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patternsqlModerate

Central stored procedure to execute in calling database context

Submitted by: @import:stackexchange-dba··
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storedcentralproceduredatabasecontextcallingexecute

Problem

I am working on a customized maintenance solution using the sys.dm_db_index_physical_stats view. I currently have it being referenced from a stored procedure. Now when that stored procedure runs on one of my databases, it does what I want it to do and pulls down a listing of all records regarding any database. When I place it on a different database it pulls down a listing of all records relating to only that DB.

For example (code at bottom):

  • Query run against Database 6 shows [requested] information for databases 1-10.



  • Query run against Database 3 shows [requested] information for only database 3.



The reason I want this procedure specifically on database three is because I'd prefer to keep all maintenance objects within the same database. I'd like to have this job sit in the maintenance database and work as if it were in that application database.

Code:

```
ALTER PROCEDURE [dbo].[GetFragStats]
@databaseName NVARCHAR(64) = NULL
,@tableName NVARCHAR(64) = NULL
,@indexID INT = NULL
,@partNumber INT = NULL
,@Mode NVARCHAR(64) = 'DETAILED'
AS
BEGIN
SET NOCOUNT ON;

DECLARE @databaseID INT, @tableID INT

IF @databaseName IS NOT NULL
AND @databaseName NOT IN ('tempdb','ReportServerTempDB')
BEGIN
SET @databaseID = DB_ID(@databaseName)
END

IF @tableName IS NOT NULL
BEGIN
SET @tableID = OBJECT_ID(@tableName)
END

SELECT D.name AS DatabaseName,
T.name AS TableName,
I.name AS IndexName,
S.index_id AS IndexID,
S.avg_fragmentation_in_percent AS PercentFragment,
S.fragment_count AS TotalFrags,
S.avg_fragment_size_in_pages AS PagesPerFrag,
S.page_count AS NumPages,
S.index_type_desc AS IndexType
FROM sys.dm_db_index_physical_stats(@databaseID, @tableID,
@indexID, @partNumber, @Mode) AS S
JOIN
sys.databases AS D ON S.database_id = D.database_id
JOIN
sys.tables

Solution

One way would be to make a system procedure in master and then create a wrapper in your maintenance database. Note that this will only work for one database at a time.

First, in master:

USE [master];
GO
CREATE PROCEDURE dbo.sp_GetFragStats -- sp_prefix required
  @tableName    NVARCHAR(128) = NULL,
  @indexID      INT           = NULL,
  @partNumber   INT           = NULL,
  @Mode         NVARCHAR(20)  = N'DETAILED'
AS
BEGIN
  SET NOCOUNT ON;

  SELECT
    DatabaseName    = DB_NAME(),
    TableName       = t.name,
    IndexName       = i.name,
    IndexID         = s.index_id,
    PercentFragment = s.avg_fragmentation_in_percent,
    TotalFrags      = s.fragment_count,
    PagesPerFrag    = s.avg_fragment_size_in_pages,
    NumPages        = s.page_count,
    IndexType       = s.index_type_desc
    -- shouldn't s.partition_number be part of the output as well?
  FROM sys.tables AS t
  INNER JOIN sys.indexes AS i
    ON t.[object_id] = i.[object_id]
    AND i.index_id = COALESCE(@indexID, i.index_id)
    AND t.name = COALESCE(@tableName, t.name)
  CROSS APPLY
    sys.dm_db_index_physical_stats(DB_ID(), t.[object_id], 
      i.index_id, @partNumber, @Mode) AS s
  WHERE s.avg_fragmentation_in_percent > 10
  -- probably also want to filter on minimum page count too
  -- do you really care about a table that has 100 pages?
  ORDER BY 
    DatabaseName, TableName, IndexName, PercentFragment DESC;
END
GO
-- needs to be marked as a system object:
EXEC sp_MS_MarkSystemObject N'dbo.sp_GetFragStats';
GO


