Re: Postgres will not allow new connections, suspended process, waiting error

More details.

Environment
PostgreSQL 9.5, EnterpriseDB Postgres installer
Windows Server 2012R2 with Active Directory
Symantec End Point Protection

Symptom:

After about 1 week of running, one of PostgreSQL process (postgres.exe)
showed "suspended" in task manager, and I cannot kill it in the task
manager ("Access Denied" error message appeared). This "suspended" process
was not the master PID as indicated in postmaster.pid file.
Current live connections still work but one cannot establish new
connections. The only solution that I have is to restart the Server
Other information:

The PostgreSQL service is run under a domain account.
The maximum connection was never reached as it is set as 1000 and we only
had about 10 connections.
There was plenty of available memory there. The total memory is 288GB and
only 8% was used
There were minimum hard drive activities as it occurred. The C drive where
PostgreSQL was installed had about 86GB of free space.
There are additional 4 table spaces that are not on C drive but spread over
4 hard drives. Each of 4 hard drives has more than 500GB of space.
we have been using the same configuration files for years and the same file
is also used on a second PostgreSQL server, which does not have the issue
at all.
The PostgreSQL logs had something like this when this happened and it
continues to produce this warning message every minute or so:

2017-06-28 19:40:21 CDT WARNING: worker took too long to start; canceled
2017-06-28 19:41:21 CDT WARNING: worker took too long to start; canceled
2017-06-28 19:42:21 CDT WARNING: worker took too long to start; canceled
2017-06-28 19:43:21 CDT WARNING: worker took too long to start; canceled

On Fri, Jun 30, 2017 at 4:28 PM, Prateek Mahajan <prateekm99(at)gmail(dot)com>
wrote:

> Maximum connection is never reached
>
> *--*
> *Prateek Mahajan*
> McCombs School of Business | Business Honors and Finance
> Cockrell School of Engineering | Mechanical Engineering
> The University of Texas at Austin
> (832) 420-2622 | prateekm99(at)gmail(dot)com
>
>
>
> On Fri, Jun 30, 2017 at 3:46 PM, Brian Farrell <brian(dot)farrell(at)vt(dot)edu>
> wrote:
>
>> Have you checked to see if you're bumping up against the max_connections
>> limit? https://www.postgresql.org/docs/current/static/runtim
>> e-config-connection.html#GUC-MAX-CONNECTIONS
>>
>> -Brian
>>
>> On Fri, Jun 30, 2017 at 4:39 PM, Prateek Mahajan <prateekm99(at)gmail(dot)com>
>> wrote:
>>
>>> We have a recurring problem where Postgres will not allow any new
>>> connections. Any connection already made keeps working fine. Every time
>>> this happens, we also have one suspended postgres.exe process that can not
>>> be cancelled. Also, we get the following error in the logs every minute:
>>> ‘WARNING: worker took too long to start; canceled’.
>>>
>>>
>>> We’re using Postgres 9.5 on Windows Server 2012 R2. Our original
>>> hypothesis was that there was something wrong with the autovac settings,
>>> but we copied the settings over from our other server that does not have
>>> this problem and still continue to have problem.
>>>
>>>
>>>
>>
>>
>> --
>> Brian Farrell
>> Project Associate
>> Center for Geospatial Information Technology
>>
>>
>