Refreshing Materialized View and (Bitmap) indexes

In my data warehouse I have an MV that is re-built every night.
1. Initially it was fully refreshed, but dropping and re-creating was shown to be quicker as a general rule
2. It was sometimes sensitive to changes in the underlying objects
3. Its has union alls in it so is complex
It has 6 indexes (4 bitmap and 2 b-tree) built on it which take between 8 and 20 minutes each to create. I would like to reduce this time. I'm already doing the index creation as parallel jobs.
I can re-organise the underlying tables so that the MV is no longer complex, and put an MV log on, to enable a fast refresh. Then, ideally, the indexes can be permanent But I know that bitmap indexes don't like certain changes (they can multiply in size an become unusable). Does this include refreshes of MVs? If it does I might be able to switch to b-tree indexes as our report performance is well within the allowable window, unlike my nightly ETL.
The MV has 160M rows in it and the rate of change is rarely more than 1%/day
I'm on 9i

<Initially it was fully refreshed, but dropping and re-creating was shown to be quicker as a general rule >
Huh? I wouldn't think that a drop and recreate would be any faster, but won't argue with your results. I assume the same events happen for both and take the same amount of time, with the drop/refresh promoting fragmentation.
< It was sometimes sensitive to changes in the underlying objects >
Yup. All kinds of views are, even real ones. I've found that on 10g MVs are also very tempermental
< Simplest answer from me is that I will go for a fast refresh with MV logs. >
I'm not sure you can fast refresh a query with UNIONS. There's a list of restrictions for fast refreshes that's so long I can't keep track of all the rules.
< would you drop and recreate the bitmp indexes either side of the fast refresh? >
If you're doing a fast refresh you shoud not need to.
You might also consider using the NOLOGGING option on index dropping recreation, used to turn archivel logging off. Since you won't be restoring a failed index creation in case of database failure anyway it should be fairly safe.
Also, when creating the bitmaps make sure you're allocating enough memory to the process. Check your initialization/session parameters, particularly the ones pertianing to bitmap indexes.
Message was edited by:
riedelme

Similar Messages

Materialized View and I_SNAP$ Indexes

Hello Everybody,
At the time of doing REFRESH of the Materialized View, we are getting error like -
SQL> EXECUTE DBMS_MVIEW.REFRESH('MV_TEST.MY_VIEW,'CF');
BEGIN DBMS_MVIEW.REFRESH('MV_TEST.MY_VIEW,'CF'); END;
ERROR at line 1:
ORA-12008: error in materialized view refresh path
ORA-00001: unique constraint (MV_TEST.I_SNAP$_FIN_RESULT_EXPENSE1) violated
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2545
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2751
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2720
ORA-06512: at line 1
I tried to drop and recreate the index I_SNAP$_FIN_RESULT_EXPENSE1 but it didn’t helped.
Later I dropped the index I_SNAP$_FIN_RESULT_EXPENSE1 and refreshed the materialized view and it was successful (obvious). But when I tried to recreate the index, I got the following error –
SYS_OP_MAP_NONNULL("FIN_MULT"), SYS_OP_MAP_NONNULL("FIN_CD"))
ERROR at line 8:
ORA-01452: cannot CREATE UNIQUE INDEX; duplicate keys found
When I look at the value of SYS_OP_MAP_NONNULL('FIN_CD'), it seems to be unique.
SQL> select SYS_OP_MAP_NONNULL('FIN_CD') from dual;
SYS_OP_MAP_NONNULL('FIN_CD’)
46494E5F5650545F4C564C5F335F434400
My questions are:
1.     Why are the indexes (I_SNAP$_*) automatically created for?
2.     What is the purpose of these (I_SNAP$_*) indexes?
3.     What harm can be there if we drop these (I_SNAP$_*) indexes?
4.     Why it is complaining about the Duplicate records / Uniqueness?
5.     How to know where exactly the problem is in this case?
6.     What is the solution for this problem? How to recreate these indexes successfully?
Thanks!

