Disabling Materialized View Logs for a session

Hi all.
I was wondering if it is possible to disable the fast refresh log for materialized views for just a given session. So for all other sessions except this one the log would be added to. I'm using 11g.
In Oracle Database 11g, The Complete Reference on page 447 it states:
"As of Oracle 11g, the capture of changes in materialized view logs can be disabled for an individual session while logging continues for changes made by other sessions". But no instructions are given
Does anyone know how to do this? I have not been able to find the answer by looking around.
Thanks!

Yeah, I had saw that Oracle mentioned it here also: http://download.oracle.com/docs/cd/B28359_01/server.111/b28279/chapter1.htm#FEATURENO07197
Any idea of what the code might look like? I've never had to alter an individual session for Oracle before.

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Materialized view logs for Fast refreshes

Hi,
I created MV and MV logs on the base table/main table. I set the base table in NOLOGGING MODE. so ofcourse redo is not gonna generate during DML but i wanted to know that:
Will NOLOGGING effect the MV logs for fast refreshes?
I came up on conclusion that MV logs are nothing to do with Redo Logs and would have no impact on MV logs for fast refresh since i have set my all base table in NOLOGGING MODE.
Looking forward for expert opinion.
REGARDS,

Though I'm not an expert...
SQL> alter table emp nologging;
Table altered.
SQL> create materialized view log on emp;
Materialized view log created.
SQL> select * from tab;
TNAME TABTYPE CLUSTERID
EMP TABLE
BONUS TABLE
SALGRADE TABLE
RUPD$_EMP TABLE
MLOG$_EMP TABLE
SQL> insert into emp values(1000,'Matt','Test',100,sysdate,1000,1000,10,11,11);
1 row created.
SQL> select *From mlog$_emp;
EMPNO SNAPTIME$ D O
CHANGE_VECTOR$$
1000 01-JAN-00 I N
FEFF

How to CREATE MATERIALIZED VIEW LOG (MV fast refresh) with some JOINS

Hi @ all,
i'm trying to create a MATERIALIZED VIEW LOG for a fast refresh of a MATERIALIZED VIEW.
It works fine with a simple Request in the MATERIALIZED VIEW:
CREATE MATERIALIZED VIEW MV_ZOTD43_P
TABLESPACE GDII
BUILD IMMEDIATE
REFRESH FORCE AS
SELECT * FROM ZOTD43_P;
COMMIT;
CREATE MATERIALIZED VIEW LOG ON ZOTD43_P
TABLESPACE "GDII"
WITH PRIMARY KEY, ROWID, SEQUENCE INCLUDING NEW VALUES;
call DBMS_MVIEW.REFRESH('MV_ZOTD43_P', 'f');
But when I use a complex SQL-Request with some JOINS (one of the Table with spatial Data) in the MATERIALIZED VIEW, I get an error:
CREATE MATERIALIZED VIEW MV_TEST
TABLESPACE GDII
BUILD IMMEDIATE
REFRESH FORCE AS
SELECT lptd04_p.sst_nr AS sst_nr,
lptd03_p.aaaa AS aaaa,
lptd04_geom.geom as geom
FROM lptd04_p lptd04_p
JOIN lptd01_p lptd01_p ON lptd01_p.cre_nr = lptd04_p.sst_nr
JOIN lptd04_geom ON lptd04_geom.sst_nr = lptd04_p.sst_nr
JOIN lptd03_p lptd03_p ON lptd03_p.lief_nr = lptd04_p.lief_nr;
COMMIT;
CREATE MATERIALIZED VIEW LOG ON LPTD04_P
TABLESPACE "GDII"
WITH PRIMARY KEY, ROWID, SEQUENCE INCLUDING NEW VALUES;
call DBMS_MVIEW.REFRESH('MV_TEST', 'f');
Error report:
SQL Error: ORA-12004: REFRESH FAST kann für Materialized View "GDI"."MV_GDI_SST_STAMM" nicht benutzt werden
ORA-06512: in "SYS.DBMS_SNAPSHOT", Zeile 2255
ORA-06512: in "SYS.DBMS_SNAPSHOT", Zeile 2461
ORA-06512: in "SYS.DBMS_SNAPSHOT", Zeile 2430
ORA-06512: in Zeile 1
12004. 00000 - "REFRESH FAST cannot be used for materialized view \"%s\".\"%s\""
*Cause: The materialized view log does not exist or cannot be used. PCT
refresh is also not enabled on the materialized view
*Action: Use just REFRESH, which will reinstantiate the entire table.
If a materialized view log exists and the form of the materialized
view allows the use of a materialized view log or PCT refresh is
possible after a given set of changes, REFRESH FAST will
be available starting the next time the materialized view is
refreshed.
Am I doing something wrong or is it not possible CREATE MATERIALIZED VIEW LOG when the MATERIALIZED VIEW got some JOINS?
Regards,
Greq

