employees who are reporting to JONES
5. Display all the employees who are reporting to Jones Manager
6. Display all the managers in SALES and ACCOUNTING department
7. Display all the employee names in Research and Sales Department who are having at least 1 person reporting to them
8. Display all employees who do not have any reportees
9. List employees who are having at least 2 reporting
10. List the department names which are having more than 5 employees
11. List department name having at-least 3 salesman
12. List employees from research and accounting having at-least 2 reporting
13. Display second max salary
14. Display 4th max salary
15. Display 5th max salary -- Answer for nth Max Salary
Co-Related Subqueries:
16. Write a query to get 4th max salary from EMP table
17. Write a query to get 2nd…

'Linux-x86_64 Error: 28: No space left on device' While trying to start the database -- Error

SQL> startup mount pfile='/tmp/initdlfasp12.ora'
ORA-27102: out of memory
Linux-x86_64 Error: 28: No space left on device

This as you can see is on Linux x86 with 64 bit processor. We got this error after we changed SGA on 10gR2 database. So was sure that this is something to do with the OS.

Parameters to check for this are shmall.

shmall is the total amount of shared memory, in pages, that the system can use at one time.

$cat /proc/sys/kernel/shmmax
53687091200

$ getconf PAGE_SIZE
4096

As per Oracle SHMALL should be set to the total amount of physical RAM divided by page size.

Our system has 64GB memory, so change kernel.shmall = 1024 * 1024 * 1024 * 64 / 4096 = 16777216

Once this value is calculated you can modify Linux system configuration file directly.

$ su - root
vi /etc/sysctl.conf file:
kernel.shmall=16777216

and

# sysctl -p

Once this is done the database was started without any problem.

Answers for SUB Queries

1. SQL> select empno, ename from emp where deptno=(select deptno from dept where dname='RESEARCH');

2. SQL> select empno, ename from emp where deptno in (select deptno from dept where loc in ('NEW YORK','CHICAGO'));

3. SQL> select dname from dept where deptno in ( select deptno from emp where job ='ANALYST');

4. SQL> select empno, ename, mgr from emp where mgr = (select empno from emp where ename='JONES');

5. SQL> select empno, ename, mgr from emp where mgr = (select mgr from emp where ename='JONES')

6. SQL> select empno, ename, job from emp where deptno in ( select deptno from dept where dname in ('SALES','ACCOUNTING'))

7. SQL> select empno, ename, job from emp where deptno in ( select deptno from dept where dname in ('SALES','RESEARCH')) and empno in (select mgr from emp)

8. SQL> select empno, ename from emp where empno not in ( select mgr from emp where mgr is not null)

9. select…

Sharing Knowledge by Mithun Ashok

Search This Blog