Creating the operation's queue in PostgreSQL RDBMS

The following example shows how to create an operation queue in PostgreSQL.

1. For information on how to download and install PostgreSQL go here .
2. Create a database instance (e.g. provisi)
3. Create operation's queue

   CREATE TABLE operations_queue (
       id               VARCHAR (20)   NOT NULL,
       type             VARCHAR (5)    NOT NULL,
       status           VARCHAR (5)    NOT NULL,
       insert_date      TIMESTAMP      DEFAULT NOW(),
       execution_date   TIMESTAMP,
       xml_string       VARCHAR (1000) NOT NULL,
       username         VARCHAR (15)   NOT NULL,
       response         VARCHAR (1000),
       
       CONSTRAINT pk_id PRIMARY KEY (id)
   );
   

   Where:

   Column	Description
   id	Unique identifier of the operation.
   type	Operation Type.
   status	The state the operation is in.
   insert_date	Date and time when the operation was added to the queue.
   execution_date	and time when the execution of the operation was completed.
   xml_string	The column xml_string stores the XML string that contains the parameters related to the operation.
   user	stores the user ID of the management system that inserts the operation. The user is provided by the management system. The provisioning system does not authenticate the user.
   response	This column stores a description of the latest response received by the provisioning system. This column will be updated with each execution of the operation.

4. Configure ~config/database.xml to access operation's queue

   The Provisioner accesses the database where the operations queue is stored using information contained in the file ~config/database.xml.

   The file ~config/database.xml is a text file in XML format that contains information about connections to one or more databases. Each connection contains the following data:

   Parameter	Description
   server type	Type of the database engine.
   server name	Name of the database server machine.
   driver classname	Name of the class that implements the driver for this type of database.
   driver type	Type of the driver implemented by the class.
   database name	Name of the database instance.
   database user	User name for the database.
   database password	User's password.

   This is a sample database.xml:

   <?xml version="1.0" encoding="UTF-8"?> 
   <connections xmlns="http://connections.org"> 
           <description> 
                   Connection string information. 
           </description> 
           <connection> 
                   <server type="postgresql" name="localhost"/> 
                   <driver className="org.postgresql.Driver" type="jdbc"/> 
                   <database name="provisioning" user="postgres" password="Ericsson1"/> 
           </connection> 
   </connections> 
   

To modify this file, use your favourite text editor (e.g. vi, emacs, etc.).

Maintaining the operations queue

The operations queue stores request with their parameters and states as well as the response obtained during the processing of the request. These data consume resources of the database. Therefore, you should regularly clean the operations queue to avoid exceeding the capacity of the database.

Remove only those requirements that have already been processed and are in a final state, i. e. ERRO or DONE.

To remove requirements that have already been processed execute the following database command:

delete from operations_queue where status in ('ERRO','DONE');