I have a stored procedure and materialized view in same DB.The purpose of this procedure is to refresh the materialized view.
When I run the procedure directly from db mview is refreshed properly means the mview returns more data.
Now I done an informatica mapping ,this mapping call the store procedure to refresh the mview.
It runs properly but mview does not refresh properly that means the mview contains less data rather than first try.
My Question is that why the materialized view does not contain the all data after refreshing through informatica?
materialized view refresh type is complete.
Most likely the problem is that you've not invoked the stored procedure successfully at all but have convinced yourself that you have. Please include the excerpt of the session logs that confirms the stored procedure ran successfully (also check the connection used when the stored procedure call is made is the same as it should be i.e. you may have chosen a connection when writing the mapping but in the workflow it will be set to the default which most likely isnt the same)
Related
I want to ask you if there is a solution to auto-synchronize a table ,e.g., every one minute based on view created in oracle.
This view is using data from another table. I've created a trigger but I noticed a big slowness in database whenever a user update a column or insert a row.
Furthermore, I've tested to create a job schedule on the specified table (Which I wanted to be synchronized with the view), however we don't have the privilege to do this.
Is there any other way to keep data updated between the table and the view ?
PS : I'm using toad for oracle V 12.9.0.71
A materialized view in Oracle is a database object that contains the results of a query. They are local copies of data located remotely, or are used to create summary tables based on aggregations of a table's data. Materialized views, which store data based on remote tables, are also known as snapshots.
Example:
SQL> CREATE MATERIALIZED VIEW mv_emp_pk
REFRESH FAST START WITH SYSDATE
NEXT SYSDATE + 1/48
WITH PRIMARY KEY
AS SELECT * FROM emp#remote_db;
You can use cronjob or dbms_jobs to schedule a snapshot.
Good day,
Is it technically possible to create a materialized view against a another view in the master database (as opposed to a solid table)?
My DBA advises that oracle does not allow creation of materialized view logs against a view. IMO a view is pretty much the same as a table, so it ought to be possible.
Has anyone ever done this successfully (Oracle 11g).
The documentation is pretty clear about this:
Restrictions on Master Tables of Materialized View Logs
The following restrictions apply to master tables of materialized view logs:
You cannot create a materialized view log for a temporary table or for a view.
You cannot create a materialized view log for a master table with a virtual column.
A view is not pretty much the same as a table. It's a stored query, so it has no storage and DML is only possible through instead-of triggers. It doesn't have the basis for noticing an underlying data change.
Just thinking about it, in order to support a view log - even for a simple single-table view - an update to the view's base table would have to check if there were any views; check if any of those had materialized view logs; and then work out if the change needed to be logged - which would mean executing each view's query and looking at the entire result set. Imagine doing that for every change to the underlying table. And then imagine a more complicated view query, with aggregates or multiple tables, etc.
You'd effectively be materialising the view query to decide whether was a change that needed to be logged, to update an actual materialized view. This is partly what actual materialized views do - stop you having to repeatedly re-execute an expensive view query by tracking changes on the master table(s).
You have to create the materialized view logs on the (normal) view's base tables.
Using Oracle 10g
Is it possible to get the value of a newly updated field within the same transaction before it is committed.
I am executing a stored procedure which calls 2 other stored procedures.
The first stored procedure gets a record from a table and then updates that record.
The second stored procedure gets that same record but needs to use the newly updated fields from the first stored procedure.
Then the commit is carried out.
The commit can only be done if both procedures are carried out sucessfully.
Will the second stored procedure get the newly updated data or will it get a copy of the same data that was returned in the first procedure without the update ?
Oracle has a very simple and robust implementation of read consistency:
a user sees the latest version of the data, including any changes made by the current transaction, but ...
a user cannot see the changes made by any other user until that other user issues a commit, and even then not until executing a new statement.
This is covered in the Concepts Guide. Find out more.
In one of our applications, we have a massive Materialized View that refreshes three times a day, and takes seven hours to refresh. (Not ideal, I know). This perplexed me, because I surely thought that users and sessions could not access this materialized view while it was being refreshed, but apparently they can!. (The type of refresh is a complete refresh)
During a complete refresh, to my understanding, the existing dataset is dropped and the query is then re-executed. If this is true, then how are users/other sessions able to access the materialized view while the materialized view is being refreshed?
There are two different ways that a complete refresh can happen-- an atomic refresh or a non-atomic refresh. An atomic refresh simply issues a DELETE to delete all the rows in the materialized view and then does an INSERT to insert the new data. This is all within a single transaction so Oracle's standard multi-version read consistency architecture lets Oracle show other sessions the old data until the refresh completes. In a non-atomic refresh, Oracle does a TRUNCATE on the materialized view and then a direct-path INSERT to insert the new data. This is substantially more efficient but since TRUNCATE is DDL, it means that the old data is not visible to other sessions during the refresh.
I have the following materialized view -
CREATE MATERIALIZED VIEW TESTRESULT
ON PREBUILT TABLE WITH REDUCED PRECISION
REFRESH FORCE ON DEMAND
WITH PRIMARY KEY
AS
SELECT...
FROM...
WHERE...
This materialized view has no backing MATERIALIZED VIEW LOG. As seen in the clause above this MV has "ON DEMAND" specifies, and according to Oracle documentation,
"[ON DEMAND] indicate[s] that the materialized
view will be refreshed on demand by
calling one of the three DBMS_MVIEW
refresh procedures."
When I call DBMS_MVIEW.REFRESH('TESTRESULT') , what is occuring? Is it manually checking each record to see if it has been updated?
Oracle Version: 10g
By default (and this default changes in different versions of Oracle), that will do a full, atomic refresh on the materialized view. That means that the data in the materialized view will be deleted, the underlying query will be re-executed, and the results will be loaded into the materialized view. You can make the refresh more efficient by passing in a value of FALSE for the ATOMIC_REFRESH parameter, i.e.
dbms_mview.refresh( 'TESTRESULT', atomic_refresh => false );
That will cause the materialized view to be truncated, the query re-executed, and the results inserted into the materialized view via a direct path insert. That will be more efficient than an atomic refresh but the materialized view will be empty during the refresh.