Get the latest record from mongodb collection

Question

I want to know the most recent record in a collection  How to do that   Note  I know the following command line queries works   1  db test find   sort   idate  -1   limit 1  forEach printjson   2  db test find   skip db test count  -1  forEach printjson    where idate has the timestamp added   The problem is longer the collection is the time to get back the data and my  test  collection is really really huge  I need a query with constant time response   If there is any better mongodb command line query  do let me know

User · Answer

I need a query with constant time response

By default, the indexes in MongoDB are B-Trees. Searching a B-Tree is a O(logN) operation, so even find({_id:...}) will not provide constant time, O(1) responses.

That stated, you can also sort by the _id if you are using ObjectId for you IDs. See here for details. Of course, even that is only good to the last second.

You may to resort to "writing twice". Write once to the main collection and write again to a "last updated" collection. Without transactions this will not be perfect, but with only one item in the "last updated" collection it will always be fast.

User · Answer

If you are using auto-generated Mongo Object Ids in your document  it contains timestamp in it as first 4 bytes using which latest doc inserted into the collection could be found out  I understand this is an old question  but if someone is still ending up here looking for one more alternative   db collectionName aggregate     group    id  null  latestDocId     max     id        project    id  0  latestDocId  1       Above query would give the  id for the latest doc inserted into the collection

User · Answer

php7 1 mongoDB   data    collection- gt findOne      sort    gt     id    gt  -1   projection    gt     id    gt  1

User · Answer

This is how to get the last record from all MongoDB documents from the  foo  collection  change foo x y   etc    db foo aggregate    sort   x   1  date   1       group     id    x   y    last   y   yz    last   yz   date     last     date            allowDiskUse true       you can add or remove from the group  help articles  https   docs mongodb com manual reference operator aggregation group  pipe  S group  https   docs mongodb com manual reference operator aggregation last

User · Answer

This is a rehash of the previous answer but it s more likely to work on different mongodb versions   db collection find   limit 1  sort   natural -1

User · Answer

This will give you one last document for a collection  db collectionName findOne      sort   natural -1       natural -1 means order opposite of the one that records are inserted in   Edit  For all the downvoters  above is a Mongoose syntax  mongo CLI syntax is  db collectionName find     sort   natural -1   limit 1

User · Answer

My Solution     db collection  name of collection   find      limit  1   sort   natural  -1

User · Answer

Yet another way of getting the last item from a MongoDB Collection  don t mind about the examples     gt  db collection find   sort    id  -1   limit 1    Normal Projection   gt  db Sports find       id    ObjectId  5bfb5f82dea65504b456ab12     Type     NFL    Head     Patriots Won SuperBowl 2017    Body     Again  the Pats won the Super Bowl         id    ObjectId  5bfb6011dea65504b456ab13     Type     World Cup 2018    Head     Brazil Qualified for Round of 16    Body     The Brazilians are happy today  due to the qualification of the Brazilian Team for the Round of 16 for the World Cup 2018         id    ObjectId  5bfb60b1dea65504b456ab14     Type     F1    Head     Ferrari Lost Championship    Body     By two positions  Ferrari loses the F1 Championship  leaving the Italians in tears       Sorted Projection    id  reverse order     gt  db Sports find   sort    id  -1       id    ObjectId  5bfb60b1dea65504b456ab14     Type     F1    Head     Ferrari Lost Championship    Body     By two positions  Ferrari loses the F1 Championship  leaving the Italians in tears         id    ObjectId  5bfb6011dea65504b456ab13     Type     World Cup 2018    Head     Brazil Qualified for Round of 16    Body     The Brazilians are happy today  due to the qualification of the Brazilian Team for the Round of 16 for the World Cup 2018         id    ObjectId  5bfb5f82dea65504b456ab12     Type     NFL    Head     Patriots Won SuperBowl 2018    Body     Again  the Pats won the Super Bowl      sort    id  -1    defines a projection in descending order of all documents  based on their  ids   Sorted Projection    id  reverse order    getting the latest  last  document from a collection    gt  db Sports find   sort    id  -1   limit 1      id    ObjectId  5bfb60b1dea65504b456ab14     Type     F1    Head     Ferrari Lost Championship    Body     By two positions  Ferrari loses the F1 Championship  leaving the Italians in tears

[mongodb] Get the latest record from mongodb collection

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