Overview of Oracle Data Blocks

•Oracle data block is smallest unit of data that oracle use to store data.

•Oracle store data in the datafile in terms of oracle data block.

•As we know each operating system has a block size. Oracle data block is not same as operating system block size. In fact oracle block size is multiple of OS block size.

•How much of a standard oracle block size will be is defined by the DB_BLOCK_SIZE initialization parameter.

•We can also define up to five non standard block sizes.

•Data block format is discussed in Oracle data block format

•How we can choose non standard block size is discussed in Choose of a non standard Blocksize