索引管理的脚本

索引管理的脚本
1 需要重建的索引
REM =============================================================
REM
REM rebuild_indx.sql
REM
REM Copyright (c) Oracle Software, 1998 - 2000
REM
REM Author : Jurgen Schelfhout
REM
REM The sample program in this article is provided for educational
REM purposes only and is NOT supported by Oracle Support Services.
REM It has been tested internally, however, and works as documented.
REM We do not guarantee that it will work for you, so be sure to test
REM it in your environment before relying on it.
REM
REM This script will analyze all the indexes for a given schema
REM or for a subset of schema's. After this the dynamic view
REM index_stats is consulted to see if an index is a good
REM candidate for a rebuild or for a bitmap index.
REM
REM Database Version : 7.3.X and above.
REM
REM =============================================================
prompt
ACCEPT spoolfile CHAR prompt 'Output-file : ';
ACCEPT schema CHAR prompt 'Schema name (% allowed) : ';
prompt
prompt
prompt Rebuild the index when :
prompt - deleted entries represent 20% or more of the current entries
prompt - the index depth is more then 4 levels.
prompt Possible candidate for bitmap index :
prompt - when distinctiveness is more than 99%
prompt
spool &spoolfile
set serveroutput on
set verify off
declare
c_name INTEGER;
ignore INTEGER;
height index_stats.height%TYPE := 0;
lf_rows index_stats.lf_rows%TYPE := 0;
del_lf_rows index_stats.del_lf_rows%TYPE := 0;
distinct_keys index_stats.distinct_keys%TYPE := 0;
cursor c_indx is
select owner, table_name, index_name
from dba_indexes
where owner like upper('&schema')
and owner not in ('SYS','SYSTEM');
begin
dbms_output.enable (1000000);
dbms_output.put_line ('Owner Index Name % Deleted Entries Blevel Distinctiveness');
dbms_output.put_line ('-------- -------------- ----------------- ------ ---------------');
c_name := DBMS_SQL.OPEN_CURSOR;
for r_indx in c_indx loop
DBMS_SQL.PARSE(c_name,'analyze index ' || r_indx.owner || '.' ||
r_indx.index_name || ' validate structure',DBMS_SQL.NATIVE);
ignore := DBMS_SQL.EXECUTE(c_name);
select HEIGHT, decode (LF_ROWS,0,1,LF_ROWS), DEL_LF_ROWS,
decode (DISTINCT_KEYS,0,1,DISTINCT_KEYS)
into height, lf_rows, del_lf_rows, distinct_keys
from index_stats;
--
-- Index is considered as candidate for rebuild when :
-- - when deleted entries represent 20% or more of the current entries
-- - when the index depth is more then 4 levels.(height starts counting from 1 so > 5)
-- Index is (possible) candidate for a bitmap index when :
-- - distinctiveness is more than 99%
--
if ( height > 5 ) OR ( (del_lf_rows/lf_rows) > 0.2 ) then
dbms_output.put_line (rpad(r_indx.owner,16,' ') || rpad(r_indx.index_name,40,' ') ||
lpad(round((del_lf_rows/lf_rows)*100,3),17,' ') ||
lpad(height-1,7,' ') ||
lpad(round((lf_rows-distinct_keys)*100/lf_rows,3),16,' '));
end if;
end loop;
DBMS_SQL.CLOSE_CURSOR(c_name);
end;
/
spool off
set verify on
2 将索引从一个表空间移到另一个表空间
alter index rebuild tablspace <目标表空间名字> [online];
3 监测某一个索引的使用状况
--**************************************************************************
--**************************************************************************
col c1 heading ‘Begin|Interval|time’ format a20
col c2 heading ‘Search Columns’ format 999
col c3 heading ‘Invocation|Count’ format 99,999,999
break on c1 ship 2
accept idxname char prompt ‘Enter Index Name: ’
ttile ‘Invocation Counts for index|&idxname’
select
to_char(sn.begin_interval_time, ‘yy-mm-dd hh24’) c1,
p.search_columns c2,
count(*) c3
from
dba_hist_snapshot sn,
dba_hist_sql_plan p,
dba_hist_sqlstat st
where
st.sql_id = p.sql_id
and
sn.snap_id = st.snap_id
and
p.object_name = ‘&idxname’
group by
begin_interval_time, search_columns;