Hello Rafi,
I don't have any MLOG$_<table> in the database, After connecting as SYS -
SQL> select tname from tab where tname like '%MLOG%';
TNAME
MLOG_REFCOL$
MLOG$
C_MLOG#
SQL> select count(*) from mlog$;
COUNT(*)
0
I am not using Replication here -
SQL> select tname from tab where tname like '%RUPD%';
no rows selected
Why you think that granting SELECT access to MLOG$_* tables will solve this issue?
Thanks,
Roopesh

Issue with materialized view and fast refresh between Oracle 10g and 11g

Hi all,
I've hit a problem when trying to create a fast-refreshable materialized view.
I've got two databases, one 10.2.0.10, another 11.2.0.1.0, running on 32-bit Windows. Both are enterprise edition, and I'm trying to pull data from the 10g one into the 11g one. I can happily query across the database link from 11g to 10g, and can use complete refresh with no problem except the time it takes.
On the 10g side, I've got tables with primary keys and m.v. logs created, the logs being of this form ...
CREATE MATERIALIZED VIEW LOG ON table WITH PRIMARY KEY INCLUDING NEW VALUES
On the 11g side, when I try to create an m.v. against that ...
CREATE MATERIALIZED VIEW mv_table REFRESH FAST WITH PRIMARY KEY AS SELECT col1, col2 FROM table@dblink;
... I get an ORA-12028 error (materialized view type is not supported by master site).
After running the EXPLAIN_MVIEW procedure it shows this;
REFRESH_FAST_AFTER_INSERT not supported for this type mv by Oracle version at master site
A colleague has managed to build a fast-refresh m.v. from the same source database, but pulling to a different one than I'm using; his target is also 10g, like the (common) source, so I've no idea why I'm getting the 'not supported' message whilst he isn't.
I've been able, on previous projects, to do exactly what I'm trying to achieve but on those someone with more knowledge than me has configured the database!
I'm now stumped. I'm also no DBA but despite that it's been left to me to install the new 11g database on the 32-bit Windows server from scratch, so there are probably a couple of things I'm missing. It's probably something really obvious but I don't really know where to look now.
If anyone can give me any pointers at all, I'd be really grateful. This question is also duplicated in the Replication forum but hasn't had any replies as yet, so I'm reproducing it here in hope!
Thanks in advance,
Steve

Hi Steve,
You should have a look at metalink, Doc ID 1059547.1
If that does not help, there may be something else in Mater note ID 1353040.1
Best regards
Peter

Need to refresh materialized view from procedure and pl/sql block

Hi,
I need to refresh materialized view (complete refresh)from procedure and pl/sql block .can some one help.
MV name:MV_DGN_TEST_SESSION
Thanks,
Rajasekhar

dbms_mview.REFRESH ('MV_DGN_TEST_SESSION', 'C');Regards,
Mahesh Kaila
Edited by: user4211491 on Dec 1, 2009 10:41 PM

Error While Creating Fast Refresh Materialized view.

