SQL Server DBCC command Daquan
Original Source: https://www.cnblogs.com/lyhabc/archive/2013/01/19/2867174.html
DBCC DROPCLEANBUFFERS: Delete all from the buffer pool cache, clear the buffer
During the test, use this command to clear all the test data from the data cache SQLSERVER data cache (buffer), in order to ensure the fairness of the test.
Note that this command only to remove and clean the cache, do not remove the dirty cache. For this reason, before executing this command, you should perform CheckPoint, all dirty buffers written to disk,
So when you run the DBCC RROPCLEANBUFFERS, we can guarantee that all the data cache is cleared rather than part of it.
DBCC CacheStats: Displays information exists in the current buffer Cache of objects, such as: hit rates, compiled object and an implementation plan
DBCC ErrorLog: If you rarely restart mssqlserver service, the server log (not the database transaction log) will grow quickly, but also open and view the log speed will be very slow
Using this command, you can cut off the current server logs, mainly to generate a new log. Consider setting up a scheduled task, execute this command automatically truncate the server logs weekly.
Sp_cycle_errorlog stored procedure can achieve the same purpose
A, DBCC command helper
DBCC HELP ( '?'): DBCC command to query all
DBCC HELP ( 'command'): description of the syntax of the query specified DBCC command
DBCC USEROPTIONS: return to the active (set) currently connected SET options
Two, DBCC check command validation class
Consistency of disk space allocation structures inspection specified database: DBCC CHECKALLOC ( 'database name')
Consistency between tables in the system checks the specified database and system tables: DBCC CHECKCATALOG ( 'database name')
( 'Tablename') DBCC CHECKCONSTRAINTS: specify constraints on the specified table or check the integrity of all of the constraints
DBCC CHECKDB: distribution and checks the structural integrity of all objects in the database
All database tables in the current distribution and structural integrity checks specified file group: DBCC CHECKFILEGROUP
DBCC CHECKTABLE: Check the integrity of the data in the specified table or indexed view, and the index test, ntest and image pages
DBCC CHECKIDENT: If you delete large amounts of data exist, consider after you delete, use dbcc checkident reset it from value-added
Check the specified value of the current identity
DBCC SQLPERF (UMSSTATS): the most critical reference data num runnable: that the current number of threads waiting to run again, if more than 2, consider the CPU bottleneck reach
Scheduler ID: current machine how many there are that many logical CPU Scheduler ID, specifically to see how I can look at this article
SQLSERVER unique task scheduling algorithm "SQLOS"
Three, DBCC maintenance commands of
DBCC CLEANTABLE ( 'db_name', 'table_name'): recovering Alter table drop column delete statement variable-length columns, or text
DBCC DBREINDEX: one or more indexes rebuild the specified database with ALTER INDEX REBUILD almost
DBCC INDEXDEFRAG: the index and non-clustered index on the table or view defragment
DBCC PINTABLE (db_id, object_id): table data reside in memory
Which method table resides in memory of view is: 0: not resident 1: resident
1 USE [GPOSDB]
2 GO
3 SELECT OBJECTPROPERTY(OBJECT_ID('dbo.SystemPara'), 'tableispinned')
DBCC UNPINTABLE (db_id, object_id): Undo table resident in memory
DBCC SHRINKDATABASE (db_id, int): shrinking the size of the data files and log files specified database
DBCC SHRINKFILE (file_name, int): shrink the specified data files and log files related to the size of the database
Four, DBCC performance adjustment command
DBCC dllname (FREE): Uninstall the specified extension process dynamic link library (dll) in memory
sp_helpextendedproc view the extended PROC loaded
DBCC DROPCLEANBUFFERS: remove all buffers from the buffer pool
DBCC FREEPROCCACHE: Buffer delete all cached execution plan from execution plans
DBCC INPUTBUFFER: Displays the last statement sent from the client to the server
DBCC OPENTRAN (db_name): a database query execution time of the longest transaction, which is owned by the program
