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Administration Guide

Database Manager Parameters

Database manager parameters are stored in a file named db2systm. This file is created when the instance of the database manager is created. In UNIX-based environments, this file can be found in the sqllib subdirectory for the instance of the database manager. In all other environments, the default location of this file is the instance subdirectory of the sqllib directory. If the DB2INSTPROF variable is set, the file is in the instance subdirectory of the directory specified by the DB2INSTPROF variable.

In a partitioned database environment, this file resides on a shared file system so that all database partition servers have access to the same file. The configuration of the database manager is the same on all database partition servers.

Most of the parameters either affect the amount of system resources that will be allocated to a single instance of the database manager, or they configure the setup of the database manager and the different communications subsystems based on environmental considerations. In addition, there are other parameters that serve informative purposes only and cannot be changed. All of these parameters have global applicability independent of any single database stored under that instance of the database manager.

The db2systm file cannot be directly edited. It can only be changed or viewed using a supplied API or by a tool which calls that API.

Attention: If you edit the file using a method other than those provided by the product, you may make your system unusable. We strongly recommend that you do not change this file using methods other than those documented and supported by DB2.

You may use one of the following three methods to reset, update, and view the database manager configuration parameters:

After changing the parameters, the database manager must be stopped (db2stop) and then restarted (db2start) for the new parameter values to take effect. For clients, changes in the database manager configuration parameters take effect the next time the client connects to a server. While new parameter values are not immediately effective, viewing the parameter settings will always show the latest updates.
Note:You do not need to restart the database manager if you update the value of the dft_monswitches parameter; this parameter is updated automatically when you change its value.

Database Manager Configuration Parameter Summary

The following table lists the parameters in the database manager configuration file for database servers. When changing the database manager configuration parameters, consider the detailed information for each parameter. Specific operating environment information including defaults is part of each parameter description.

The column "Performance Impact" in the following table provides an indication of the relative importance of each parameter as it relates to system performance. It is impossible for this column to apply accurately to all environments; you should view this information as a generalization.

