This section describes objects that Replication Agent creates in the primary database to support replication. Replication Agent creates these objects when you initialize it using pdb_xlog init.
There are two variables in the Replication Agent object names shown in this chapter:
prefix – represents the one- to three-character string value of the pdb_xlog_prefix parameter (the default is ra_).
xxx – represents an alphanumeric counter, a string of characters that is (or may be) added to a table name to make that name unique in the database.
The value of the pdb_xlog_prefix parameter is the prefix string used in all Replication Agent object names.
If this value conflicts with the names of existing database objects in your primary database, you can change the value of the pdb_xlog_prefix parameter by using the ra_config command.
Replication Agent uses the value of pdb_xlog_prefix to
find its objects in the primary database. If you change the value
of pdb_xlog_prefix after you create
the Replication Agent objects, the Replication Agent instance will
not be able to find the objects that use the old prefix.
You can use the pdb_xlog command to view the names of Replication Agent objects in the primary database.
See the Replication Agent Administration Guide for details on setting up replication object names.
Table 4-1 lists the Replication Agent tables. No permissions are granted on these tables when they are created. All of these tables contain at least one index, and some contain more than one index.
Table |
Database name |
|---|---|
System table |
prefixxlog_system_ |
Marked objects table |
prefixmarked_objs_xxx |
LOB columns table |
prefixblob_columns_xxx |
Log Admin work table |
prefixrawork_xxx |
Proc active table |
prefixprocactive_xxx |
Force record table |
prefixforce_record_xxx |
rs_marker shadow table |
prefixmarkersh_xxx |
rs_dump shadow table |
prefixdumpsh_xxx |
Replication Agent for UDB installs SYBRAUJAR.jar and SYBTRUNCJAR.jar into the following directories.
On Windows, the files are installed in %DB2DIR%/SQLLIB/FUNCTION/jar/pds_username. Here, $DB2DIR is the path to the UDB installation, and pds_username is the name of the primary database user specified by the pds_username Replication Agent configuration parameter.
On UNIX, the files are installed in $HOME/sqllib/function/jar/pds_username. Here, $HOME is the home directory of the UDB instance owner and the pds_username is the name of the primary database user specified by the pds_username Replication Agent configuration parameter.
These jar files implement several Java procedures in the UDB primary database. Table 4-2 lists the Java procedures that are created during the Replication Agent initialization and used in log truncation.
Procedure |
Database name |
|---|---|
Retrieves the name of the log file that contains the current LSN |
prefixget_log_name_ |
Retrieves the version of the get_log_name Java class |
prefixget_version_str_ |
Truncates the database log file or files from the archive log directory |
prefixtrunc_log_files_ |
Retrieves the version of the trunc_log_files Java class |
prefixget_trunc_ver_str_ |
The Replication Agent instance generates the names of its database objects. To find out the actual names of these objects, use the pdb_xlog command.
To find out the names of Replication Agent objects
At the Replication Agent administration port, invoke the pdb_xlog command with no keywords:
pdb_xlog
The pdb_xlog command returns a list of objects created by the Replication Agent in the primary database.
