---
title: "DBCC FREESYSTEMCACHE (Transact-SQL)"
description: "DBCC FREESYSTEMCACHE releases all unused cache entries from all caches."
author: rwestMSFT
ms.author: randolphwest
ms.date: 12/05/2022
ms.service: sql
ms.subservice: t-sql
ms.topic: "language-reference"
f1_keywords:
  - "FREESYSTEMCACHE_TSQL"
  - "DBCC_FREESYSTEMCACHE_TSQL"
  - "DBCC FREESYSTEMCACHE"
  - "FREESYSTEMCACHE"
helpviewer_keywords:
  - "clearing unused cache entries"
  - "DBCC FREESYSTEMCACHE statement"
  - "unused cache entries"
  - "releasing unused cache entries"
  - "freeing unused cache entries"
  - "cleaning unused cache entries"
dev_langs:
  - "TSQL"
---
# DBCC FREESYSTEMCACHE (Transact-SQL)

[!INCLUDE [SQL Server SQL Database Azure SQL Managed Instance](../../includes/applies-to-version/sql-asdb-asdbmi.md)]

Releases all unused cache entries from all caches. The [!INCLUDE[ssDEnoversion](../../includes/ssdenoversion-md.md)] proactively cleans up unused cache entries in the background to make memory available for current entries. However, you can use this command to manually remove unused entries from every cache or from a specified Resource Governor pool cache.

:::image type="icon" source="../../database-engine/configure-windows/media/topic-link.gif" border="false"::: [Transact-SQL syntax conventions](../../t-sql/language-elements/transact-sql-syntax-conventions-transact-sql.md)

## Syntax

```syntaxsql
DBCC FREESYSTEMCACHE
    ( 'ALL' [ , pool_name ] )
    [ WITH
    { [ MARK_IN_USE_FOR_REMOVAL ] , [ NO_INFOMSGS ]  }
    ]
```

[!INCLUDE[sql-server-tsql-previous-offline-documentation](../../includes/sql-server-tsql-previous-offline-documentation.md)]

## Arguments

#### ( 'ALL' [ , *pool_name* ] )

- ALL

  Specifies all supported caches.

- *pool_name*

  Specifies a resource governor pool cache. Only entries associated with this pool are freed. To list the available pool names, run:

  ```sql
  SELECT name FROM sys.dm_resource_governor_resource_pools;
  ```

Most, but not all, caches can be individually freed using this command.

#### MARK_IN_USE_FOR_REMOVAL

Asynchronously frees currently used entries from their respective caches after they're unused. After the `DBCC FREESYSTEMCACHE WITH MARK_IN_USE_FOR_REMOVAL` runs, new entries created in the cache aren't affected.

#### NO_INFOMSGS

Suppresses all informational messages.

## Remarks

Running `DBCC FREESYSTEMCACHE` clears the plan cache for the instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)]. Clearing the plan cache causes a recompilation of all upcoming execution plans and can cause a sudden, temporary reduction in query performance. For each cleared cache store in the plan cache, the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] error log contains the following informational message:

```output
SQL Server has encountered %d occurrence(s) of cachestore flush for the '%s' cachestore (part of plan cache) due to 'DBCC FREEPROCCACHE' or 'DBCC FREESYSTEMCACHE' operations.
```

 This message is logged every five minutes as long as the cache is flushed within that time interval.

## Result sets

`DBCC FREESYSTEMCACHE` returns:

```output
DBCC execution completed. If DBCC printed error messages, contact your system administrator.
```

## Permissions

Requires ALTER SERVER STATE permission on the server.

## Examples

### A. Release unused cache entries from a Resource Governor pool cache

The following example illustrates how to clean caches that are dedicated to a specified Resource Governor resource pool.

```sql
-- Clean all the caches with entries specific to the
-- resource pool named "default".
DBCC FREESYSTEMCACHE ('ALL', [default]);
```

### B. Release entries from their respective caches after they become unused

The following example uses the MARK_IN_USE_FOR_REMOVAL clause to release entries from all current caches once the entries become unused.

```sql
DBCC FREESYSTEMCACHE ('ALL') WITH MARK_IN_USE_FOR_REMOVAL;
```

## See also

- [DBCC (Transact-SQL)](../../t-sql/database-console-commands/dbcc-transact-sql.md)
- [DBCC FREEPROCCACHE (Transact-SQL)](../../t-sql/database-console-commands/dbcc-freeproccache-transact-sql.md)
- [DBCC FREESESSIONCACHE (Transact-SQL)](../../t-sql/database-console-commands/dbcc-freesessioncache-transact-sql.md)
- [Resource Governor](../../relational-databases/resource-governor/resource-governor.md)