Now, in your maintenance database, create a wrapper that uses dynamic SQL to set the context correctly:

USE YourMaintenanceDatabase;
GO
CREATE PROCEDURE dbo.GetFragStats
  @DatabaseName SYSNAME,      -- can't really be NULL, right?
  @tableName    NVARCHAR(128) = NULL,
  @indexID      INT           = NULL,
  @partNumber   INT           = NULL,
  @Mode         NVARCHAR(20)  = N'DETAILED'
AS
BEGIN
  DECLARE @sql NVARCHAR(MAX);

  SET @sql = N'USE ' + QUOTENAME(@DatabaseName) + ';
    EXEC dbo.sp_GetFragStats @tableName, @indexID, @partNumber, @Mode;';

  EXEC sp_executesql 
    @sql,
    N'@tableName NVARCHAR(128),@indexID INT,@partNumber INT,@Mode NVARCHAR(20)',
    @tableName, @indexID, @partNumber, @Mode;
END
GO


(The reason the database name can't really be NULL is because you can't join to things like sys.objects and sys.indexes since they exist independently in each database. So perhaps have a different procedure if you want instance-wide information.)

Now you can call this for any other database, e.g.

EXEC YourMaintenanceDatabase.dbo.GetFragStats 
  @DatabaseName = N'AdventureWorks2012',
  @TableName    = N'SalesOrderHeader';


And you can always create a synonym in each database so you don't even have to reference the name of the maintenance database:

USE SomeOtherDatabase;`enter code here`
GO
CREATE SYNONYM dbo.GetFragStats FOR YourMaintenanceDatabase.dbo.GetFragStats;


Another way would be to use dynamic SQL, however this, too, will only work for one database at a time:

USE YourMaintenanceDatabase;
GO
CREATE PROCEDURE dbo.GetFragStats
  @DatabaseName SYSNAME,
  @tableName    NVARCHAR(128) = NULL,
  @indexID      INT           = NULL,
  @partNumber   INT           = NULL,
  @Mode         NVARCHAR(20)  = N'DETAILED'
AS
BEGIN
  SET NOCOUNT ON;

  DECLARE @sql NVARCHAR(MAX) = N'SELECT
    DatabaseName    = @DatabaseName,
    TableName       = t.name,
    IndexName       = i.name,
    IndexID         = s.index_id,
    PercentFragment = s.avg_fragmentation_in_percent,
    TotalFrags      = s.fragment_count,
    PagesPerFrag    = s.avg_fragment_size_in_pages,
    NumPages        = s.page_count,
    IndexType       = s.index_type_desc
  FROM ' + QUOTENAME(@DatabaseName) + '.sys.tables AS t
  INNER JOIN ' + QUOTENAME(@DatabaseName) + '.sys.indexes AS i
    ON t.[object_id] = i.[object_id]
    AND i.index_id = COALESCE(@indexID, i.index_id)
    AND t.name = COALESCE(@tableName, t.name)
  CROSS APPLY
    ' + QUOTENAME(@DatabaseName) + '.sys.dm_db_index_physical_stats(
        DB_ID(@DatabaseName), t.[object_id], i.index_id, @partNumber, @Mode) AS s
  WHERE s.avg_fragmentation_in_percent > 10
  ORDER BY 
    DatabaseName, TableName, IndexName, PercentFragment DESC;';

  EXEC sp_executesql @sql, 
    N'@DatabaseName SYSNAME, @tableName NVARCHAR(128), @indexID INT,
      @partNumber INT, @Mode NVARCHAR(20)',
    @DatabaseName, @tableName, @indexID, @partNumber, @Mode;
END
GO


Yet another way would be to create a view (or table-valued function) to union the table and index names of all your databases, however you'd have to hard-code the database names into the view, and maintain them as you add/remove databases that you want to allow to be included in this query. This would, unlike the others, allow you to retrieve stats for multiple databases at once.

First, the view:

```
CREATE VIEW dbo.CertainTablesAndIndexes
AS
SELECT
db = N'AdventureWorks2012',
t.[obje

Code Snippets

USE [master];
GO
CREATE PROCEDURE dbo.sp_GetFragStats -- sp_prefix required
  @tableName    NVARCHAR(128) = NULL,
  @indexID      INT           = NULL,
  @partNumber   INT           = NULL,
  @Mode         NVARCHAR(20)  = N'DETAILED'
AS
BEGIN
  SET NOCOUNT ON;

