Using DB2 Universal Database on 64-bit Platforms

Chapter 5. Configuration

Some database manager and database configuration parameters now have higher upper limits, but only for 64-bit releases. To take full advantage of the larger address space available to 64-bit executables, you may need to tune memory-related configuration parameters. The following tables denote previous and current upper limits for affected database and database manager configuration parameters.

Table 1. Memory-related Database Manager Configuration Parameters
Parameter Previous Upper Limit Current Upper Limit
AGENT_STACK_SZ 1000 same
APPLHEAPSZ 128 256
ASLHEAPSZ 524288 same
AUDIT_BUF_SZ 65000 same
BACKBUFSZ 524288 same
DOS_RQRIOBLK 65535 same
DRDA_HEAP_SZ 60000 same
FCM_NUM_ANCHORS 120000 524288
FCM_NUM_BUFFERS 65300 524288
FCM_NUM_CONNECT 120000 524288
FCM_NUM_RQB 120000 524288
JAVA_HEAP_SZ 4096 same
MIN_PRIV_MEM 112000 same
MON_HEAP_SZ 60000 same
PRIV_MEM_THRESH 112000 same
QUERY_HEAP_SZ 524288 same
RESTBUFSZ 524288 same
RQIOBLK 65535 same
SHEAPTHRES 2097152 2147483647
STMTHEAP 2048 4096
UDF_MEM_SZ 60000 same

Table 2. Memory-related Database Configuration Parameters
Parameter Previous Upper Limit Current Upper Limit
APP_CTL_HEAP_SZ 64000 same
APPLHEAPSZ 60000 same
BUFFPAGE 524288 2147483647
CATALOGCACHE_SZ 60000 same
DBHEAP 60000 524288 (for both 32-bit and 64-bit)
ESTORE_SEG_SZa 1048575 same
LOGBUFSZ 4096 65535
PCKCACHESZ 64000 524288
SORTHEAP 524288 same
STAT_HEAP_SZ 524288 same
STMTHEAP 60000 same
UTIL_HEAP_SZ 524288 same
Note:a This parameter has been disabled for all 64-bit platforms.

The internal representation of the DBHEAP database configuration parameter has changed from 16 bits to 64 bits for 64-bit releases, and to 32 bits for 32-bit releases.

The old DBHEAP token (SQLF_DBTN_DBHEAP) has been replaced with a new one (SQLF_DBTN_DB_HEAP). If the old token is used with sqlfudb (Update Database Configuration API), or sqlfxdb (Get Database Configuration API), DB2 will cast 16 bits to 64 or 32 bits, as appropriate, to maintain source code compatibility. If the DBHEAP value is greater than 65535, the cast results in a wrapped value, and DB2 returns a new warning message (SQL5066W; see Chapter 7, Messages).


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