Error : Pool is closed


We are getting Pool is closed error in node-red.

Flow is clear, I have deleted all nodes.

Please find attached backup of nodered also.

Thanks & Regards,

You will still have a configuration node defined. Select "configuration nodes" from the menu. Find the mysql one and delete it.

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Hi - this is now the third time this specific question has been asked (and answered) in the last couple of days. Is that a coincidence or are you asking again and again hoping for a different answer?

Those messages are coming from a node. The node id begins with 1a47... - in the top right corner of the debug messages.

  1. Have you searched for the node id to find it (starts 1a47 in the top right corner of the debug messages)?
  2. Have you opened the Configuration Nodes sidebar and checked you have no nodes hiding in there?
  3. Have you restarted Node-RED since deleting everything just to make sure it wasn't a badly implemented node that hasn't tidied up after you deleted it.
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This and another almost identical question from @aanand were created together.

Please don't waste people's time by asking the same thing more than once thanks.

thanks guys.

I have the same problem, i can´t find the node id
and send the data to the mysql database.

my configuration nodes not have that node id
how do I (which use command) to restart the node-red?

The command to restart node-red will depend on what system you are running. If it is a pi, check on the raspberry pi page in the docs.

i´m use windows 7

I have had the same problem in combination with writing and may be reading from a MariaDB based on my NAS. The node number was the internal server connection to MariaDB. That one when you click to select the database server.
My search was:
First I reboot my Pi with Nodered. - No change
I found that the DB on the NAS was apr. 1Gb in size. So I did export it and cleared it after the export - The Problem remains.
Than I reboot my Pi again - and it works fine
Tooks me 1 Day :slight_smile: to find this out


Folks, rebooting Pi when this message occurs isn't an option (because that box does other thigs as well ...) is there a way to find the root cause for the message and then fix that ? thanks !!

Hi All,

I'd just like to add that I have just had this issue using Node-RED v1.0.4 and node-red-node-mysql 0.1.0. I have Node-RED running in a docker container on my 4GB raspberry pi and MySQL on another machine on my subnet running in a docker container too in order to test the use of MySQL. I had no problems running this initially but found that over a few days, when MySQL wasn't running and the pi was that I get this error, even after a full deploy - when MySQL is running fine. The node would cycle between OK and POOL CLOSED but I'd have streams of debug messages.

Deleting the mysql node from the flow doesn't stop it. Neither does deleting the nodes from configuration nodes tab.

Is it possible that this a a list of historic errors that just get processed and time stamped with the current date and time jst to get through them?

I've spent about 10 mins ctrl-alt-l'ing' them to test this out but I figure their could be 1000's of them queued. However this is just a guess. The alternative would be that this node won't die nicely!

I was inserting into an even table every event and selecting from the table every 5 seconds. This went on whether or not MySQL was running (of course the inserts and selects didn't work but I still tried to do them)


PS Rebooting cleared the error but how would I check if they were really a backlog of errors?

Have you restarted node red? I believe some config node related stuff may may not get cleaned up fully until you do that.

[Edit] just noticed that you said that rebooting cleared it. A node-red restart would have cleared it too. It isn't caused by a backlog of messages, I believe it is caused by the fact that some code installed with the mysql node is not removed from the system even though you removed the config node. It is necessary to restart node-red to get rid of it. I remember seeing a general warning about this somewhere but can't find it now.

I have set the debug to "current flow" but I'm still getting "Error: Pool is closed.". My other flow is using the mySQL (no connection at this moment) but I don't want to change the working configuration, is there anyway I can keep this "Error: Pool is closed." quiet? Thx