In the Oracle 9i database, support the same database using different size Oracle blocks, which can define the size of the data block at the tablespace level, for example:
Create TableSpace TBS1 ... blocksize 16k;
Create TableSpace TBS2 ... blocksize 8192;
Among them, blocksize can take 2K, 4K, 8K, 16K, if the operating system is supported, even 32K. The block size of the table space can be viewed via the block_size column value in the DBA_TABLESPACES view.
Like the previous version of Oracle 9i, when you create a database, you still need to specify a DB_BLOCK_SIZE parameter (default database data block size, also a standard block size, Standard block size). The value of this parameter will be used as the default block size when creating a table space (if the new table size of the new table space is not specified), and the value of the db_block_size parameter is still specified when the database is created, unless the database is reconstructed, otherwise it cannot be changed .
have to be aware of is:
• When using partitions, all partitions of a partition table must be in the same blocksize tablespace.
· Index and corresponding tables can be placed in different blocksize tablespaces.
· The block size of the system table space can only be the value of the DB_BLOCK_SIZE parameter.
In the Oracle 9i, the parameter db_cache_size replaces the previous DB_BLOCK_BUFFERS parameter and uses bytes to indicate the size of the high-speed buffer (instead of block).
When we use multiple blocks in a database, you must specify the db_cache_size parameter and set the db_nk_cache_size parameter for the tablespace set for different blocks (at least one DB_NK_CACHE_SIZE parameter), where n can be 2, 4, 8, 16, 32, ie:
The buffer of DB_2K_CACHE_SIZE is a cache specified to access a tablespace object having a 2K data block size;
The buffer of DB_4K_CACHE_SIZE is a cache specified for the tablespace object of the 4K data block size;
The buffer of db_8k_cache_size is a cache specified to access tablespace objects of 8K data block size;
The buffer of db_16k_cache_size is a cache specified to access a tablespace object with a 16K data block size;
The buffer of DB_32K_CACHE_SIZE is a cache specified to access tablespace objects of 32K data block sizes;
Note that N cannot be specified as values identified as the size of the default data block, for example, if DB_BLOCK_SIZE = 8192 (8KB), then the DB_8K_Cache_SIZE parameter cannot be set.
E.g:
Max_sga_size = 700m
Share_pool_size = 80m
DB_BLOCK_SIZE = 8192
DB_CACHE_SIZE = 290M
DB_2K_CACHE_SIZE = 4M
DB_16K_Cache_Size = 16m
