How to Update Statistics

There are two ways to update statistics. The first way is the easy way. It is one line of code that will update all the statistics in the database using the default sample size of 20,000 rows per table. [cc lang=”sql”] EXEC sp_updatestats [/cc] The other way, is to use the UPDATE STATISTICS command. This command gives much better granularity of control: [cc lang=”sql”] — Update all statistics on a table UPDATE STATISTICS Sales.SalesOrderDetail — Update a specific index on a table UPDATE STATISTICS Sales.SalesOrderDetail IX_SalesOrderDetail — Update one column on a table specifying sample size UPDATE STATISTICS Production.Product(Products) WITH SAMPLE 50 PERCENT [/cc] Using update statistics can give you the granularity of control to only update the out of date statistics, thus having less impact on your production system. The following script updates all out of date statistics. Set the @MaxDaysOld variable to the number of days you will allow the statistics to be out of date by. Setting the @SamplePercent variable to null will use the SQL Server default value of 20,000 rows. You can also change the sample type to specify rows or percent. [cc lang=”sql”] DECLARE @MaxDaysOld int DECLARE @SamplePercent int DECLARE @SampleType nvarchar(50) SET @MaxDaysOld = 0 SET @SamplePercent = NULL –25 SET @SampleType = ‘PERCENT’ –‘ROWS’ BEGIN TRY DROP TABLE #OldStats END TRY BEGIN CATCH SELECT 1 END CATCH SELECT RowNum = ROW_NUMBER() OVER (ORDER BY ISNULL(STATS_DATE(object_id, st.stats_id),1)) ,TableName = OBJECT_SCHEMA_NAME(st.object_id) + ‘.’ + OBJECT_NAME(st.object_id) ,StatName = ,StatDate = ISNULL(STATS_DATE(object_id, st.stats_id),1) INTO #OldStats […]

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Query Which Tables are Partitioned

List out which tables are partitioned, and what partition scheme and partition function they use: [cc lang=”sql”] select as TableName, as PartitionScheme, ps.data_space_id, as PartitionFunction, pf.function_id from sys.tables t join sys.indexes i on t.object_id = i.object_id join sys.partition_schemes ps on i.data_space_id = ps.data_space_id join sys.partition_functions pf on ps.function_id = pf.function_id where i.index_id < 2 [/cc] For a given partition function, list each of the boundary values [cc lang=”sql”] select r.boundary_id, r.value from sys.partition_range_values r join sys.partition_functions pf on r.function_id = pf.function_id where = ‘fnQuarters’ — partition function name order by r.value [/cc]

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A Better sp_who2 using DMVs (sp_who3)

The following code generates the same information found in sp_who2, along with some additional troubleshooting information. It also contains the SQL Statement being run, so instead of having to execute a separate DBCC INPUTBUFFER, the statement being executed is shown in the results. Unlike sp_who2, this custom sp_who3 only shows sessions that have a current executing request. What is also shown is the reads and writes for the current command, along with the number of reads and writes for the entire SPID. It also shows the protocol being used (TCP, NamedPipes, or Shared Memory). The lead blocker below will show in the BlkBy column as -1. [cc lang=”sql”] USE [master] GO CREATE PROCEDURE [dbo].[sp_who3] AS BEGIN SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED; SELECT SPID = er.session_id ,BlkBy = CASE WHEN lead_blocker = 1 THEN -1 ELSE er.blocking_session_id END ,ElapsedMS = er.total_elapsed_time ,CPU = er.cpu_time ,IOReads = er.logical_reads + er.reads ,IOWrites = er.writes ,Executions = ec.execution_count ,CommandType = er.command ,LastWaitType = er.last_wait_type ,ObjectName = OBJECT_SCHEMA_NAME(qt.objectid,dbid) + ‘.’ + OBJECT_NAME(qt.objectid, qt.dbid) ,SQLStatement = SUBSTRING ( qt.text, er.statement_start_offset/2, CASE WHEN ( CASE WHEN er.statement_end_offset = -1 THEN LEN(CONVERT(nvarchar(MAX), qt.text)) * 2 ELSE er.statement_end_offset END – er.statement_start_offset / 2 ) < 0 THEN 0 ELSE CASE WHEN er.statement_end_offset = -1 THEN LEN(CONVERT(nvarchar(MAX), qt.text)) * 2 ELSE er.statement_end_offset END - er.statement_start_offset / 2 END ) ,STATUS = ses.STATUS ,[Login] = ses.login_name ,Host = ses.host_name ,DBName = DB_Name(er.database_id) ,StartTime = er.start_time ,Protocol = con.net_transport ,transaction_isolation = CASE ses.transaction_isolation_level WHEN 0 THEN 'Unspecified' WHEN 1 THEN 'Read […]

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Local Linked Server

When using OPENQUERY you will sometimes want to make calls to the same server you are working from. The most common reason for this is to query the output of a stored procedure into a temporary table. For that example, follow this link: (Insert Results of Stored Procedure Into Table) Before doing that you will have to create a linked server. You can either create the server programatically: [cc lang=”sql”] EXEC sp_addlinkedserver @server=’LOCALSERVER’, @srvproduct=’SQLSERVER’, @provider=’SQLNCLI’, @datasrc=’SERVERNAMEINSTANCENAME’ [/cc] Or you can create the linked server manually: In SSMS, Expand Server Objects -> Linked Servers -> (Right click on the Linked Server Folder and select “New Linked Server”) The “New Linked Server” Dialog appears. Type in a friendly name that describes your local server (without spaces). I use LOCALSERVER. Provider – Select “Microsoft OLE DB Provider for SQL Server” Product Name – type: SQLSERVER (with no spaces) Datasource – type the SERVERNAMEINSTANCENAME ProviderString – Blank Catalog – Optional (If entered use the default database you will be using) Within the same Dialog on the left menu under “Select a Page”, select Security Select the radio button named “Be made using the login’s current security context” Click OK, and the new linked server is created

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Rowcount for All Tables

SELECT SUM(rowcnt)
FROM sysindexes
WHERE indid < 2

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