Replication :: Pausing And Resuming Of Refreshing Materialized Views
Oct 15, 2011
We have some materialized views in our environment which refreshes after every 1 hour. In the same environment, we have some big processes and we do not want the performance of these big processes to get affected because of refreshing these materialized views.
if there is a way to pause the refreshing of materialized views before running the big processes and later after the big processes are completed, then resume the refreshing of the materialized views?
One way I can think of is to drop the materialized views and create the materialized views back.
I have a Multi layer Mviews and Views which i use to load a table. There are three base level Mview which is accessed by 4 views ... which are in turn accessed by a view which is used to load a table.
Before the insert called for the table .. the base mviews are refreshed.
I get the "ORA-01410 Invalid Rowid" error while inserting in to the table and while refreshing the mviews. They don't occur every time and not together as well.
The Mviews contains table joins and the top level views which accessing these mviews does aggregation. Below is the mview query for one of the mview.
1. I have created a materialized view with following syntax in 11g R1 database.
CREATE MATERIALIZED VIEW fr_emp_bonus_record_vw BUILD IMMEDIATE REFRESH COMPLETE START WITH SYSDATE NEXT SYSDATE+1/48 ENABLE QUERY REWRITE AS SELECT person_id, <columns>
This MV will have around 300K records and this MV will be used in other queries based on person_id. So I have created an index on mv.person_id with following syntax. I have chosen REFRESH COMPLETE, I am assuming that, Oracle truncates this table and recreates it. When it recreates this MV, does it analyze automatically or do I need to do it manually.
CREATE UNIQUE INDEX mv_u1 ON mv(person_id);
2. It takes around 2 minutes to populate 300K. While it is populating the data, if somebody accessing this view or query where this view is being used, are they going to get any error?
There is a database db1 which has user U1 in in it contains T1 as table.
Likely,
There is also another database db2 which also has a user named U2 containing table T2 in it.
Now
I want to use the concept of JOINS and Join Table T1 of database named DB1 and Table T2 of database named DB2 and access from database named DB3 using Materialized View Concept.
what shall i do to access tables of DB1 and DB2 from database DB3 using Materialized View.
I have a view with complex query that have grouping and aggregations in sub-queries.
Now we would like to change it to a materialized view. However, materialized view does not support GROUP BY clause in sub-query. The solution is to create several view for the sub-queries and then create a materialized view based on it. It seems it can work, but I guest every time complete refresh is required.
I have a database link between 2 databases and that works fine. Now the tables of one database are having thier materialized views in the other. The materialized views are not getting refreshed. They hang when i try refreshing them. I have tried everything said on the forums. I changed the job_queue_processes. Also changed the query_reqrite_enabled to true. Still it won't work.
CREATE Materialized View log on t1 with rowid; CREATE Materialized View log on t2 with rowid; CREATE Materialized View log on t3 with rowid; CREATE Materialized View MV_test BUILD IMMEDIATE FAST REFRESH ON COMMIT [code].......
I have created a Materialized View by joining the above 3 tables. The Materialized View logs with ROWID has been created on each of the 3 base tables. One of the base tables has around 160 million rows and i expect the Materialized View to have the same number of rows.
The Materialized View has been built for FAST REFRESH on COMMIT. The SELECT list of the CREATE Materialized View statement includes all the ROWIDS from each base tables for doing the fast refresh.
The DBMS_MVIEW explain view shows that the view is capable of doing fast refresh on any DML. The Materialized View took 3 hrs to get built. I have also created indexes on all the three rowid columns (t1rowid,t2rowid,t3rowid) on the Materialized View.
Now, When i do any update on one of the base table and do a commit,
UPDATE t1 set value=500 where tx_id='1234';
The commit is taking around around 15 minutes. I have generated the trace and had a look at it, and it shows that, to refresh the Materialized View, ORACLE is first deleting that record from the Materialized View and then inserting the new record from the base table to the Materialized View. This delete done by oracle is being done on the basis of the rowid of the updated record stored on the Materialized View log,
However its not using the index created on the t1rowid of the Materialized View and doing a full scan of the MV and hence the delete is taking a lot of time. The delete statement is using a hint NO_MERGE and HASH_SJ which is causing it to do the full table scan of the MV. why is ORACLE not using the index on the t1rowid column of the MV to do this delete?
