Contents
How many indexes can MongoDB have?
one index
Generally, MongoDB only uses one index to fulfill most queries. However, each clause of an $or query may use a different index, and in addition, MongoDB can use an intersection of multiple indexes. The following documents introduce indexing strategies: Create Indexes to Support Your Queries.
How many fields in a BSON can be indexed in MongoDB?
MongoDB imposes a limit of 32 fields for any compound index. Compound indexes can support queries that match on multiple fields.
Which is the index used for multiple fields in MongoDB?
compound indexes
MongoDB also supports user-defined indexes on multiple fields, i.e. compound indexes. The order of fields listed in a compound index has significance. For instance, if a compound index consists of { userid: 1, score: -1 } , the index sorts first by userid and then, within each userid value, sorts by score .
Does sort use index?
Yes, MySQL uses your index to sort the information when the order is by the sorted column. Also, if you have indexes in all columns that you have added to the SELECT clause, MySQL will not load the data from the table itself, but from the index (which is faster).
Does MongoDB support secondary index?
MongoDB supports secondary indexes. To create an index, you just specify the field or combination of fields, and for each field specify the direction of the index for that field; 1 for ascending and -1 for descending.
How many indexes do I need with MongoDB?
1 Answer 1. MongoDB can use an index when the queried field(s) are contained in an index. Furthermore, there can be only on text index per collection (though multiple fields can be indexed).
Why are compound indexes so resource intensive in MongoDB?
Compound indexes may include fields with low cardinality, but the value of the combined fields should exhibit high cardinality. Indexes are resource-intensive: even with compression in the MongoDB WiredTiger storage engine, they consume RAM and disk.
Which is the best geospatial index for MongoDB?
To support efficient queries of geospatial coordinate data, MongoDB provides two special indexes: 2d indexes that uses planar geometry when returning results and 2dsphere indexes that use spherical geometry to return results. See 2d Index Internals for a high level introduction to geospatial indexes.
Is it bad to have too many indexes in a database?
Having too many indexes can be almost as damaging to your performance as having too few, making this feature is especially valuable in helping you identify and remove indexes that are not being used. This helps you free working set space, and eliminates database overhead that comes from maintaining the index.