Exclusive locks - requests take a long time

Neo4j Graph Platform Cypher
,
1

I have many long term requests like:


MATCH (tx: Survey {uuid: {Id}}), (p: Person {personId: {personId}}), 
MATCH (d: Day {day: {day}})
MATCH (rs: Result {ResultId: {resultId}, isActual: true})
CREATE (ex: SurveyResult) 
CREATE (ex)-->(rs) 
CREATE (ex)-[:comesFrom]->(tx) 
CREATE (ex)-[:executedBy]->(p) 
CREATE (ex)-[:savedOn]->(d) WITH ex UNWIND {answers} AS answer MATCH (a:Answer {uuid: answer}) CREATE (ex)-[:respondedWith]->(a)"

with status=waiting with deadlocks (CALL dbms.listQueries()) like:

resourceInformation
{
"waitTimeMillis": 10788,
"lockMode": "EXCLUSIVE",
"resourceType": "NODE",
"resourceIds": [
8199666
]
}

Requests take a long time, they don't want to end. I checked resourceIds and they are the identifiers of Result objects. These objects are involved in both getSurvey and saveSurveyResult requests. What's wrong?

image
image1361×747 147 KB

I'm using neo4jDriver 1.7.91 that is compatible with neo4j 3.6.2

2

Can you run an EXPLAIN of the query and add that here?

Also, there have been significant locking improvements with respect to relationship creation and deletion in 4.3.x. We'd recommend upgrading to 4.3.4 or later.

3

This type of errors stopped appearing after adding index to the uuid field.