Also to do the insert in the MV, its selecting the new changed value from the base tables t1,t2 and t2. Here again its doing a full table scan of the base table t1, rather then using the rowid directly or the index coulmn.which is taking a lot of time.
I have a Problem regarding Data Replication, I am using Standard Version of Oracle 9i,I am having 5 remote servers , I am replicating the data from all of these servers using Materialized views on a Centralized server , I have created 5 schema for them, there is a application which is Consolidating the Data from all the locations.
When I create materialized views from these Materialized views I am facing problems to Fast refresh them as I am using "Union All" to combine data of all Users (Error is ora -12004) . I would like to know that is there any other way to do this, also I have tried all the ways to solve the problem of Ora-12004.
while replicating the master site via materialized views, in mViewGroups i issued:
BEGIN DBMS_REFRESH.MAKE ( name => 'mvadmin.hamza_refg', list => '', next_date => SYSDATE, interval => 'SYSDATE + 1/1440', -- for test purpose i used such a small interval implicit_destroy => FALSE, rollback_seg => '', push_deferred_rpc => TRUE, refresh_after_errors => FALSE); END;
in my previous attempt it worked all fine... i had a change in senerio, so i did my replication again from scractch using the same old spool in a new installation but even after 3 tries on replicating from scratch my objects are not getting refreshed automatically. even when i attempt to refresh the group it does not work. it works only when i refresh each of the participating object of the group manually.
CREATE MATERIALIZED VIEW LOG ON ABC; CREATE MATERIALIZED VIEW MV_ABC REFRESH FAST START WITH SYSDATE NEXT SYSDATE+20/(24*60) FOR UPDATE AS SELECT * FROM ABC WHERE TMSTP> SYSDATE-1;
It is working fine. Appended the Query with WHERE clause in MV_ABC MVIEWS.
DROP MATERIALIZED VIEW LOG ON ABC; DROP MATERIALIZED VIEW MV_ABC; CREATE MATERIALIZED VIEW LOG ON ABC; CREATE MATERIALIZED VIEW MV_ABC REFRESH FAST START WITH SYSDATE NEXT SYSDATE+20/(24*60) FOR UPDATE AS SELECT * FROM ABC WHERE TMSTP> SYSDATE-1;
ORA-12013: updatable materialized VIEWS must be simple enough TO DO fast refresh
I have to convert some existing materialized views (fast refresh) to partition materialized views.
Database version is oracle 10.1.0.4. I have decided to use on prebuilt table option to do the partitioning as it minimizes the time to transfer from the master site.
1) stop replication 1) create interim tables with similar structure as the materialized views 2) transfer all data from the materialized views to the interim tables 4) script out the materialized views structure and add in on prebuilt table option in the scripts 5) drop the materialized views 6) rename the interim tables with the same name as the materialized views 7) run the scripts to create the materialized views with on prebuilt table option 8) refresh the newly created materialized views -> it should take a short time since I am using on prebuilt table option
But I am facing one major issue. That is if I drop the materialized views, the materialized view logs of the master tables are purged. When the materialized views are refreshed fast, there are some data missing. the data that are purged out when the materialized view are dropped.
Do you happen to know other ways that existing materialized views can be converted to partitioned materialized views? Do you have any workaround to prevent the materialized view logs from being purged?
I have a created a materialized view which is based on a view on remote database. Now how do I refresh the view.
Materialized view is created by
CREATE MATERIALIZED VIEW mv_employee_name AS SELECT EMPLID, EMPL_NAME FROM VEMPDATA@REMOTEDB WHERE REGION = 'US';
I am wondering how the refersh happens or how do I specify the refresh clause.REFRESH FAST option is looking for VIEW LOG on the master table but in this case its a remote view, so I cannot create any object on remote db.
