Neo4J clog up RAM memory

Hi,
I have a problem with clogging up RAM memory by neo4j, it wasn't first time...

Neo4j 4.4.0 community edition

#1
I was inputting 25mln entries by 5 clients, then occurs this message:

on all of clients.
#2
I restarted database
#3
RAM memory is clogged up. I suppose, that garbage collector not responding.

Thank You in advance,
Jakub

Hello,

4.4.0 is brand new, there may be some bugs around it. Please report any here:

Also, the error you see seems to be not about memory, but about the concurrent number of transactions (which WILL contribute to issues around memory, but the number of concurrent transactions is the root of the problem). You have too many transactions executing simultaneously, which either means (excepting bugs) that the queries being run are untuned and never finishing (do you have an index backing those MERGE operations? Have you looked at adding transaction timeouts in your config) or that your client code isn't properly closing your transactions, and they remain open taking up heap memory.

You may want to show the transactions or queries executing, and once you make a note of which queries are hanging around and what state they're in, manually killing the ones that are not finishing.

1 Like

Goodafternoon,
I also get these problems with 4.4.
Maybe there is something wrong with 'gentle' transition from: the Deprecated function USING PERIODIC COMMIT to CALL {SUBQUERY} IN TRANSACTIONS see*.

For me it worked to transform to statement to
LOAD CSV WITH HEADERS FROM 'filexyz' AS row
CALL {
WITH row
MERGE ...... etc
} IN TRANSACTIONS
;
This will periodic commit 1000 lines a time.
To change this use
} IN TRANSACTIONS OF 15000 ROWS
;

Yours kindly Omer
*
Deprecations, additions and compatibility - Neo4j Cypher Manual