|Oracle® Database SQL Language Reference
12c Release 1 (12.1)
|PDF · Mobi · ePub|
A permanent tablespace contains persistent schema objects. Objects in permanent tablespaces are stored in data files.
An undo tablespace is a type of permanent tablespace used by Oracle Database to manage undo data if you are running your database in automatic undo management mode. Oracle strongly recommends that you use automatic undo management mode rather than using rollback segments for undo.
A temporary tablespace contains schema objects only for the duration of a session. Objects in temporary tablespaces are stored in temp files.
When you create a tablespace, it is initially a read/write tablespace. You can subsequently use the
TABLESPACE statement to take the tablespace offline or online, add data files or temp files to it, or make it a read-only tablespace.
You can also drop a tablespace from the database with the
You must have the
TABLESPACE system privilege. To create the
SYSAUX tablespace, you must have the
SYSDBA system privilege.
Before you can create a tablespace, you must create a database to contain it, and the database must be open.
See Also:CREATE DATABASE
To use objects in a tablespace other than the
If you are running the database in automatic undo management mode, then at least one
UNDO tablespace must be online.
If you are running the database in manual undo management mode, then at least one rollback segment other than the
SYSTEM rollback segment must be online.
Note:Oracle strongly recommends that you run your database in automatic undo management mode. For more information, refer to Oracle Database Administrator's Guide.
(file_specification::=, size_clause::=, logging_clause ::=, tablespace_encryption_spec::=, table_compression::=—part of
TABLE, storage_clause::=, extent_management_clause ::=, segment_management_clause ::=, flashback_mode_clause ::=)
Use this clause to determine whether the tablespace is a bigfile or smallfile tablespace. This clause overrides any default tablespace type setting for the database.
A bigfile tablespace contains only one data file or temp file, which can contain up to approximately 4 billion (232) blocks. The maximum size of the single data file or temp file is 128 terabytes (TB) for a tablespace with 32K blocks and 32TB for a tablespace with 8K blocks.
A smallfile tablespace is a traditional Oracle tablespace, which can contain 1022 data files or temp files, each of which can contain up to approximately 4 million (222) blocks.
If you omit this clause, then Oracle Database uses the current default tablespace type of permanent or temporary tablespace set for the database. If you specify
BIGFILE for a permanent tablespace, then the database by default creates a locally managed tablespace with automatic segment-space management.
Use the following clauses to create a permanent tablespace. (Some of these clauses are also used to create a temporary or undo tablespace.)
Specify the name of the tablespace to be created. The name must satisfy the requirements listed in "Database Object Naming Rules".
SYSAUX is a required auxiliary system tablespace. You must use the
TABLESPACE statement to create the
SYSAUX tablespace if you are upgrading from a release earlier than Oracle Database 11g. You must have the
SYSDBA system privilege to specify this clause, and you must have opened the database in
You must specify
AUTO for the
SYSAUX tablespace. The
DATAFILE clause is optional only if you have enabled Oracle Managed Files. See "DATAFILE | TEMPFILE Clause" for the behavior of the
Take care to allocate sufficient space for the
SYSAUX tablespace. For guidelines on creating this tablespace, refer to Oracle Database Upgrade Guide.
Specify the data files to make up the permanent tablespace or the temp files to make up the temporary tablespace. Use the
datafile_tempfile_spec form of
file_specification to create regular data files and temp files in an operating system file system or to create Oracle Automatic Storage Management (Oracle ASM) disk group files.
You must specify the
TEMPFILE clause unless you have enabled Oracle Managed Files by setting a value for the
DB_CREATE_FILE_DEST initialization parameter. For Oracle ASM disk group files, the parameter must be set to a multiple file creation form of Oracle ASM filenames. If this parameter is set, then the database creates a system-named 100 MB file in the default file destination specified in the parameter. The file has
AUTOEXTEND enabled and an unlimited maximum size.
Note:Media recovery does not recognize temp files.
