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In the neighborhood Controlled Tablespaces

Extent control has historically been managed by means of gadget tables, inflicting rivalry in busy programs with quite a lot of inserts and deletes. In Oracle 8i the EXTENT MANAGEMENT clause used to be offered into the CREATE TABLESPACE commentary permitting extent control to be LOCAL or DICTIONARY. In the neighborhood Manages Tablespaces (LMT) have a bitmap of the blocks, or teams of blocks, they comprise permitting them to monitor extent allocation irrespective of the information dictionary.

Extent dimension inside LMTs is progressive by means of the UNIFORM and AUTOALLOCATE clauses. If UNIFORM is specified,
all extents throughout the tablespace would be the identical dimension, with 1M being the default extent dimension. The AUTOALLOCATE clause lets you dimension the preliminary extent depart Oracle to decide the optimal dimension for next extents, with 64K being the minimal.

The bank parameters NEXT, PCTINCREASE, MINEXTENTS, MAXEXTENTS, and DEFAULT STORAGE don’t seem to be legitimate for extents which can be controlled in the community.

• Creation
• Maintenance

Inauguration

The instance under presentations the 4 tactics a tablespace can also be created, together with the default starting which is equal to the usage of the DICTIONARY clause.

-- Default extent control (DICTIONARY)
CREATE TABLESPACE tsh_data_1
DATAFILE 'c:\Oracle\Oradata\TSH1\tsh101.dbf' SIZE 50M;

-- Particular dictionary extent control
CREATE TABLESPACE tsh_data_2
DATAFILE 'c:\Oracl\eOradata\TSH1\tsh201.dbf' SIZE 50M
EXTENT MANAGEMENT DICTIONARY;

-- Native extent control the usage of autoallocate
CREATE TABLESPACE tsh_data_3
DATAFILE 'c:\Oracle\Oradata\TSH1\tsh301.dbf' SIZE 50M
EXTENT MANAGEMENT LOCAL AUTOALLOCATE;

-- Native extent control the usage of uniform extents
CREATE TABLESPACE tsh_data_4
DATAFILE 'c:\Oracle\Oradata\TSH1\tsh401.dbf' SIZE 50M
EXTENT MANAGEMENT LOCAL UNIFORM SIZE 1M;

Upkeep

The DBMS_SPACE_ADMIN bundle accommodates numerous repairs routines for in the community controlled tablespaces, together with routines to transform from native to dictionary control. From Oracle 8.1.6 onwards the conversion from dictionary to native could also be imaginable.

-- Native to dictionary
EXEC DBMS_SPACE_ADMIN.tablespace_migrate_from_local('TSH_DATA_3');

-- Dictionary to native
EXEC DBMS_SPACE_ADMIN.tablespace_migrate_to_local('TSH_DATA_3');

For more info see:

• Managing Tablespaces
• DBMS_SPACE_ADMIN

Hope this is helping. Regards Tim…

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