在ArangoDB中插入或更新文档失败，但违反了约束

我想在ArangoDB中实现Upsert，但我无法使用create-document文档中提供的示例 . 我的请求因 unique constraint violated 错误消息而失败 .

我正在集合中插入具有特定 _key 的文档，并且 overwrite 选项设置为 true ，如文档中所述，但我仍然收到错误消息 . 这是我环境中描述的curl调用的结果 .

call #1:

curl -X POST --header 'accept: application/json'\
             --data-binary @- --dump - \
             http://localhost:8529/_api/document/products\?overwrite\=true \
<<EOF
{ "Hello": "Universe", "_key" : "lock" }
EOF

response #1:

HTTP/1.1 202 Accepted
X-Content-Type-Options: nosniff
Location: /_db/_system/_api/document/products/lock
Etag: "_X28xHz---_"
Server: ArangoDB
Connection: Keep-Alive
Content-Type: application/json; charset=utf-8
Content-Length: 58  

{"_id":"products/lock","_key":"lock","_rev":"_X28xHz---_"}

call #2: （标识为第一个）

curl -X POST --header 'accept: application/json'\
             --data-binary @- --dump - \
             http://localhost:8529/_api/document/products\?overwrite\=true \
<<EOF
{ "Hello": "Universe", "_key" : "lock" }
EOF

response #2:

HTTP/1.1 409 Conflict
X-Content-Type-Options: nosniff
Server: ArangoDB
Connection: Keep-Alive
Content-Type: application/json; charset=utf-8
Content-Length: 153

{"error":true,"errorMessage":"unique constraint violated - in index 0 of type primary over [\"_key\"]; conflicting key: lock","code":409,"errorNum":1210}

我浏览了文档，启用并查看了服务器日志，但我无法弄清楚 . 任何帮助将受到高度赞赏 .

Edit 1:

为了以防万一，如果这可以提供任何帮助，我使用以下docker-compose在Docker本地运行ArangoDB服务器

version: '3'
services:
  db:
    image: arangodb
    ports:
    - "8529:8529"
    environment:
      ARANGO_NO_AUTH: 1
    volumes:
      - ./arangodb3:/var/lib/arangodb3
    command: "--log.level startup=trace --log.level requests=trace --log.level info"

这是来自服务器的日志：

db_1  | 2018-12-09T08:56:16Z [1] DEBUG {requests} "http-request-begin","0x7f51ac946010","172.20.0.1","POST","HTTP/1.1","/_api/document/products?overwrite=true"
db_1  | 2018-12-09T08:56:16Z [1] TRACE {requests} "http-request-body","0x7f51ac946010","{ \"Hello\": \"Universe\", \"_key\" : \"lock\" }\n"
db_1  | 2018-12-09T08:56:16Z [1] TRACE {requests} "http-request-response","0x7f51ac946010","/_api/document/products?overwrite=true","HTTP\/1.1 409 Conflict\r\nX-Content-Type-Options: nosniff\r\nServer: ArangoDB\r\nConnection: Keep-Alive\r\nContent-Type: application\/json; charset=utf-8\r\nContent-Length: 153\r\n\r\n{\"error\":true,\"errorMessage\":\"unique constraint violated - in index 0 of type primary over [\\\"_key\\\"]; conflicting key: lock\",\"code\":409,\"errorNum\":1210}"
db_1  | 2018-12-09T08:56:16Z [1] TRACE {requests} "http-request-statistics","0x7f51ac946010","172.20.0.1","POST","HTTP/1.1",409,41,153,"/_api/document/products?overwrite=true",read,0.000124931,queue,0.000000000,queue-size,0,request,0.000008106,total,0.017638445,error,false
db_1  | 2018-12-09T08:56:16Z [1] INFO {requests} "http-request-end","0x7f51ac946010","172.20.0.1","POST","HTTP/1.1",409,41,153,"/_api/document/products?overwrite=true",0.017630