CODEWITHSUNDEEP
mongodbparse-platform
user3770313
user3770313

Reputation: 73

Parse-server + mongoDB - high server overload

We are using parse-server + mongoDB on the own server for the mobile game backend. There are about 200K users with ~2k connected at the same time. The "_Session" collection is about 1 million records and continues to grow.

Servers CPUs are constantly loaded on 100% each. In the MongoDB logs I can see 95% records like:

2017-05-11T16:25:24.738+0300 I COMMAND [conn1] command appdb1._Session command: find { find: "_Session", filter: { _session_token: "r:9eaba843dc3f8b482dbc76009f94c18a" }, sort: {}, projection: {}, limit: 1 } planSummary: COLLSCAN keysExamined:0 docsExamined:1015131 cursorExhausted:1 keyUpdates:0 writeConflicts:0 numYields:7930 nreturned:1 resle n:428 locks:{ Global: { acquireCount: { r: 15862 } }, Database: { acquireCount: { r: 7931 } }, Collection: { acquireCount: { r: 7931 } } } protocol:op_query 556ms

I've created index for the _Session collection, db.getCollection("_Session").getIndexes() [

{
    "v" : 1,
    "key" : {
        "_id" : 1
    },
    "name" : "_id_",
    "ns" : "appdb1._Session"
},
{
    "v" : 1,
    "key" : {
        "sessionToken" : 1
    },
    "name" : "sessionToken_1",
    "ns" : "appdb1._Session",
    "background" : true
}

]

but, as I understand, it is not used, and DB performs full collection scan every time when it searches for a record.

So server кesponds with great delays, please, help with this problem.

Thanks!

Upvotes: 1

Views: 184

Answers (1)

Atish
Atish

Reputation: 4417

Try creating index on key _session_token in background:

db.yourCollection.ensureIndex({ "_session_token":1}, {background:true})

This will avoid collection scan for the query with key _session_token.

Upvotes: 1

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