Aggregation pipeline example mongodb
Top 10 users by paid order amount
db.orders.aggregate([{$match:{status:'paid'}},{$group:{_id:'$userId',total:{$sum:'$amount'}}},{$sort:{total:-1}},{$limit:10}])
more mongodb
all 20 commands →
Check replication lag
rs.printSecondaryReplicationInfo()
Current operations (slow queries)
db.currentOp({active:true, secs_running:{$gt:5}})
Dump a database
mongodump --uri='mongodb://localhost:27017' --db=mydb --out=/backup/$(date +%F)
Replica set status
mongosh --eval 'rs.status().members.forEach(m=>print(m.name,m.stateStr,m.optimeDate))'
Kill long-running ops
mongosh --eval 'db.currentOp({secs_running:{$gt:5},op:{$ne:"none"}}).inprog.forEach(o=>{print(o.opid,o.secs_running,o.ns); db.killOp(o.opid)})'