6.2. Subscriber
6.2.1. Creating a new Subscription
To create a new subscription, start the subscriber console the same way as the publisher, and then when the main window is open, execute the following steps.
Select "Create Subscription" from the Subscriber menu
Fill in the dialog fields as shown below
Subscription Name: Enter a name for the subscription you are creating.
Publication Name: Enter the name of a publication that exists on the publisher server to which you are connecting
Publication System Name: The hostname or IP Address of the publisher server
Publication Port Number: The port that the publisher server is listening on
Then click the "Subscribe" button
You should then see the "Subsciption Created Successfully" dialog
You can then view the subscription information by expanding the tree in the main window
if the subscribed tables do not exist, they will be created upon creating the subscription, but they will not be populated until a snapshot is taken.
6.2.2. Getting the snapshot
To take the Snapshot of a Publication, click on Subscriber menu and select Snapshot OR Right click on the name of subscriber and click on Snapshot.
A Snapshot dialog appears
Fill in the fields in the dialog as shown below
Enter a name for the subscription
Enter the name of the publication server
Enter the port number on which the publisher is listening
Click on 'Get Snapshot'
On success, you will see the message 'Snapshot taken successfully'
After taking the snapshot, the data in the publisher and subscriber should be identical
6.2.3. Synchronizing the data (Merge Replication)
There are three different methods of database synchronization available in DBReplicator. Merge, Push and Pull.
6.2.3.1. Merge Replication (synchronize)
Synchronization takes changes from Publisher's database and sends them down to subscriber, and vice versa.
To synchronize data between Publisher and Subscriber, click on subscriber menu and select synchronize, OR right-click on the name of the subscription and select 'synchronize'
A 'synchronize' dialog appears, very similar to the 'snapshot' dialog.
Fill in the dialog's fields as illustrated below:
Enter the subscription name
Enter the name of the publication server
Enter the port number on which the publisher is listening
Only the subscriber can initiate syncronization sessions
Click on 'Synchronize'
On success, you'll get the message 'Synchronized Successfully'
6.2.3.2. Push Replication
Push Replication is peformed in exactly the same way as synchronization, except that 'Push' is selected from the subscriber menu.
In this operation, data is sent up to the publisher, but no data is retrieved back to the subscriber
6.2.3.3. Pull Replication
Pull Replication is performed in exactly the same was as synchronization and push, except that 'Pull' is selected from the subscriber menu.
In this operation, data is pulled down from the publisher, but changes on the subscriber are not sent back to the publisher
6.2.4. Updating the subscription
Whenever publisher modifies his publication by adding or dropping tables from publication, subscriber must update its subscription .
Follow the steps given below to do so.
Click on the menu Subscriber->Update Subscription
The following dialog will appear
Enter the name of the subscription you wish to update, the name of the publisher server and the publisher's port number, and click the 'Update' button
Upon successfully updating, the subscriber will display the success dialog
6.2.5. Adding, Editing and Removing Schedules
Scheduling is the process of assigning tasks to a set of resources. It is an important concept in many areas such as computing, production processes or airlines. In the replication process, scheduling can be very handy as it automates the process of replication. Scheduling reduces the overhead of requesting the replication process time and again. A user can add a schedule once and remain free from sending a replication request to publisher again. Replicator will automatically replicate data on that scheduled time
Replicator takes over your whole responsibility of sending replication request. Whenever user starts his Sub server, whatever schedule user has added, replicator will automatically start replication according to it.
DBReplicator permits two modes of replication using scheduling: Real time and Non Real Time. In Real Time mode of replication, replication mode specified in schedule will be performed continuously without any time delay. In Non-Real Time mode of replication, whatever schedule is added by user, replication process specified in schedule will be performed at the scheduled time only.
6.2.5.1. Add Schedule
To add a new replication schedule, follow steps below.
If you're using the linux server process for running as a background service, you'll want to specify your interval in the config file "subscriber.conf" for now.
Select "Add Schedule" from the subscriber menu
A dialog box will appear, as shown below. Fill in the fields in the following manner
Pick a name for the schedule
Enter the subscription name
Enter the publication server name
Enter the publisher port number
Select the replication type, Snapshot, Synchronize, Push or Pull
If non-continuous replication is desired, select 'Non-realtime scheduling'
select the recurrence frequency units
select the unit counter
select the start date of the schedule
select the start time
Upon success, a dialog will indicate so
6.2.5.2. Edit Schedule
To modify an existing schedule, follow the steps below
Select "Edit Schedule" from the subscriber menu
An Edit Schedule dialog box will appear
Click the "Load" button to load the schedules
Enter new publisher information, and select "Edit"
6.2.5.3. Remove Schedule
To remove a schedule, follow the steps outlined below
Select "Remove Schedule" from the subscriber menu
click the "Load" button to load the schedules
select the schedule you wish to remove, and click "Remove"
6.2.6. Dropping the subscription
From the subscriber menu, select "Drop Subscription"
Enter the subscription name, publication server name and port number and click "Unsubscribe"