Thanks for the link Alessandro ,
the error seems something to do with the Column-Type SDO_GEOMETRY, so
i create a new thread in the Spatial Discussion forum:
FAST REFRESHing of Oracle Materialized Views containing SDO_GEOMETRY column
Regards,
Greq

Identifying updated column in materialized view logs

Hi all,
I created a materialized view log for a table with three columns(say colA,colB,colC). Is there any way to identify which column got updated among these three columns? through the entries in mat view logs?
any inputs on this ll be of great help.
Thanks in advance.
gopi

Can someone tell me about M_ROWS$$ column in Materialized view.
I am in confucion.

INCLUDING NEW VALUES in materialized view log

CREATE MATERIALIZED VIEW products_mv
REFRESH FAST ON COMMIT
AS SELECT SUM(list_price - min_price), category_id
FROM product_information
GROUP BY category_id;
Could anybody tell me why INCLUDING NEW VALUES are necessary in materialized view log for such an aggregate materialized view?
Thanks,
P.

Answer depends on your need; do you need these values on your mv log -
http://download.oracle.com/docs/cd/B19306_01/server.102/b14223/basicmv.htm#sthref545
Best regards.

Materialized view log timestamp

I'm arranging materialized view logs for my developers that need to collect just the delta of some tables.
I've created materialized view logs with option sequence so that they can have an additional ordering information.
They are now asking me if there is an option for collecting even the transaction timestamp.
I didn't find any thing better solution then adding a trigger on each mview log which writes sequence and timestamp on separate table.
I don't want to use this additional triggers. Is there an option/workaround on mview logs to gather even this transaction timestamp?
thanks in advance for your response,
Max

Ask your developers to add the TIMESTAMP column and trigger.

Overhead of Triggers VS Materialized View Logs

If I need to log INSERTs, UPDTEs, and DELETEs on a table - is there a difference in the overhead of doing so via triggers vs MV logs?
Thanks

You said that MV log is marginally more efficient than a trigger. I am curious why. In what way do they work differently under the hood?If the essence of discussion is only why MV log is more efficient than trigger than I think Justin has pointed out below good technical points i.e.
1.You don't have to pass control over to the PL/SQL engine.
2.You're also writing the binary data that you'd put in the redo logs rather than column level data.
And below text from docs :
Internal Trigger for the Materialized View Log
When changes are made to the master table or master materialized view using DML, an internal trigger records information about the affected rows in the materialized view log. This information includes the values of the primary key, rowid, or object id, or both, as well as the values of the other columns logged in the materialized view log. This is an internal AFTER ROW trigger that is automatically activated when you create a materialized view log for the target master table or master materialized view. It inserts a row into the materialized view log whenever an INSERT, UPDATE, or DELETE statement modifies the table's data. This trigger is always the last trigger to fire.http://docs.oracle.com/cd/B28359_01/server.111/b28326/repmview.htm#i30732
3.Trigger i.e. we are coding to track the changes, MV log i.e. tool/technology which is provided by Oracle itself; so definately "We are not that much capable to write the code which is equal or more efficient than Oracle itself right ?"
In fact, functionality of MV is Instead of Trigger, but under the cover, with near to Oracle's internals.
Regards
Girish Sharma

