SQL> analyze table scott.emp compute statistics; Table analyzed.
SQL> select num_rows,AVG_ROW_LEN from dba_tables where table_name='EMP'; NUM_ROWS AVG_ROW_LEN ---------- ----------- 14 40
SQL> SELECT table_name, initial_extent, next_extent, max_extents, num_rows,pct_free FROM dba_tables WHERE table_name = 'EMP'; TABLE_NAME INITIAL_EXTENT NEXT_EXTENT MAX_EXTENTS NUM_ROWS PCT_FREE --------------- -------------- ----------- ----------- ---------- ------------------------------------------------------------------------------- EMP 65536 2147483645 14 10
SQL> SELECT BYTES FROM DBA_SEGMENTS WHERE SEGMENT_NAME='EMP'; BYTES ---------- 65536
SQL> ALTER TABLE SCOTT.EMP ALLOCATE EXTENT; Table altered.
SQL> analyze table scott.emp compute statistics; Table analyzed.
SQL> SELECT BYTES FROM DBA_SEGMENTS WHERE SEGMENT_NAME='EMP'; BYTES ---------- 131072
SQL> ALTER TABLE SCOTT.EMP DEALLOCATE UNUSED; Table altered.
SQL> SELECT BYTES FROM DBA_SEGMENTS WHERE SEGMENT_NAME='EMP'; BYTES ---------- 65536
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