| title | DBCC DROPCLEANBUFFERS (Transact-SQL) | ||||||
|---|---|---|---|---|---|---|---|
| description | DBCC DROPCLEANBUFFERS (Transact-SQL) | ||||||
| author | rwestMSFT | ||||||
| ms.author | randolphwest | ||||||
| ms.date | 11/5/2021 | ||||||
| ms.prod | sql | ||||||
| ms.technology | t-sql | ||||||
| ms.topic | language-reference | ||||||
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| monikerRange | >=aps-pdw-2016||=azure-sqldw-latest||>=sql-server-2016||>=sql-server-linux-2017||=azuresqldb-mi-current |
[!INCLUDE sql-asdb-asdbmi-asa-pdw]
Removes all clean buffers from the buffer pool, and columnstore objects from the columnstore object pool.
Transact-SQL Syntax Conventions
Syntax for [!INCLUDEssNoVersion] and [!INCLUDEssSOD]:
DBCC DROPCLEANBUFFERS [ WITH NO_INFOMSGS ]
Syntax for [!INCLUDEssSDW] and [!INCLUDEssPDW]:
DBCC DROPCLEANBUFFERS ( COMPUTE | ALL ) [ WITH NO_INFOMSGS ]
[!INCLUDEsql-server-tsql-previous-offline-documentation]
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 setting is the default if you don't 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. CHECKPOINT forces all dirty pages for the current database to be written to disk and cleans the buffers. After you checkpoint the database, 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 for [!INCLUDEssNoVersion] and [!INCLUDEssPDW].
Requires membership in the DB_OWNER fixed server role for [!INCLUDEssSDW].