Increasing Processes, Sessions and Transactions in Oracle XE

Out of the box, Oracle Database 10g Express Edition RDBMS is fast and powerful. The stated limitations of 2GB of maximum RAM usage and 2GB of total datafile management are plentiful for it to easily run as the back-end for a small to medium-sized office application.

However, we soon hit a connection limit as characterised by the following Oracle Errors:

ORA-12516: TNS:listener could not find available handler with matching protocol stack

ORA-00020: maximum number of processes (%s) exceeded

We can get this second message because Oracle creates Operating System processes to handle Connections (or Sessions) - which means Processes, Sessions (and as we'll soon see..) Transactions are all related.

The default values in Oracle XE for these parameters are:

• Processes = 40
• Sessions = 49
• Transactions = 53

I was able to generate the above error message (ORA-00020) from about ~30 connections on a vanilla Oracle XE installation (on Windows 7).

So, let's increase these limits to allow more connections to our Oracle Server..

1. Log in as SYSDBA

From the menu 'Oracle Database 10g Express Edition', find and select 'Run SQL Command Line', then type:

connect sys as sysdba

and enter your SYS, or SYSTEM password at the prompt

2. ALTER SYSTEM commands

Update: The Oracle XE 10g documentation links below were broken, so they now point to the Oracle 11g R2 Standard Edition documentation instead - note that the default values are greater in 11g R2 Standard than the Express Edition (XE).

The Oracle Documentation states that TRANSACTIONS is derived from SESSIONS, which in turn is derived fromPROCESSES, thus:

PROCESSES = 40 to Operating System Dependant

SESSIONS = (1.1 * PROCESSES) + 5

TRANSACTIONS = 1.1 * SESSIONS

So, what value to start with for PROCESSES?  Trebling it is as good a start as any, then I'd add a few more for good measure..  Here are the values I recommend:

• PROCESSES = 150
• SESSIONS = 300
• TRANSACTIONS = 330

type the following commands:

alter system set processes = 150 scope = spfile;

alter system set sessions = 300 scope = spfile;

alter system set transactions = 330 scope = spfile;

then to make the settings take effect, we need to bounce the database..

shutdown immediate;

startup;

3. Verify the new parameters

with this simple select statement..

select name, value  
from v$parameter  
where name in ('processes', 'sessions', 'transactions');

How Do I Access or Mount Windows/USB NTFS Partition in RHEL/CentOS/Fedora

How Do I Access or Mount Windows/USB NTFS Partition in RHEL/CentOS/Fedora

Sometimes it may happens in some stage, you may have to access data on a Windows partition, USB device or any similar device. Today most of the modern Linux systems automatically recognize and mount any disks.

However, in some occasions where you may required to configure your system manually to mount ntfs partitions on your Linux system. Specially when you are using dual boot operating environment. Fortunately, this process is not so complicated task its just very fairly straight forward.

This article explains you on how to access or mount Windows XP, Vista NTFS or USB filesystem using the ‘mount‘ command in RHEL/CentOS/Fedora systems.

How to Mount Windows NTFS Partition in Linux

First you need to enable EPEL (Extra Packages for Enterprise Linux) Repository. You may refer the article on how to enable EPEL Repository under RHEL, CentOS and Fedora systems.

To mount any NTFS based filesystem, you need to install a tool called NTFS3G. Before heading up for installation let’s understand NTGS3G.

What is NTFS3G

NTFS3G is an open source cross-platform, stable, GPL licensed, POSIX, NTFS R/W driver used in Linux. It provides safe handling of Windows NTFS file systems viz create, remove, rename, move files, directories, hard links, etc.

Once EPEL is installed and enabled, let’s install ntfs-3g package using the below command with root user.

# yum -y install ntfs-3g

Fuse Install

Next, install and load FUSE driver to mount detected devices with below command. FUSE module is included in the kernel itself in version 2.6.18-164 or newer.

# yum install fuse
# modprobe fuse

Identify NTFS Partition

Once fuse module is loaded, type below command to find out NTFS Partitions in Linux.

# fdisk -l

 Device Boot      Start    End      Blocks   Id  System
/dev/sdb1         1    21270    7816688   b  W95 FAT32

Mount NTFS partition

First create a mount point to mount the NTFS partition.

# mkdir /mnt/nts

Simply run the following command to mount the partition. Replace sda1 with your actual partition found.

# mount -t ntfs-3g /dev/sda1 /mnt/nts

Once it’s mounted on /mnt/ntfs, you may use regular Linux ls -l command to list the content of mounted filesystem.

[root@tecmint ntfs]# ls -l
total 27328
drwx------.  2 root root    16384 Sep  2 19:37 Cert
drwx------. 20 root root    16384 Aug 24  2011 club_application
drwx------.  6 root root    16384 Aug 11 15:37 docs
drwx------.  7 root root    16384 Jul 31  2012 Downloads
drwx------.  2 root root    16384 Dec 10 20:28 images
-rwxr-xr-x.  1 root root    31744 Jan 18 00:29 Material List.doc

If you want to make mount point permanent at the boot time, then simple add the following line at the end of/etc/fstab file. This will remain as permanent.

/dev/sda1    /mnt/usb    ntfs-3g        defaults    0    0

Umount NTFS Partition

Simply, use the following command to unmount the mounted partition.

# umount /mnt/usb