B Operating System Dependent Variables

This appendix contains the z/OS-specific allowed, default, and maximum values for Oracle initialization and storage parameters. For a complete discussion of these parameters, refer to Oracle Database Reference. To find out which parameters described in Oracle Database Reference are supported or not supported by Oracle Database for z/OS, refer to Oracle Database Installation Guide for IBM z/OS

The topics in this appendix include:

Initialization Parameters with z/OS-Specific Defaults or Limits
Database Limits
SQL Language Parameters
Storage Parameters

B.1 Initialization Parameters with z/OS-Specific Defaults or Limits

The following table lists the Oracle Database initialization parameters that have z/OS-specific defaults or limits. You can separate the keywords with commas or blanks. For more information, refer to the section "Oracle Initialization Parameter Considerations" in Chapter 3, "Configuring a Database Service and Creating a New Database".

Table B-1 Initialization Parameters with z/OS-Specific Defaults or Limits

Parameter	Default	Maximum	Minimum
ASM_DISKSTRING	None	Not supported	Not supported
AUDIT_FILE_DEST^Foot 1	0 (zero) means "do not write SMF records"	255	128
AUDIT_TRAIL¹	N/A	N/A	N/A
BACKGROUND_CORE_DUMP	None	Not supported	Not supported
BACKGROUND_DUMP_DEST	None	Not supported	Not supported
BITMAP_MERGE_AREA_SIZE	N/A	Limited by address space size	0
COMMIT_POINT_STRENGTH	1	N/A^Foot 2	N/A
CONTROL_FILES¹	&ORAPREFD..&ORASRVN..DFLCNTL.DBF	N/A	N/A
CORE_DUMP_DEST	None	Not supported	Not supported
CPU_COUNT	N/A	N/A	N/A
CREATE_BITMAP_AREA_SIZE	N/A	Limited by address space size	65,536
DB_nK_CACHE_SIZE	0 - only 4, 8, 16, and 32 are supported for n	Limited by address space size	0
DB_BLOCK_BUFFERS	N/A	Limited by address space size	N/A
DB_BLOCK_SIZE¹	4096	32768	4096
DB_CREATE_FILE_DEST¹	N/A	23	N/A
DB_CREATE_ONLINE_LOG_DEST_n ¹	N/A	29	N/A
DB_FILE_MULTIBLOCK_READ_COUNT	Derived	256	1
DB_FILE_NAME_CONVERT¹	N/A	N/A	N/A
DB_FILES	N/A	65,534	N/A
DB_KEEP_CACHE_SIZE	N/A	Limited by address space size	0
DB_RECYCLE_CACHE_SIZE	N/A	Limited by address space size	0
DBWR_IO_SLAVES	0	N/A	N/A
DG_BROKER_CONFIG_FILEn	&ORAPREFD.&ORASRVN.DRn.DAT	None	None
DISPATCHERS (SESSIONS, CONNECTIONS)	N/A	1	0
HASH_AREA_SIZE	N/A	Limited by address space size	0
INSTANCE_NUMBER	N/A	No limit	0
JAVA_POOL_SIZE	N/A	Limited by address space size	0
LARGE_POOL_SIZE	N/A	Limited by address space size	N/A
LOCK_SGA¹	None	Not supported	Not supported
LOG_ARCHIVE_DEST¹	NULL	None	None
LOG_ARCHIVE_FORMAT¹	"T%T.S%S.R%R"	None	None
LOG_BUFFER	16384	Limited by address space size	N/A
LOG_FILE_NAME_CONVERT¹	N/A	N/A	N/A
MAX_DISPATCHERS	None	1	0
MAX_DUMP_FILE_SIZE	None	Not supported	Not supported
MAX_SHARED_SERVERS	None	Limited by address space size	0
NLS_LANGUAGE	AMERICAN	N/A	N/A
NLS_TERRITORY	AMERICA	N/A	N/A
OBJECT_CACHE_MAX_SIZE_PERCENT	N/A	Limited by address space size	0
OBJECT_CACHE_OPTIMAL_SIZE	N/A	Limited by address space size	10240
OPEN_CURSORS	N/A	Limited by address space size	1
OS_AUTHENT_PREFIX	OPS$	None	None
PARALLEL_EXECUTION_MESSAGE_SIZE	N/A	N/A	N/A
PARALLEL_THREADS_PER_CPU	2	N/A	N/A
PROCESSES	Derived	Limited by address space size	N/A
RECOVERY_PARALLELISM	Number of processors minus 1.	Limited by PARALLEL_ MAX_SERVERS	0
SESSION_CACHED_CURSORS	N/A	Limited by address space size	0
SESSION_MAX_OPEN_FILES	N/A	N/A	N/A
SGA_MAX_SIZE¹	The actual SGA size (This parameter should not be specified on z/OS)	N/A	N/A
SGA_TARGET	0 (SGA tuning disabled)	N/A	64
SHADOW_CORE_DUMP	None	Not supported	Not supported
SHARED_POOL_SIZE	32000000	Limited by address space size	4194304
SORT_AREA_SIZE	N/A	Limited by address space size	N/A
SPFILE¹	N/A	N/A	N/A
STANDBY_ARCHIVE_DEST¹	&ORAPREFD..&ORASRVN..ARCHLOG.	None	None
STREAMS_POOL_SIZE	N/A	Limited by address space size	0
TIMED_OS_STATISTICS	0 (Default is recommended value on z/OS)	N/A	N/A
TRACEFILE_IDENTIFIER¹	N/A	N/A	N/A
TRANSACTIONS_PER_ROLLBACK_SEGMENT	5	34	N/A
USER_DUMP_DEST	None	Not supported	Not supported

