How to Implement Efficient Paging in MongoDB with mgo.v2 without Native cursor.min() Support?

Efficient Paging in MongoDB with mgo using cursor.min()

MongoDB's paging capabilities, commonly implemented using Query.Skip() and Query.Limit(), can become slow when the page number increases. To address this, MongoDB introduced cursor.min(), which allows specifying the first index entry to begin listing results from.

Limitations of mgo.v2

Unfortunately, the mgo.v2 driver lacks support for cursor.min(). However, this functionality can be achieved using the Database.Run() method to execute MongoDB commands, including the find command.

Implementing Efficient Paging Manually

1. Construct the find command with a filter, sort, limit, and optionally the cursor.min() argument.
2. Execute the command using Database.Run() and decode the results.
3. Transform the results to the desired type using Collection.NewIter().
4. Generate the new cursor data from the last document in the batch.
5. Use base64 encoding to convert the cursor data to a web-safe string.

Using github.com/icza/minquery

The minquery package provides a wrapper that simplifies the process of executing a find command with cursor.min() support.

Note: When using minquery.All(), specify the names of the cursor fields when decoding the results, even if not used directly. This is crucial for generating the cursor data for subsequent queries.

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