Is it possible to create materialized view log file for force refresh

Is it possible to create materialized view log file for force refresh with join condition.
Say for example:
CREATE MATERIALIZED VIEW VU1
REFRESH FORCE
ON DEMAND
AS
SELECT e.employee_id, d.department_id from emp e and departments d
where e.department_id = d.department_id;
how can we create log file using 2 tables?
Also am copying M.View result to new table. Is it possible to have the same values into the new table once the m.view get refreshed?

You cannot create a record as a materialized view within the Application Designer.
But there is workaround.
Create the record as a table within the Application Designer. Don't build it.
Inside your database, create the materialized with same name and columns as the record created previously.
After that, you'll be able to work on that record as for all other within the Peoplesoft tools.
But keep in mind do never build that object, that'll drop your materialized view and create a table instead.
Same problem exists for partitioned tables, for function based-indexes and some other objects database vendor dependant. Same workaround is used.
Nicolas.

Materialized View Log - Compress Clause for List Partition

Hi All,
In Syntax diagram it states that Compress Clause for List Partition of Materialized View Log is valid , but when we run any script with compress clause for list partition on Materialized view log then Database throws error as ORA-14020: this physical attribute may not be specified for a table partition
So in any chance we can have the compress clause for the partition of materialized view log.
Thanks in advance,
Manu.

The "CREATE MATERIALIZED VIEW LOG" syntax refers to the "Table Partitioning" section of the CREATE TABLE documentation.
The "Table Partitioning" section refers to "table_partition_description" which then refers to "table_compression". "table_compression" then states that you can specify compression for entire table in the physical_properties clause and for range partition / list partition in the "table_partition_description". The Restrictions section on Table Compression says "You cannot define table compression explicitly for hash partitions or hash and list subpartitions" which implies that you can define partition for list partitions.
Moreover, error 14020 lists valid options for Range or Composite Range and for Hash partitoins -- which implies that all other Table physical attributes are applicable for List partitions. (But then, is Compression a physical attribute -- it is really part of "physical properties" not "physical attributes").
I think that the documentation isn't explicit enough and needs to be fixed.
N.B : Referencing the 10.2 documentation.
Hemant K Chitale
Edited by: Hemant K Chitale on Feb 1, 2010 4:12 PM

Materialized View Log table with sequence

I have a materialized view log in Database A..a very simple one...similar to "create materialized view log on t WITH PRIMARY KEY"...The primary key is a composite key of 2 columns...Description of the mlog table looks like this...
desc mlog$_t
emp_ctr NUMBER
emp_date DATE
SNAPTIME$$ DATE
DMLTYPE$$ VARCHAR2(1)
OLD_NEW$$ VARCHAR2(1)
CHANGE_VECTOR$$ RAW(255)
The Materialized view is in database B...again a simple one...no aggregation...This gets refreshed on demand manually evey week. The records that get accumulated in the MLOG every week is ~ 300K..The manual refresh used to finish in about 20mins but since last week it is running for ever. Upon reviewing the contents of MLOG I noticed that it contained a mixture of inserts and updates. I'm not sure if the MLOG contanied only inserts in the past when the MV used to refresh very quickly...Based on the documentation, Oracle recommends creating MLOGS with "sequence" whenever inserts/updates/deleted are expected. I'm planning to drop and recreate the MLOG with sequence with the hope that this would fix the slow refresh issue...Appreciate if you could let me know your thoughs...
I'm also planning to trace the session to get some wait event statistics to find out the reason for the slow refresh...

