> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

# planCacheSetFilter (database command)

## Definition

Set an [index filter](https://www.mongodb.com/docs/manual/core/query-plans.md#std-label-index-filters) for a collection. If an index filter already exists for the [plan cache query shape](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-plan-cache-query-shape), the command overrides the previous index filter.

### Query Settings

**New in version 8.0**

Starting in MongoDB 8.0, use query settings instead of adding [index filters](https://www.mongodb.com/docs/manual/core/query-plans.md#std-label-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`.](https://www.mongodb.com/docs/manual/reference/command/setquerysettings.md#mongodb-dbcommand-dbcmd.setQuerySettings)

The [query optimizer](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-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](https://www.mongodb.com/docs/manual/reference/operator/aggregation/querystats.md#std-label-queryStats-queryShape) on the entire cluster. The cluster retains the settings after shutdown.

You can add query settings for [`find`](https://www.mongodb.com/docs/manual/reference/command/find.md#mongodb-dbcommand-dbcmd.find), [`distinct`](https://www.mongodb.com/docs/manual/reference/command/distinct.md#mongodb-dbcommand-dbcmd.distinct), and [`aggregate`](https://www.mongodb.com/docs/manual/reference/command/aggregate.md#mongodb-dbcommand-dbcmd.aggregate) commands.

To remove query settings, use [`removeQuerySettings`](https://www.mongodb.com/docs/manual/reference/command/removequerysettings.md#mongodb-dbcommand-dbcmd.removeQuerySettings). To obtain the query settings, use a [`$querySettings`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/querysettings.md#mongodb-pipeline-pipe.-querySettings) stage in an aggregation pipeline.

## Compatibility

This command is available in deployments hosted in the following environments:

- [MongoDB Atlas](https://www.mongodb.com/docs/atlas): The fully managed service for MongoDB deployments in the cloud

**Important:**

This command is not supported in M0 and Flex clusters. For more information, see [Unsupported Commands.](https://www.mongodb.com/docs/atlas/unsupported-commands/)

- [MongoDB Enterprise](https://www.mongodb.com/docs/manual/administration/install-enterprise.md#std-label-install-mdb-enterprise): The subscription-based, self-managed version of MongoDB

- [MongoDB Community](https://www.mongodb.com/docs/manual/administration/install-community.md#std-label-install-mdb-community-edition): The source-available, free-to-use, and self-managed version of MongoDB

## Syntax

The command has the following syntax:

```javascript
db.runCommand(
   {
      planCacheSetFilter: <collection>,
      query: <query>,
      sort: <sort>,
      projection: <projection>,
      collation: { <collation> },
      indexes: [ <index1>, <index2>, ...],
      comment: <any>
   }
)
```

The plan cache query shape for the index filter is the combination of:

- `query`

- `sort`

- `projection`

- `collation`

## Command Fields

The command has the following fields:

