How to close cursors in MongoDB

Question

Hi I am fetching documents from mongdb using mongo_collection.find() , this collection has 600k documents. after traversing 400k documents I am geting below error

Traceback (most recent call last):
  File "mongo_opp.py", line 324, in <module>
    obj.indexAnswer()
  File "mongo_opp.py", line 241, in indexAnswer
    for dict_result in result:
  File "build/bdist.linux-x86_64/egg/pymongo/cursor.py", line 1032, in next
  File "build/bdist.linux-x86_64/egg/pymongo/cursor.py", line 974, in _refresh
  File "build/bdist.linux-x86_64/egg/pymongo/cursor.py", line 864, in __send_message
  File "build/bdist.linux-x86_64/egg/pymongo/helpers.py", line 112, in _unpack_response
pymongo.errors.CursorNotFound: Cursor not found, cursor id: 83302133311

The solutions to this problem is setting timeout paramter mongo_collection.find(timeout=False) which I found in below links,

StackOveflowLink1

StacKOverflowLink2

Setting timeout parameter makes cursor open for unlimited time, which will affect system performance. Can anybody help me with cursor close connection. Help appreciated :)

score 1 · Answer 1 · edited May 23 '17 at 12:30

1

Hey you can solve this using del keyword

result = mongo_collection.find(no_cursor_timeout=True)

del result

Check Link1, Link2

edited May 23 '17 at 12:30

Community

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answered Oct 06 '15 at 14:33

score 1 · Answer 2 · answered Aug 01 '17 at 23:34

1

To closing the cursor you need to remove the variable where you're put the query result

del cursor

or

cursor.close()

you can also fix the probleme by choosing a low value of batch_size:

(with Pymongo for example)

col.find({}).batch_size(10)

answered Aug 01 '17 at 23:34

HISI

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score 0 · Answer 3 · answered Oct 07 '15 at 05:44

Python uses reference counting for object lifetime management, when the Cursor object goes out of scope the garbage collector would call __die() which closes the cursor. If you want explicit control, you can call close() by yourself.

Close() call __die() internally.Check this out

How to close cursors in MongoDB

3 Answers3