1.使用语句监控应用帐号的normal索引
select owner,
'alter index ' || owner || '.'||'"'||index_name||'"'||' monitoring usage;'
from dba_indexes
where index_type = 'NORMAL'
and uniqueness = 'NONUNIQUE'
and owner in ( select username from dba_users t where t.account_status='OPEN' and t.default_tablespace not in ('SYSTEM','USERS','SYSAUX'));
2.查询索引是否被使用
select us.username owner,
io.name index_name,
t.name table_name,
decode(bitand(i.flags, 65536), 0, 'NO', 'YES') monitoring,
decode(bitand(ou.flags, 1), 0, 'NO', 'YES') used,
ou.start_monitoring,
ou.end_monitoring
from sys.obj$ io,
sys.obj$ t,
sys.ind$ i,
sys.object_usage ou,
sys.dba_users us
where us.username in
(select username
from dba_users t
where t.account_status = 'OPEN'
and t.default_tablespace not in ('SYSTEM', 'USERS', 'SYSAUX'))
and io.owner# = us.user_id
and i.obj# = ou.obj#
and io.obj# = ou.obj#
and t.obj# = i.bo#
and decode(bitand(i.flags, 65536), 0, 'NO', 'YES') = 'YES'
and decode(bitand(ou.flags, 1), 0, 'NO', 'YES') = 'NO';
3.对已经使用的索引不进行监控
select 'alter index '||owner||'.'||'"'||index_name||'"'||' nomonitoring usage;' from
(
select us.username owner,
io.name index_name,
t.name table_name,
decode(bitand(i.flags, 65536), 0, 'NO', 'YES') monitoring,
decode(bitand(ou.flags, 1), 0, 'NO', 'YES') used,
ou.start_monitoring,
ou.end_monitoring
from sys.obj$ io, sys.obj$ t, sys.ind$ i, sys.object_usage ou, sys.dba_users us
where us.username in ( select username from dba_users t where t.account_status='OPEN' and t.default_tablespace not in ('SYSTEM','USERS','SYSAUX'))
and io.owner# =us.user_id
and i.obj# = ou.obj#
and io.obj# = ou.obj#
and t.obj# = i.bo#
) where used='YES' and monitoring='YES' ;4.在一段时间之后。对不使用的索引进行invisible处理(目的：让CBO产生执行计划的时候，排除该索引)。
select * from DBA_HIST_SQL_PLAN t where object_type like '%INDEX%' and object_name=<index_name>; ---在invisible处理之前，检查该索引被哪些sql语句使用
alter index <index_name> invisible; ---对索引进行invisible处理。建议一次invisible少量索引，然后监控系统运行状态。
来源：https://www.cnblogs.com/erwadba/p/8041158.html