There are a few reasons why refreshes slow down over time.
1. Is the log table being cleared out after a refresh? If not, you may have another mview (maybe even one that doesn't exist any more) registered against this log. When this happens, the log table never stops growing.
2. How big is the segment occupied by the table? If it has grown very large at some time in the past (e.g., because refresh was delayed), then when the refresh does a FTS on the log it will scan the whole segment - even if only a few rows are present.
3. It may help to add an index to the PK columns, and another to SNAPTIME$$. Without them, the refresh will FTS the log. For a big segment, that can take a long time.
-- Phil

Materialized View Log not empty

Hello all
I have an oracle database (11g version), connecting via dbLink to another DB (10g version), and using it's tables as masters for fast refresh materialized views.
To make it simple: I have master DB, with master table X, and Materialized View Log MLOG$_X.
Then, I have replicate DB, with dblink pointing to Master, and Materialized View MV_X, using X.
The materialized view is refreshed fast, on demand.
The problem is, the MV log is never getting empty... how can I solve this issue?
/* code for creating MView */
CREATE MATERIALIZED VIEW "MY_USER"."SI_BANK" ("ID", "NAME", "ACRONYM")
ORGANIZATION HEAP PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE(INITIAL 163840 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "USERS"
BUILD IMMEDIATE
USING INDEX
REFRESH FAST ON DEMAND START WITH sysdate+0 NEXT SYSDATE + 1
WITH PRIMARY KEY USING DEFAULT LOCAL ROLLBACK SEGMENT
USING ENFORCED CONSTRAINTS DISABLE QUERY REWRITE
AS SELECT ibanco id, nbanco name, nsigla acronym FROM USER.tgtbanc0@DB_LINK;
/* code for refresh group*/
BEGIN
DBMS_REFRESH.MAKE ( name => 'si2p_grp',
list => '', next_date => 'SYSDATE +1' , interval => 'SYSDATE + 1', implicit_destroy => FALSE, rollback_seg => '', push_deferred_rpc => TRUE, refresh_after_errors => FALSE);
END;
/* ADD MATERIALIZED VIEWS TO GROUP */
BEGIN
DBMS_REFRESH.ADD ( name => 'si2p_grp', list => 'SI_BANK', lax => TRUE);
END;
Thank you for any help

One MV log serve to many materialized views. Check dba_registered_mviews on master DB to see how many MViews you have build on you master table X.
After MV (materialized view) is refreshed than all data logged in MVlog for this MV are deleted. But new are recorded when DML are performed against table X.
If you can stop DML on table X for some period of time then do MV refresh and then you can see that MVlog is empty.

Creating a Materialized View Log After the Data has been instered

Hi,
I am trying to create a method of replication from Oracle to MySQL using the Materialized View Log table.
This has been done before and works quite well, the only problem is that I am trying to impliment the log after the table has been created and populated and wish to push all the existing data through the log file...
Does anyone know if it is possible to refresh the Materialized View Log and not a Materialized View.
The way the replication is intended to work is:
Oracle> Data inserted into table
Oracle> writes the vector data to the MVL
Script> Monitors the MVL and can see the changes being made to the Oracle Table
Script> Updates MySQL with the data and removes the rows from the MVL
MySQL is then used with other unix systems
Currently we export the data from the table using Triggers and a cronjob running every x minute to check for changes in the TriggerTables
Many thanks for your time on this, I have been checking for almost a whole working day and not found the answer to this problem.

Thats what I thought, the MVL will only read data that has changed since it was created and wont have the option to load in all the data as though it was made before the table was created.
From what I have read, the MVL is quicker than a Trigger and I have some free code that prooved to work from a MVL using it as a reference to know what records to update. There is not that much to a MVL, a record ID and type of update, New, Update or Delete.
I think what I will have to do is work on a the same principle for the MVL but use a Trigger as this way we can do a full reload if required at any point.
Many thanks for your help.