Oracle Automatic Storage Management Administrator's Guide for more information on using Oracle ASM
file_specification for a full description, including the
AUTOEXTEND parameter and the multiple file creation form of Oracle ASM filenames
You can create a tablespace within an Oracle ASM disk group by providing only the disk group name in the
datafile_tempfile_spec. In this case, Oracle ASM creates a data file in the specified disk group with a system-generated filename. The data file is auto-extensible with an unlimited maximum size and a default size of 100 MB. You can use the
autoextend_clause to override the default size.
If you use one of the reference forms of the
ASM_filename, which refers to an existing file, then you must also specify
Note:On some operating systems, Oracle does not allocate space for a temp file until the temp file blocks are actually accessed. This delay in space allocation results in faster creation and resizing of temp files, but it requires that sufficient disk space is available when the temp files are later used. To avoid potential problems, before you create or resize a temp file, ensure that the available disk space exceeds the size of the new temp file or the increased size of a resized temp file. The excess space should allow for anticipated increases in disk space use by unrelated operations as well. Then proceed with the creation or resizing operation.
This clause is valid only for a dictionary-managed tablespace. Specify the minimum size of an extent in the tablespace. This clause lets you control free space fragmentation in the tablespace by ensuring that the size of every used or free extent in a tablespace is at least as large as, and is a multiple of, the value specified in the
See Also:size_clause for information on that clause and Oracle Database VLDB and Partitioning Guide for more information about using
EXTENTto control fragmentation
BLOCKSIZE clause to specify a nonstandard block size for the tablespace. In order to specify this clause, the
DB_CACHE_SIZE and at least one
K_CACHE_SIZE parameter must be set, and the integer you specify in this clause must correspond with the setting of one
K_CACHE_SIZE parameter setting.
Note:Oracle recommend that you do not store tablespaces with a 2K block size on 4K sector size disks, because performance degradation can result.
See Also:Oracle Database Reference for information on the
K_CACHE_SIZEparameter and Oracle Database Concepts for information on multiple block sizes
Specify the default logging attributes of all tables, indexes, materialized views, materialized view logs, and partitions within the tablespace.
LOGGING is the default. This clause is not valid for a temporary or undo tablespace.
The tablespace-level logging attribute can be overridden by logging specifications at the table, index, materialized view, materialized view log, and partition levels.
See Also:logging_clause for a full description of this clause
Use this clause to put the tablespace into
LOGGING mode. Oracle Database will log all changes to all objects in the tablespace except changes to temporary segments, overriding any
NOLOGGING setting for individual objects. The database must be open and in
This setting does not exclude the
NOLOGGING attribute. You can specify both
NOLOGGING. In this case,
NOLOGGING is the default logging mode for objects subsequently created in the tablespace, but the database ignores this default as long as the tablespace or the database is in
LOGGING mode. If you subsequently take the tablespace out of
LOGGING mode, then the
NOLOGGING default is once again enforced.
LOGGINGmode can have performance effects. Refer to Oracle Database Administrator's Guide for information on when to use this setting.
Use this clause to specify the encryption properties of the tablespace. This clause does not actually encrypt the tablespace. You must also specify the
ENCRYPT keyword as part of the
storage_clause in this statement in order for the tablespace to be encrypted. In addition, you must already have used
BY ... to load the TDE master key into database memory for the duration of the instance, or establish a connection to the HSM to send the encrypted table and tablespace keys to the HSM and receive them back decrypted. For more information, see "SET ENCRYPTION WALLET Clause".
Note:You cannot decrypt a tablespace that has been created encrypted. You must create an unencrypted tablespace and re-create the database objects in the unencrypted tablespace.
encrypt_algorithm' to indicate the name of the encryption algorithm to be used. Valid algorithms are
3DES168. If you omit this clause, then the database uses
This clause lets you specify default storage parameters for all objects created in the tablespace and default compression of data for all tables created in the tablespace. This clause is not valid for a temporary tablespace or a locally managed tablespace.
For a dictionary-managed tablespace, you can specify the following storage parameters with this clause:
Use these clauses to determine whether the tablespace is online or offline. This clause is not valid for a temporary tablespace.
