Export queue is backlogged as Export is running very slow. Export slow. (4224468)

Why are messages backlogged in the export queue?

If the network is nomal and no I/O issues, it could be that the import write commit values on the target are set high

On Target, make sure that SP_IMP_WCMT_MSGCNT & SP_IMP_WCMT_TIMEOUT are set to default.

SP_IMP_WCMT_MSGCNT
This parameter works in conjunction with the SP_IMP_WCMT_TIMEOUT parameter. It defines the number of messages that are processed before the Import process checkpoints. Checkpointing saves the state of the process in case it is needed for failure recovery. When Import checkpoints, it triggers the Export process to perform its own checkpoint. If the value for this parameter is reached before the value set for SP_IMP_WCMT_TIMEOUT, it triggers the checkpoint. In a WAN environment, you can increase this parameter to as many as 10,000 messages, with the understanding that increasing the message interval between checkpoints can negatively affect SharePlex's fault tolerance. If you are using SharePlex in an environment where the network continually fails, you can decrease this parameter.
Default: 1,000 messages
Range of valid values: any positive integer
Takes effect: immediately
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SP_IMP_WCMT_TIMEOUT
This parameter works in conjunction with the SP_IMP_WCMT_MSGCNT parameter. It defines the number of seconds that pass before the Import process checkpoints.Checkpointing saves the state of the process in case it is needed for failure recovery.When Import checkpoints, it triggers the Export process to perform its own checkpoint. If the value for this parameter is reached before the value set for SP_IMP_WCMT_MSGCNT, it triggers the checkpoint.
Default: 30 seconds
Range of valid values: any positive integer
Takes effect: immediately

Additional Information:

Setting import writecommit values on the target high, may increase performance on the target. However, messages in the export queue are readreleased when import writecommits, not when the messages are posted.

 

You can run a number of diagnostics like truss, snoop, pfiles, etc on both Export (sp_xport) and Import (sp_mport) processes to get more clues to determine if the disk I/O and fdsync() calls were slow. One thing that can certainly be checked is whether the parameter SP_QUE_SYNC is set to a value other than the default of 0, and if so, you can unset it. This workaround will mitigate the issue since it will cause less I/O which are typical when the parameter is set to a value other than the default.