planCacheSetFilter

Query Settings

Starting in MongoDB 8.0, use query settings instead of adding index filters. Index filters are deprecated starting in MongoDB 8.0.

Query settings have more functionality than index filters. Also, index filters aren't persistent and you cannot easily create index filters for all cluster nodes. To add query settings and explore examples, see setQuerySettings.

The query optimizer uses the query settings as an additional input during query planning, which affects the plan selected to run the query.

The settings apply to the query shape on the entire cluster. The cluster retains the settings after shutdown.

You can add query settings for find, distinct, and aggregate commands.

To remove query settings, use removeQuerySettings. To obtain the query settings, use a $querySettings stage in an aggregation pipeline.

Set Filter on Plan Cache Query Shape Consisting of Predicate Only

The following example creates an index filter on the orders collection such that for queries that consist only of an equality match on the status field without any projection and sort, the query optimizer evaluates only the two specified indexes and the collection scan for the winning plan:

db.runCommand(
   {
      planCacheSetFilter: "orders",
      query: { status: "A" },
      indexes: [
         { cust_id: 1, status: 1 },
         { status: 1, order_date: -1 }
      ]
   }
)

In the query predicate, only the structure of the predicate, including the field names, are significant; the values are insignificant. As such, the created filter applies to the following operations:

db.orders.find( { status: "D" } )
db.orders.find( { status: "P" } )

To see whether MongoDB will apply an index filter for a plan cache query shape, check the indexFilterSet field of either the db.collection.explain() or the cursor.explain() method.

Set Filter on Plan Cache Query Shape Consisting of Predicate, Projection, and Sort

The following example creates an index filter for the orders collection. The filter applies to queries whose predicate is an equality match on the item field, where only the quantity field is projected and an ascending sort by order_date is specified.

db.runCommand(
   {
      planCacheSetFilter: "orders",
      query: { item: "ABC" },
      projection: { quantity: 1, _id: 0 },
      sort: { order_date: 1 },
      indexes: [
         { item: 1, order_date: 1 , quantity: 1 }
      ]
   }
)

For the plan cache query shape, the query optimizer will only consider indexed plans which use the index { item: 1, order_date: 1, quantity: 1 }.

Set Filter on Plan Cache Query Shape Consisting of Predicate and Collation

The following example creates an index filter for the orders collection. The filter applies to queries whose predicate is an equality match on the item field and the collation en_US (English United States).

db.runCommand(
   {
      planCacheSetFilter: "orders",
      query: { item: "Movie" },
      collation: { locale: "en_US" },
      indexes: [
         { item: 1, order_date: 1 , quantity: 1 }
      ]
   }
)

For the plan cache query shape, the query optimizer only uses indexed plans that use the index { item: 1, order_date: 1, quantity: 1 }.

Starting in MongoDB 6.0, an index filter uses the collation previously set using the planCacheSetFilter command.

Starting in MongoDB 8.0, use query settings instead of adding index filters. Index filters are deprecated starting in MongoDB 8.0.

Query settings have more functionality than index filters. Also, index filters aren't persistent and you cannot easily create index filters for all cluster nodes. To add query settings and explore examples, see setQuerySettings.