Internet Express for Tru64 UNIX Version 6.8 Administration Guide (14233)

Note:
The crontab entry that you created using the using the Setup Vacuum Crontab form should
only be edited from the Administration utility. Directly editing this entry in the crontab file or
adding additional entries which call /usr/internet/pgsql/bin/ix_vacuumdb can produce
errors.
If you want to create custom crontab entries for vacuuming your database, set the command
for your crontab entry to call /usr/internet/pgsql/bin/vacuumdb. See the reference
pages for crontab and vacuumdb for more information.
17.6 Scaling PostgreSQL
After installing the PostgreSQL subset, a postmaster process runs. The postmaster manages
communication between front and backend processes. By default, the postmaster is started with
settings that limits to 32 the number of backend server processes that can be started by the
postmaster. This value may be increased to as high as 1024.
For each backend process the postmaster needs to allocate two shared-memory buffers. All the
buffers are allocated when postmaster is started.
Notes:
If you increase these values, you might surpass your kernel's limit on the size of shared memory
areas and need to reconfigure your kernel and reboot your machine in order to use your higher
settings.
The following instructions for increasing the number of concurrent backend server processes
are for nonclustered systems only.
To increase the number of concurrent backend server processes, you edit the postgresql.conf
file located in /usr/internet/pgsql/data.
Perform the following steps:
1. Change the max_connections value to indicate the number of processes you want to
allow, up to a maximum of 1024. Follow the syntax specified in the postgresql.conf file.
2. Change the shared_buffers value to be at least twice the number of connections specified
in Step 1. This value represents the number of shared-memory buffers that the postmaster
will allocate and manage for the backend server processes it starts.
3. Stop the currently running postmaster process:
#/sbin/init.d/postgres stop
4. Restart the postmaster process with the new values:
#/sbin/init.d/postgres start.
5. Look for the postmaster process:
#ps -ef | grep postmaster
If the postmaster process failed to start, increase your kernel's shared memory size limits,
as follows:
a. Review the /usr/internet/pgsql/data/postmaster.log file for an error message
produced when trying to startup the postmaster. Most likely, you will see an error
message similar to the following message:
IpcMemoryCreate: shmget(key=5432001, size=28901376, 03600) failed: Invalid argument
1. The maximum size for shared memory segments on your system was
exceeded. You need to raise the SHMMAX parameter in your kernel
to be at least the size number reported in the error, in this case,
28901376 bytes.
260 PostgreSQL Database and MySQL Administration