Table Scripts:
CREATE TABLE CONTRACT_MASTER
CONTRACT_SEQ                    NUMBER(10)    NOT NULL,
PDN                             CHAR(5)       NOT NULL,
APPID                           NUMBER(10)    NOT NULL,
CONTRACT_LOB_DESC               VARCHAR2(20) NOT NULL,
CUSTOMER_NAME                   VARCHAR2(57) NOT NULL,
CONTRACT_DT                     DATE          NOT NULL,
CONTRACT_RECD_DT                DATE          NOT NULL,
HELD_OFFERING_DT                DATE          NOT NULL,
DRAFT_AMT                       NUMBER(15,2) NOT NULL,
STATUS_DESC                                   VARCHAR2(20) NOT NULL,
GIF_UPLOAD_TM                                            TIMESTAMP     NOT NULL
CREATE table CONTRACT_COMMENTS
CONTRACT_COMMENTS_SEQ           NUMBER(10)     NOT NULL,
APPID                           NUMBER(10)     NOT NULL,
COMMENTS                        VARCHAR2(1000) NOT NULL,
GIF_UPLOAD_TM                                            TIMESTAMP      NOT NULL
Constraints on tables
ALTER TABLE CONTRACT_MASTER ADD
CONSTRAINT XPKCONTRACT_MASTER PRIMARY KEY (CONTRACT_SEQ) USING INDEX ;
ALTER TABLE CONTRACT_COMMENTS ADD
CONSTRAINT XPKCONTRACT_COMMENTS PRIMARY KEY (CONTRACT_COMMENTS_SEQ) USING INDEX ;
alter table CONTRACT_MASTER add CONSTRAINT XUIAPPCONTRACT_MASTER UNIQUE (APPID) USING INDEX;
CREATE INDEX XUIAPPCONTRACT_COMMENTS ON
CONTRACT_COMMENTS(APPID) ;
Materialized View Creation:
CREATE MATERIALIZED VIEW LOG ON CONTRACT_MASTER WITH PRIMARY KEY,ROWID;
CREATE MATERIALIZED VIEW LOG ON CONTRACT_COMMENTS WITH PRIMARY KEY, ROWID;
CREATE MATERIALIZED VIEW MV_CONTRACT_COMMENTS_HELDOFFERING
REFRESH FAST
ENABLE QUERY REWRITE AS
SELECT APPID,COMMENTS FROM CONTRACT_COMMENTS WHERE APPID IN (
SELECT APPID FROM CONTRACT_MASTER WHERE STATUS_DESC = 'Held Offering' )
Errors generated:
ERROR at line 4:
ORA-12015: cannot create a fast refresh materialized view from a complex query
_*Afer That I have changed the query but still it was not created like:*_
CREATE MATERIALIZED VIEW MV_CONT_COMMNTS_HELDOFFERNG
REFRESH FAST
ENABLE QUERY REWRITE AS
SELECT CONTRACT_COMMENTS_SEQ,c.APPID,COMMENTS
FROM CONTRACT_COMMENTS c,CONTRACT_MASTER m
WHERE m.APPID = c.APPID and m.STATUS_DESC = 'Held Offering'
*even though error displayed:
SQL> CREATE MATERIALIZED VIEW MV_CONT_COMMNTS_HELDOFFERNG*
   2 REFRESH FAST
   3 ENABLE QUERY REWRITE AS
   4 SELECT CONTRACT_COMMENTS_SEQ,c.APPID,COMMENTS
   5 FROM CONTRACT_COMMENTS c,CONTRACT_MASTER m
   6 WHERE m.APPID = c.APPID and m.STATUS_DESC = 'Held Offering';
FROM CONTRACT_COMMENTS c,CONTRACT_MASTER m
ERROR at line 5:
ORA-12052: cannot fast refresh materialized view GSSIO.MV_CONT_COMMNTS_HELDOFFERNG
*Again I have done "Analyzing Materialized Views for Fast Refresh" as follows:*
1: exec dbms_mview.explain_mview('MV_CONT_COMMNTS_HELDOFFERNG');
2: SELECT capability_name, possible, SUBSTR(msgtxt,1,60) AS msgtxt
           FROM mv_capabilities_table
           WHERE capability_name like '%FAST%';
Output is :
CAPABILITY_NAME                               P              MSGTXT
REFRESH_FAST                                   N
REFRESH_FAST_AFTER_INSERT            N the SELECT list does not have the rowids of all the detail t
REFRESH_FAST_AFTER_ONETAB_DML   N see the reason why REFRESH_FAST_AFTER_INSERT is disabled
REFRESH_FAST_AFTER_ANY_DML         N see the reason why REFRESH_FAST_AFTER_ONETAB_DML is disabled
REFRESH_FAST_PCT                            N PCT is not possible on any of the detail tables in the mater
Please suggest what to do to implement fast refresh materialized view for same.Edited by: dba on Sep 20, 2010 12:00 AM

If the two MVs have to be consistent with each other as of a specific time, put them into a Refresh Group and refresh them with DBMS_MVIEW.REFRESH
If an MV is dependent on another, use DBMS_MVIEW.REFRESH_DEPENDENT
See the "Oracle® Database PL/SQL Packages and Types Reference" documentation pages for DBMS_MVIEW.
Hemant K Chitale
http://hemantoracledba.blogspot.com --- this is NOT a documentation site.
Edited by: Hemant K Chitale on Sep 20, 2010 5:19 PM

Materialized view and Partition

Hi,
I want to discuss a scenario, with which i am dealing nowadays. there is only a single table (named livecdr ) has 22-23 fields and the records are updating in every sec (on daily basis) and in 24hrs livecdr contains approximately more than 2 crore records.
Problem is that the query processing time is so slow due to large number of records and query is fetching records from a view created on livecdr table. I want to know the options, how the query would fetch these records in a short time. Firstly i did range partitioning on livecdr and then i created materlized view but the view didn't create on partition table and when i removed partitioning it was created. After view creation, query performance is much better. i also applied indexing on livecdr.
Can you please tell me, whether this approach is okay or i am doing mistake. should i create partitioning on materialized view and how would i select records from view if partitioning would be applied on materialized view. Please guide me with best approaches.
thankyou.

