When executing certain queries, the following error may occur. The cause is a processing conflict.
{
"requestId": "c4b8f484-2de1-b8a4-81dd-6b225981653f",
"code": "ConcurrentModificationException",
"detailedMessage": "Operation failed due to conflicting concurrent operations (please retry), 0 transactions are currently rolling back."
}
To check what other queries are running, use the SPARQL Query Status API. The queryString field contains the actual SPARQL query being executed.
[ec2-user@bastin ~]$ curl https://xxxxxxxx.xxxxxx.ap-northeast-1.neptune.amazonaws.com:8182/sparql/status | jq
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 205 0 205 0 0 9318 0 --:--:-- --:--:-- --:--:-- 9318
{
"acceptedQueryCount": 8,
"runningQueryCount": 1,
"queries": [
{
"queryId": "372954e5-f674-497e-ae1f-0d772e636e41",
"queryEvalStats": {
"subqueries": 0,
"elapsed": 1034223,
"cancelled": false
},
"queryString": "clear all"
}
]
}
Reference
SPARQL Query Status API - Amazon Neptune https://docs.aws.amazon.com/ja_jp/neptune/latest/userguide/sparql-api-status.html