|Built-in System Procedures / Callback Configuration Procedures|
Attach a custom error handler implementation to address failures that occur when GemFire XD cannot apply DML events that were received over a WAN connection, or applied using DBSynchronizer. Any custom error handler that you install is called in addition to the default error handling. You can install only a single error handler implementation.
By default, GemFire XD logs all failed DML events in the files dbsync_failed_dmls.xml or dbsync_failed_dmls_entries.xml (for DBSynchronizer failures) or failed_gateway_dmls.xml and failed_gateway_dmls_entries.xml (for WAN failures). These files are created in the same directory as the GemFire XD member's log messages. A custom handler is typically used to log failed events in a different format from the native GemFire XD handler. Note, however, that the gfxd replay-failed-dml command can only operate with files that use the native XML structure.
SYS.ATTACH_GATEWAY_EVENT_ERROR_HANDLER ( IN FUNCTION_STR VARCHAR(32672), IN INIT_INFO_STR VARCHAR(32672) )
See Resolving WAN Errors.