One of my client’s sites had been running slowly and I was not able to run an update script after upgrading a plugin without timing out. In the process of moving the site to a new host, I found the [wp-prefix]_options table was really big – over 300,000 entries. After doing some digging, I found the table was full of rows named _transients… and _wc_session… Once I cleared these out, the database dropped in size from over 200MiB to 12MiB and the site sped up considerably. I was also able to run update scripts on the database for WooCommerce and upgrade to ACF Pro 5+ both of which were timing out before.
I read this can be caused by the cron job not running. Hopefully moving to a different host will solve that issue. And hopefully this will save someone from banging their head like I was – all day yesterday! This issue caused the site to load slow, timeout errors and just weird stuff all around.