The data dictionary view
DBA_TABLESPACES indicates whether each tablespace is online or offline.
extent_management_clause lets you specify how the extents of the tablespace will be managed.
Note:After you have specified extent management with this clause, you can change extent management only by migrating the tablespace.
UNIFORM specifies that the tablespace is managed with uniform extents of
SIZE bytes.The default
SIZE is 1 megabyte. All extents of temporary tablespaces are of uniform size, so this keyword is optional for a temporary tablespace. However, you must specify
UNIFORM in order to specify
SIZE. You cannot specify
UNIFORM for an undo tablespace.
If you do not specify
UNIFORM, then the default is
UNIFORM for temporary tablespaces and
AUTOALLOCATE for all other types of tablespaces.
If you do not specify the
extent_management_clause, then Oracle Database interprets the
EXTENT clause and the
storage_clause to determine extent management.
DICTIONARYkeyword is deprecated. It is still supported for backward compatibility. However, Oracle recommends that you create locally managed tablespaces. Locally managed tablespaces are much more efficiently managed than dictionary-managed tablespaces. The creation of new dictionary-managed tablespaces is scheduled for desupport.
See Also:Oracle Database Concepts for a discussion of locally managed tablespaces
A permanent locally managed tablespace can contain only permanent objects. If you need a locally managed tablespace to store temporary objects, for example, if you will assign it as a user's temporary tablespace, then use the
If you specify this clause, then you cannot specify
EXTENT, or the
See Also:Oracle Database Administrator's Guide for information on changing extent management by migrating tablespaces and "Creating a Locally Managed Tablespace: Example"
segment_management_clause is relevant only for permanent, locally managed tablespaces. It lets you specify whether Oracle Database should track the used and free space in the segments in the tablespace using free lists or bitmaps. This clause is not valid for a temporary tablespace.
AUTO if you want the database to manage the free space of segments in the tablespace using a bitmap. If you specify
AUTO, then the database ignores any specification for
GROUPS in subsequent storage specifications for objects in this tablespace. This setting is called automatic segment-space management and is the default.
MANUAL if you want the database to manage the free space of segments in the tablespace using free lists. Oracle strongly recommends that you do not use this setting and that you create tablespaces with automatic segment-space management.
To determine the segment management of an existing tablespace, query the
SEGMENT_SPACE_MANAGEMENT column of the
USER_TABLESPACES data dictionary view.
Notes:If you specify
AUTOsegment management, then:
If you set extent management to
UNIFORM, then you must ensure that each extent contains at least 5 database blocks.
If you set extent management to
AUTOALLOCATE, and if the database block size is 16K or greater, then Oracle manages segment space by creating extents with a minimum size of 5 blocks rounded up to 64K.
You can specify this clause only for a permanent, locally managed tablespace.
You cannot specify this clause for the
Oracle Automatic Storage Management Administrator's Guide for information on automatic segment-space management and when to use it
Oracle Database Reference for information on the data dictionary views
Use this clause in conjunction with the
FLASHBACK clause to specify whether the tablespace can participate in
DATABASE operations. This clause is useful if you have the database in
FLASHBACK mode but you do not want Oracle Database to maintain Flashback log data for this tablespace.
This clause is not valid for temporary or undo tablespaces.
FLASHBACK ON Specify
ON to put the tablespace in
FLASHBACK mode. Oracle Database will save Flashback log data for this tablespace and the tablespace can participate in a
DATABASE operation. If you omit the
ON is the default.
FLASHBACK OFF Specify
OFF to take the tablespace out of
FLASHBACK mode. Oracle Database will not save any Flashback log data for this tablespace. You must take the data files in this tablespace offline or drop them prior to any subsequent
DATABASE operation. Alternatively, you can take the entire tablespace offline. In either case, the database does not drop existing Flashback logs.
FLASHBACKmode of a tablespace is independent of the
FLASHBACKmode of an individual table.
Use this clause to create a locally managed temporary tablespace, which is an allocation of space in the database that can contain transient data that persists only for the duration of a session. This transient data cannot be recovered after process or instance failure.
