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- collStats
collStats¶
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Definition¶
-
collStats
¶ The
collStats
command returns a variety of storage statistics for a given collection. Use the following syntax:Specify the
collection
you want statistics for, and use thescale
argument to scale the output. The above example will display values in kilobytes.Examine the following example output, which uses the
db.collection.stats()
helper in themongo
shell.Note
The scale factor rounds values to whole numbers. This can produce unpredictable and unexpected results in some situations.
Output¶
-
collStats.
ns
¶ The namespace of the current collection, which follows the format
[database].[collection]
.
-
collStats.
count
¶ The number of objects or documents in this collection.
-
collStats.
size
¶ The total size of all records in a collection. This value does not include the record header, which is 16 bytes per record, but does include the record’s padding. Additionally
size
does not include the size of any indexes associated with the collection, which thetotalIndexSize
field reports.The
scale
argument affects this value.
-
collStats.
avgObjSize
¶ The average size of an object in the collection. The
scale
argument affects this value.
-
collStats.
storageSize
¶ The total amount of storage allocated to this collection for document storage. The
scale
argument affects this value. ThestorageSize
does not decrease as you remove or shrink documents.
-
collStats.
numExtents
¶ The total number of contiguously allocated data file regions.
-
collStats.
nindexes
¶ The number of indexes on the collection. All collections have at least one index on the _id field.
Changed in version 2.2: Before 2.2, capped collections did not necessarily have an index on the
_id
field, and some capped collections created with pre-2.2 versions ofmongod
may not have an_id
index.
-
collStats.
lastExtentSize
¶ The size of the last extent allocated. The
scale
argument affects this value.
-
collStats.
paddingFactor
¶ The amount of space added to the end of each document at insert time. The document padding provides a small amount of extra space on disk to allow a document to grow slightly without needing to move the document.
mongod
automatically calculates this padding factor
-
collStats.
flags
¶ Changed in version 2.2: Removed in version 2.2 and replaced with the
userFlags
andsystemFlags
fields.Indicates the number of flags on the current collection. In version 2.0, the only flag notes the existence of an index on the _id field.
-
collStats.
systemFlags
¶ New in version 2.2.
Reports the flags on this collection that reflect internal server options. Typically this value is
1
and reflects the existence of an index on the_id
field.
-
collStats.
userFlags
¶ New in version 2.2.
Reports the flags on this collection set by the user. In version 2.2 the only user flag is
usePowerOf2Sizes
. IfusePowerOf2Sizes
is enabled,userFlags
will be set to1
, otherwiseuserFlags
will be0
.See the
collMod
command for more information on setting user flags andusePowerOf2Sizes
.
-
collStats.
totalIndexSize
¶ The total size of all indexes. The
scale
argument affects this value.
-
collStats.
indexSizes
¶ This field specifies the key and size of every existing index on the collection. The
scale
argument affects this value.
Example¶
The following is an example of db.collection.stats()
and
collStats
output: