OBJECT_CACHE_MAX_SIZE_PERCENT

Property	Description
Parameter type	Integer
Default value	10
Modifiable	ALTER SESSION, ALTER SYSTEM ... DEFERRED
Range of values	0 to operating system-dependent maximum

The object cache is a memory block on the client that allows applications to store entire objects and to navigate among them without round trips to the server. OBJECT_CACHE_MAX_SIZE_PERCENT specifies the percentage of the optimal cache size that the session object cache can grow past the optimal size. The maximum size is equal to the optimal size plus the product of this percentage and the optimal size. When the cache size exceeds this maximum size, the system will attempt to shrink the cache to the optimal size.

Note:

1. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter

where upper(name) = ‘OBJECT_CACHE_MAX_SIZE_PERCENT’;

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
object_cache_max_size_percent	10	TRUE	TRUE	DEFERRED	TRUE	FALSE	percentage of maximum size over optimal of the user session's object cache

Oracle initializatoin parameters

OBJECT_CACHE_OPTIMAL_SIZE

Property	Description
Parameter type	Integer
Default value	102400 (100K)
Modifiable	ALTER SESSION, ALTER SYSTEM ... DEFERRED
Range of values	10 KB to operating system-dependent maximum

The object cache is a memory block on the client that allows applications to store entire objects and to navigate among them without round trips to the server. OBJECT_CACHE_OPTIMAL_SIZE specifies (in bytes) the size to which the session object cache is reduced when the size of the cache exceeds the maximum size.

See Also:

Note:

1. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter

where upper(name) = ‘OBJECT_CACHE_OPTIMAL_SIZE’;

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
object_cache_optimal_size	102400	TRUE	TRUE	DEFERRED	TRUE	FALSE	optimal size of the user session's object cache in bytes

Oracle initializatoin parameters

OLAP_PAGE_POOL_SIZE

Property	Description
Parameter type	Big integer
Syntax	OLAP_PAGE_POOL_SIZE = integer [K | M | G]
Default value	0
Modifiable	ALTER SESSION, ALTER SYSTEM ... DEFERRED
Range of values	0 to 2 GB

OLAP_PAGE_POOL_SIZE specifies (in bytes) the size of the OLAP page pool.

Note:

1. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter

where upper(name) = ‘OLAP_PAGE_POOL_SIZE’;

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
olap_page_pool_size	0	TRUE	TRUE	DEFERRED	TRUE	FALSE	size of the olap page pool in bytes

Oracle initializatoin parameters

OPEN_CURSORS

Property	Description
Parameter type	Integer
Default value	50
Modifiable	ALTER SYSTEM
Range of values	0 to 65535
Basic	Yes

OPEN_CURSORS specifies the maximum number of open cursors (handles to private SQL areas) a session can have at once. You can use this parameter to prevent a session from opening an excessive number of cursors.

It is important to set the value of OPEN_CURSORS high enough to prevent your application from running out of open cursors. The number will vary from one application to another. Assuming that a session does not open the number of cursors specified by OPEN_CURSORS, there is no added overhead to setting this value higher than actually needed.

Note:

1. It is important to have the value of OPEN_CURSORS set high enough to prevent your application from running out of open cursors otherwise ORA-1000 errors can occur.

2. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter

where upper(name) = ‘OPEN_CURSORS’;

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
open_cursors	4000	FALSE	FALSE	IMMEDIATE	TRUE	FALSE	max # cursors per session

Oracle initializatoin parameters

OPEN_LINKS

Property	Description
Parameter type	Integer
Default value	4
Modifiable	No
Range of values	0 to 255

OPEN_LINKS specifies the maximum number of concurrent open connections to remote databases in one session. These connections include database links, as well as external procedures and cartridges, each of which uses a separate process.

Oracle counts one open link for the following:

· For each user that references a public or private database link

· For each external procedure or cartridge connection when it is executed for the first time

Both types of connections close when the session ends. You can also close a database link connection explicitly by issuing an ALTER SESSION CLOSE DATABASE LINK statement.

You should set this parameter to allow for the external procedure and cartridge connections expected during the session plus the number of databases referred to in typical distributed transactions (that is, a single SQL statement that references multiple databases), so that all the databases can be open to execute the statement. For example, if queries alternately access databases A, B, and C, and OPEN_LINKS is set to 2, time will be lost waiting while one connection is broken and another made. Increase the value if many different databases are accessed over time.

This parameter refers only to connections used for distributed transactions. Direct connections to a remote database specified as an application connects are not counted.

If you set OPEN_LINKS to 0, then no distributed transactions are allowed.

Note:

1. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter

where upper(name) = ‘OPEN_LINKS’;

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
open_links	10	FALSE	FALSE	FALSE	FALSE	FALSE	max # open links per session

Oracle initializatoin parameters

OPEN_LINKS_PER_INSTANCE

Property	Description
Parameter type	Integer
Default value	4
Modifiable	No
Range of values	0 to 4294967295 (4 GB -1)
Real Application Clusters	Multiple instances can have different values.

OPEN_LINKS_PER_INSTANCE specifies the maximum number of migratable open connections globally for each database instance. XA transactions use migratable open connections so that the connections are cached after a transaction is committed. Another transaction can use the connection, provided the user who created the connection is the same as the user who owns the transaction.

OPEN_LINKS_PER_INSTANCE is different from OPEN_LINKS, which indicates the number of connections from a session. The OPEN_LINKS parameter is not applicable to XA applications.

Note:

2. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter

where upper(name) = ‘OPEN_LINKS_PER_INSTANCE’;

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
open_links_per_instance	4	TRUE	FALSE	FALSE	FALSE	FALSE	max # open links per instance

Oracle initializatoin parameters