The transient data can be user-generated schema objects such as temporary tables or system-generated data such as temp space used by hash joins and sort operations. When a temporary tablespace, or a tablespace group of which this tablespace is a member, is assigned to a particular user, then Oracle Database uses the tablespace for sorting operations in transactions initiated by that user.
See Also:Oracle Database Security Guide for information on assigning temporary tablespaces to users
This clause is relevant only for temporary tablespaces. Use this clause to determine whether
tablespace is a member of a tablespace group. A tablespace group lets you assign multiple temporary tablespaces to a single user and increases the addressability of temporary tablespaces.
Specify a group name to indicate that
tablespace is a member of this tablespace group. The group name cannot be the same as
tablespace or any other existing tablespace. If the tablespace group already exists, then Oracle Database adds the new tablespace to that group. If the tablespace group does not exist, then the database creates the group and adds the new tablespace to that group.
Specify an empty string (' ') to indicate that
tablespace is not a member of any tablespace group.
ALTER TABLESPACE and "Adding a Temporary Tablespace to a Tablespace Group: Example" for information on adding a tablespace to a tablespace group
CREATE USER for information on assigning a temporary tablespace to a user
Oracle Database Administrator's Guide for more information on tablespace groups
Restrictions on Temporary Tablespaces The data stored in temporary tablespaces persists only for the duration of a session. Therefore, only a subset of the
TABLESPACE clauses are relevant for temporary tablespaces. The only clauses you can specify for a temporary tablespace are the
TEMPFILE clause, the
tablespace_group_clause, and the
UNDO to create an undo tablespace. When you run the database in automatic undo management mode, Oracle Database manages undo space using the undo tablespace instead of rollback segments. This clause is useful if you are now running in automatic undo management mode but your database was not created in automatic undo management mode.
Oracle Database always assigns an undo tablespace when you start up the database in automatic undo management mode. If no undo tablespace has been assigned to this instance, then the database uses the
SYSTEM rollback segment. You can avoid this by creating an undo tablespace, which the database will implicitly assign to the instance if no other undo tablespace is currently assigned.
DATAFILE clause is described in "DATAFILE | TEMPFILE Clause".
It is unnecessary to specify the
extent_management_clause when creating an undo tablespace, because undo tablespaces must be locally managed tablespaces that use
AUTOALLOCATE extent management. If you do specify this clause, then you must specify
AUTOALLOCATE, both of which are the same as omitting this clause. Refer to extent_management_clause for the full semantics of this clause.
This clause is valid only for undo tablespaces.
GUARANTEE specifies that Oracle Database should preserve unexpired undo data in all undo segments of
tablespace even if doing so forces the failure of ongoing operations that need undo space in those segments. This setting is useful if you need to issue an Oracle Flashback Query or an Oracle Flashback Transaction Query to diagnose and correct a problem with the data.
NOGUARANTEE returns the undo behavior to normal. Space occupied by unexpired undo data in undo segments can be consumed if necessary by ongoing transactions. This is the default.
You cannot create database objects in this tablespace. It is reserved for system-managed undo data.
The only clauses you can specify for an undo tablespace are the
DATAFILE clause and the
extent_management_clause to specify local
AUTOALLOCATE extent management. You cannot specify local
UNIFORM extent management or dictionary extent management using the
extent_management_clause. All undo tablespaces are created permanent, read/write, and in logging mode. Values for
STORAGE are system generated.
These examples assume that your database is using 8K blocks.
CREATE BIGFILE TABLESPACE bigtbs_01 DATAFILE 'bigtbs_f1.dbf' SIZE 20M AUTOEXTEND ON;
CREATE UNDO TABLESPACE undots1 DATAFILE 'undotbs_1a.dbf' SIZE 10M AUTOEXTEND ON RETENTION GUARANTEE;
CREATE TEMPORARY TABLESPACE temp_demo TEMPFILE 'temp01.dbf' SIZE 5M AUTOEXTEND ON;
Assuming that the default database block size is 2K, and that each bit in the map represents one extent, then each bit maps 2,500 blocks.
