索引聚簇因子相关

create or replace function clustering_factor(
p_owner in varchar2,
p_table_name in varchar2,
p_column_name in varchar2)
return number is
l_cursor sys_refcursor;
l_clustering_factor binary_integer:=0;
l_block_nr binary_integer:=0;
l_previous_block_nr binary_integer:=0;
l_file_nr binary_integer :=0;
l_previous_file_nr binary_integer:=0;
begin
open l_cursor for
' select dbms_rowid.rowid_block_number(rowid) block_nr,'||
' dbms_rowid.rowid_to_absolute_fno(rowid,'''||
p_owner||''','''||
p_table_name||''') file_nr '||
'FROM ' ||p_owner||'.'||p_table_name||' ' ||
'where '||p_column_name||' is not null '||
' order by '||p_column_name;
loop
fetch l_cursor into l_block_nr,l_file_nr;
exit when l_cursor%notfound;
if (l_previous_block_nr <> l_block_nr or l_previous_file_nr <>l_file_nr )
then
l_clustering_factor:=l_clustering_factor+1;
end if;
l_previous_block_nr:=l_block_nr;
l_previous_file_nr:=l_file_nr;
end loop;
close l_cursor;
return l_clustering_factor;
end clustering_factor;

1636
select i.index_name,i.clustering_factor,clustering_factor(user,i.table_name,ic.COLUMN_NAME) as my_clstf
from user_indexes i,user_ind_columns ic
where i.table_name='T' and i.index_name=ic.INDEX_NAME;

INDEX_NAME CLUSTERING_FACTOR MY_CLSTF
------------------------------ ----------------- ----------
T_PK 972 972
T_VAL1_I 508 508
T_VAL2_I 174 174