DBCC SHOW_STATISTICS: Displays the current distribution statistics for the specified target on the specified table
DBCC SHOWCONTIG: display fragmentation information for the data and indexes of the specified table
DBCC SQLPERF (logspace): the case of each DB View Log
(Iostats) View IO case
(Threads) View thread consumption
Return a variety of useful statistics
DBCC CACHESTATS: SQL Server 2000 statistics show memory
DBCC CURSORSTATS: display statistics for SQL Server 2000 cursor
DBCC MEMORYSTATS: SQL Server 2000 shows how memory is broken down
DBCC SQLMGRSTATS: display buffer in the first reading and pre-reading prepared SQL statement
Five, DBCC command undisclosed
DBCC ERRLOG: initializing SQL Server 2000 error log file
DBCC FLUSHPROCINDB (db_id): Clear the stored procedure in SQL Server 2005 server memory cache contents of a database
DBCC BUFFER (db_name, object_name, int (buffer number)): the display buffer header information and page information
DBCC DBINFO (db_name): shows the structure of the information database
DBCC DBTABLE: display table management data (data dictionary) information
DBCC IND (db_name, table_name, index_id): View an index page information used
DBCC REBUILDLOG: rebuild SQL Server 2000 transaction log files
DBCC LOG (db_name, 3) (-1 ~ 4): See the database transaction log information for a display format may be: -1,0,1,2,3,4 and each number represents a different format
DBCC PAGE: View a database data page information
DBCC PROCBUF: display process buffer pool buffer headers and header stored procedure
DBCC PRTIPAGE: page number for each index page to view a line pointing
DBCC PSS (user, spid, 1): Displays the current connection to SQL Server 2000 server process information
DBCC RESOURCE: display server resources currently used
DBCC TAB (db_id, object_id): shows the structure of the data page
Six, DBCC trace flag
Wherein tracking marks for a particular server is temporarily set on or off a particular behavior, commonly used to debug or diagnose performance problems or complex systems stored procedure
DBCC TRACEON (3604): Open the trace flag
DBCC TRACEOFF: Close tracking tag
DBCC TRACESTATS: View tracking tag status
Seven, the official use DBCC advice
1, Run CHECKDB when system usage is low.
2, make sure that no other perform disk I / O operations at the same time, for example, a backup disk.
3, the system tempdb into a separate disk or fast disk subsystem.
4, allowing sufficient room for expansion tempdb on the drive. Tempdb estimate how much space will be required to use the DBCC with ESTIMATE ONLY.
5. Avoid running CPU-intensive queries or batch jobs.
6, the DBCC command is running, reducing active transaction.
7, using NO_INFOMSGS option to reduce some of the information output.
8, consider DBCC CHECKDB with PHYSICAL_ONLY option to check the physical structure pages and recorded.
PHYSICAL_ONLY options: only checks the physical errors, error checking logic
A physical errors more serious than logical, because the physical SQLSERVER error generally can not be repaired, and logical errors can be repaired most SQLSERVER
Original Source: https://www.cnblogs.com/lyhabc/archive/2013/01/19/2867174.html
DBCC DROPCLEANBUFFERS: Delete all from the buffer pool cache, clear the buffer
During the test, use this command to clear all the test data from the data cache SQLSERVER data cache (buffer), in order to ensure the fairness of the test.
Note that this command only to remove and clean the cache, do not remove the dirty cache. For this reason, before executing this command, you should perform CheckPoint, all dirty buffers written to disk,
So when you run the DBCC RROPCLEANBUFFERS, we can guarantee that all the data cache is cleared rather than part of it.
DBCC CacheStats: Displays information exists in the current buffer Cache of objects, such as: hit rates, compiled object and an implementation plan
DBCC ErrorLog: If you rarely restart mssqlserver service, the server log (not the database transaction log) will grow quickly, but also open and view the log speed will be very slow
Using this command, you can cut off the current server logs, mainly to generate a new log. Consider setting up a scheduled task, execute this command automatically truncate the server logs weekly.
