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phpmongodbcursor

MongoDB kills immortal cursors

I'm using PHP mongodb/mongodb driver v 1.1.2

Low-level driver info:

mongodb version => 1.1.7
mongodb stability => stable
libmongoc version => 1.3.5
libbson version => 1.3.5

MongoDB 3.4.7 and 3.4.10

Connection options:

socketTimeoutMS=3600000

Cursor options:

maxTimeMs: 360000
noCursorTimeout: true

So I assume that cursor must be immortal

The program was running normally, then it crashed with the following error:

[29-Nov-2017 15:23:04 UTC] PHP Fatal error:  Uncaught MongoDB\Driver\Exception\RuntimeException: Cursor not found (namespace: 'xxxx.yyyy', id: 6220790657981310420).

In mongos logs I see

2017-11-29T15:21:12.025+0000 I QUERY    [ClusterCursorCleanupJob] Marking cursor id 6220790657981310420 for deletion, idle since 2017-11-29T15:11:11.139+0000
2017-11-29T15:21:16.026+0000 I QUERY    [ClusterCursorCleanupJob] Marking cursor id 6220790657981310420 for deletion, idle since 2017-11-29T15:11:11.139+0000
2017-11-29T15:21:20.026+0000 I QUERY    [ClusterCursorCleanupJob] Marking cursor id 6220790657981310420 for deletion, idle since 2017-11-29T15:11:11.139+0000
...
2017-11-29T15:22:56.029+0000 I QUERY    [ClusterCursorCleanupJob] Marking cursor id 6220790657981310420 for deletion, idle since 2017-11-29T15:11:11.139+0000
2017-11-29T15:23:00.029+0000 I QUERY    [ClusterCursorCleanupJob] Marking cursor id 6220790657981310420 for deletion, idle since 2017-11-29T15:11:11.139+0000
2017-11-29T15:23:04.029+0000 I QUERY    [ClusterCursorCleanupJob] Marking cursor id 6220790657981310420 for deletion, idle since 2017-11-29T15:11:11.139+0000

Notice that "idle since" timestamp is identical for all lines. I am pretty sure that program was actively fetching data from that cursor.

I have no exact time when cursor was created, but it happened not earlier than 15:03:35.

The issue is very rare. I have lot of active cursors, some of them lives for hours. This one was cleaned up after 20 minutes

Solution

  • The only supported Collection options are

    • readConcern
    • readPreference
    • typeMap
    • writeConcern

    DocsRef

    maxTimeMS and noCursorTimeout are options of the Cursor. You need to pass them in find() and similar commands.

    DocsRef