^Footnote 1More information on using this parameter can be found in the section "Oracle Initialization Parameter Considerations" in Chapter 3, "Configuring a Database Service and Creating a New Database".
^Footnote 2N/A means that the platform-specific value is the same as the generic value.

B.2 Database Limits

Oracle database files, with exceptions, are limited to 4 GB each in size. The exceptions are as follows:

Control files, which are limited to 20,000 logical blocks of size DB_BLOCK_SIZE
Bigfile tablespace files, which are limited to the lesser of 4 GB blocks of size DB_BLOCK_SIZE, or, the maximum size of an extended-format extended addressability data set (up to 59 volumes or 16, if striping). For more information, refer to the IBM document DFSMS: Using Data Sets.

A maximum of 255 redo log files can be specified for a database.

A database can contain up to 65, 534 datafiles over all tablespaces. A single smallfile tablespace is limited to 4094 datafiles.

B.3 SQL Language Parameters

This section lists the parameters for the CREATE CONTROLFILE and CREATE DATABASE SQL statements that have z/OS-specific defaults or limits.

B.3.1 CREATE CONTROLFILE

The parameters for the CREATE CONTROLFILE SQL statement are listed in the following table:

Table B-2 CREATE CONTROLFILE Parameters with z/OS-Specific Defaults or Limits

Parameter	Default	Maximum	Minimum
CHARACTER SET	WE8EBCDIC1047	N/A	N/A^Foot 1
MAXDATAFILES	32	65534^Foot 2	N/A
MAXINSTANCES	1	15	N/A
MAXLOGFILES	32	256	N/A
MAXLOGMEMBERS	2	5	N/A
MAXLOGHISTORY	100	65534	N/A

^Footnote 1N/A means that the platform-specific value is the same as the generic value.
^Footnote 2Specifying MAXDATAFILES larger than 40,000 requires using a value of 8K or larger for the DB_BLOCK_SIZE initialization parameter.

B.3.2 CREATE DATABASE

The parameters for the CREATE DATABASE SQL statement are listed in the following table:

Table B-3 CREATE DATABASE Parameters with z/OS-Specific Defaults or Limits

Parameter	Default	Maximum	Minimum
CHARACTER SET	WE8EBCDIC1047	N/A	N/A^Foot 1
DATAFILE	Refer to "Oracle Database Files" in Chapter 4, "Defining z/OS Data Sets for the Oracle Database".	N/A	16K or one VSAM control area, whichever is larger
LOGFILE	Refer to "Oracle Database Files" in Chapter 4, "Defining z/OS Data Sets for the Oracle Database".	N/A	N/A
MAXDATAFILES	32	65534^Foot 2	N/A
MAXINSTANCES	1	15	N/A
MAXLOGFILES	32	256	2
MAXLOGMEMBERS	2	5	N/A
MAXLOGHISTORY	N/A	N/A	N/A

B.4 Storage Parameters

The maximum values for DATAFILE, MINEXTENTS, NEXT, OPTIMAL, and PCTINCREASE are all limited by file size, which is limited by the size of the disk device.