statistics on the b-tree

Columns ___________________________ OPT_CMPR_PCTSAVE percentage storage saving expected from optimal prefix compression HEIGHT height of the b-tree BLOCKS blocks allocated to the segment NAME name of the index PARTITION_NAME name of the index partition,if partitioned LF_ROWS number of leaf rows (values in the index) LF_BLKS number of leaf blocks in the b-tree LF_ROWS_LEN sum of the lengths of all the leaf rows LF_BLK_LEN useable space in a leaf block BR_ROWS number of branch rows BR_BLKS number of branch blocks in the b-tree BR_ROWS_LEN sum of the lengths of all the branch blocks in the b-tree BR_BLK_LEN useable space in a branch block DEL_LF_ROWS number of deleted leaf rows in the index DEL_LF_ROWS_LEN total length of all deleted rows in the index DISTINCT_KEYS number of distinct keys in the index MOST_REPEATED_KEY how many times the most repeated key is repeated BTREE_SPACE total space currently allocated in the b-tree USED_SPACE total space that is currently being used in the b-tree PCT_USED percent of space allocated in the b-tree that is being used ROWS_PER_KEY average number of rows per distinct key BLKS_GETS_PER_ACCESS Expected number of consistent mode block gets per row. This assumes that a row chosen at random from the table is being searched for using the index PRE_ROWS number of prefix rows (values in the index) PRE_ROWS_LEN sum of lengths of all prefix rows OPT_CMPR_COUNT optimal prefix compression count for the index