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Siebel Installation Guide for UNIX: Servers, Mobile Web Clients, Tools > Guidelines for Configuring the RDBMS > Configuring IBM DB2 UDB for Siebel Applications >
Guidelines for the DB2 UDB Database Manager Configuration Parameters
You can set the database configuration parameters using the update database manager configuration command of the DB2 Command Line Processor or using the DB2 Control Center. See the IBM DB2 technical documentation for more information on modifying the database configuration parameters. Table 6 describes DB2 database manager configuration parameters that differ from the default settings. Set these parameters for each DB2 instance. Use the configuration information in Table 6 for the listed parameters. For parameters not listed in this table, accept the default settings.
Table 6. DB2 Database Manager Configuration Parameters
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SHEAPTHRES
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Sort heap threshold (4 KB) |
200000
Deployments with 3,000 or more concurrent users and using over 5 GB of RAM can increase this to 300000. |
DIR_CACHE
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Directory cache support |
YES
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ASLHEAPSZ
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Application support layer heap size |
15
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RQRIOBLK
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Maximum requester I/O block size (bytes) |
65535
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MON_HEAP_SZ
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Database monitor heap size (4 KB) |
128 (minimum)
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QUERY_HEAP_SZ
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Query heap size (4 KB) |
16384
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KEEPFENCED
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Keep Fenced process (replaces KEEPDARI in DB2 v7) |
YES
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KEEPDARI
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Keep DARI process (only for DB2 v7) |
YES
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MAXAGENTS
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Maximum number existing agents |
20000 (minimum)
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NUM_INITAGENTS
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Initial number agents in pool |
10
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NUM_POOLAGENTS
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Number of agents in the agent pool kept active at all times |
80
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MAX_COORDAGENTS
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Maximum number coordinating agents |
MAXAGENTS
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INDEXREC
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Index re-creation time |
RESTART
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MAX_QUERYDEGREE
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Maximum query degree of parallelism |
Between 1 and 6 |
INTRA_PARALLEL
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Enable intra-partition parallelism |
NO
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DB2set Parameters
Use the db2set command to set the parameters (for example, db2set DB2_HASH_JOIN = NO) referenced in Table 7.
Table 7. db2set Parameters
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DB2MEMDISCLAIM
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For AIX only. When set to YES, DB2 agents explicitly request that the database server disassociate the reserved paging space from freed memory. Affects how DB2 frees shared memory. |
YES |
DB2MEMMAXFREE
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For AIX only. Max. amount of unused memory in bytes retained by DB2 processes. It affects how DB2 frees shared memory and causes DB2 to release memory as soon as the size of the DB2 agent goes above the listed value. |
3000000 |
DB2_HASH_JOIN
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Turns off hash joins in the optimizer. |
NO |
DB2_RR_TO_RS
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Improves DB2 v7 performance with Siebel eBusiness Applications. This parameter does not apply to DB2 v8. NOTE: Set to YES only in production environment servers.
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YES |
DB2_MMAP_WRITE
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AIX Only. Recommended setting only; you should evaluate this setting for your particular configuration and environment. |
OFF |
DB2_MMAP_READ
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AIX Only. Recommended setting only; you should evaluate this setting for your particular configuration and environment. |
OFF |
DB2_CORRELATED_PREDICATES
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When set to YES, the optimizer is able to determine whether predicates in a query are related, which permits DB2 to calculate the filter factor more accurately. |
YES |
DB2_INDEX_2BYTEVARLEN
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If you use DB2 v7, set this parameter to ON. Otherwise, you will not be able to create indexes with columns greater than 255 bytes. You do not need to set this parameter for DB2 v8 because DB2 v8 supports type-2 indexes. |
ON |
DB2_PIPELINED_PLANS
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Tells the DB2 optimizer to favor pipeline execution plans—plans that are left deep and have no temporary result sets. |
ON |
DB2_INTERESTING_KEYS
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Limits the number of execution plans generated by the DB2 optimizer. |
ON |
DB2_PARALLEL_IO
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Useful when using RAID devices. For more information, see your DB2 vendor documentation. |
* |
DB2_STRIPED_CONTAINERS
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Useful when using RAID devices. For more information, see your DB2 vendor documentation. |
ON |
EXTSHM
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This parameter only applies to AIX. Use this parameter only when you have the DB Server and the Siebel Server on the same AIX machine. For more information, see When to Set the EXTSHM Parameter. |
ON |
DB2ENVLIST
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When starting a DB2 UDB server and running EXTSHM, EXTSHM must be part of the DB2 environment. This parameter must be set when the database is created. |
EXTSHM |
DB2_NO_PKG_LOCK
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To bind the Siebel package with siebbind, this package must be off. |
OFF |
When to Set the EXTSHM Parameter
The EXTSHM parameter must be set when the DB2 UDB database is created and must be included in the script that starts it. The parameter also must appear in the sqllib/db2profile file for the DB2 UDB server. Additionally, you should include this parameter in the script that starts the DB2 client. After changing any of these settings, you must perform a db2stop, then db2start, to implement the changes in your DB2 UDB database.
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