Querying RESOURCE_VIEW using /Resource/XMLRef as key

Question

Hi:
I am trying to query resource_view efficiently but instead of using equals_path or under_path which uses the domain index XDB.XDBHI_IDX using /Resource/XMLRef column.
For example, for a resource stored in a object relational table with a registered schema:
select extractValue(res,'/Resource/VCRUID'),any_path from resource_view
where extractValue(res,'/Resource/XMLRef')=make_ref(cms_docs,'27F5F5642ACA600AE040A8C00301464E');I am getting this execution plan:
| Id  | Operation                   | Name         | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT            |              |     1 |   152 |     9   (0)| 00:00:01 |
|*  1 |  TABLE ACCESS BY INDEX ROWID| XDB$RESOURCE |     1 |   152 |     9   (0)| 00:00:01 |
|*  2 |   DOMAIN INDEX              | XDBHI_IDX    |     1 |       |            |          |
Predicate Information (identified by operation id):
   1 - filter("P"."SYS_NC00024$"=MAKE_REF("CMS_DOCS",HEXTORAW('27F5F5642ACA600AE040A
              8C00301464E') ))
   2 - access("XDB"."UNDER_PATH"(SYS_MAKEXML('8758D485E6004793E034080020B242C6',734,
              "XMLEXTRA","XMLDATA"),'/',9999)=1)
17 rows selected.For a query using sys_op_r2o operator, used to create the index XDB.XDB$RESOURCE_OID_INDEX on XDB$RESOURCE table:
select extractValue(res,'/Resource/VCRUID'),any_path from resource_view
where sys_op_r2o(extractValue(res,'/Resource/XMLRef'))=hextoraw('27F5F5642ACA600AE040A8C00301464E');I am getting a similar execution plan:
| Id  | Operation                   | Name         | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT            |              |     1 |   152 |     9   (0)| 00:00:01 |
|*  1 |  TABLE ACCESS BY INDEX ROWID| XDB$RESOURCE |     1 |   152 |     9   (0)| 00:00:01 |
|*  2 |   DOMAIN INDEX              | XDBHI_IDX    |     1 |       |            |          |
Predicate Information (identified by operation id):
   1 - filter("P"."SYS_NC00024$"=HEXTORAW('27F5F5642ACA600AE040A8C00301464E') )
   2 - access("XDB"."UNDER_PATH"(SYS_MAKEXML('8758D485E6004793E034080020B242C6',734,
              "XMLEXTRA","XMLDATA"),'/',9999)=1)
16 rows selected.What a I am doing wrong :(
Best regards, Marcelo.

Answer 1

Hi:
Gathering the stats with null solve the problems, here the commands logged as XDB:
SQL> begin
  2 DBMS_STATS.GATHER_TABLE_STATS (
  3   ownname => 'XDB',
  4   tabname => 'XDB$RESOURCE',
  5   estimate_percent =>  null);
  6 end;
  7 /
SQL> begin
  2  DBMS_STATS.GATHER_INDEX_STATS (
  3    ownname => 'XDB',
  4    INDNAME => 'XDBHI_IDX',
  5    estimate_percent => null);
  6    end;
  7   /
SQL> begin
  2  DBMS_STATS.GATHER_INDEX_STATS (
  3    ownname => 'XDB',
  4    INDNAME => 'XDB$RESOURCE_OID_INDEX',
  5    estimate_percent => null);
  6  end;
  7  /Many thanks for the hint. Marcelo.
PD: I tested it on 11g beta 4 Linux 32