Collect Statistics

Collect Statistics analyzes the contents of tables. When you analyze a table, the database collects statistics about expressions occurring in any function-based indexes as well. Therefore, be sure to create function-based indexes on the table before analyzing the table.

Oracle Database collects the following statistics for a table. Statistics marked with an asterisk (*) are always computed exactly.

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