If the index is on linux, you can run this cli command in the frozen directory to list the human readable start and end dates/times for the buckets and pipe it to a txt file for review...
Format to list bucket names with start and end dates
ls -d1 db_* | gawk -F'_' '{print $0} {print " " strftime("%c", $3)} {print " " strftime("%c", $2)}'
sample output
db_1549387088_1541611191_68_9E0CD82F-4920-47E4-8142-B1FE5AD9E314
Wed 07 Nov 2018 12:19:51 PM EST
Tue 05 Feb 2019 12:18:08 PM EST
db_1549775541_1549387335_69_9E0CD82F-4920-47E4-8142-B1FE5AD9E314
Tue 05 Feb 2019 12:22:15 PM EST
Sun 10 Feb 2019 12:12:21 AM EST
Rich
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