Database seems inexplicably large

Our Discourse post-timings table size is about 17GB. Is this normal?

table_name row_estimate table_size index_size total_size
post_timings 120967448 6676 MB 10 GB 17 GB
posts 3616224 2413 MB 3219 MB 5632 MB
user_actions 15159571 1215 MB 3699 MB 4914 MB
post_search_data 3531969 3756 MB 1031 MB 4787 MB
notifications 2241273 687 MB 824 MB 1510 MB
topic_views 7696258 369 MB 1110 MB 1478 MB
post_actions 3475097 350 MB 618 MB 968 MB
topic_users 3343623 365 MB 257 MB 622 MB
user_auth_token_logs 1123545 410 MB 110 MB 520 MB
post_stats 2779471 354 MB 155 MB 509 MB
incoming_links 3154654 219 MB 251 MB 469 MB
topics 64301 142 MB 286 MB 429 MB
post_replies 2327812 220 MB 120 MB 340 MB
user_visits 289994 17 MB 229 MB 246 MB
stylesheet_cache 4605 204 MB 840 kB 205 MB
top_topics 40202 19 MB 148 MB 167 MB
user_profile_views 593591 61 MB 97 MB 158 MB
post_revisions 102832 87 MB 8072 kB 95 MB