| title | DBCC DROPCLEANBUFFERS (Transact-SQL) | Microsoft Docs | ||||||
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| ms.date | 03/14/2017 | ||||||
| ms.prod | sql-non-specified | ||||||
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| ms.topic | language-reference | ||||||
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| ms.assetid | a4121927-f2ce-4926-aa2c-9b1519dac048 | ||||||
| caps.latest.revision | 35 | ||||||
| author | JennieHubbard | ||||||
| ms.author | jhubbard | ||||||
| manager | jhubbard |
[!INCLUDEtsql-appliesto-ss2008-xxxx-asdw-pdw_md]
Removes all clean buffers from the buffer pool, and columnstore objects from the columnstore object pool.
Transact-SQL Syntax Conventions
-- Syntax for SQL Server
DBCC DROPCLEANBUFFERS [ WITH NO_INFOMSGS ]
-- Syntax for Azure SQL Data Warehouse and Parallel Data Warehouse
DBCC DROPCLEANBUFFERS ( COMPUTE | ALL ) [ WITH NO_INFOMSGS ]
WITH NO_INFOMSGS
Suppresses all informational messages. Informational messages are always suppressed on [!INCLUDEssSDW] and [!INCLUDEssPDW].
COMPUTE
Purge the query plan cache from each Compute node.
ALL
Purge the query plan cache from each Compute node and from the Control node. This is the default if you do not specify a value.
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.
DBCC DROPCLEANBUFFERS on [!INCLUDEssNoVersion] returns:
DBCC execution completed. If DBCC printed error messages, contact your system administrator.
Requires membership in the sysadmin fixed server role on [!INCLUDEssNoVersion].
Requires CONTROL permission on [!INCLUDEssSDW].
Requires ALTER SERVER STATE permission on [!INCLUDEssPDW].