Hi, On 2017-06-19 14:49:07 +0000, josef.machytka@gmail.com wrote: > The following bug has been logged on the website: > > Bug reference: 14714 > Logged by: Josef Machytka > Email address: josef.machytka@gmail.com > PostgreSQL version: 9.6.3 > Operating system: Debian jessie > Description: > > On pg 9.6.* we have sometimes strange problem with some sessions. We > experienced it from bash scripts, golang program and node.js applications. > Environment are Google Compute Engine instances with Debian 8. > > Sometimes some session goes into some kind of "drowsy" state and runs > incredibly slowly. It causes some very low disk IO and runs like 20x slower > then usual. This happens mainly when database is under heavy load and it > happens randomly to different tasks. It happens randomly to both connections > from local instance (cronjob running on instance with PG) and remote > connections from other instances. > > When we restart task it runs normally. I cannot see any changes in process > priority in OS, process switches between sleeping and running state and I do > not see any locks or waits in pg_stat_activity or pg_locks. Usually all > other processes finish OK and this "drowsy" one runs "for ever..."
Which version of the os & kernel is this? This kind of sounds like the symptoms that we've observed more frequently a while ago with the kernel's transparent_hugepages management.