Hello,
Here is how I created partitioned table (monthly partitions) and partitioned mview on the table. This is just an example you might have to change the mview partitions from monhtly to yearly or quartely.
CREATE TABLE live_cdr
   CALLID              VARCHAR2 (20),
   CD                  VARCHAR2 (25),
   CG                  VARCHAR2 (25),
   RE                  VARCHAR2 (25),
   OPC                 VARCHAR2 (12),
   DPC                 VARCHAR2 (12),
   STIME               VARCHAR2 (25),
   SDATE               DATE,
   ATIME               VARCHAR2 (25),
   ADATE               DATE,
   ETIME               VARCHAR2 (25),
   EDATE               DATE,
   schangeTime         VARCHAR2 (25),
   schangeDate         DATE,
   STATUS              VARCHAR2 (25),
   bucket              NUMBER (20),
   CIC                 NUMBER (20),
   charge              VARCHAR2 (30),
   ported              VARCHAR2 (30),
   jurisdiction_Info   VARCHAR2 (30),
   origLine_Info       CHAR (1),
   Variant             NUMBER,
   auto_inc            NUMBER
PARTITION BY RANGE (EDATE)
PARTITION LIVE_CDR_JAN_2009 VALUES LESS THAN (TO_DATE(' 2009-02-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN'))
    LOGGING
    NOCOMPRESS,
PARTITION LIVE_CDR_FEB_2009 VALUES LESS THAN (TO_DATE(' 2009-03-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN'))
    LOGGING
    NOCOMPRESS
);Mview definition
CREATE MATERIALIZED VIEW KLONDIKE.LIVE_CDR_MV
LOGGING
PARTITION BY RANGE (EDATE)
PARTITION LIVE_CDR_MV_JAN_2009 VALUES LESS THAN (TO_DATE('20090201',
      'YYYYMMDD'))
    LOGGING
    NOCOMPRESS,
PARTITION LIVE_CDR_MV_FEB_2009 VALUES LESS THAN (TO_DATE('20090301',
      'YYYYMMDD'))
    LOGGING
    NOCOMPRESS
BUILD IMMEDIATE
REFRESH COMPLETE
START WITH SYSDATE
NEXT SYSDATE + 2 /24
AS
SELECT   DISTINCT (ic.callid) callid,
                  ic.CG,
                  ic.CD,
                  ic.RE,
                  ic.OPC,
                  ic.DPC,
                  ic.SDATE,
                  ic.STIME,
                  ac.ADATE,
                  ac.ATIME,
                  ec.ETIME,
                  ec.EDATE,
                  ec.STATUS
FROM   live_cdr ic, live_cdr ac, live_cdr ec
WHERE       ic.callid = ac.callid
         AND ic.callid = ec.callid
         AND ic.stime = ac.stime
         AND ic.stime = ec.stime
         AND ic.sdate = ac.sdate
         AND ic.sdate = ec.sdate
         AND ac.ADATE IS NOT NULL
         AND ec.EDATe IS NOT NULL
         AND ec.etime IS NOT NULL
         AND ic.CD IS NOT NULL
         AND ic.cg IS NOT NULL;Regards

Questions on Materialized Views and MV Log tables

Hello all,
Have a few questions with regards to Materialized View.
1) Once the Materialized View reads the records from the MLOG table the MLOG's records get purged. correct? or is it not the case? In some cases I still see (old) records in the MLOG table even after the MV refresh.
2) How does the MLOG table distinguish between a read that comes from an MV and a read that comes from a user? If I manually execute
"select * from <MLOG table>" would the MLOG table's record get purged just the same way as it does after an MV refresh?
3) One of our MV refreshes hangs intermittently. Based on the wait events I noticed that it was doing a "db file sequential read" against the master table. Finally I had to terminate the refresh. I'm not sure why it was doing sequential read on the master table when it should be reading from the MLOG table. Any ideas?
4) I've seen "db file scattered read" (full table scan) in general against tables but I was surprised to see "db file sequential read" against the table. I thought sequential read normally happens against indexes. Has anyone noticed this behaviour?
Thanks for your time.