The following example sets the default location for data file creation and then creates a tablespace with an Oracle-managed temp file in the default location. The temp file is 100 M and is autoextensible with unlimited maximum size. These are the default values for Oracle Managed Files:
ALTER SYSTEM SET DB_CREATE_FILE_DEST = '$ORACLE_HOME/rdbms/dbs'; CREATE TEMPORARY TABLESPACE tbs_05;
Adding a Temporary Tablespace to a Tablespace Group: Example The following statement creates the
tbs_temp_02 temporary tablespace as a member of the
tbs_grp_01 tablespace group. If the tablespace group does not already exist, then Oracle Database creates it during execution of this statement:
CREATE TEMPORARY TABLESPACE tbs_temp_02 TEMPFILE 'temp02.dbf' SIZE 5M AUTOEXTEND ON TABLESPACE GROUP tbs_grp_01;
CREATE TABLESPACE tbs_01 DATAFILE 'tbs_f2.dbf' SIZE 40M ONLINE;
This statement creates tablespace
tbs_03 with one data file and allocates every extent as a multiple of 500K:
CREATE TABLESPACE tbs_03 DATAFILE 'tbs_f03.dbf' SIZE 20M LOGGING;
Enabling Autoextend for a Tablespace: Example This statement creates a tablespace named
tbs_02 with one data file. When more space is required, 500 kilobyte extents will be added up to a maximum size of 100 megabytes:
CREATE TABLESPACE tbs_02 DATAFILE 'diskb:tbs_f5.dbf' SIZE 500K REUSE AUTOEXTEND ON NEXT 500K MAXSIZE 100M;
CREATE TABLESPACE tbs_04 DATAFILE 'file_1.dbf' SIZE 10M EXTENT MANAGEMENT LOCAL UNIFORM SIZE 128K;
This statement creates a locally managed tablespace in which every extent is 128K and each bit in the bit map describes 64 blocks.
The following statement creates a locally managed tablespace with uniform extents and shows an example of a table stored in that tablespace:
CREATE TABLESPACE lmt1 DATAFILE 'lmt_file2.dbf' SIZE 100m REUSE EXTENT MANAGEMENT LOCAL UNIFORM SIZE 1M; CREATE TABLE lmt_table1 (col1 NUMBER, col2 VARCHAR2(20)) TABLESPACE lmt1 STORAGE (INITIAL 2m);
The initial segment size of the table is 2M.
The following example creates a locally managed tablespace without uniform extents:
CREATE TABLESPACE lmt2 DATAFILE 'lmt_file3.dbf' SIZE 100m REUSE EXTENT MANAGEMENT LOCAL; CREATE TABLE lmt_table2 (col1 NUMBER, col2 VARCHAR2(20)) TABLESPACE lmt2 STORAGE (INITIAL 2m MAXSIZE 100m);
The initial segment size of the table is 2M. Oracle Database determines the size of each extent and the total number of extents allocated to satisfy the initial segment size. The segment's maximum size is limited to 100M.
Creating an Encrypted Tablespace: Example In the following example, the first statement enables encryption for the database by opening the wallet. The second statement creates an encrypted tablespace.
ALTER SYSTEM SET ENCRYPTION WALLET OPEN IDENTIFIED BY "wallet_password"; CREATE TABLESPACE encrypt_ts DATAFILE '$ORACLE_HOME/dbs/encrypt_df.dbf' SIZE 1M ENCRYPTION USING 'AES256' DEFAULT STORAGE (ENCRYPT);
CREATE TABLESPACE auto_seg_ts DATAFILE 'file_2.dbf' SIZE 1M EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO;
Creating Oracle Managed Files: Examples The following example sets the default location for data file creation and creates a tablespace with a data file in the default location. The data file is 100M and is autoextensible with an unlimited maximum size:
ALTER SYSTEM SET DB_CREATE_FILE_DEST = '$ORACLE_HOME/rdbms/dbs'; CREATE TABLESPACE omf_ts1;
The following example creates a tablespace with an Oracle-managed data file of 100M that is not autoextensible:
CREATE TABLESPACE omf_ts2 DATAFILE AUTOEXTEND OFF;