Linan, I tried your sample code and confirmed the behaviour you reported. Then I changed mnesia:s_write/1 to mnesia:write/1 and it worked as expected. -Vance On Sat, Nov 22, 2008 at 04:32:52PM +0000, Linan Wang wrote: } thanks for the suggestion.I changed all s_write, wread, s_delete to } straightforward write, read, delete. it does not help.