Sybase 12.4.2 User Manual

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. 

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.

 -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.