Re: "Sending Data" is taking time post migration from 5.1 to 5.6

[Peter Brawley]

Default_tmp_storage_engine specifies the temp table storage engine, which before 5.6.3 was just default_storage_engine, so in your case it was probably MyISAM, which might be faster if the temp table fits in memory and is keyless. Have you tried changing default_tmp_storage_engine?

Did you try the update with and without the query_cache?

You could try, while this update is dawdling along, logging into mysql to run Show InnoDB Engine Statusand look for stalled locks in the Clustered Index.

If those fiddles don't help, let's see Show Create Temporary Table result, and the result of running Explain on the update query.