41. What are
the steps required to add a new table to an existing replication setup?
The
steps to be executed would be the following:
- Include the new table to
the Extract & pump process.
- Obtain starting database
SCN and Copy the source table data to the target database
- Start Replicat on target
at the source SCN database point.
42. What
does the GoldenGate CSN equate to, in the Oracle Database?
It
is equivalent of the Oracle database SCN transaction number.
43. How do
you create a CSV file from the Extracted data?
You
will have to use the CSV Flat File Adaptor to create CSV files. The source
would be the extract trail files which use the configuration of the adaptor
settings to generate CSV files.
44. What is
the purpose of the DEFGEN utility?
When
the source and the target schema objects are not the same (different DDL’s) the
Replicat process needs to know the source definition of the objects. The output
from the DEFGEN utility is used in conjunction with the trail data to determine
which column value in the trail belongs to which column.
45. We want
to setup one-way data replication for my online transaction processing
application. However, there are compressed tables in the environment. Please
suggest how I can achieve it.
You
must use OGG 11.2 and configure GoldenGate Integrated Capture process to extract
data from compressed tables.
Note:
Pre OGG 11.2 doesn’t support extracting data from compressed tables
46. We want
to setup one-way data replication using Integrated Extract for my Oracle
database running 10.2.0.4. Please suggest the best architecture to achieve it.
Oracle
GoldenGate Integrated Capture process supports Oracle databases 10.2 and
higher. But if you are running Oracle database 10.2 and want to you Oracle
GoldenGate Integrated Capture process then you must configure downstream
topology.
47. I am
migrating my Oracle database from non-exadata to exadata but my source OGG
software and target OGG software versions are different (Say Source is running
OGG 11.1 and target is running OGG 11.2). How can I configure my OGG process to
work in such configuration?
It
is recommended that all instances of Oracle GoldenGate be the same version to
take advantage of the new functionality, but this is not possible all the time
and is not required. In this scenario, OGG provides a parameter called ‘FORMAT RELEASE’ which allows customers
to use different versions of Oracle GoldenGate Extract, trail files, and
Replicat together.
Example:
RmtTrail /u01/app/oracle/dirdat, Format Release 11.1
Note: The input and output
trails of a data pump must have the same trail file version.
48. What are
the different OGG Initial load methods available?
OGG
has 2 functionalities, one it is used for Online Data Replication and second
for Initial Loading.
If
you are replicating data between 2 homogeneous databases then the best method
is to use database specific method (Exp/Imp, RMAN, Transportable tablespaces,
Physical Standby and so on). Database specific methods are usually faster than
the other methods.
—If
you are replicating data between 2 heterogeneous databases or your replicat
involves complex transformations, then the database specific method can’t be
used. In those cases, you can always use Oracle GoldenGate to perform initial
load.
Within
Oracle GoldenGate you have 4 different ways to perform initial load.
- Direct Load – Faster but
doesn’t support LOB data types (12c include support for LOB)
- Direct Bulk Load – Uses
SQL*LOAD API for Oracle and SSIS for MS SQL SERVER
- File to replicat – Fast
but the rmtfile limit is 2GB. If the table can’t be fit in 1 rmtfile you
can use maxfiles but the replicat need to be registered on the target OGG
home to read the rmtfiles from source.
- File to Database utility
– depending on the target database, use SQL*LOAD for Oracle and SSIS for
MS SQL SERVER and so on.
Oracle
GoldenGate initial loading reads data directly from the source database tables
without locking them. So, you don’t need downtime but it will use database
resources and can cause performance issues. Take extra precaution to perform
the initial load during the non-peak time so that you don’t run into resource
contention.
49. I have a
table called ‘TEST’ on source and target with same name, structure and data
type but in a different column order. How can your setup replication for this
table?
OGG
by default assumes that the sources and target tables are identical. A table is
said to be identical if and only if the table structure, data type and column
order are the same on both the source and the target.
If
the tables are not identical you must use the parameter ‘SOURCEDEFS’ pointing to the source table definition and ‘COLMAP’ parameter to map the columns
from source to target.
50. What is
the best practice to delete the extract files in OGG?
Use
the manager process to delete the extract files after they are consumed by the
extract/replicat process
PURGEOLDEXTRACTS
/u01/app/oracle/dirdat/et*, USECHECKPOINTS, MINKEEPHOURS 2
No comments:
Post a Comment