Hi Sergei, Actually I was thinking a different way of implementing this. in function ha_write_row , after it calls storage engine write, we can check for inserted values and see if it is inserted more than once. Of course, it can be I/O intensive (or it may not be , because data should be in buffer ). We have to do this only when there is multiple clients doing inserts in same table. But I am not sure if there is any way to find this. What do you think ? Regards sachin