26 January 2014

SQL browser service is not running on server.

1. Rename the MSSQLentries and start browser

 
Start the broser after this will create new entries on the same, 

OR
 
http://blogs.msdn.com/b/sqlserverfaq/archive/2009/09/18/sql-browser-service-is-not-running-on-server.aspx

Environment
Windows Server 2003
SQL Express 2005
Service Pack: SP2

· We followed the KB http://support.microsoft.com/default.aspx?scid=kb;EN-US;914277
· SQL browser service was already set to “automatic”.
· When we try to start the service ,we got this error :
TITLE: Surface Area Configuration
------------------------------

The service did not respond to the start or control request in a timely fashion, you need administrator privileges to be able to start/stop this service. (SQLSAC)
· The application event logs had the following errors :
The configuration of the SQL instance MSSQLServer is not valid.
The configuration of the AdminConnection\TCP protocol in the SQL instance is not valid.

The SQLBrowser service was unable to establish SQL instance and connectivity discovery.
The SQLBrowser is enabling SQL instance and connectivity discovery support

To get more information on reason for service failure, you can start the SQL Browser as a console application
· When we try starting SQL browser as a console application we got the following errors :
C:\Program Files\Microsoft SQL Server\90\Shared>sqlbrowser.exe -c
SQLBrowser: starting up in console mode
SQLBrowser: starting up SSRP redirection service
SQLBrowser is successfully listening on 0.0.0.0[1434]
SQLBrowser: failed starting SSRP redirection services -- shutting down.
What is SSRP Redirection?
SQL Server Resolution Protocol (SSRP) was developed to listen on port 1434, beginning with SQL Server 2000. This was how we managed to have multiple SQL Server instances on the same machine. The SSRP redirector as the name suggests “redirected” the client requests to the appropriate instance based on the Instance Name or Port # or Named Pipe.

· We found a key  under SQL server registry hive:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\CurrentVersion
· This is from an older default installation of SQL server 2000. This should not exist anymore since SQL Browser is a replacement for the SSRP mechanism.
· If above key exists, SQL Browser during startup tries to connect to this instance (non-existent) and hence fails
· So we renamed above key it to CurrentVersion_Old and tried to restart the browser services, this time we were able to do so.
Note: -
1. Please check for the existence of this key under the wow6432node key as well.
HKLM\SOFTWARE\WOW6432\Microsoft\MSSQLSERVER

2. Please make sure that you do not have any SQL Server 2000 instances running anymore before making the registry change.
Amrutha Varshini
SE, Microsoft SQL Server

Reviewed by
Sudarshan Narasimhan
TL, Microsoft SQL Server

10 January 2014

SQL Server - Performance Counter


 