  SELECT
    DatabaseName    = DB_NAME(),
    TableName       = t.name,
    IndexName       = i.name,
    IndexID         = s.index_id,
    PercentFragment = s.avg_fragmentation_in_percent,
    TotalFrags      = s.fragment_count,
    PagesPerFrag    = s.avg_fragment_size_in_pages,
    NumPages        = s.page_count,
    IndexType       = s.index_type_desc
    -- shouldn't s.partition_number be part of the output as well?
  FROM sys.tables AS t
  INNER JOIN sys.indexes AS i
    ON t.[object_id] = i.[object_id]
    AND i.index_id = COALESCE(@indexID, i.index_id)
    AND t.name = COALESCE(@tableName, t.name)
  CROSS APPLY
    sys.dm_db_index_physical_stats(DB_ID(), t.[object_id], 
      i.index_id, @partNumber, @Mode) AS s
  WHERE s.avg_fragmentation_in_percent > 10
  -- probably also want to filter on minimum page count too
  -- do you really care about a table that has 100 pages?
  ORDER BY 
    DatabaseName, TableName, IndexName, PercentFragment DESC;
END
GO
-- needs to be marked as a system object:
EXEC sp_MS_MarkSystemObject N'dbo.sp_GetFragStats';
GO
USE YourMaintenanceDatabase;
GO
CREATE PROCEDURE dbo.GetFragStats
  @DatabaseName SYSNAME,      -- can't really be NULL, right?
  @tableName    NVARCHAR(128) = NULL,
  @indexID      INT           = NULL,
  @partNumber   INT           = NULL,
  @Mode         NVARCHAR(20)  = N'DETAILED'
AS
BEGIN
  DECLARE @sql NVARCHAR(MAX);

  SET @sql = N'USE ' + QUOTENAME(@DatabaseName) + ';
    EXEC dbo.sp_GetFragStats @tableName, @indexID, @partNumber, @Mode;';

  EXEC sp_executesql 
    @sql,
    N'@tableName NVARCHAR(128),@indexID INT,@partNumber INT,@Mode NVARCHAR(20)',
    @tableName, @indexID, @partNumber, @Mode;
END
GO
EXEC YourMaintenanceDatabase.dbo.GetFragStats 
  @DatabaseName = N'AdventureWorks2012',
  @TableName    = N'SalesOrderHeader';
USE SomeOtherDatabase;`enter code here`
GO
CREATE SYNONYM dbo.GetFragStats FOR YourMaintenanceDatabase.dbo.GetFragStats;
USE YourMaintenanceDatabase;
GO
CREATE PROCEDURE dbo.GetFragStats
  @DatabaseName SYSNAME,
  @tableName    NVARCHAR(128) = NULL,
  @indexID      INT           = NULL,
  @partNumber   INT           = NULL,
  @Mode         NVARCHAR(20)  = N'DETAILED'
AS
BEGIN
  SET NOCOUNT ON;

  DECLARE @sql NVARCHAR(MAX) = N'SELECT
    DatabaseName    = @DatabaseName,
    TableName       = t.name,
    IndexName       = i.name,
    IndexID         = s.index_id,
    PercentFragment = s.avg_fragmentation_in_percent,
    TotalFrags      = s.fragment_count,
    PagesPerFrag    = s.avg_fragment_size_in_pages,
    NumPages        = s.page_count,
    IndexType       = s.index_type_desc
  FROM ' + QUOTENAME(@DatabaseName) + '.sys.tables AS t
  INNER JOIN ' + QUOTENAME(@DatabaseName) + '.sys.indexes AS i
    ON t.[object_id] = i.[object_id]
    AND i.index_id = COALESCE(@indexID, i.index_id)
    AND t.name = COALESCE(@tableName, t.name)
  CROSS APPLY
    ' + QUOTENAME(@DatabaseName) + '.sys.dm_db_index_physical_stats(
        DB_ID(@DatabaseName), t.[object_id], i.index_id, @partNumber, @Mode) AS s
  WHERE s.avg_fragmentation_in_percent > 10
  ORDER BY 
    DatabaseName, TableName, IndexName, PercentFragment DESC;';

  EXEC sp_executesql @sql, 
    N'@DatabaseName SYSNAME, @tableName NVARCHAR(128), @indexID INT,
      @partNumber INT, @Mode NVARCHAR(20)',
    @DatabaseName, @tableName, @indexID, @partNumber, @Mode;
END
GO

Context

StackExchange Database Administrators Q#44764, answer score: 15

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