I'm just playing around on tools-sgebastion-08. I can dump the first 1 million image names about half a minute:
tools.spi-tools-dev:xw-join$ time mysql --defaults-file=$HOME/replica.my.cnf -h commonswiki.web.db.svc.wikimedia.cloud commonswiki_p -N -e 'select img_name from image limit 10000000 ' > /dev/null
real 0m36.586s
user 0m9.678s
sys 0m1.324s
but if I try 10 million, it fails:
tools.spi-tools-dev:xw-join$ time mysql --defaults-file=$HOME/replica.my.cnf -h commonswiki.web.db.svc.wikimedia.cloud commonswiki_p -N -e 'select img_name from image limit 100000000 ' > /dev/null
Killed
real 0m9.875s
user 0m1.417s
sys 0m1.561s
Is there some maximum query size configured by default? The full image table on commons is about 70M rows, so extrapolating from the first example, something like 1 hour to move all that data.
That could be RAM limits on the bastion.
Actually, scratch that, I’ve confirmed you were killed by the OOM killer on that bastion:
Mar 31 23:29:17 tools-sgebastion-08 kernel: [2860588.199138] mysql invoked oom-killer: gfp_mask=0x6000c0(GFP_KERNEL), nodemask=(null), order=0, oom_score_adj=0