Hi, HAWQ sometimes use gettimeofday() syscall for some timeout check in various module, however it could be affected by ntp, so the timeout checking logic could be wrong sometimes. I would propose to use clock_gettime() to replace it on Linux (I have not investigated the alternative on other platforms e.g. mac). Both gettimeofday() and clock_gettime() are fast vdso sys call so I do not expect there is performance loss in some case where there are frequent calls of gettimeofday(). By the way, I found some gettimeofday() calls on postgresql and gpdb, so they might have this issue also.
Regards, Paul
