"Maximum number of concurrently executed transactions" error encountered

[a_teste]

Hello ,

I am currently working with the 4.4.0 version of the Neo4j Desktop, on mac of version 11.6.2.
I have been able to load 1.24M nodes and am now trying to load the associated 3.1M relationships.

I have tried loading them with the following command

:auto USING PERIODIC COMMIT 1000
LOAD CSV WITH HEADERS
FROM "file:///2022-01-05_seattle_users_relationships.csv" as row
MATCH (follower:user {id:row.user_id})
MATCH (followed:user {id:row.follows_id})
MERGE (follower)-[r:FOLLOWS]->(followed)
  ON CREATE SET
  r.age=row.relationship_age

but am getting the following error:

Neo.TransientError.Transaction.MaximumTransactionLimitReached
Unable to start new transaction since limit of concurrently executed transactions is reached. See setting dbms.transaction.concurrent.maximum

I also tried running the same command with smaller files. The first 2 were processed properly, but the 3rd one showed the same error.

I tried looking for the dbms.transaction.concurrent.maximum field in the neo4j.conf file, but could not find it.
Could you please let me know if I should add that field to that file? And if so, what value I should assign to it? if not that, could you let me know how I could solve this problem?

If that can help, the rows in my relationship file look like the below:

user_id,follows_id,created,relationship_age
12345,98765,2019-05-05 07:00:00 UTC,976

Thank you very much for any help you can provide.
Alexandra.

[david_allen]

To answer you on the config question, yes you can just add a new line into your neo4j.conf to accomplish that.

But separately - a single LOAD CSV statement (no matter what the data is) should never run into this problem, so it might be a symptom that something else is going on. What other programs are talking to this database at the time?

[a_teste]

Hello David,

Thank you for your helpful response. I will add the dbms.transaction.concurrent.maximum field to the neo4j.conf file then. I will try with something like 1000, and see if that works. If not, I will increase it.

Actually nothing else was talking to the database. I was just trying to visualize and explore data on the Neo4j Desktop.

[Freymaurer]

I too, am trying to load a larger .tsv file into my db. I run the docker version which has no further connections and use the .NET driver.

My query is:

USING PERIODIC COMMIT LOAD CSV WITH HEADERS FROM 'file:///SanatizedTerms.tsv' AS line FIELDTERMINATOR '\t'
CREATE (:Term {accession: line.TermAccession, name: line.Name, description: line.Description, isObsolete: line.IsObsolete})
RETURN linenumber() AS number, line

The file contains information for 2604648 nodes and i get the same error:

One or more errors occurred. (Unable to start new transaction since limit of concurrently executed transactions is reached. See setting dbms.transaction.concurrent.maximum)

Where you able to resolve the issue?

[tirtharajsengup]

If you set the value of dbms.transaction.concurrent.maximum to 0 then it will disable the limit to number of transactions and you don't have to worry about exceeding the transaction limit.

[andrew_bowman]

We've identified a bug causing this error.

Please be on the lookout for a fix in an upcoming Neo4j 4.4.4 patch.