Today's script provides amongst other information Index compression estimates based on existing index information. All you need to do is set the database context and specify a schema, table and compression type. This script has been useful several times in the past so hopefully you will also find it useful.
/*
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Index Compression Estimations
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THIS CODE AND INFORMATION ARE PROVIDED "AS IS"
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*/
USE DatabaseNameHere;
GO
-- Get estimated data compression savings and other index info
-- for every index in the specified table
SET NOCOUNT ON;
DECLARE @SchemaName SYSNAME = N'SchemaNameHere'; -- Specify schema name
DECLARE @TableName SYSNAME = N'TableNameHere'; -- Specify table name
DECLARE @IndexID INT = 1;
DECLARE @CompressionType NVARCHAR(60) = N'CompressionTypeHere' -- Specify data compression type (PAGE, ROW, or NONE)
-- Get table name, row count, and compression status
-- for clustered index or heap table
SELECT OBJECT_NAME([object_id]) AS [ObjectName],
SUM([Rows]) AS [RowCount],
data_compression_desc AS [CompressionType]
FROM sys.partitions
WHERE index_id < 2 -- ignore the partitions from the non-clustered index if any
AND OBJECT_NAME([object_id]) = @TableName
GROUP BY [object_id], data_compression_desc
ORDER BY SUM([Rows]) DESC;
-- Breaks down buffers used by current database by object (table, index) in the buffer pool
SELECT OBJECT_NAME(p.[object_id]) AS [ObjectName],
p.index_id,
COUNT(*)/128 AS [Buffer size(MB)],
COUNT(*) AS [BufferCount],
p.data_compression_desc AS [CompressionType]
FROM sys.allocation_units AS a
INNER JOIN sys.dm_os_buffer_descriptors AS b ON a.allocation_unit_id = b.allocation_unit_id
INNER JOIN sys.partitions AS p ON a.container_id = p.hobt_id
WHERE b.database_id = DB_ID()
AND OBJECT_NAME(p.[object_id]) = @TableName
AND p.[object_id] > 100
GROUP BY p.[object_id], p.index_id, p.data_compression_desc
ORDER BY [BufferCount] DESC;
-- Shows you which indexes are taking the most space in the buffer cache
-- Get current and estimated size for every index in specified table
DECLARE curIndexID CURSOR
FAST_FORWARD
FOR
-- Get list of index IDs for this table
SELECT s.index_id
FROM sys.dm_db_index_usage_stats AS s
WHERE OBJECT_NAME(s.[object_id]) = @TableName
AND s.database_id = DB_ID()
ORDER BY s.index_id;
OPEN curIndexID;
FETCH NEXT
FROM curIndexID
INTO @IndexID;
-- Loop through every index in the table and run sp_estimate_data_compression_savings
WHILE @@FETCH_STATUS = 0
BEGIN
-- Get current and estimated size for specified index with specified compression type
EXEC sp_estimate_data_compression_savings @SchemaName, @TableName, @IndexID, NULL, @CompressionType;
FETCH NEXT
FROM curIndexID
INTO @IndexID;
END
CLOSE curIndexID;
DEALLOCATE curIndexID;
-- Index Read/Write stats for a single table
SELECT OBJECT_NAME(s.[object_id]) AS [TableName],
i.name AS [IndexName],
i.index_id,
SUM(user_seeks) AS [User Seeks],
SUM(user_scans) AS [User Scans],
SUM(user_lookups)AS [User Lookups],
SUM(user_seeks + user_scans + user_lookups)AS [Total Reads],
SUM(user_updates) AS [Total Writes]
FROM sys.dm_db_index_usage_stats AS s
INNER JOIN sys.indexes AS i ON s.[object_id] = i.[object_id]
AND i.index_id = s.index_id
WHERE OBJECTPROPERTY(s.[object_id],'IsUserTable') = 1
AND s.database_id = DB_ID()
AND OBJECT_NAME(s.[object_id]) = @TableName
GROUP BY OBJECT_NAME(s.[object_id]), i.name, i.index_id
ORDER BY [Total Writes] DESC, [Total Reads] DESC;
-- Get basic index information (does not include filtered indexes or included columns)
--EXEC sp_helpindex @TableName;
-- Get size and available space for files in current database
SELECT name AS [File Name],
physical_name AS [Physical Name],
size / 128.0 AS [Total Size in MB],
size / 128.0 - CAST(FILEPROPERTY(name, 'SpaceUsed') AS INT)/128.0 AS [Available Space In MB],
[file_id]
FROM sys.database_files;
Enjoy!
Chris