1) Once all registered materialized views have read a particular row from a materialized view log, it is removed, yes. If there are multiple materialized views that depend on the same log, they would all need to refresh before it would be safe to remove the MV log entry. If one of the materialized views does a non-incremental refresh, there may be cases where the log doesn't get purged automatically.
2) No, your query wouldn't cause anything to be purged (though you wouldn't see anything interesting unless you happen to implement lots of code to parse the change vectors stored in the log). I don't know that the exact mechanism that Oracle uses has been published, though you could go through and trace a session to get an idea of the moving pieces. From a practical standpoint, you just need to know that when you create a fast-refreshable materialized view, it's going to register itself as being interested in particular MV logs.
3) It would depend on what is stored in the MV log. The refresh process may need to grab particular columns from the table if your log is just storing the fact that data for a particular key changed. You can specify when you create a materialized view log that you want to store particular columns or to include new values (with the INCLUDING NEW VALUES) clause. That may be beneficial (or necessary) to the fast refresh process but it would tend to increase the storage space for the materialized view log and to increase the cost of maintianing the materialized view log.
4) Sequential reads against a table are perfectly normal-- it just implies that someone is looking at a particular block in the table (i.e. looking up a row in the table by ROWID based on the ROWID in an index or in a materialized view log).
Justin

Reg:package code to refresh materialized views

i am new to pl/sql packages and procedures.i want it to execute for running mappings in informatica which takes 0 and gives 1 when executed successfully
create or replace PACKAGE BODY pkg_refresh_mv as
procedure prc_mv (p_mv_name varchar2) is
begin
dbms_mview.refresh (p_mv_name);
end prc_mv;
procedure refresh_all_mv (proc_response IN OUT number) is
begin
dbms_mview.refresh('materialized view','C');
dbms_mview.refresh('materialized view','C');
proc_response := 1;
exception
when others then
proc_response := 0;
end refresh_all_mv ;
end pkg_refresh_mv;
when i execute this code i get the following errors
PLS-00201: identifier 'PKG_REFRESH_MV' must be declared
PLS-00304: cannot compile body of 'PKG_REFRESH_MV' without its specification
what needs to be changed
thanks

try this one :
CREATE OR REPLACE PACKAGE pkg_refresh_mv
AS
   PROCEDURE prc_mv (p_mv_name VARCHAR2);
   PROCEDURE refresh_all_mv (proc_response IN OUT NUMBER);
END pkg_refresh_mv;
CREATE OR REPLACE PACKAGE BODY pkg_refresh_mv
AS
   PROCEDURE prc_mv (p_mv_name VARCHAR2)
   IS
   BEGIN
      dbms_mview.refresh (p_mv_name);
   END prc_mv;
   PROCEDURE refresh_all_mv (proc_response IN OUT NUMBER)
   IS
   BEGIN
      dbms_mview.refresh ('materialized view', 'C');
      dbms_mview.refresh ('materialized view', 'C');
      proc_response := 1;
   EXCEPTION
      WHEN OTHERS
      THEN
         proc_response := 0;
   END refresh_all_mv;
END pkg_refresh_mv;
/

Refresh Materialized View in a package

Refresh Materialized View in a process.
I have a USER2.Materialized view and when I want to refresh it I execute:
execute dbms_mview.refresh('MV_FACT_SALES','C');
But I have the ETL process in a USER1.package
The User1 needs any Materialized View Grant or any privilegie?
How can I refresh the Materialized View in a procedure in the USER1.package?

I 'm sorry, but I want to create a procedure under USER2 and when I execute the script to create it I receive the error:
ORA-06550: line 4, column 12:
PLS-00103: Encountered the symbol "DBMS_MVIEW" when expecting one of the following:
:= . ( @ % ; immediate
The symbol ":=" was substituted for "DBMS_MVIEW" to continue.
Te script procedure is:
PROCEDURE REFRESH_MV IS
BEGIN
execute dbms_mview.refresh('MV_FACT_SALES','C');
END;
How can I refresh a Materialized view in a procedure?
Thanks!

