How can I use mongodump to dump out records matching a specific date range?

Question

I'm trying to use the mongodump command to dump out a bunch of records created on a specific date. The records include a "ts" field which is a MongoDB Date() object.

mongodump takes a -q argument which can be used to run a query to select the records to be included in the dump. Unfortunately, the -q argument needs to be provided in JSON, and it's not clear how to express a "less-than-this-date, more-than-this-date" query in pure JSON (normally such queries would use a 'new Date()' constructor)"

Any tips? I've tried using the {$date: unix-timestamp-in-milliseconds} format but it's not working for me.

Answer 1

I solved it - the magic incantation I was looking for is:

mongodump --query "{\"ts\":{\"\$gt\":{\"\$date\":`date -d 2011-08-10 +%s`000},\"\$lte\":{\"\$date\":`date -d 2011-08-11 +%s`000}}}" 

Answer 2

A more human-readable version than @SimonWillison's escaped version:

--query "{ time: { \$gt: new Date(1312959600000), \$lt: new Date(1313046000000) }}"

(Note the dollarsigns still need to be escaped.)

I got the millisecond timestamps by creating dates in the shell, e.g.:

> var targetDateStart = new Date(2011, 7, 10); > var targetDateEnd = new Date(2011, 7, 11); > targetDateStart.getTime(); 1312959600000 > targetDateEnd.getTime(); 1313046000000