MySQL query suck in NULL state (1 reply)

Hello,
I'm using Oracle MySQL 5.6.26, Running the query which stuck in the "NULL" state. Time to time it changes the state to "Opening tables" and then back to "NULL" state. Have tried to double size "table_open_cache" parameter, but that doesn't help. No locks or deadlocks related to the code. Nothing strange in logs or inside innodb status. Query just keeps running with "NULL" state infinitely.
Please help.
Thank you.