Java Solutions: October 2020

Monday, October 26, 2020

How to find out all the Java versions installed on a linux machine?

Use the command below to get all the java versions installed.

update-alternatives --display java

-----------------------------------------------------------------------------------------------------------------

If you have ever asked the questions below, you will benefit from reading this book.
What is the meaning of life?
Why do I have to suffer?
How can I have the life I like to have?
How can I be the person I want to be?
How can I have good and harmonious relations with others?

What is the true meaning of spiritual practice? Check it out here.

Tuesday, October 20, 2020

Crystal Reports: ORA-12170: TNS:Connect timeout occurred [Database Vendor Code: 12170]

In the SAP Crystal Reports editor, you open the Database Expert and trying to view/edit the command, after you have entered your database login credentials you received the following error.

This can be caused by several issues. The following are some of the ways to fix it.

1. ping the database machine to make sure you can access that machine.

2. Check if the database host of your Oracle Instant Client is using the correct IP address. If you are accessing the database on a remote machine, localhost or 127.0.0.1 will not work.

a. Open your Control Panel.

b. Open the Administrative Tools window.

c. Right-click on the ODBC Data Sources and open it.

d. Select the System DSN tab to look for the Driver used by your data source.

e. Select the Drivers tab and locate your driver.

f. Open a file explorer, go to Program Files (x86)\Oracle Instant Client\<your driver>.

g. Open the tnsnames.ora file in a text editor, change the HOST = <the correct database IP address>

3. Make sure the firewall is not blocking the connection.

-----------------------------------------------------------------------------------------------------------------

If you have ever asked yourself these questions, this is the book for you. What is the meaning of life? Why do people suffer? What is in control of my life? Why is life the way it is? How can I stop suffering and be happy? How can I have a successful life? How can I have a life I like to have? How can I be the person I like to be? How can I be wiser and smarter? How can I have good and harmonious relations with others? Why do people meditate to achieve enlightenment? What is the true meaning of spiritual practice? Why all beings are one? Read the book for free here.

Friday, October 9, 2020

ORA-27125: unable to create shared memory segment; Error: 28: No space left on device

You got the below error when starting up the Oracle database.

SQL> STARTUP

ORA-27125: unable to create shared memory segment

Linux-x86_64 Error: 28: No space left on device

Additional information: 3760

Additional information: 4278190080

This occurs when the Kernel parameter kernel.shmall is too small.

Follow the steps below to fix the problem.

1. Determine the page size.

> getconf PAGE_SIZE

4096

2. Determine the Total System Global Area (SGA).

SQL> SHOW SGA

Total System Global Area 6442450944 bytes

Fixed Size 2938792 bytes

Variable Size 3892316248 bytes

Database Buffers 2533359616 bytes

Redo Buffers 13836288 bytes

3. Calculate the recommended value for shmall.

shmall = SGA / PAGE_SIZE

With SGA = 6 GB and PAGE_SIZE = 4096, the shmall is

shmall = 6 * 1024 * 1024 * 1024 / 4096 = 1572864

4. Update the kernel.shmall parameter.

> vi /etc/sysctl.conf

Scroll down to find kernel.shmall and change it's value to 1572864.

* If you could not find the SGA at step 2, you may try to double the current value of shmall.

5. Apply the change.

> sysctl -p

6. Verify the value.

> cat /proc/sys/kernel/shmall

1572864

7. Login to the Oracle database as sysdba and start the database.

SQL> STARTUP

ORACLE instance started.

-----------------------------------------------------------------------------------------------------------------

Watch the blessing and loving online channel: SupremeMasterTV live