Category: GoldenGate

ORACLE GOLDENGATE CHECKPOINTS

Each and every processes in Oracle GoldenGate has it’s own checkpoints to maintain data integrity.

This article explains the different types of checkpoints and the uses of it.

As we know there are multiple processes involved in Oracle GoldenGate replication, the below are the processes which maintains the checkpoint information for each and every operations it does.,

1. Extract or Capture Process
2. Secondary Extract or DataPump Process
3. Replicat Process

EXTRACT PROCESS

This process captures the committed changes from the Redo Log or Archive Log files and writes them to the Trail files called Local Trails. The Extract Process
not only captures the committed changes but also keeps track of all the Open transactions so that it ensures that it does not misses any data or no data loss.
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ORACLE GOLDENGATE INSERTALLRECORDS – To Maintain Transaction History

This parameter is used at the Replicat Side. When using this parameter, it causes Replicat process to insert each and every change that has been made to a record as a new record in the database. So whatever operations are performed in the source table (Insert or Delete or Update), everything will be converted in to the insert statement and will be inserted to the target table. The initial insert and subsequent updates and deletes are maintained as point-in-time snapshots.

There are two major reasons for using the parameter INSERTALLRECORDS,

1. When exception MAP statement is used in the target. The operations which causes error will be inserted in the Exception table. This is called as Error Handling.
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How to start the Oracle GoldenGate Collector Process Manually?

Oracle GoldenGate Server Collector process plays a vital role in the Oracle GoldenGate Replication. But we could not see this process in the INFO ALL command output. Because this process is started internally by the manager process automatically. But we all know that, we can also start the Collector process manually. But How to start it? Searched in google for the document but couldn’t find one. So thought of creating this article.

SERVER COLLECTOR PROCESS

There are two Extract Processes. Primary Extract and Secondary Extract (called DataPump / Extract Pump).The Extract Pump is the process at the Source side which communicates with the Target Manager process and requests manager to open the port for the Server Collector process at the Target Side.
So the Server Collector process will be invoked by the Target Manager process. The Collector process in turn receives the changes from the Extract Pump process and writes the changes to the Remote Trail files.

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COLS and COLSEXCEPT in Oracle GoldenGate

COLS | COLSEXCEPT

These parameters are used to Replicat only specific columns from the Source to Target. Suppose, let us consider a scenario, we have 10 columns in the source and we need only 9 columns to be replicated to the target table. Yes, this is possible using the above parameters.

COLS and COLSEXCEPT controls the columns for which data is captured. It means, only data of specific columns are captured and not all the columns.

This parameters are valid for Extract Process and should. Upon using this parameters, only the specified columns values are captured by the Extract Process and not all column’s values.
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Oracle GoldenGate 12c – Silent Installation

We all know that installation of Oracle GoldenGate 10g and 11g was simple,  just unzipping the software binaries. But we did not have any
Graphical Mode Installation. From Oracle GoldenGate 12c onwards, Oracle has introduced a new mechanism of installation with a most familiar
framework Oracle Universal Installer (OUI). This is the Graphical Mode of Installation (GUI Mode).

Please click here to know how to install Oracle GoldenGate 12c (Graphical Mode – Oracle Universal Installer).

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Oracle GodlenGate 12c New Feature – CREDENTIALSTORE AND USERIDALIAS

From Oracle GoldenGate 12c onwards, a new feature for security purpose has been introduced known as CREDENTIALSTORE. Using this feature, we can manage the USER ID’s and it’s corresponding passwords which are used by the Oracle GoldenGate processes to interact with the Local Databases for the use of Replication.

 

So the usernames and passwords will be secured. Upon using this feature the usernames and passwords used in the Oracle GoldenGate process groups or even when we login as an Admin user in the GGSCI, will not be displayed. An optional ALIAS name can be used instead of entering the username and password.

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SHOWSYNTAX : Oracle GoldenGate Tool To Debug A Replicat

SHOWSYNTAX

Oracle GoldenGate has provided an excellent parameter to debug the Replicat process called SHOWSYNTAX. Obviously this should be used in the Target side (Replicat). This parameter is used to start an interactive session. That is, whenever an INSERT is replicated from Source to Target, before it is getting applied to the Target, the respective SQL statement will be displayed on screen. Upon using this parameter, you can view each and every Replicat SQL statement before it is applied.

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Oracle GoldenGate HANDLECOLLISIONS – NOHANDLECOLLISIONS

HANDLECOLLISIONS – NOHANDLECOLLISIONS

These parameters are configured in the Replicat side and they are set to continue the data processing if there are some data integrity issues on the Target tables. Upon setting these parameters Replicat Process tries to resolve the duplicate and missing records when applying the sql on the Target tables. These parameters are mainly used during the Initial Loads, when loading the data for synchronizing the Target Tables with Source.

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