bectl slow

Preparing to update the OS, I created a new boot environment. Creation 
took a long time, subsequent bectl commands are extraordinarily slow.

Whilst composing this e-mail I'm awaiting completion of a simple list.

Any ideas?

zpool status shows no problem. Last scrubbed 27th December, I'll begin a 
scrub after the current 'bectl list' command completes …

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grahamperrin_at_momh167-gjp4-8570p:~ % su -
Password:
root_at_momh167-gjp4-8570p:~ # svn up /usr/src
Updating '/usr/src':
U    /usr/src/lib/libmemstat/memstat_uma.c
U    /usr/src/lib/clang/libllvmminimal/Makefile
U    /usr/src/stand/common/part.c
U    /usr/src/stand/common/disk.c
U    /usr/src/stand/uboot/common/main.c
U    /usr/src/stand/uboot/lib/libuboot.h
U    /usr/src/stand/libsa/cd9660.c
U    /usr/src/stand/libsa/zfs/zfs.c
U    /usr/src/stand/lua/password.lua
U    /usr/src/stand/powerpc/uboot/Makefile
U    /usr/src/sys/arm/freescale/imx/imx6_snvs.c
U    /usr/src/sys/amd64/amd64/pmap.c
U    /usr/src/sys/amd64/sgx/sgx_linux.c
U    /usr/src/sys/dev/netmap/netmap_freebsd.c
U    /usr/src/sys/dev/netmap/netmap_kern.h
U    /usr/src/sys/conf/ldscript.riscv
U    /usr/src/sys/contrib/libnv/nvpair.c
U    /usr/src/sys/kern/sys_pipe.c
U    /usr/src/contrib/libc++/include/type_traits
U    /usr/src/usr.bin/kdump/kdump.c
U /usr/src/usr.sbin/bsnmpd/modules/snmp_hostres/hostres_partition_tbl.c
U    /usr/src/usr.sbin/rpc.ypupdated/update.c
U    /usr/src/usr.sbin/bsdinstall/partedit/partedit_powerpc.c
U    /usr/src/etc/mtree/BSD.root.dist
Updated to revision 344269.
root_at_momh167-gjp4-8570p:~ # svn up /usr/src
Updating '/usr/src':
At revision 344269.
root_at_momh167-gjp4-8570p:~ # bectl create r344269
load: 0.64  cmd: bectl 33517 [fu_ans] 29.69r 0.00u 0.01s 0% 4460k
load: 0.49  cmd: bectl 33517 [fu_ans] 53.59r 0.00u 0.01s 0% 4460k
root_at_momh167-gjp4-8570p:~ # date ; uptime ; uname -v
Tue Feb 19 01:46:46 GMT 2019
  1:46AM  up  1:11, 4 users, load averages: 0.42, 0.57, 0.79
FreeBSD 13.0-CURRENT r344013 GENERIC-NODEBUG
root_at_momh167-gjp4-8570p:~ # time bectl list | sort
load: 0.10  cmd: sort 33904 [piperd] 1145.34r 0.00u 0.00s 0% 2612k
^C^C
load: 0.18  cmd: bectl 33903 [fu_ans] 1175.24r 0.01u 0.03s 0% 4740k
^Croot_at_momh167-gjp4-8570p:~ # date
Tue Feb 19 02:07:07 GMT 2019
root_at_momh167-gjp4-8570p:~ # time bectl list
BE            Active Mountpoint Space Created
r344013       NR     /          22.6G 2019-02-11 16:17
r344231       -      -          3.81G 2019-02-17 16:38
r343747       -      -          6.57G 2019-02-04 18:04
r343883       -      -          6.90G 2019-02-07 23:11
r342466       -      -          521M  2019-01-07 07:53
r344269       -      -          392K  2019-02-19 01:42
20190131-0125 -      -          487M  2019-01-31 01:25
default       -      -          2.16M 2018-12-22 05:01