Threads stuck in COMMIT phase

I’m encountering an issue on an Amazon RDS box running mysql 5.6.
There’s a application process that runs lots of concurrent single-row updates on an innodb table, using the primary key.
update a set blah=blah … where ID = X;

We’ve been consistently seeing 8-10 threads stuck in a commit state for 2-8 seconds.

This RDS instance is dedicated to this one schema, and this is the only table receiving any significant write activity during this time.
Table has approx 70k records.


The table has 3 text columns and one mediumtext column, which seems significant based on what I’ve googled.

We updated the server to run file_format=barracuda and row_format=compressed

Still get similar behavior, but now the 8-10 threads are stuck in “query end” state for several seconds at a time.

What should I check for next?

We tracked this down last week. It seems to have been due to bumping up against an iops threshold on AWS. Increasing to a higher level of provisioned IOPS sorted us out.