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Thread: Attunity CDC Solution Life Cycle Guidelines

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    Attunity CDC Solution Life Cycle Guidelines

    This article discusses the proper steps to take to start, suspend, resume or stop an Attunity CDC Solution.

    An Attunity CDC Solution is typically composed of 3 components:
    1. Change Data Capture Agent (CDC Agent) that runs on the system where the source database is installed
    2. CDC Router that runs on a Windows or a Unix-based system
    3. Staging Area (SA) as server processes or local PODBC data provider
    Of those three components, the CDC Agent and the Staging Area are 'passive' components in the sense that they are being operated by other components:
    • The CDC Agent is operated by the change router
    • The Staging Area is operated by the ETL tool accessing the change data
    While the CDC Router and Staging Area share the same storage, there is no direct operational dependency between them. This means that the ETL tool can access the Staging Area even if the Change Router is disabled and the Change Router can process captured changes even if the Staging Area server is disabled.

    With these dependencies in mind, it is easy to follow the Attunity CDC solution life cycle guidelines:
    • When starting up, the CDC agent should be started first, followed by the Change Router.
    • When stopping down, the Change Router should be stopped first, followed by the CDC Agent
    • If using Staging Area servers, it is OK to start and stop these servers regardless of the other components
    • To quite down activity on the CDC Agent machine (the source database machine), it is enough to pause the Change Router (instructions appear below). Pausing the Change Router is better than stopping it since the
    Most of the Attunity CDC solution components are represented by specific server instances (workspaces). The following commands can be used to stop or start a workspace:

    To start:

    HTML Code:
    irpcd -u <admin-user> [-p <password>] -l <w.x.y.z:p> enable <workspace>
    To stop:

    HTML Code:
    irpcd -u <admin-user> [-p <password>] -l <w.x.y.z:p> disable <workspace>
    It is important to perform these operations according to the dependencies listed above. For example, to stop the Change Router before stopping the CDC Agent.

    On all machines where an Attunity solution components is installed, there is a daemon process that is responsible for starting workspace server instances. In most cases, this daemon is started at (or just after) boot time and is stopped only during system shutdown. Exceptions to this may be cases where maintenance needs to be done that affects the daemon environment and setting. Stopping and starting CDC activities should not, in most cases, involve stopping or restating the daemons.

    Pausing and resuming the Change Router is achieved by updating a special table in the Staging Area called CONTROL_TABLE. This can be done via any tool that can run SQL commands against the Staging Area but it can also be done using the NAV_UTIL porgram. For example, if the Staging Area binding name and datasource name are OraHP4_sa then the following command pauses the Change Router:

    $ nav_util -b OraHP4_sa execute OraHP4_sa
    NavSQL > insert into CONTROL_TABLE values('pause','');
    With this, the Change Router would stop reading change events from the CDC Agent and will idle keeping its internal state, ready to be resumed. Resuming operation of the Change router is done as follows:

    $ nav_util -b OraHP4_sa execute OraHP4_sa
    NavSQL > insert into CONTROL_TABLE values('resume','');
    Last edited by DrorHarari; 05-30-2008 at 03:10 AM.
    By Dror Harari

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