Sybase 12.4.2 manual Optimizing for large numbers of users, IQ command line option changes, 432

Overview of memory use

Use the following guideline to determine BLOCK FACTOR:

record size * BLOCK FACTOR = memory required

You need extra memory for this option, in addition to the memory for the buffers. If you have a lot of memory available, or if no other users are active concurrently, increasing the value of BLOCK FACTOR can improve load performance.

Optimizing for large numbers of users

Adaptive Server IQ, running on Tru64-UNIX, Solaris/32, and Solaris/64, handles up to 500 user connections. In order to support this greater number of users you must adjust both operating system parameters and start_asiq server parameters.

IQ command line option changes:

	-gm#_connections_to_support
	-iqgovern#_ ACTIVE_ queries_to_support
	-gn#_Catalog_Store_front_end_threads
	-c
-gm	This is the total number of connections the server will support. Statistically,
	some of these are expected to be connected and idle while others are connected
	and actively using the database.

-iqgovern

-gn

Although 500 users can be connected to IQ, for best throughput it is recommended that far fewer users are allowed to query at once in order to allow each of them sufficient resources to be productive. The -iqgovernvalue places a ceiling on the maximum number of queries to execute at once. If more users than the -iqgovernlimit have submitted queries, new queries will be queued until one of the active queries is finished.

The optimal value for -iqgoverndepends on the nature of your queries, number of CPUs, and size of the IQ buffer cache. The default value is 2*numcpus + 10.

The correct value for -gndepends on the value of -gm. Setting -gntoo low can result in a hung server. Setting -gnabove 480 is not recommended. For this reason, for 500 users an -iqgovernvalue of 40 is required.

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