Table 46. Configurable Database Manager Configuration Parameters
Parameter Performance Impact Additional Information
agentpri High "Priority of Agents (agentpri)"
agent_stack_sz Low "Agent Stack Size (agent_stack_sz)"
aslheapsz High "Application Support Layer Heap Size (aslheapsz)"
audit_buf_sz High "Audit Buffer Size (audit_buf_sz)"
authentication Low "Authentication Type (authentication)"
backbufsz Medium "Default Backup Buffer Size (backbufsz)"
catalog_noauth None "Cataloging Allowed without Authority (catalog_noauth)"
comm_bandwidth Medium "Communications Bandwidth (comm_bandwidth)"
conn_elapse Medium "Connection Elapse Time (conn_elapse)"
cpuspeed Low (see note) "CPU Speed (cpuspeed)"
dft_account_str None "Default Charge-Back Account (dft_account_str)"
dft_client_adpt None "Default Client Adapter Number (dft_client_adpt)"
dft_client_comm None "Default Client Communication Protocol (dft_client_comm)"
  • dft_mon_bufpool
  • dft_mon_lock
  • dft_mon_sort
  • dft_mon_stmt
  • dft_mon_table
  • dft_mon_uow
Medium "Default Database System Monitor Switches (dft_monswitches)"
dftdbpath None "Default Database Path (dftdbpath)"
diaglevel Low "Diagnostic Error Capture Level (diaglevel)"
diagpath None "Diagnostic Data Directory Path (diagpath)"
dir_cache Medium "Directory Cache Support (dir_cache)"
dir_obj_name None "Object Name in DCE Namespace (dir_obj_name)"
dir_path_name None "Directory Path Name in DCE Namespace (dir_path_name)"
dir_type None "Directory Services Type (dir_type)"
discover Medium "Discovery Mode (discover)"
discover_comm Low "Search Discovery Communications Protocols (discover_comm)"
discover_inst Low "Discover Server Instance (discover_inst)"
dos_rqrioblk High "DOS Requester I/O Block Size (dos_rqrioblk)"
drda_heap_sz Low "DRDA Heap Size (drda_heap_sz)"
fcm_num_anchors High "Number of FCM Message Anchors (fcm_num_anchors)"
fcm_num_buffers High "Number of FCM Buffers (fcm_num_buffers)"
fcm_num_connect High "Number of FCM Connection Entries (fcm_num_connect)"
fcm_num_rqb High "Number of FCM Request Blocks (fcm_num_rqb)"
fileserver None "IPX/SPX File Server Name (fileserver)"
indexrec Medium "Index Re-creation Time (indexrec)"
intra_parallel High "Enable Intra-Partition Parallelism (intra_parallel)"
ipx_socket None "IPX/SPX Socket Number (ipx_socket)"
java_heap_sz High "Maximum Java Interpreter Heap Size (java_heap_sz)"
jdk11_path None "Java Development Kit 1.1 Installation Path (jdk11_path)"
keepdari Medium "Keep DARI Process Indicator (keepdari)"
maxagents High "Maximum Number of Agents (maxagents)"
maxcagents High "Maximum Number of Concurrent Agents (maxcagents)"
max_connretries Medium "Node Connection Retries (max_connretries)"
max_coordagents High "Maximum Number of Coordinating Agents (max_coordagents)"
maxdari Medium "Maximum Number of DARI Processes (maxdari)"
max_querydegree High "Maximum Query Degree of Parallelism (max_querydegree)"
max_time_diff Medium "Maximum Time Difference Among Nodes (max_time_diff)"
maxtotfilop Medium "Maximum Total Files Open per Application (maxtotfilop)"
min_priv_mem Medium "Minimum Committed Private Memory (min_priv_mem)"
mon_heap_sz Low "Database System Monitor Heap Size (mon_heap_sz)"
nname None "NetBIOS Workstation Name (nname)"
numdb Low "Maximum Number of Concurrently Active Databases (numdb)"
num_initagents Medium "Initial Number of Agents in Pool (num_initagents)"
num_poolagents High "Agent Pool Size (num_poolagents)"
objectname None "IPX/SPX DB2 Server Object Name (objectname)"
priv_mem_thresh Medium "Private Memory Threshold (priv_mem_thresh)"
query_heap_sz Medium "Query Heap Size (query_heap_sz)"
restbufsz Medium "Default Restore Buffer Size (restbufsz)"
resync_interval None "Transaction Resync Interval (resync_interval)"
route_obj_name None "Routing Information Object Name (route_obj_name)"
rqrioblk High "Client I/O Block Size (rqrioblk)"
sheapthres High "Sort Heap Threshold (sheapthres)"
spm_log_file_sz Low "Sync Point Manager Log File Size (spm_log_file_sz)"
spm_log_path Medium "Sync Point Manager Log File Path (spm_log_path)"
spm_max_resync Low "Sync Point Manager Resync Agent Limit (spm_max_resync)"
spm_name None "Sync Point Manager Name (spm_name)"
ss_logon None "LOGON Required for DB2START/DB2STOP (ss_logon)"
start_stop_time Low "Start and Stop Timeout (start_stop_time)"
svcename None "TCP/IP Service Name (svcename)"
sysadm_group None "System Administration Authority Group Name (sysadm_group)"
sysctrl_group None "System Control Authority Group Name (sysctrl_group)"
sysmaint_group None "System Maintenance Authority Group Name (sysmaint_group)"
tm_database None "Transaction Manager Database Name (tm_database)"
tp_mon_name None "Transaction Processor Monitor Name (tp_mon_name)"
tpname None "APPC Transaction Program Name (tpname)"
trust_allclnts None "Trust All Clients (trust_allclnts)"
trust_clntauth None "Trusted Clients Authentication (trust_clntauth)"
udf_mem_sz Low "UDF Shared Memory Set Size (udf_mem_sz)"
Note:The cpuspeed parameter can have a significant impact on performance but you should use the default value, except in very specific circumstances, as documented in the parameter description.

Table 47. Informational Database Manager Configuration Parameters
Parameter Additional Information
nodetype "Machine Node Type (nodetype)"
release "Configuration File Release Level (release)"

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