Oracle Database collects the following statistics for a table. Statistics marked with an
asterisk are always computed exactly. Table statistics, including the status of domain
indexes, appear in the data dictionary views USER_TABLES, ALL_TABLES, and DBA_
TABLES in the columns shown in parentheses.

■ Number of rows (NUM_ROWS)
■ * Number of data blocks below the high water mark--that is, the number of data
blocks that have been formatted to receive data, regardless whether they currently
contain data or are empty (BLOCKS)
■ * Number of data blocks allocated to the table that have never been used (EMPTY_
BLOCKS)
■ Average available free space in each data block in bytes (AVG_SPACE)
■ Number of chained rows (CHAIN_COUNT)
■ Average row length, including the row overhead, in bytes (AVG_ROW_LEN)