I am removing sal column from table tab_emp; i want to check whether any materialized view or view using this column by querying using data dictionary :- if i use like condition against query column of all_mviews it is throwing error sicne it is long data type. is there a way to search it without creating any function and use it in a query.
Error:- ORA-02448: constraint does not exist ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2254 ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2460 ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2429 ORA-06512: at line 1
The Primary Key Constraint on the base table/MV is deferrable, the base table and the MV are in different schemas and the user trying to refresh the MV has an explicit grant on "ALTER ANY MATERILIZED VIEW" and "SELECT ANY TABLE" through a role.
Its refreshing successfully when I make the PK constraint (Base Table, MV) NOT DEFERRABLE (or) when I explicitly grant "SELECT ANY TABLE" to the user trying to refresh the MV.
I have a database schema with a Materialized View (MV) that updates a products table shown on a website. This schema was recently imported to an 11g database from 8i, but since this import I have been unable to refresh my schema's Materialized View.
The MV_PRODUCT_MASTER Materialized View attaches price data to product data that is stored in a normal WEB_PRODUCT table, and create an MV table as a result. The output MV table is what the website pulls data from to display to the site users. Since it is an MV table, this table cannot be edited directly. In order to change, say, a product description, I need to alter the description field in WEB_PRODUCT and manually refresh the MV_PRODUCT_MASTER table. Only through the refresh will the upstream edits appear in the MV_PRODUCT_MASTER table and be visible on the website.
In my old 7.6.0.11 copy of TOAD, I could manually refresh these MVs easily, by opening the "Snapshots" tab, right clicking on the MV I wanted to refresh and selecting the "Refresh" option. Since the schema was imported to 11g, I have been using the Oracle SQLDeveloper tool to manage the schema. SQLDeveloper doesn't have a clear method for manually refreshing an MV, or else the method I am using isn't working.
If I right click on the MV_PRODUCT_MASTER Materialized View object, and choose "Other Actions", I see the following choices:
I assumed that -Force Materialized View Refresh- was the right choice, and chose that. This option displays the SQL:
alter materialized view "WEBADMIN"."MV_PRODUCT_MASTER" consider fresh
When I apply this, I get the message: Materialized view - MV_PRODUCT_MASTER - has been set torefreshed. However, no changes appear in the MV output table. i.e. if I make a specific change to a row in the WEB_PRODUCT table, the change is not being carried into the MV_PRODUCT_MASTER table, so that indicated that the refresh is not actually happening. The MV table appears to believe it is being refreshed:
REWRITE_CAPABILITY GENERAL REFRESH_MODE DEMAND REFRESH_METHOD COMPLETE BUILD_MODE IMMEDIATE FAST_REFRESHABLE NO LAST_REFRESH_TYPE COMPLETE LAST_REFRESH_DATE 06-APR-10 STALENESS UNKNOWN
But it isn't showing any changes.What am I doing wrong? Is there a plain SQL statement I can run in order to run these refreshes, instead of using the SQLDeveloper GUI?
I have a list of materialized views in schema A. I want to create a refresh group and then refresh it from Schema B (Dynamically-run time based on some criteria). What Grants are necessary on schema B in order for it to be able to create and refresh the groups on Materialized views in Schema A.
I know that one of the Options is to, GRANT ALTER ANY MATERIALIZED VIEW as a SYS user. But I do not have any SYS privileges.
i need to set up a central server with all the master tables and two other local database which will hold the updatable materialized view of the master table...the databases must be synchronized with central server..and user will work on the materialized view database...
I have a problem Mat view refresh...I have to take a snapshot of the table before nsert or update to the table....below is the code written to achieve this..
create materialized view my_view refresh complete as select * from t2; create or replace trigger TRG_T2 before insert or update on T2 declare X number;
[code]....
However this is not getting refreshed... Also i noticed that it works for the very first time (after first insert or update) and then for successive ones it doesnt.. ..
