Magento 1.9.2.4
Ubuntu 14.04
MySQL 5.6
When users subscribe or unsubscribe from a newsletter, it's taking over a minute for the site to respond.
Enabled myQSL logs. I can see the delay between SQL calls, all of the queries/updates run in milliseconds when executed manually. Looked for slow queries and none were logged. Enabled debug profiling but it doesn't show anything running for too long - I think it's displaying the profile data for the page that renders after submission is complete. Seems to be in the code somewhere, but not sure what else to enable/debug to further t-shoot the issue.
System resources look good. Mostly idle CPU 95%+ idle. Memory ok. Other functions in the store/site work ok.
Any help appreciated. Thanks.
