Rows per block

Question

hi.
how do i know number of rows per blocks

Answer 1

One way is to use dbms_stats as howardjr suggested.
YAS@10GR2 > drop table t;
Table dropped.
YAS@10GR2 > create table t as select * from all_objects where rownum<=100;
Table created.
YAS@10GR2 > exec dbms_stats.gather_table_stats(ownname=>null,tabname=>'T');
PL/SQL procedure successfully completed.
YAS@10GR2 > select NUM_ROWS,BLOCKS,NUM_ROWS/BLOCKS from user_tables where table_name='T';
  NUM_ROWS     BLOCKS NUM_ROWS/BLOCKS
       100          5              20Another way is to use dbms_rowid to find out how many rows each block has.
YAS@10GR2 > select dbms_rowid.rowid_block_number(rowid) block,count(*)
  2  from t
  3  group by dbms_rowid.rowid_block_number(rowid);
     BLOCK   COUNT(*)
      1501          9
      1500         91