Sp_cycle_errorlog stored procedure can achieve the same purpose
A, DBCC command helper
DBCC HELP ( '?'): DBCC command to query all
DBCC HELP ( 'command'): description of the syntax of the query specified DBCC command
DBCC USEROPTIONS: return to the active (set) currently connected SET options
Two, DBCC check command validation class
Consistency of disk space allocation structures inspection specified database: DBCC CHECKALLOC ( 'database name')
Consistency between tables in the system checks the specified database and system tables: DBCC CHECKCATALOG ( 'database name')
( 'Tablename') DBCC CHECKCONSTRAINTS: specify constraints on the specified table or check the integrity of all of the constraints
DBCC CHECKDB: distribution and checks the structural integrity of all objects in the database
All database tables in the current distribution and structural integrity checks specified file group: DBCC CHECKFILEGROUP
DBCC CHECKTABLE: Check the integrity of the data in the specified table or indexed view, and the index test, ntest and image pages
DBCC CHECKIDENT: If you delete large amounts of data exist, consider after you delete, use dbcc checkident reset it from value-added
Check the specified value of the current identity
DBCC SQLPERF (UMSSTATS): the most critical reference data num runnable: that the current number of threads waiting to run again, if more than 2, consider the CPU bottleneck reach
Scheduler ID: current machine how many there are that many logical CPU Scheduler ID, specifically to see how I can look at this article
SQLSERVER unique task scheduling algorithm "SQLOS"
Three, DBCC maintenance commands of
DBCC CLEANTABLE ( 'db_name', 'table_name'): recovering Alter table drop column delete statement variable-length columns, or text
DBCC DBREINDEX: one or more indexes rebuild the specified database with ALTER INDEX REBUILD almost
DBCC INDEXDEFRAG: the index and non-clustered index on the table or view defragment
DBCC PINTABLE (db_id, object_id): table data reside in memory
Which method table resides in memory of view is: 0: not resident 1: resident
1 USE [GPOSDB]
2 GO
3 SELECT OBJECTPROPERTY(OBJECT_ID('dbo.SystemPara'), 'tableispinned')
DBCC UNPINTABLE (db_id, object_id): Undo table resident in memory
DBCC SHRINKDATABASE (db_id, int): shrinking the size of the data files and log files specified database
DBCC SHRINKFILE (file_name, int): shrink the specified data files and log files related to the size of the database
Four, DBCC performance adjustment command
DBCC dllname (FREE): Uninstall the specified extension process dynamic link library (dll) in memory
sp_helpextendedproc view the extended PROC loaded
DBCC DROPCLEANBUFFERS: remove all buffers from the buffer pool
DBCC FREEPROCCACHE: Buffer delete all cached execution plan from execution plans
DBCC INPUTBUFFER: Displays the last statement sent from the client to the server
DBCC OPENTRAN (db_name): a database query execution time of the longest transaction, which is owned by the program
DBCC SHOW_STATISTICS: Displays the current distribution statistics for the specified target on the specified table
DBCC SHOWCONTIG: display fragmentation information for the data and indexes of the specified table
DBCC SQLPERF (logspace): the case of each DB View Log
(Iostats) View IO case
(Threads) View thread consumption
Return a variety of useful statistics
DBCC CACHESTATS: SQL Server 2000 statistics show memory
DBCC CURSORSTATS: display statistics for SQL Server 2000 cursor
DBCC MEMORYSTATS: SQL Server 2000 shows how memory is broken down
DBCC SQLMGRSTATS: display buffer in the first reading and pre-reading prepared SQL statement
Five, DBCC command undisclosed
DBCC ERRLOG: initializing SQL Server 2000 error log file
DBCC FLUSHPROCINDB (db_id): Clear the stored procedure in SQL Server 2005 server memory cache contents of a database
DBCC BUFFER (db_name, object_name, int (buffer number)): the display buffer header information and page information
DBCC DBINFO (db_name): shows the structure of the information database
DBCC DBTABLE: display table management data (data dictionary) information
DBCC IND (db_name, table_name, index_id): View an index page information used
DBCC REBUILDLOG: rebuild SQL Server 2000 transaction log files
DBCC LOG (db_name, 3) (-1 ~ 4): See the database transaction log information for a display format may be: -1,0,1,2,3,4 and each number represents a different format
DBCC PAGE: View a database data page information
DBCC PROCBUF: display process buffer pool buffer headers and header stored procedure
DBCC PRTIPAGE: page number for each index page to view a line pointing
DBCC PSS (user, spid, 1): Displays the current connection to SQL Server 2000 server process information
DBCC RESOURCE: display server resources currently used
DBCC TAB (db_id, object_id): shows the structure of the data page
Six, DBCC trace flag
Wherein tracking marks for a particular server is temporarily set on or off a particular behavior, commonly used to debug or diagnose performance problems or complex systems stored procedure
DBCC TRACEON (3604): Open the trace flag
DBCC TRACEOFF: Close tracking tag
DBCC TRACESTATS: View tracking tag status
Seven, the official use DBCC advice
1, Run CHECKDB when system usage is low.
2, make sure that no other perform disk I / O operations at the same time, for example, a backup disk.
3, the system tempdb into a separate disk or fast disk subsystem.
4, allowing sufficient room for expansion tempdb on the drive. Tempdb estimate how much space will be required to use the DBCC with ESTIMATE ONLY.
5. Avoid running CPU-intensive queries or batch jobs.
6, the DBCC command is running, reducing active transaction.
7, using NO_INFOMSGS option to reduce some of the information output.
8, consider DBCC CHECKDB with PHYSICAL_ONLY option to check the physical structure pages and recorded.
PHYSICAL_ONLY options: only checks the physical errors, error checking logic
A physical errors more serious than logical, because the physical SQLSERVER error generally can not be repaired, and logical errors can be repaired most SQLSERVER