Creation of fast refresh materialized view

Hi,
I am creating fast refreshable materialized view.At that time i am getting error message
ORA-12052: cannot fast refresh materialized view OPS$QDW.EMP_DEPT_MV
I created log's also on that tables(emp,dept)
Please Help me any body.
I am using oracle 8.1.7.4.0
below the scripts i created
CREATE MATERIALIZED VIEW LOG ON emp
tablesspace vijay_test
WITH ROWID
INCLUDING NEW VALUES
CREATE MATERIALIZED VIEW LOG ON DEPT
tablesspace vijay_test
WITH ROWID
INCLUDING NEW VALUES
CREATE MATERIALIZED VIEW emp_dept_mv
TABLESPACE vijay_test
BUILD IMMEDIATE
REFRESH FAST
ENABLE QUERY REWRITE
as
select e.ename,e.empno,e.deptno,d.loc from emp e, dept d
where e.deptno=d.deptno

It will be possible to create a Materialised view with up to 20 tables, but you have to understand the restrictions on complex Materialised views with regards to fast refresh.
To help your understanding, refer to Materialized View Concepts and Architecture
<br>
Oracle Database FAQs
</br>

Creation of Materialized view and Materialized view log.

I wanted to create materialized view with 'REFRESH FAST ON COMMIT' option.
1) Table1 --it is partitioned range + list -- Added primary key
2) view1   -- having primary keys on view's base table
Steps:
1) create materialized view log on Table1 ; -- default primary key
2) create materialized view log on view1. --- It is giving below error.
ORA-00942: table or view does not exist
i wanted to create Materialized view like below
create materialized view
REFRESH fast ON commit
as
select ...
... from table1
where c1 in (select c1 from view1 where ... );
Question:
1) As i am getting above error while creating MV log on view. Can we create MV log on view or we have to create MV log on view base table?
2) To create MV with ''REFRESH FAST ON COMMIT' option , do we need to have primary key on master tables?
Any pointers on this will really helpful.
Thanks
Prasad

Also created MV LOG on 3 tables and tried with joins ..
create materialized view
REFRESH fast ON commit
as
select ...
... from table1 , tab2 t2,tab3 t3
where ....
and ...
Get same error ORA-12052: cannot fast refresh materialized view AVSYS.EVENT_LOG_MV
2052. 00000 - "cannot fast refresh materialized view %s.%s"
*Cause:    Either ROWIDs of certain tables were missing in the definition or
           the inner table of an outer join did not have UNIQUE constraints on
           join columns.
*Action:   Specify the FORCE or COMPLETE option. If this error is got
           during creation, the materialized view definition may have be
           changed. Refer to the documentation on materialized views.

Unable to refresh Materialized view group when an Mview is added

Hi,
I have 8 MVs present in my DB and added them to a MV refresh group. But I am getting the error below when I try to refresh the group.
SQL> exec DBMS_REFRESH.refresh('MVRFRSHGRP_EAIGHD');
begin DBMS_REFRESH.refresh('MVRFRSHGRP_EAIGHD'); end;
ORA-12048: error encountered while refreshing materialized view "MYUAT"."MV_EAI_PJRM_EMP_ALLOC_DTLS"
ORA-12018: following error encountered during code generation for "MYUAT"."MV_EAI_PJRM_EMP_ALLOC_DTLS"
ORA-00942: table or view does not exist
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2563
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2776
ORA-06512: at "SYS.DBMS_IREFRESH", line 685
ORA-06512: at "SYS.DBMS_REFRESH", line 195
ORA-06512: at line 1
SQL> Actually the view MV_EAI_PJRM_EMP_ALLOC_DTLS exists and MVlog$ are present at source site.
When I remove this view from the group, I am able to refresh it successfully.
I destroyed the group, recreated and added all the views and tried. But no luck.
Can some one suggest what could be the problem?
Regards
Deep

Hi,
You didn't leave a version (Again), so I can only guess.
You may be suffering from
Bug 10096159 ORA-12048 error message raised by DBMS_REFRESH.REFRESH is not corrrect
Meaning it could be a different MV that fails to refresh.
Regards
Peter
Edit:
Versions confirmed as being affected (There could be others, mind)
11.2.0.1
11.1.0.7
10.2.0.5
10.2.0.3
Edited by: Peter on Sep 4, 2012 8:45 AM

Materialized Views and Substr ?

