Revision as of 19:10, 20 October 2021

Development

rename a field, or paste one field to another collection-wide

Methods are: updateOne, updateMany or update

db.collection.<update method>(
    {},
    [
        {"$set": {"name": { "$concat": ["$firstName", " ", "$lastName"]}}}
    ]
)

Count Documents

db.collection.aggregate(
  [
    { $group: { _id: null, count: { $sum: 1 } } }
  ]
)

Install MongoDB on ubuntu

From: https://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/

This is probably obsolete.

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv EA312927
echo "deb http://repo.mongodb.org/apt/ubuntu trusty/mongodb-org/3.2 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.2.list
sudo apt-get update -y
sudo apt-get install -y mongodb-org

Performance Tuning

db.getProfilingStatus()
db.getProfilingLevel()
db.setProfilingLevel(1, 10)
db.getCollection('system.profile').find({})

add member to cluster

operaeventrsX:PRIMARY> rs.add("10.138.96.89")
operaeventrsX:PRIMARY> rs.conf()

profiling

Profiling. From: https://docs.mongodb.com/manual/reference/method/db.setProfilingLevel/

The profiler writes all the data it collects to the system.profile collection, a capped collection in the admin database.

db.getProfilingStatus()
# db.setProfilingLevel(level, options)
db.setProfilingLevel(1, { "slowms": 500 })

db.enableFreeMonitoring()

use creek_development
db.setProfilingLevel(1, { "slowms": 500 })
db.getCollection('system.profile').find({}).sort({"ts": -1}).limit( 5 )

db.lineitems.getIndexes()