db.swiss_pairing.dropIndexes()
db.swiss.ensureIndex({teamId:1,startsAt:-1})
db.swiss_player.ensureIndex({s:1,u:1})
db.swiss_player.ensureIndex({s:1,n:1},{unique:true})
db.swiss_player.ensureIndex({s:1,c:-1})
db.swiss_pairing.ensureIndex({s:1,r:1})
db.swiss_pairing.ensureIndex({s:1,p:1,r:1})
db.swiss_pairing.ensureIndex({t:1}, {partialFilterExpression:{t:true}})

db.swiss.dropIndexes()
db.swiss_player.dropIndexes()
db.swiss_pairing.dropIndexes()

db.swiss.ensureIndex({teamId:1,startsAt:-1})

db.swiss_player.ensureIndex({s:1,u:1})
db.swiss_player.ensureIndex({s:1,n:1},{unique:true})
db.swiss_player.ensureIndex({s:1,c:-1})

db.swiss_pairing.ensureIndex({s:1,r:1})
db.swiss_pairing.ensureIndex({s:1,p:1,r:1})
db.swiss_pairing.ensureIndex({t:1}, {partialFilterExpression:{t:true}})

tweak mongo indexing