SQL Performance Counters


Object
Counter
Preferred Value
Description
SQLServer:Access Methods
Forwarded Records/sec
< 10 per 100 Batch Requests/Sec
Rows with varchar columns can experience expansion when varchar values are updated with a longer string.  In the case where the row cannot fit in the existing page, the row migrates and access to the row will traverse a pointer.  This only happens on heaps (tables without clustered indexes). Evaluate clustered index for heap tables.  In cases where clustered indexes cannot be used, drop non-clustered indexes, build a clustered index to reorg pages and rows, drop the clustered index, then recreate non-clustered indexes.
SQLServer:Access Methods
Full Scans / sec
(Index Searches/sec)/(Full Scans/sec) > 1000
This counter monitors the number of full scans on base tables or indexes. Values greater than 1 or 2 indicate that we are having table / Index page scans. If we see high CPU then we need to investigate this counter, otherwise if the full scans are on small tables we can ignore this counter.  A few of the main causes of high Full Scans/sec are
• Missing indexes
• Too many rows requested
Queries with missing indexes or too many rows requested will have a large number of logical reads and an increased CPU time.
SQLServer:Access Methods
Index Searches/sec
(Index Searches/sec)/(Full Scans/sec) > 1000
Number of index searches. Index searches are used to start range scans, single index record fetches, and to reposition within an index. Index searches are preferable to index and table scans.  For OLTP applications, optimize for more index searches and less scans (preferably, 1 full scan for every 1000 index searches). Index and table scans are expensive I/O operations.
SQLServer:Access Methods
Page Splits/sec
< 20 per 100 Batch Requests/Sec
Number of page splits per second that occur as the result of overflowing index pages. Interesting counter that can lead us to our table / index design. This value needs to be low as possible. If you find out that the number of page splits is high, consider increasing the fillfactor of your indexes. An increased fillfactor helps to reduce page splits because there is more room in data pages before it fills up and a page split has to occur.
Note that this counter also includes the new page allocations as well and doesn’t necessarily pose a problem.  The other place we can confirm the page splits that involve data or index rows moves are the fragmented indexes on page splits.
SQL Server:Buffer Manager
Buffer Cache hit ratio
> 90%
This counter indicates how often SQL Server goes to the buffer, not the hard disk, to get data. The higher this ratio, the less often SQL Server has to go to the hard disk to fetch data, and performance overall is boosted. Unlike many of the other counters available for monitoring SQL Server, this counter averages the Buffer Cache Hit Ratio from the time the last instance of SQL Server was restarted. In other words, this counter is not a real-time measurement, but an average of all the days since SQL Server was last restarted. In OLTP applications, this ratio should exceed 90-95%. If it doesn't, then you need to add more RAM to your server to increase performance. In OLAP applications, the ratio could be much less because of the nature of how OLAP works. In any case, more RAM should increase the performance of SQL Server OLAP activity.
SQL Server:Buffer Manager
Free list stalls/sec
< 2
Free list stalls/sec is the frequency with which requests for available database pages are suspended because no buffers are available. Free list stall rates of 3 or 4 per second indicate too little SQL memory available.
SQL Server:Buffer Manager
Free pages
> 640
Total number of pages on all free lists.
SQL Server:Buffer Manager
Lazy Writes/Sec
< 20
This counter tracks how many times a second that the Lazy Writer process is moving dirty pages from the buffer to disk in order to free up buffer space. Generally speaking, this should not be a high value, say more than 20 per second or so.  Ideally, it should be close to zero. If it is zero, this indicates that your SQL Server's buffer cache is plenty big and SQL Server doesn't have to free up dirty pages, instead waiting for this to occur during regular checkpoints. If this value is high, then a need for more memory is indicated.
SQL Server:Buffer Manager
Page Life Expectancy
> 300
This performance monitor counter tells you, on average, how long data pages are staying in the buffer. If this value gets below 300 seconds, this is a potential indication that your SQL Server could use more memory in order to boost performance.
SQLServer:Buffer Manager
Page lookups/sec
(Page lookups/sec) / (Batch Requests/sec) < 100
Number of requests to find a page in the buffer pool. When the ratio of page lookups to batch requests is much greater than 100, this is an indication that while query plans are looking up data in the buffer pool, these plans are inefficient. Identify queries with the highest amount of logical I/O's and tune them.
SQL Server:Buffer Manager
Page reads/sec
< 90
Number of physical database page reads issued. 80 – 90 per second is normal, anything that is above indicates indexing or memory constraint.
SQL Server:Buffer Manager
Page writes/sec
< 90
Number of physical database page writes issued. 80 – 90 per second is normal, anything more we need to check the lazy writer/sec and checkpoint counters, if these counters are also relatively high then, it’s memory constraint.
SQLServer:General Statistics
Logins/sec
< 2
> 2 per second indicates that the application is not correctly using connection pooling.
SQLServer:General Statistics
Logouts/sec
< 2
> 2 per second indicates that the application is not correctly using connection pooling.
SQLServer:General Statistics
User Connections
See Description
The number of users currently connected to the SQL Server.

Note: It is recommended to review this counter along with “Batch Requests/Sec”.   A surge in “user connections” may result in a surge of “Batch Requests/Sec”.  So if there is a disparity (one going up and the other staying flat or going down), then that may be a cause for concern. With a blocking problem, for example, you might see user connections, lock waits and lock wait time all increase while batch requests/sec decreases. 
SQL Server:Latches
Latch Waits/sec
(Total Latch Wait Time) / (Latch Waits/Sec) < 10
This is the number of latch requests that could not be granted immediately. In other words, these are the amount of latches, in a one second period that had to wait.
SQL Server:Latches
Total Latch Wait Time (ms)
(Total Latch Wait Time) / (Latch Waits/Sec) < 10
This is the total latch wait time (in milliseconds) for latch requests in the last second
SQL Server:Locks 
Lock Wait Time (ms)
See Description”


Total wait time (milliseconds) for locks in the last second.

Note: For “Lock Wait Time” it is recommended to look beyond the Avg value.  Look for any peaks that are close (or exceeds) to a wait of 60 sec.   Though this counter counts how many total milliseconds SQL Server is  waiting on locks during the last second, but the counter actually records  at the end of locking event.  So most probably the peaks represent one huge locking event.  If those events exceeds more than 60seconds then they may have extended blocking and could be an issue. In such cases, thoroughly analyze the blocking script output. Some applications are written for timing out after 60 seconds and that’s not acceptable response for those applications.

