Sybase 12.4.2 - Manual (Page 452)

Overview of memory use
432
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 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
-iqgovern value places
a ceiling on the maximum number of queries to execute at once. If more users
than the
-iqgovern limit have submitted queries, new queries will be queued
until one of the active queries is finished.
The optimal value for -iqgovern depends on the nature of your queries, number
of CPUs, and size of the IQ buffer cache. The default value is 2*numcpus + 10.
-gn The correct value for -gn depends on the value of -gm . Setting -gn too low can
result in a hung server. Setting -gn above 480 is not recommended. For this
reason, for 500 users an -iqgovern value of 40 is required.