Check out the thread on the JIRA ticket that increased the value from 4MB to 16MB. There is a sizeable debate on the ticket: https://jira.mongodb.org/browse/SERVER-431 It seems to be arbitrary why they chose 16MB, and not say 32MB. It was increased because many people needed to store documents larger than 4MB (and I presume lower … Read more
This solution above is correct for older versions of MongoDB and the pymongo driver but it no longer works with pymongo3 and MongoDB3+ You now need to add document_class=OrderedDict to the MongoClient constructor. Modifying the above answer for pymongo3 compatibility. from collections import OrderedDict from pymongo import MongoClient import bson client = MongoClient(document_class=OrderedDict) sample_db = … Read more
The problem is that the current bson codecs do not support encoding / decoding string into / from null. One way to handle this is to create a custom decoder for string type in which we handle null values: we just use the empty string (and more importantly don’t report error). Custom decoders are described … Read more
… And, since 3.0.0, you can: import org.bson.Document; final Document doc = new Document(“myKey”, “myValue”); final String jsonString = doc.toJson(); final Document doc = Document.parse(jsonString); Official docs: Document.parse(String) Document.toJson()
If you want an exact representation for financial purposes, then doubles or floating point values are unsuitable as the fractional parts are subject to rounding error. Certain decimal values cannot not be represented using binary-based floating points and must be approximated. For a less technical intro, see The trouble with rounding floating point numbers; if … Read more
Although $date is a part of MongoDB Extended JSON and that’s what you get as default with mongoexport, I don’t think you can really use it as a part of the query. If try exact search with $date like below: db.foo.find({dt: {“$date”: “2012-01-01T15:00:00.000Z”}}) you’ll get the error: error: { “$err” : “invalid operator: $date”, “code” … Read more
First off, this actually is being raised in the next version to 8MB or 16MB … but I think to put this into perspective, Eliot from 10gen (who developed MongoDB) puts it best: EDIT: The size has been officially ‘raised’ to 16MB So, on your blog example, 4MB is actually a whole lot.. For example, … Read more
db.messages.find( { headers : { From: “[email protected]” } } ) This queries for documents where headers equals { From: … }, i.e. contains no other fields. db.messages.find( { ‘headers.From’: “[email protected]” } ) This only looks at the headers.From field, not affected by other fields contained in, or missing from, headers. Dot-notation docs