MongoDB：ensureIndex不能同时处理单键和复合键

Question

From hours I'm trying to add bulk data in my locally setup MongoDB collection, all is set except unique index for a key or keys :(

I've used this:

ensureIndex({appid:1, userid:1}, {unique:true, dropDups:true, background:true})

then this (coz I guess for whatever reason, multiple keys index is not working)

ensureIndex({userid:1}, {unique:true, dropDups:true, background:true})

after using above lines I tried to insert millions of rows from a php script (via both insert and batchInsert) and everytime duplicate userids are there :'( please please guide me on this :(

Answer 1

It is probably a good idea to look and make sure the index was created. By default write operations (like creating indexes) are fire-and-forget and don't wait for error/success. This could be a bug in the driver (php client lib).

You can run

db.coll.getIndexes()

to list the indexes for the collection.