On Wed, Aug 17, 2016 at 4:28 PM, Andres Freund <and...@anarazel.de> wrote: > Could you also provide a strace -ttt -T -c and a cpu cycles flamegraph?
Here is the output from that strace invocation, plus a -p (to attach to the relevant backend): strace: -t has no effect with -c strace: -T has no effect with -c strace: Process 27986 attached strace: Process 27986 detached % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 55.75 0.629331 17981 35 16 unlink 17.49 0.197422 0 2505449 write 11.69 0.132000 11000 12 fsync 8.13 0.091799 0 2078837 read 5.32 0.060000 12000 5 ftruncate 0.98 0.011011 24 460 brk 0.64 0.007218 1805 4 munmap 0.00 0.000050 0 6382 lseek 0.00 0.000000 0 58 5 open 0.00 0.000000 0 58 close 0.00 0.000000 0 14 stat 0.00 0.000000 0 4 mmap 0.00 0.000000 0 2 rt_sigprocmask 0.00 0.000000 0 12 6 rt_sigreturn 0.00 0.000000 0 1 select 0.00 0.000000 0 16 sendto 0.00 0.000000 0 2 1 recvfrom 0.00 0.000000 0 16 kill 0.00 0.000000 0 19 semop 0.00 0.000000 0 63 getrusage 0.00 0.000000 0 5 epoll_create 0.00 0.000000 0 9 4 epoll_wait 0.00 0.000000 0 10 epoll_ctl ------ ----------- ----------- --------- --------- ---------------- 100.00 1.128831 4591473 32 total This doesn't seem that interesting, but not sure what you're looking for. I also attach cycles flamegraph. trace_sort indicated that the tuplesort CLUSTER takes just under 3 minutes (this includes writing out the new heap, of course). -- Peter Geoghegan
cycles-cluster-presorted-flamegraph.svg.gz
Description: GNU Zip compressed data
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