> I think it could fail that way for two reasons: /dev/shm size limit > (mount option, which I think you are saying you have set to 4GB?), or > your system ran out of RAM +swap. df /dev/shm Filesystem 1K-blocks Used Available Use% Mounted on shm 4194304 351176 3843128 9% /dev/shm mount | grep /dev/shm shm on /dev/shm type tmpfs (rw,nosuid,nodev,noexec,relatime,size=4194304k) I have no swap and 8GB of RAM, when there is no active queries only ~800MB of RAM is used. So I don't believe that it is out of memory problem. > The directly listing in your first > message only shows 1.4GB, not 4GB, so perhaps it's the second problem. I cannot catch the right moment with ls, but I've run bash for-loop that that logs "df /dev/shm" every minute and the last entry before fail shows that 89% of /dev/shm is used: Filesystem 1K-blocks Used Available Use% Mounted on shm 4194304 3732368 461936 89% /dev/shm There is no other processes that use /dev/shm. > It's strange that it's hashing the ~20B row table instead of the ~30M row table. It could be a question for another mail thread =) Konstantin