Hi,
I'm currently trying to create a materialized view that can be fast refreshed, but it complains each time. I think it's because I'm using a constraint substr(x,1,10) so complete refreshes are all that can be done?
My steps are :
create materialized view log on a_table with rowid;
create materialized view log on b_table with rowid;
create materialized view log on c_table with rowid;
create materialized view log on d_table with rowid;
and the materialized view is
create materialized view MY_VIEW
build immediate
enable query rewrite
REFRESH FAST
as
SELECT bt.mid AS mid, ct.imid AS imid, bt.iid AS iid, vendor_name AS make, at.dname AS dname, bt.timestamp AS timestamp
          FROM b_table bt, c_table ct, d_table dt, a_table at
               WHERE bt.mid=ct.mid
                    AND substr(bt.iid,1,5)=dt.val1
                    AND at.profile_id=dt.profile_id
          order by bt.timestamp desc;
ORA-12052: cannot fast refresh materialized view MY_VIEW
I'm at a loss, I can make it without the fast refresh, but the table view is huge and updating it completely each time isn't going to work :(
Any help or suggestions would be greatly appreciated,
Regards,
Brian

Well, basically, you can relatively easily find it out yourself.
First, there is a very useful script $ORACLE_HOME/rdbms/admin/utlxmv.sql
You should execute under the same account as you create materialized views like this
@?/rdbms/admin/utlxmvThen you are prepared to check, whether your mv is fast refresheable and if not - why.
SQL> create table new_dept as select * from dept
2 /
Table created.
SQL> -- Now create table emp with new join column of type varchar2
SQL> create table new_emp as
2 select e.*,d.dname
3 from emp e,dept d
4 where e.deptno=d.deptno
5 /
Table created.
SQL> create materialized view log on new_emp with rowid
2 /
Materialized view log created.
SQL> create materialized view log on new_dept with rowid
2 /
Materialized view log created.
SQL> begin
2          dbms_mview.explain_mview('select e.*,d.loc
3                  from new_emp e,new_dept d
4                  where substr(d.dname,1,10)=e.dname');
5 end;
6 /
PL/SQL procedure successfully completed.
SQL> select capability_name,possible,msgtxt
2 from mv_capabilities_table
3 where capability_name like '%FAST%'
4 /
CAPABILITY_NAME                PO MSGTXT
REFRESH_FAST                   N
REFRESH_FAST_AFTER_INSERT      N the SELECT list does not have the rowids
                                   of all the detail tables
REFRESH_FAST_AFTER_ONETAB_DML N see the reason why REFRESH_FAST_AFTER_IN
                                  SERT is disabled
REFRESH_FAST_AFTER_ANY_DML     N see the reason why REFRESH_FAST_AFTER_ON
                                  ETAB_DML is disabled
REFRESH_FAST_PCT               N PCT is not possible on any of the detail
                                   tables in the materialized view
SQL> rollback
2 /
Rollback complete.
SQL> -- Now we know - for materialized view rowid of all involved in join tables
SQL> -- should be in the select list to make possible fast refresh
SQL> -- of course they should get proper aliases. Yet one attempt
SQL> begin
2    dbms_mview.explain_mview('select e.*,e.rowid erow_id,d.loc,d.rowid drow_id
3      from new_emp e,new_dept d
4      where substr(d.dname,1,10)=e.dname');
5 end;
6 /
PL/SQL procedure successfully completed.
SQL> select capability_name,possible,msgtxt
2 from mv_capabilities_table
3 where capability_name like '%FAST%'
4 /
CAPABILITY_NAME                PO MSGTXT
REFRESH_FAST                   Y
REFRESH_FAST_AFTER_INSERT      Y
REFRESH_FAST_AFTER_ONETAB_DML Y
REFRESH_FAST_AFTER_ANY_DML     Y
REFRESH_FAST_PCT               N PCT is not possible on any of the detail
                                   tables in the materialized view
SQL> -- Mission successful - refresh_fast is possibleBest regards
Maxim