Materialized view (fast refresh mode) + Materialized view log on another DB

Hi all,
I created a materizalied view using this script :
CREATE MATERIALIZED VIEW GIPS.DOSSIER_MEDICAL_MV2
TABLESPACE GIPS_T
NOCACHE
NOLOGGING
NOCOMPRESS
NOPARALLEL
BUILD IMMEDIATE
USING INDEX
TABLESPACE GIPS_I
+ REFRESH FAST ON DEMAND +
START WITH TO_DATE('11-janv.-2011 16:00:00','dd-mon-yyyy hh24:mi:ss')
NEXT sysdate (1/96)+
AS
SELECT N0_SEQ_BLOB_PDF,
EXAM_ID,
MPR,
RSM,
rub,
date_deb,
SPE,
commentaire,
SPR,
MEP,
MSJ,
TTD,
exam_type
FROM DOSSIER_MEDICAL@dbdoc_lk
WHERE DOSSIER_MEDICAL.EXAM_TYPE IN ('TELEM', 'SCANNER', 'EPPO_SECMED');
So you can see I'm using a dblink in the select statement ( DBDOC_LK )
On the DB referenced by this dblink, I created a materialized view log using this script :
CREATE MATERIALIZED VIEW LOG ON "DOSMED"."DOSSIER_MEDICAL"
TABLESPACE "DOC_T"
WITH PRIMARY KEY
INCLUDING NEW VALUES;
The problem is that my materialized view has never refreshed since its creation ! and I don't understand why ?
Can someone help me ?
Thank you.

The REFRESH schedule causes a job to be created for the execution of the Refresh. You should see this job in DBA_JOBS / USER_JOBS.
The job would run only if the instance parameter JOB_QUEUE_PROCESSES is set to 1 or higher (the default is 0). This parameter can be modified dynamically with an ALTER SYSTEM command.
Hemant K Chitale
http://hemantoracledba.blogspot.com

Help with sql query on materialized view logs

I am in need of a query to find out what tablespace and snap shot site a long list of materialized view logs are associated with.
something like below except tablespace and snap_shot_site are not an option for this table.
select log_owner, master, log_table, tablespace, snap_shot_site from dba_mview_logs;

What is the refresh method set as?
Could you paste the full MV log creation script and the corresponding MV creation script.

Can't update master table when creating a materialized view log.

Hi all,
I am facing a very strange issue when trying to update a table on which I have created a materialized view log (to enable downstream fast refresh of MV's). The database I am working on is 10.2.0.4. Here is my issue:
1. I can successfully update (via merge) a dimension table, call it TABLEA, with 100k updates. However when I create a materialized view log on TABLEA the merge statement hangs (I killed the query after leaving it to run for 8 hrs!). TABLEA has 11m records and has a number of indexes (bitmaps and btree) and constraints on it.
2. I then create a copy of TABLEA, call it TABLEB and re-created all the indexes and constraints that exist on TABLEA. I created a materialzied view log on TABLEB and ran the same update....the merge completed in under 5min!
The only difference between TABLEA and TABLEB is that the dimension TABLEA is referenced by a number of FACT tables (by FKs on the FACTS) however this surely should not cause a problem. I don't understand why the merge on TABLEA is not completing...even though it works fine on its copy TABLEB? I have tried rebuilding the indexes on TABLEA but this did not work.
Any help or ideas on this would be most appreciated.
Kind Regards
Mitesh
email: [email protected]

Thats what I thought, the MVL will only read data that has changed since it was created and wont have the option to load in all the data as though it was made before the table was created.
From what I have read, the MVL is quicker than a Trigger and I have some free code that prooved to work from a MVL using it as a reference to know what records to update. There is not that much to a MVL, a record ID and type of update, New, Update or Delete.
I think what I will have to do is work on a the same principle for the MVL but use a Trigger as this way we can do a full reload if required at any point.
Many thanks for your help.

Disabling Materialized View Logs for a session

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