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title DBCC DROPCLEANBUFFERS (Transact-SQL) | Microsoft Docs
ms.custom
ms.date 07/16/2017
ms.prod sql-non-specified
ms.prod_service sql-data-warehouse, pdw, sql-database
ms.service
ms.component t-sql|database-console-commands
ms.reviewer
ms.suite sql
ms.technology
database-engine
ms.tgt_pltfrm
ms.topic language-reference
f1_keywords
DROPCLEANBUFFERS
DBCC_DROPCLEANBUFFERS_TSQL
DROPCLEANBUFFERS_TSQL
DBCC DROPCLEANBUFFERS
dev_langs
TSQL
helpviewer_keywords
clean buffers
cold buffer cache
buffer pools [SQL Server]
dropping buffers
removing buffers
DBCC DROPCLEANBUFFERS statement
ms.assetid a4121927-f2ce-4926-aa2c-9b1519dac048
caps.latest.revision 35
author barbkess
ms.author barbkess
manager craigg
ms.workload On Demand

DBCC DROPCLEANBUFFERS (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2008-xxxx-asdw-pdw-md]

Removes all clean buffers from the buffer pool, and columnstore objects from the columnstore object pool.

Topic link icon Transact-SQL Syntax Conventions

Syntax

Syntax for SQL Server:

DBCC DROPCLEANBUFFERS [ WITH NO_INFOMSGS ]

Syntax for Azure SQL Warehouse and Parallel Data Warehouse:

DBCC DROPCLEANBUFFERS ( COMPUTE | ALL ) [ WITH NO_INFOMSGS ]

Arguments

WITH NO_INFOMSGS
Suppresses all informational messages. Informational messages are always suppressed on [!INCLUDEssSDW] and [!INCLUDEssPDW].

COMPUTE
Purge the data cache in memory from each Compute node.

ALL
Purge the data cache in memory from each Compute node and from the Control node. This is the default if you do not specify a value.

Remarks

Use DBCC DROPCLEANBUFFERS to test queries with a cold buffer cache without shutting down and restarting the server. To drop clean buffers from the buffer pool and columnstore objects from the columnstore object pool, first use CHECKPOINT to produce a cold buffer cache. This forces all dirty pages for the current database to be written to disk and cleans the buffers. After you do this, you can issue DBCC DROPCLEANBUFFERS command to remove all buffers from the buffer pool.

Result Sets

DBCC DROPCLEANBUFFERS on [!INCLUDEssNoVersion] returns:

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

Permissions

Applies to: SQL Server, Parallel Data Warehouse

  • Requires membership in the sysadmin fixed server role.

Applies to: Azure SQL Data Warehouse

  • Requires membership in the DB_OWNER fixed server role.

See Also

DBCC (Transact-SQL)
CHECKPOINT (Transact-SQL)