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DBCC DROPCLEANBUFFERS (Transact-SQL)

 

THIS TOPIC APPLIES TO:yesSQL Server (starting with 2008)noAzure SQL DatabasenoAzure SQL Data Warehouse noParallel Data Warehouse

Removes all clean buffers from the buffer pool.

Topic link icon 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 SQL Data Warehouse and Parallel Data Warehouse.

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, 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 SQL Server returns:

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

Requires membership in the sysadmin fixed server role on SQL Server.

Requires CONTROL permission on SQL Data Warehouse.

Requires ALTER SERVER STATE permission on Parallel Data Warehouse.

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

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