| Field | Type | Description |
| --- | --- | --- |
| `planCacheSetFilter` | string | The name of the collection for the index filter. |
| `query` | document | The query predicate for the index filter. Only the predicate structure, including the field names, is used in the index filter. The field values in the query predicate are not used. Therefore, the query predicate in an index filter is used by similar queries that differ only in the field values. |
| `sort` | document | Optional. The sort for the index filter. |
| `projection` | document | Optional. The projection for the index filter. |
| `collation` | document | Optional. Specifies the [collation](https://www.mongodb.com/docs/manual/reference/collation.md#std-label-collation)  to use for the operation. [Collation](https://www.mongodb.com/docs/manual/reference/collation.md#std-label-collation) allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks. The collation option has the following syntax: `collation: {
    locale: <string>,
    caseLevel: <boolean>,
    caseFirst: <string>,
    strength: <int>,
    numericOrdering: <boolean>,
    alternate: <string>,
    maxVariable: <string>,
    backwards: <boolean>
 }` When specifying collation, the `locale` field is mandatory; all other collation fields are optional. For descriptions of the fields, see [Collation Document.](https://www.mongodb.com/docs/manual/reference/collation.md#std-label-collation-document-fields) If the collation is unspecified but the collection has a default collation (see [`db.createCollection()`](https://www.mongodb.com/docs/manual/reference/method/db.createcollection.md#mongodb-method-db.createCollection)), the operation uses the collation specified for the collection. If no collation is specified for the collection or for the operations, MongoDB uses the simple binary comparison used in prior versions for string comparisons. You cannot specify multiple collations for an operation. For example, you cannot specify different collations per field, or if performing a find with a sort, you cannot use one collation for the find and another for the sort. Starting in MongoDB 6.0, an index filter uses the [collation](https://www.mongodb.com/docs/manual/reference/collation.md#std-label-collation) previously set using the [`planCacheSetFilter`](https://www.mongodb.com/docs/manual/reference/command/plancachesetfilter.md#mongodb-dbcommand-dbcmd.planCacheSetFilter) command. Starting in MongoDB 8.0, use query settings instead of adding [index filters](https://www.mongodb.com/docs/manual/core/query-plans.md#std-label-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`.](https://www.mongodb.com/docs/manual/reference/command/setquerysettings.md#mongodb-dbcommand-dbcmd.setQuerySettings) |
| `indexes` | array | An array of index filters for the specified plan cache query shape. Specify the index filters as one of these arrays: Index specification documents. For example, `[ { x : 1 }, ...
]`.; Index names. For example, `[ "x_1", ... ]`. The [query optimizer](https://www.mongodb.com/docs/manual/core/query-plans.md#std-label-read-operations-query-optimization) uses either a collection scan or the index arrays for the query plan. If the specified indexes do not exist or are [hidden](https://www.mongodb.com/docs/manual/core/index-hidden.md), the optimizer uses a collection scan. For multiple indexes with the same key pattern, you must specify the index as an array of names. |
| `comment` | any | Optional. A user-provided comment to attach to this command. Once set, this comment appears alongside records of this command in the following locations: [mongod log messages](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-messages-ref), in the `attr.command.cursor.comment` field.; [Database profiler](https://www.mongodb.com/docs/manual/reference/database-profiler.md#std-label-profiler) output, in the [`command.comment`](https://www.mongodb.com/docs/manual/reference/database-profiler.md#mongodb-data-system.profile.command) field.; [`currentOp`](https://www.mongodb.com/docs/manual/reference/command/currentop.md#mongodb-dbcommand-dbcmd.currentOp) output, in the [`command.comment`](https://www.mongodb.com/docs/manual/reference/command/currentop.md#mongodb-data-currentOp.command) field. A comment can be any valid [BSON type](https://www.mongodb.com/docs/manual/reference/bson-types.md#std-label-bson-types) (string, integer, object, array, etc). |

Index filters only exist for the duration of the server process and do not persist after shutdown. To clear the index filters, use the [`planCacheClearFilters`](https://www.mongodb.com/docs/manual/reference/command/plancacheclearfilters.md#mongodb-dbcommand-dbcmd.planCacheClearFilters) command.

## Required Access

A user must have access that includes the [`planCacheIndexFilter`](https://www.mongodb.com/docs/manual/reference/privilege-actions.md#mongodb-authaction-planCacheIndexFilter) action.

## Examples

### 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:

```javascript
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:

```javascript
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`](https://www.mongodb.com/docs/manual/reference/explain-results.md#mongodb-data-explain.queryPlanner.indexFilterSet) field of either the [`db.collection.explain()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.explain.md#mongodb-method-db.collection.explain) or the [`cursor.explain()`](https://www.mongodb.com/docs/manual/reference/method/cursor.explain.md#mongodb-method-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.

```javascript
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).

```javascript
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](https://www.mongodb.com/docs/manual/reference/collation.md#std-label-collation) previously set using the [`planCacheSetFilter`](https://www.mongodb.com/docs/manual/reference/command/plancachesetfilter.md#mongodb-dbcommand-dbcmd.planCacheSetFilter) command.

Starting in MongoDB 8.0, use query settings instead of adding [index filters](https://www.mongodb.com/docs/manual/core/query-plans.md#std-label-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`.](https://www.mongodb.com/docs/manual/reference/command/setquerysettings.md#mongodb-dbcommand-dbcmd.setQuerySettings)

**See also:**

- [`planCacheClearFilters`](https://www.mongodb.com/docs/manual/reference/command/plancacheclearfilters.md#mongodb-dbcommand-dbcmd.planCacheClearFilters)

- [`planCacheListFilters`](https://www.mongodb.com/docs/manual/reference/command/plancachelistfilters.md#mongodb-dbcommand-dbcmd.planCacheListFilters)

- [`$planCacheStats`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/plancachestats.md#mongodb-pipeline-pipe.-planCacheStats)