How can you determine if a collection is limited?

Question

I used the PHP mongo command:

$db->command(array("create" => $name, "size" => $size, "capped" => true, "max" => $max));

And my collections grew far from their supposed limitations. I put on the fix:

$db->createCollection($name, true, $size, $max);

Currently the counts are so low that I can’t determine if the fix worked.

How can you determine if a collection is limited, either from a shell or from PHP? I could not find this information in the system.names namespace.

Answer 1

In the shell, use db.collection.stats (). If the collection is limited:

> db.my_collection.stats()["capped"]
1

If the collection is not limited, the capped key will not be present.

The following are examples from stats () for a private collection:

> db.my_coll.stats()
{
    "ns" : "my_db.my_coll",
    "count" : 221,
    "size" : 318556,
    "avgObjSize" : 1441.4298642533936,
    "storageSize" : 1000192,
    "numExtents" : 1,
    "nindexes" : 0,
    "lastExtentSize" : 1000192,
    "paddingFactor" : 1,
    "flags" : 0,
    "totalIndexSize" : 0,
    "indexSizes" : {

    },
    "capped" : 1,
    "max" : 2147483647,
    "ok" : 1
}

This is with MongoDB 1.7.4.

Answer 2

isCapped().

db.foo.isCapped()

Answer 3

:

  db.system.namespaces.find()

db. , .

Answer 4

For PHP:

$collection = $db->selectCollection($name);
$result = $collection->validate();
$isCapped = isset($result['capped']);