In progress
On UNIX/Linux systems before installing application, you must in general configure the following:
In addition for timesten, you need to perform the following:
Before installing TimesTen, ensure that, the user installing TimesTen is a member of the administrator's group and has read and write permissions on the /etc/TimesTen directory
TimesTen consumes:
Semaphore | Per Active Database | Plus | Example |
---|---|---|---|
SEMMNI | one | one additional per TT instance (where Client/Server communication is done through shared memory.) | |
SEMMSL | 155 | one for each connection | With a Connections attribute value of 100, TT requires a minimum of 255. |
It is best to set the SEMMSL parameter to a higher value, for example for Linux x8664 to support 2000 connections you should set the following line to the /etc/sysctl.conf
kernel.sem = 2200 6400 200 25
kernel.sem = SEMMSL SEMMNS SEMOPM SEMMNI
On Red Hat Linux systems, to enable more than 6 ShmIpc Client/Server connections, add the following line to the /etc/sysctl.conf file:
kernel.sem = 270 32000 100 128
The maximum number of concurrent IPC connections to a TimesTen Server allowed by TimesTen is 9,999.
However, system limits can take precedence on the number of connections to a single DSN. Client/Server users can increase the file descriptor limit to support a large number of connections and processes.
For example, on Solaris, you may change the file descriptor limit to have a maximum of 1024 simultaneous server connections by adding the following line to /etc/system:
set rlim_fd_max = 1080
In this case, 1080 is greater than the number of anticipated client/server connections and allows for a few extra connections.
For Linux, TimesTen has been tested with:
TimesTen does not support SELinux. When installing Linux for use with TimesTen, ensure that the SELinux option is disabled.
To increase the shared memory size to 2048 MB, log in as root and edit the /etc/sysctl.conf file by adding the line:
kernel.shmmax=2147483648
If your configuration is greater than 8 GB, you should also increase the value of the shmall parameter. The value is in KB and should be equal to
Page size is generally 4K on x86 systems and 16K on Itanium. For example, for a 64 GB database on Itanium, you should specify the following parameters values:
kernel.shmmax=68719476736
kernel.shmall=4194304
To increase the shared memory size without rebooting, use:
% /sbin/sysctl -w kernel.shmmax=2147483648
If you have your kernel configured with the /proc file system and it is mounted, then the current maximum shared memory segment size (in bytes) can be viewed by the following command:
% cat /proc/sys/kernel/shmmax
You can also change this value by the following command:
% echo 2147483648 > /proc/sys/kernel/shmmax
This command has the same effect as the sysctl command.
Each process connected to a TimesTen database keeps at least one operating-system file descriptor open from the time of the first connection until the process terminates.
Additional file descriptors may be opened for each database connection:
For multithreaded applications that maintain many concurrent TimesTen database connections, the default number of open files permitted to each process by the operating system may be too low.
Most of the open file descriptors are used for reading and writing database recovery log files. If a process fails to open a log file, the database is marked as requiring recovery and all current connections to the database are terminated.