By: Greg Robidoux | Comments (4) | Related: > Monitoring
Problem
There are several useful commands and functions that are available in SQL Server, but not knowing what they are or where to find more information about them is sometimes a problem. Having these commands at your fingertips is very helpful when trying to solve a problem or for just doing general analysis on your database instances.
Solution
Following is a list of useful commands that can be run using Query Analyzer. A lot of this information can be retrieved using Enterprise Manager, but it is often faster to use these commands directly in Query Analyzer as well as more detailed information is provided. Each of these commands has different functionality and knowing that the command exists and what types of information they produce is extremely helpful in managing your SQL Server environment
| Command | Purpose | Sample Usage |
|---|---|---|
| sp_helpdb | This gives you information about all databases in the instance or specific information about one database. |
sp_helpdb sp_helpdb databasename |
| fn_virtualfilestats | This command will show you the number of read and writes to a data file. Use sp_helpdb with the database name to see the logical file numbers for the data files and the database id. |
SELECT * FROM :: fn_virtualfilestats(dabaseid, logicalfileid)
SELECT * FROM :: fn_virtualfilestats(1, 1) |
| fn_get_sql() | Returns the text of the SQL statement for the specified SQL handle. This is similar to using DBCC INPUTBUFFER, but this command will show you additional information. This can also be embedded in a process easier then using the DBCC command. Read more: SQL Server statements currently running with fn_get_sql |
DECLARE @Handle binary(20) SELECT @Handle = sql_handle FROM sysprocesses WHERE spid = 52 SELECT * FROM ::fn_get_sql(@Handle) |
| sp_lock | This command shows you all of the locks that the system is currently tracking This is similar to information you can see in Enterprise Manager. |
sp_lock sp_lock spid sp_lock spid1, spid2 |
| sp_help | This command gives you information about the objects within a database. The command without an objectname will give you a list of all objects within the database. |
sp_help sp_help objectname |
| sp_who2 | Gives you process information similar to what you see when using Enterprise Manager. |
sp_who2 sp_who2 spid |
| sp_helpindex | Gives you information about the indexes on a table as well as the columns used for the index. |
sp_helpindex objectname |
| sp_spaceused | This command shows you how much space has been allocated for the database (or if specified an object) and how much space is being used. |
sp_spaceused sp_spaceused objectname |
| DBCC CACHESTATS | Displays information about the objects currently in the buffer cache. |
DBCC CACHESTATS |
| DBCC CHECKDB | This will check the allocation of all pages in the database as well as check for any integrity issues. |
DBCC CHECKDB |
| DBCC CHECKTABLE | This will check the allocation of all pages for a specific table or index as well as check for any integrity issues. |
DBCC CHECKTABLE (etableName') |
| DBCC DBREINDEX | This command will reindex your table. If the indexname is left out then all indexes are rebuilt. If the fillfactor is set to 0 then this will use the original fillfactor when the table was created. |
DBCC DBREINDEX (tablename, indexname, fillfactor)
DBCC DBREINDEX (authors, '', 70) DBCC DBREINDEX ('pubs.dbo.authors', UPKCL_auidind, 80) |
| DBCC PROCCACHE | This command will show you information about the procedure cache and how much is being used. Spotlight will also show you this same information. |
DBCC PROCCACHE |
| DBCC MEMORYSTATUS | Displays how the SQL Server buffer cache is divided up, including buffer activity. |
DBCC MEMORYSTATUS |
| DBCC SHOWCONTIG | This command gives you information about how much space is used for a table and indexes. Information provided includes number of pages used as well as how fragmented the data is in the database. |
DBCC SHOWCONTIG DBCC SHOWCONTIG WITH ALL_INDEXES DBCC SHOWCONTIG tablename |
| DBCC SHOW_STATISTICS | This will show how statistics are laid out for an index. You can see how distributed the data is and whether the index is really a good candidate or not. |
DBCC SHOW_STATISTICS (tablename, indexname) |
| DBCC SHRINKFILE | This will allow you to shrink one of the database files. This is equivalent to doing a database shrink, but you can specify what file and the size to shrink it to. Use the sp_helpdb command along with the database name to see the actual file names used. |
DBCC SHRINKFILE (filename, size in MB) DBCC SHRINKFILE (DataFile, 1000) |
| DBCC SQLPERF | This command will show you much of the transaction logs are being used. |
DBCC SQLPERF(LOGSPACE) |
| DBCC TRACEON | This command will turn on a trace flag to capture events in the error log. Trace Flag 1204 captures Deadlock information. |
DBCC TRACEON(traceflag) |
| DBCC TRACEOFF | This command turns off a trace flag. |
DBCC TRACEOFF(traceflag) |
Next Steps
- Get familiar with these command line functions that you can put to use immediately
- Take time to learn more about these different options and when specific commands should be used and how they should be used
- Look for future tips on each of these commands
About the author
Greg Robidoux is the President and founder of Edgewood Solutions, a technology services company delivering services and solutions for Microsoft SQL Server. He is also one of the co-founders of MSSQLTips.com. Greg has been working with SQL Server since 1999, has authored numerous database-related articles, and delivered several presentations related to SQL Server. Before SQL Server, he worked on many data platforms such as DB2, Oracle, Sybase, and Informix.This author pledges the content of this article is based on professional experience and not AI generated.
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