ECONNCLOSED: Connection is closed - Concurrent SQL connections result in first succeeding and all other failing

[tenaka30]

Recently forced to move from age old node-red install version (think 0.something) and node-red-contrib-mssql.

Flows imported fine but with node-red-contrib-mssql no longer maintained (deleted?) we have moved to node-red-contrib-mssql-plus. Now we see where concurrent table reads/writes work in the older Node they fail in mssql-plus.

A few of our flows for example read from multiple tables in a single DB, then join the results for an external report or email.

[Steve-Mcl]

Can you provide a demo flow and / or screenshots explaining what the issues are?

The old MSSQL node and this may not be 100% compatible (due to bug fixes, underlying library updates and new features) so it may be you simply need to tweak a setting.

What I can say is multiple queries are definitely supported so perhaps there is a bug (or misconfiguration).

Please provide additional feedback.

[tenaka30]

Can you provide a demo flow and / or screenshots explaining what the issues are?

The old MSSQL node and this may not be 100% compatible (due to bug fixes, underlying library updates and new features) so it may be you simply need to tweak a setting.

What I can say is multiple queries are definitely supported so perhaps there is a bug (or misconfiguration).

Please provide additional feedback.

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This is the simplest example with the server names removed, no other alterations. It seems to succeed top to bottom, if I disconnect the top SQL query the next one functions and so on.

Edit: Sorry, I assumed selecting code block would avoid wall of text. - EDIT2: Fixed code block

[tenaka30]

Can you provide a demo flow and / or screenshots explaining what the issues are?

The old MSSQL node and this may not be 100% compatible (due to bug fixes, underlying library updates and new features) so it may be you simply need to tweak a setting.

What I can say is multiple queries are definitely supported so perhaps there is a bug (or misconfiguration).

Please provide additional feedback.

Not sure what screenshots would be most helpful but this is the flow sample above whne ran.

[tenaka30]

I was mistaken, the older server is still available and I can now see we were not using the older node-red-contrib-mssql but an old version of node-red-contrib-mssql-plus v0.4.0 and node-red was 0.20.5

We have been using these versions for about 4 years I think.

[Steve-Mcl]

@tenaka30

Sorry, I assumed selecting code block would avoid wall of text.

---

So, you are trying to run concurrent queries - while this could/should work (I will look into this later), it is not the ideal composition.

There are 2 approaches i would take on this

1. Put all queries into 1 request
2. chain the requests (sending results to msg.result1, msg.result2, etc)

Here is an example of doing multiple queries in one

Settings

Results

flow...

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[tenaka30]

Hmm, that nice-ified it but still massive scroll space. EDIT: Scrap that, i realised it was because it had inherited formatting at some point. Thanks for that.

So, you are trying to run concurrent queries - while this could/should work (I will look into this later), it is not the ideal composition.

There are 2 approaches i would take on this

1. Put all queries into 1 request

2. chain the requests (sending results to `msg.result1`,  `msg.result2`, etc)

As I mentioned the older version of this node seem to have no problems with it but it was an incredibly old version so we have definitely lost something along the way. I had another thought after a bit that with the rebuild we have also brought the node-js install up to date as well so wondered if it was a possible change within the platform that has trickled down.

I've already started on putting the requests in sequence as needs-must and we rely on the reporting.

The original reasoning against putting them all in one request was that we wanted to enable or disable certain tables easily but I do prefer it for it's tidyness myself.

Thanks.

[flight2k]

Hi, I have the same issue with the lastest version. But i can't but all my query in the same request.

[Imi3est]

I had the same issue with node-red-contrib-mssql. I still use it but was thinking to replace it to this new version because of this bug, but I see that it is still exists in this version. I have a subflow to save different types of measured data to database. I use it multiple times in my flows so sometimes it is called from diffrent places in almost same time. If that occures I get an error and data is not stored. Catch node can't catch the error so I can't repeat the db call. It is easy to reproduce: Just put an inject node and link output into two paralell sql nodes. (In my case it is a stored proc call) I think it is a bug and it should be fixed because it is problematic to use the node multiple times in flows. Finally I found a workaround: Instead of subflow I use the node-red-contrib-component nodes and I limiting messages with delay node (with message rate). With subflow I can't limit messages globally because subflow nodes works as they would be copies for every instance. This is why I moved to component nodes. This is how it looks like:

[Steve-Mcl]

For anyone else reading in 2025, the component node are no longer a requirement - the same can be achieved in newer node-red using link-call nodes.

I have not got to the bottom of concurrent fails but suspect it is due to a combination of SQL server/Azure, pool size, upstream and the code in our node.

Lets see how the v0.13.0 release (#119) (where we updated to MSSQL v11 in #113 ) plays out.