I am running PSQL with PostGis extension. After the start of server, after about 3 weeks, I start getting fatal errors for connections with "too many clients already". When I restart the server, problem is gone, but is back again after aprox. 3 weeks.

If I run pg_stat_activity, I got

SELECT state, count(*) FROM pg_stat_activity GROUP BY state;


And all idle queries are the same - SELECTs.

I cannot debug this problem and restarting server all over is not a real solution.

2 Answers 2


Your application has a connection leak. There is no way to fix this on the database side - you'll have to change the application so that it closes connections again.

I guess you set max_connections so high to work around this problem (1000 is too high).

  • Connections with this idle select are from PHP. PHP should close connection at the end of the script. Commented Aug 7, 2019 at 8:37
  • @MartinPerry Perhaps it should, but the evidence indicates that it does not. So this is a PHP problem, not a PostgreSQL problem.
    – jjanes
    Commented Aug 7, 2019 at 15:18
  • I have check the code, PHP is closing connections. The idle connections are all from a narrow time window (few minutes), several times a day. But the scripts that runs on the server are used whole day. From logs, there is also no special activity or errors at those "idle" times. Just to be sure, I have explicitely added $pq = null; to the end of each script (where $pq is my Psql wrapper class) Commented Aug 7, 2019 at 15:52
  • 1
    @MartinPerry Is there a storm of new script initiations at that point? What library are you using? "I have explicitely added $pq = null;" Does your library provide a specific method such as "$pq->pg_close()" ? That should be more reliable than hoping the garbage collectors gets around to it.
    – jjanes
    Commented Aug 7, 2019 at 16:10
  • There is no difference in server scripts behaviour. I am using plain pg_connect and pg_close in my own wrapper. pg_close is called from class destructor. Commented Aug 7, 2019 at 16:12

if it possible for you, you can kill the connection based on its idle time but its always better to fix it at app level.


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