Create a table for session persistence

 

+

Search Tips   |   Advanced Search

 

Use a database table to collect and store session data. For a database table for session persistence, create and define a database table that is associated with the appserver.

Whenever the session manager is set for database persistence, the session manager creates a table for its use. To expand the column size limits to make it more appropriate for the Web site, we can create the table externally. If the external table is specified as the target table in the session manager database persistence configuration, then during the session manager start up, the external table is used. In most cases it is better to let the session manager create the table during startup.

To create a table for collecting session data, do the following:

1. Have the administrator create a database table for storing your session data using one of the following data definition language (DDL):

   For DB2:

    CREATE TABLE <SchemaName>.sessions   (
      ID VARCHAR(128) NOT NULL,
      PROPID   VARCHAR(128) NOT NULL,
      APPNAME  VARCHAR(128) NOT NULL,
      LISTENERCNT  SMALLINT,
      LASTACCESS   BIGINT,
      CREATIONTIME BIGINT,
      MAXINACTIVETIME  INTEGER,
      USERNAME     VARCHAR(256),
      SMALL    VARCHAR(3122)  FOR BIT DATA,
      MEDIUM   LONG VARCHAR FOR BIT DATA,
      LARGE    BLOB(2M)
   )
   

   For Oracle:

    CREATE TABLE SESSIONS   (
      ID   VARCHAR(128) NOT NULL,
      PROPID   VARCHAR(128) NOT NULL,
      APPNAME  VARCHAR(128) NOT NULL,
      LISTENERCNT  SMALLINT,
      LASTACCESS   INTEGER,
      CREATIONTIME INTEGER,
      MAXINACTIVETIME  INTEGER,
      USERNAME     VARCHAR(256),
      SMALL    RAW(2000),
      MEDIUM   LONG RAW,
      LARGE    RAW(1)
     )
   
   

   If the Web container custom property UseOracleBLOB is set to true then:

    CREATE TABLE SESSIONS  (
      ID   VARCHAR(128) NOT NULL,
      PROPID   VARCHAR(128) NOT NULL,
      APPNAME  VARCHAR(128) NOT NULL,
      LISTENERCNT  SMALLINT,
      LASTACCESS   INTEGER,
      CREATIONTIME INTEGER,
      MAXINACTIVETIME  INTEGER,
      USERNAME     VARCHAR(256),
      SMALL    RAW(2000),
      MEDIUM   BLOB, 
     LARGE    RAW(1)
     )
   

2. At run time, the session manager accesses the target table using the identity of the J2EE server in which the owning Web app is deployed. Any Web container configured to use persistent sessions must have both read and update access to the subject database table.

3. HTTP session processing uses the index defined using the CREATE INDEX statement to avoid database deadlocks. In some situations, such as when a relatively small table size is defined for the database, DB2 may decide not to use this index. When the index is not used, database deadlocks can occur. If database deadlocks occur, see the DB2 Administration Guide for the version of DB2 we are using for recommendations on how to calculate the space required for an index and adjust the size of the tables that we are using accordingly.

4. It might be necessary to tune DB2 to make efficient use of the sessions database table and to avoid deadlocks when accessing it.

 

Related tasks

Set for database session persistence