Indexes

Manage indexes

Open Indexes from a collection's context menu. You can:

• List every index with its keys, options and size;
• Create an index with any key type (ascending, descending, compound, multikey, text, 2dsphere, hashed, wildcard) and options such as unique, partial filter, sparse, TTL and collation;
• Drop an index;
• Hide and unhide an index. A hidden index is kept up to date but the query planner ignores it, so you can test the effect of dropping it without rebuilding it later;
• See usage statistics from $indexStats: how many times each index was used since the server started.

While an index builds, MotionQL shows live build progress, per shard when you're connected through mongos. For a sharded collection it also shows the shard key and the index that backs it.

Creating, dropping and hiding indexes are writes and are blocked on read-only connections.

Index Review

Index Review analyzes a collection's indexes and points out:

• unused indexes (no recorded use);
• duplicate or redundant indexes, such as { a: 1 } when { a: 1, b: 1 } also exists;
• missing indexes suggested by your query patterns.

With Allow AI on for the connection, the assistant can add commentary to the review. Save a review as a scheduled task to keep an eye on it.

Before you drop an index flagged as unused, remember that usage statistics reset when a server restarts and are kept per server. Check every member of a replica set, or hide the index first and watch for slow queries.

Related

• Explain plans and the profiler to see whether a query uses an index.
• The blog post Reading MongoDB explain plans: COLLSCAN vs IXSCAN.