Sybase 12.4.2 IQ Temp space, System parameters, Command and set rlimfdmax=4096 in /etc/system

CHAPTER 12 Managing System Resources

-c

IQ Temp space

The Catalog Store buffer cache is also the general memory pool for the Catalog Store (the front end of Adaptive Server IQ). Sybase recommends a 64MB minimum for 500 users.

Use of the -iqmtoption is not required. If -iqmtis set too low for the number of specified connections, the number of threads will be increased to handle the number of requested connections. That is, -gmoverrides -iqmt. However, if the number of IQ threads is elevated by means of the -iqmtoption then that factor needs to be used in setting limits, as described in "Setting Operating System Parameters" below.

You may need to increase your temp dbspace to accommodate more users.

Relative priorities of new and existing connections

If Adaptive Server IQ is very busy handling already connected users, it maybe slow to respond to new connection requests. In extreme cases (such as test scripts that fire off hundreds of connections in a loop while the server is busy with inserts) new connections may have to wait up to a minute to before becoming active or may even time out their connection request. In this situation, the server may appear to be down when it is merely very busy. A user getting this behavior should try to connect again. This issue will be addressed in a future version.

Setting operating system parameters

	To run Adaptive Server IQ with many connections you need to change certain
	system parameters.
Solaris	Although the Solaris thread limit is not a problem, developers and Sybase field
	personnel should be aware that using the Solaris debugger on IQ requires a file
	descriptor for each thread in addition to the file descriptors for each dbspace.
	You need to adjust the number of file descriptors by means of the C shell limit
	command and "set rlim_fd_max=4096" in /etc/system.

Tru64-UNIX / Digital

UNIX

Adaptive Server IQ needs three threads to support each connection plus some overhead threads the operating system needs to have its maximum number of threads adjusted upwards. To accomplish this, you must raise the Digital UNIX default number of threads, using the formula 60*NUMCPUS +10 +3*. You can change this value either by editing Digital UNIX’s /etc/sysconfigtab directly or updating it using a Compaq GUI (see Adaptive Server IQ Installation and Configuration Guide or your Compaq documentation).

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