Adjust the startup parameters for large numbers of users.
Parameter |
Description |
---|---|
-gm |
Sets the default number of connections.
Usage:
-gm #_connections_to_support
Although this represents the total number of connections the server will support, not all connections will be active at any one time. |
-iqgovern |
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.
Usage:
-iqgovern #_ ACTIVE_ queries_to_support
The optimal value for -iqgovern depends on the nature of your queries, number of CPUs, and size of the buffer cache. The default value is 2*numCPU + 10. With a large number of connected users, you may find that setting this option to 2*numCPU + 4 provides better throughput. |
-gn |
Sets the number of execution threads for the catalog store and
connectivity while running with multiple users.
Usage:
-gn number of tasks (both user
and system requests) that the database server can execute concurrently
The correct value for -gn depends on the value of -gm. The start_iq utility calculates -gn and sets it appropriately. Setting -gn too low can prevent the server from operating correctly. Setting -gn above 480 is not recommended. |
-c |
Sets the catalog store cache size.
Usage:
-c catalog_store_cache_size
The catalog cache size is highly dependent on schema size and the number of objects. The catalog store buffer cache is also the general memory pool for the catalog store. To specify in MB, use the form -c nM, for example, -c 64M. For up to 1000 users, set -c to 16MB or higher. For up to 200 users, set -c to 48MB (default). |
-cl and -ch |
Set upper (-ch) and lower (-cl) limits for the catalog store cache size. -cl minimum cache size -ch maximum cache size. If the standard catalog cache size is too small, set -cl and -ch parameters. Do not use -c in the same configuration file or command line with -ch or -cl. For related information, see the -ch cache-size option. |
-iqmt |
Sets the number of processing threads. If -iqmt is set too low for the -gm setting, then thread starvation can occur. |
Set the -c parameter
Set specific upper and lower limits for the catalog store cache size using the -ch and -cl parameters