SQL Server:Locks 
Lock Waits/sec
0
This counter reports how many times users waited to acquire a lock over the past second.  Note that while you are actually waiting on the lock that this is not reflected in this counter—it gets incremented only when you “wake up” after waiting on the lock. If this value is nonzero then it is an indication that there is at least some level of blocking occurring.  If you combine this with the Lock Wait Time counter, you can get some idea of how long the blocking lasted.  A zero value for this counter can definitively prove out blocking as a potential cause; a nonzero value will require looking at other information to determine whether it is significant. 
SQL Server:Locks 
Number of Deadlocks/sec
< 1
The number of lock requests that resulted in a deadlock.
SQLServer:Memory Manager
Total Server Memory(KB)
See Description
The Total Server Memory is the current amount of memory that SQL Server is using.  If this counter is still growing the server has not yet reached its steady-state, and it is still trying to populate the cache and get pages loaded into memory.  Performance will likely be somewhat slower during this time since more disk I/O is required at this stage.  This behavior is normal.  Eventually Total Server Memory should approximate Target Server Memory.
SQLServer:SQL Statistics
Batch Requests/Sec
See Description
This counter measures the number of batch requests that SQL Server receives per second, and generally follows in step to how busy your server's CPUs are. Generally speaking, over 1000 batch requests per second indicates a very busy SQL Server, and could mean that if you are not already experiencing a CPU bottleneck, that you may very well soon. Of course, this is a relative number, and the bigger your hardware, the more batch requests per second SQL Server can handle. From a network bottleneck approach, a typical 100Mbs network card is only able to handle about 3000 batch requests per second. If you have a server that is this busy, you may need to have two or more network cards, or go to a 1Gbs network card.

Note: Sometimes low batch requests/sec can be misleading.  If there were a SQL statements/sec counter, this would be a more accurate measure of the amount of SQL Server activity.  For example, an application may call only a few stored procedures yet each stored procedure does lot of work.  In that case, we will see a low number for batch requests/sec but each stored procedure (one batch) will execute many SQL statements that drive CPU and other resources.  As a result, many counter thresholds based on the number of batch requests/sec will seem to identify issues because the batch requests on such a server are unusually low for the level of activity on the server.  

We cannot conclude that a SQL Server is not active simply by looking at only batch requests/sec.  Rather, you have to do more investigation before deciding there is no load on the server.  If the average number of batch requests/sec is below 5 and other counters (such as SQL Server processor utilization) confirm the absence of significant activity, then there is not enough of a load to make any recommendations or identify issues regarding scalability.

SQLServer:SQL Statistics
SQL Compilations/sec
< 10% of the number of Batch Requests/Sec
The number of times per second that SQL Server compilations have occurred. This value needs to be as low as possible. If you see a high value such as over 100, then it’s an indication that there are lots of adhoc queries that are running, might cause CPU usage, solution is to re-write these adhoc as stored procedure or use sp_executeSQL.
SQLServer:SQL Statistics
SQL Re-Compilations/sec
< 10% of the number of SQL Compilations/sec
This needs to be nil in our system as much as possible. A recompile can cause deadlocks and compile locks that are not compatible with any locking type.

 NOTE :
The most important counters are in blue.
It is recommended to save the counters to a CSV file or a SQL Server database.
The sample rate should be every 15 seconds.


more on :- http://www.grumpyolddba.co.uk/monitoring/Performance%20Counter%20Guidance%20-%20SQL%20Server.htm

01 January 2014

HelpFull Querys -1

--- QUERY STATUS 

select T.text, R.Status, R.Command, DatabaseName = db_name(R.database_id)
       , R.cpu_time, R.total_elapsed_time, R.percent_complete
from   sys.dm_exec_requests R
       cross apply sys.dm_exec_sql_text(R.sql_handle) T --where  db_name(R.database_id)='tempdb'
order by Command


---- TEMPDB SHRINK

DBCC FREEPROCCACHE
GO
DBCC DROPCLEANBUFFERS
go
DBCC FREESYSTEMCACHE ('ALL')
GO
DBCC FREESESSIONCACHE
GO
dbcc shrinkfile (tempdev,5000)
go



--Troubleshoot if any opentran or locks or allocation
 
SELECT * FROM sys.dm_exec_requests WHERE database_id = 2
select * from sys.dm_tran_locks where resource_database_id= 2
select * from sys.dm_db_session_space_usage where user_objects_alloc_page_count<> 0
 
SELECT * FROM tempdb.sys.all_objects where is_ms_shipped = 0
 --if the above Query has objects it will clears by running freeproccache
 
--Some time cache prevents it to shrink
 
DBCC FREESYSTEMCACHE ('ALL')
DBCC FREESESSIONCACHE
DBCC FREEPROCCACHE
 
 

Find Nth Highest sal of emp

The following solution is for getting 5th highest sal from emp table ,

SELECT TOP 1 sal FROM (
SELECT DISTINCT TOP 5 sal
FROM emp ORDER BY sal DESC) a
ORDER BY sal


General Syntax to Find Nth Sal, N is the variable

SELECT TOP 1 sal FROM (
SELECT DISTINCT TOP n sal FROM emp
ORDER BY sal DESC) a
ORDER BY sal
where n > 1


Note :-n is always greater than one