ORA-12015: cannot create a fast refresh materialized view from a complex qu

BANNER
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
PL/SQL Release 11.2.0.1.0 - Production
CORE    11.2.0.1.0      Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - ProductionI'm trying to create a fast refresh materialized view that uses a column of xmltype. The problem is I cannot create an MV log that accounts for the xmltype column. I tried excluding it and got the above error. Is there another way I can incrementally update a materialized view where I don't have to do a COMPLETE refresh or use FAST refresh?
CREATE TABLE "DAS_DESC"."AUTHORITY_TEST"
    "NAID"      NUMBER(20,0) NOT NULL ENABLE,
    "AUTH_TYPE" VARCHAR2(40 BYTE),
    "XML_DATA" "SYS"."XMLTYPE" ,
    "TERM_NAME" VARCHAR2(4000 BYTE)
CREATE TABLE "DAS_DESC"."AUTH_ASSC_TEST"
    "NAID"    NUMBER(20,0),
    "P_NAID" NUMBER(20,0),
    "REL_TYPE"    VARCHAR2(25 BYTE),
    "XML_DATA" "SYS"."XMLTYPE"
CREATE
MATERIALIZED VIEW person_mv
AS
SELECT p.naid
      , p.auth_type
      , INSERTCHILDXML
          p.xml_data                 -- Parent XML Column
        , '//*[contains(local-name(), ''person'')]' --XPATH to Person
        , 'nonPreferredHeadingArray'                -- Value for new child element
        (                                                       -- Sub query for injecting new variant person array
          SELECT XMLELEMENT
            "nonPreferredHeadingArray"
          , XMLAGG -- Aggregator for Variant Persons Array
              XMLELEMENT
                "variantPersonName"                    -- Wrapper for each entry in array
              , extract(a.xml_data,'*/*')
          FROM auth_assc_table -- Link table
          WHERE a.p_naid = p.naid
      ) AS XML_DATA
FROM authority p -- Parent table
WHERE p.auth_type = 'Person';The views are created fine and they work perfectly for what we need. The problem is the refresh when we edit the base tables. Ideally, it should take a couple seconds. Right now, it takes a couple minutes. XMLTYPE is one problem and the Complex Query exception is the other. If there is a work-around for fast refresh, please let me know. Greatly appreciated.

jjmdb wrote:
I'm trying to create a fast refresh materialized view that uses a column of xmltype. The problem is I cannot create an MV log that accounts for the xmltype column. I tried excluding it and got the above error. Is there another way I can incrementally update a materialized view where I don't have to do a COMPLETE refresh or use FAST refresh? Besides XMLTYPE column, your MV definition has a subquery which prevents it from being fast refreshable.
I could not find any specific reference in documentation about restriction on XMLTYPE (or CLOB) columns but it seems logical that oracle will not be able to keep track of changes to binary data. What does DBMS_MVIEW.EXPLAIN_MVIEW generate for your MV definition? That should tell you which all conditions (for FAST REFRESH) your MV violates. Since you can not create a MV LOG to include XMLTYPE column, it will not be possible to create a FAST REFRESHABLE MV that includes the XMLTYPE column.
I am afraid there is not much you can do here unless you are prepared to change the way data is stored in your base tables. If you can store data in base tables using standard data types instead of binary/XML storage, you might be able to create a FAST REFRESHABLE MV.

ORA-12015: cannot create a fast refresh materialized view from a complex q

Hi,
I'm facing very strange problem. Please help me why this error is coming
I'm creating a simple materialized view, but it is giving below error since this is simple select * from.
CREATE MATERIALIZED VIEW EFMS.MS_TASK
BUILD IMMEDIATE
REFRESH FAST
START WITH SYSDATE
NEXT (SYSDATE + 1/24)
WITH ROWID
AS
SELECT * FROM MS_TASK@efms_link;
SELECT * FROM MS_TASK@efms_link
ERROR at line 8:
ORA-12015: cannot create a fast refresh materialized view from a complex query
CREATE MATERIALIZED VIEW LOG ON MSDBO.MS_TASK
TABLESPACE DBOR_MVLOG
PCTUSED 0
PCTFREE 60
INITRANS 20
MAXTRANS 255
STORAGE (
INITIAL 64K
MINEXTENTS 1
MAXEXTENTS UNLIMITED
PCTINCREASE 0
BUFFER_POOL DEFAULT
NOCACHE
NOLOGGING
PARALLEL ( DEGREE 2 INSTANCES 1 )
WITH ROWID, PRIMARY KEY
EXCLUDING NEW VALUES;

1º
Not is a best practice to use 'select *'
2º
ORA-12015: cannot create a fast refresh materialized view from a complex query
Cause: Neither ROWIDs and nor primary key constraints are supported for complex queries.
Action: Reissue the command with the REFRESH FORCE or REFRESH COMPLETE option or create a simple materialized view.
Then you have to change REFRESH FAST or create a primary key in MS_TASK@efms_link to avility fast refresh.
. :-) any help with my english is wellcome :-) .

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