[mythtv-users] backup script failing

[Tim Draper]

i've just upgraded from 30 to 31 and i noticed that while my cron job for the mythconverg_backup.pl has been running, only a small file is being created (2kb, rather than around 150mb) and has been failing since January.

manually connecting with either root or mythtv db user via 'mysql -h sql -r USERNAME -p mythconverg' successfully connects and mythtv otherwise works correctly.
i used phpmyadmin to backup my db before the v31 upgrade.

unfortunately the problem remains after the upgrade which i hoped might recreate/fix what appears to be a DB issue, as part of the db schema update.

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$ ./mythconverg_backup.pl --verbose
....
'/usr/bin/mysqldump' --defaults-extra-file='/tmp/lL5M1sscfa' --host='sql' --port='3306' --user='mythtv' --add-drop-table --add-locks --allow-keywords --complete-insert --extended-insert --lock-tables --no-create-db --quick --add-drop-table 'mythconverg' 2>&1 1>'/mnt/mythtv/dbbackups/mythconverg-1361-20200425130837.sql'

mysqldump exited with status: 2
mysqldump output:
mysqldump: Couldn't execute 'SELECT COLUMN_NAME,                       JSON_EXTRACT(HISTOGRAM, '$."number-of-buckets-specified"')                FROM information_schema.COLUMN_STATISTICS                WHERE SCHEMA_NAME = 'mythconverg' AND TABLE_NAME = 'archiveitems';': Unknown table 'COLUMN_STATISTICS' in information_schema (1109)
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What could be the problem here, and more importantly whats the fix?