sp_hook_dbmlsync_all

sp_hook_dbmlsync_all_error

Use this stored procedure to process dbmlsync error messages of all types. For example, you can implement the sp_hook_dbmlsync_all_error hook to log errors or perform a specific action when a specific error occurs.

Rows in #hook_dict table

Name	Value	Description
publication_n (in)	publication	Deprecated. Use subscription_n instead. The publications being synchronized, where n is an integer. There is one publication_n entry for each publication being synchronized. The numbering of n starts at zero.
MobiLink user (in)	MobiLink user name	The MobiLink user for which you are synchronizing.
script version (in)	script version name	The MobiLink script version that is used for the synchronization.
error message (in)	error message text	This is the same text that is displayed in the dbmlsync log.
error id (in)	integer	An ID that uniquely identifies the message. Use this row to identify the error message, as the error message text may change.
error hook user state (in\|out)	integer	This value can be set by the hook to pass state information to future calls to the sp_hook_dbmlsync_all_error, sp_hook_dbmlsync_communication_error, sp_hook_dbmlsync_misc_error, sp_hook_dbmlsync_sql_error, or sp_hook_dbmlsync_end hooks. The first time one of these hooks is called, the value of the row is 0. If a hook changes the value of the row, the new value is used in the next hook call.
subscription_n (in)	subscription name(s)	The names of subscriptions being synchronized where n is an integer. This is one subscription_n entry for each subscription being synchronized. The numbering of n starts at zero.

Remarks

Each time a dbmlsync error message is generated, the following hooks are called:

First, depending on the type of error, one of the following hooks is called: sp_hook_dbmlsync_communication_error, sp_hook_dbmlsync_misc_error, or sp_hook_dbmlsync_sql_error. These hooks contain information specific to the type of error; for example, sqlcode and sqlstate are provided for SQL errors.
Next, the sp_hook_dbmlsync_all_error is called. This hook is useful for logging all errors that occurred.

If an error occurs during startup before a synchronization has been initiated, the #hook_dict entries for MobiLink user and Script version are set to an empty string, and no publication_n or subscription_n rows are set in the #hook_dict table.

The error hook user state row provides a useful mechanism for you to pass information about the nature of the error to the sp_hook_dbmlsync_end hook, where you might use that information to decide whether to retry the synchronization.

This procedure executes on a separate connection to ensure that operations it performs are not lost if a rollback is performed on the synchronization connection. If dbmlsync cannot establish a separate connection, the procedure is not called.

Since this hook executes on a separate connection you should use care when accessing tables that are being synchronized in your hook procedure because dbmlsync may have locks on these tables. These locks could cause operations in your hook to fail or to wait indefinitely.

Actions of this procedure are committed immediately after the hook completes.

Privileges

Hook procedures can be created by any user with the MANAGE REPLICATION system privilege. However, to ensure that the hook can access the #hook_dict table, which is used to pass information in and out of hooks, hooks must meet one of the following requirements:

Be owned by a user with the SELECT ANY TABLE and UPDATE ANY TABLE system privileges.
Be defined using the SQL SECURITY INVOKER clause of the CREATE PROCEDURE statement.

Example

Assume you use the following table to log errors in the remote database.

CREATE TABLE error_log
(
 pk INTEGER DEFAULT AUTOINCREMENT PRIMARY KEY,
 err_id INTEGER,
 err_msg VARCHAR(10240),
);

The following example sets up sp_hook_dbmlsync_all_error to log errors.

CREATE PROCEDURE sp_hook_dbmlsync_all_error()
BEGIN
 DECLARE msg VARCHAR(10240);
 DECLARE id INTEGER;

 // get the error message text
 SELECT value INTO msg
  FROM #hook_dict
  WHERE name ='error message';

 // get the error id
 SELECT value INTO id
  FROM #hook_dict
  WHERE name = 'error id';

 // log the error information
 INSERT INTO error_log(err_msg, err_id)
  VALUES (msg, id);
END;

To see possible error id values, test run dbmlsync. For example, if dbmlsync returns the error "Unable to connect to MobiLink server", sp_hook_dbmlsync_all_error inserts the following row in error_log.

1,14173,
 'Unable to connect to MobiLink server'

Now, you can associate the error "Unable to connect to MobiLink server" with the error id 14173.

The following example sets up hooks to retry the synchronization whenever error 14173 occurs.

CREATE PROCEDURE sp_hook_dbmlsync_all_error()
BEGIN
 IF EXISTS( SELECT value FROM #hook_dict 
    WHERE name = 'error id' AND value = '14173' )
 THEN
    UPDATE #hook_dict SET value = '1' 
       WHERE name = 'error hook user state';
   END IF;
END;

CREATE PROCEDURE sp_hook_dbmlsync_end()
BEGIN
 IF EXISTS( SELECT value FROM #hook_dict 
    WHERE name='error hook user state' AND value='1')
 THEN
    UPDATE #hook_dict SET value = 'sync' 
       WHERE name='restart';
   END IF;
END;

See sp_hook_dbmlsync_end.

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