Archiving very slow [Solved?]

Hi, I have a “low traffic” website, and I have been using the archiving from Browser. It happens that I needed to try log importation, so I had to run archiving from CLI, and it hasn’t finished after 5 hours. More precisely,
I have got

 core:archive --force-all-websites --force-all-periods=315576000 --force-date-last-n=1000 --url= ...
INFO [2016-03-06 06:18:09] ---------------------------
INFO [2016-03-06 06:18:09] INIT
INFO [2016-03-06 06:18:09] Running Piwik 2.15.0 as Super User
INFO [2016-03-06 06:18:09] ---------------------------
INFO [2016-03-06 06:18:09] NOTES
INFO [2016-03-06 06:18:09] - If you execute this script at least once per hour (or more often) in a crontab, you may disable 'Browser trigger archiving' in Piwik UI > Settings > General Settings.
INFO [2016-03-06 06:18:09]   See the doc at: http://piwik.org/docs/setup-auto-archiving/
INFO [2016-03-06 06:18:09] - Reports for today will be processed at most every 150 seconds. You can change this value in Piwik UI > Settings > General Settings.
INFO [2016-03-06 06:18:09] - Reports for the current week/month/year will be refreshed at most every 3600 seconds.
INFO [2016-03-06 06:18:09] - Will process 1 other websites because some old data reports have b
een invalidated (eg. using the Log Import script) , IDs: 1
INFO [2016-03-06 06:18:09] - Will process all 2 websites
INFO [2016-03-06 06:18:10] ---------------------------
INFO [2016-03-06 06:18:10] START
INFO [2016-03-06 06:18:10] Starting Piwik reports archiving...
INFO [2016-03-06 06:18:10] Will pre-process for website id = 1, period = day, date = last1000
INFO [2016-03-06 06:18:10] - pre-processing all visits
INFO [2016-03-06 06:20:59] Archived website id = 1, period = day, 0 segments, 0 visits in last 1000 days, 0 visits today, Time elapsed: 169.016s
INFO [2016-03-06 06:20:59] Will pre-process for website id = 1, period = week, date = last1000
INFO [2016-03-06 06:20:59] - pre-processing all visits
INFO [2016-03-06 06:22:26] Archived website id = 1, period = week, 0 segments, 126 visits in last 1000 weeks, 21 visits this week, Time elapsed: 86.835s
INFO [2016-03-06 06:22:26] Will pre-process for website id = 1, period = month, date = last1000
INFO [2016-03-06 06:22:26] - pre-processing all visits
INFO [2016-03-06 06:22:56] Archived website id = 1, period = month, 0 segments, 126 visits in last 1000 months, 19 visits this month, Time elapsed: 29.345s
INFO [2016-03-06 06:22:56] Will pre-process for website id = 1, period = year, date = last1000
INFO [2016-03-06 06:22:56] - pre-processing all visits

Several hours later, there is no more console output.

If I do

 mysqlbinlog mysql-bin.000042 | tail -100

I see that there has been no activity related to archiving for hours. But if I do

top

I see that mysqld and php are running and consuming cpu time. Any idea on what is going on?

Could you check the list of processes in MySQL?

show full processlist\G;

I had to stop archiving and (un)fortunately, I can’t reproduce the results. Thank you anyway, and next time it happens, I will check the list of processes.