Hiding and Dropping Indexes
Dropping an index means removing the values of the fields from the index registry. Thus, any searches on the related fields will be performed in a linear fashion, provided there are no other indexes present on the field.
It is important to note that MongoDB does not allow updating an existing index. Thus, to fix an incorrectly created index, we need to drop it and recreate it correctly.
An index is deleted using the dropIndex function. It takes a single parameter, which can either be the index name or the index specification document, as follows:
db.collection.dropIndex(indexNameOrSpecification)
The index specification document is the definition of the index that is used to create it (like the following snippet, for example):
db.movies.createIndex(
{title: 1}
)
Consider the following snippet:
db.movies.dropIndex(
{title: 1}
)
This command drops the index on the title field of the movies...