functions/Test-DbaDbCompression.ps1
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function Test-DbaDbCompression { <# .SYNOPSIS Returns tables and indexes with preferred compression setting. .DESCRIPTION This function returns the results of a full table/index compression analysis. This function returns the best option to date for either NONE, Page, or Row Compression. Remember Uptime is critical, the longer uptime, the more accurate the analysis is. You would probably be best if you utilized Get-DbaUptime first, before running this command. Test-DbaCompression script derived from GitHub and the tigertoolbox (https://github.com/Microsoft/tigertoolbox/tree/master/Evaluate-Compression-Gains) In the output, you will find the following information: Column Percent_Update shows the percentage of update operations on a specific table, index, or partition, relative to total operations on that object. The lower the percentage of Updates (that is, the table, index, or partition is infrequently updated), the better candidate it is for page compression. Column Percent_Scan shows the percentage of scan operations on a table, index, or partition, relative to total operations on that object. The higher the value of Scan (that is, the table, index, or partition is mostly scanned), the better candidate it is for page compression. Column Compression_Type_Recommendation can have four possible outputs indicating where there is most gain, if any: 'PAGE', 'ROW', 'NO_GAIN' or '?'. When the output is '?' this approach could not give a recommendation, so as a rule of thumb I would lean to ROW if the object suffers mainly UPDATES, or PAGE if mainly INSERTS, but this is where knowing your workload is essential. When the output is 'NO_GAIN' well, that means that according to sp_estimate_data_compression_savings no space gains will be attained when compressing, as in the above output example, where compressing would grow the affected object. Note: Note that this script will execute on the context of the current database. Also be aware that this may take awhile to execute on large objects, because if the IS locks taken by the sp_estimate_data_compression_savings cannot be honored, the SP will be blocked. .PARAMETER SqlInstance SQL Server name or SMO object representing the SQL Server to connect to. This can be a collection and receive pipeline input to allow the function to be executed against multiple SQL Server instances. .PARAMETER SqlCredential SqlCredential object to connect as. If not specified, current Windows login will be used. .PARAMETER Database The database(s) to process - this list is autopopulated from the server. If unspecified, all databases will be processed. .PARAMETER ExcludeDatabase The database(s) to exclude - this list is autopopulated from the server .PARAMETER EnableException By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message. This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting. Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch. .NOTES Author: Jason Squires (@js_0505, jstexasdba@gmail.com) Tags: Compression, Table, Database Website: https://dbatools.io Copyright: (C) Chrissy LeMaire, clemaire@gmail.com License: MIT https://opensource.org/licenses/MIT .LINK https://dbatools.io/Test-DbaCompression .EXAMPLE Test-DbaCompression -SqlInstance localhost Returns all user database files and free space information for the local host .EXAMPLE Test-DbaCompression -SqlInstance ServerA -Database DBName | Out-GridView Returns results of all potential compression options for a single database with the recommendation of either Page or Row into and nicely formated GridView .EXAMPLE Test-DbaCompression -SqlInstance ServerA Returns results of all potential compression options for all databases with the recommendation of either Page or Row .EXAMPLE $cred = Get-Credential sqladmin Test-DbaCompression -SqlInstance ServerA -ExcludeDatabase Database -SqlCredential $cred Returns results of all potential compression options for all databases with the recommendation of either Page or Row .EXAMPLE $servers = 'Server1','Server2' foreach ($svr in $servers) { Test-DbaCompression -SqlInstance $svr | Export-Csv -Path C:\temp\CompressionAnalysisPAC.csv -Append } This produces a full analysis of all your servers listed and is pushed to a csv for you to analyize. #> [CmdletBinding(DefaultParameterSetName = "Default")] param ( [parameter(Mandatory = $true, ValueFromPipeline = $true)] [Alias("ServerInstance", "SqlServer")] [DbaInstanceParameter[]]$SqlInstance, [PSCredential]$SqlCredential, [object[]]$Database, [object[]]$ExcludeDatabase, [Alias('Silent')] [switch]$EnableException ) begin { Write-Message -Level System -Message "Bound parameters: $($PSBoundParameters.Keys -join ", ")" $sql = "SET NOCOUNT ON; IF OBJECT_ID('tempdb..##testdbacompression', 'U') IS NOT NULL DROP TABLE ##testdbacompression IF OBJECT_ID('tempdb..##tmpEstimateRow', 'U') IS NOT NULL DROP TABLE ##tmpEstimateRow IF OBJECT_ID('tempdb..##tmpEstimatePage', 'U') IS NOT NULL DROP TABLE ##tmpEstimatePage CREATE TABLE ##testdbacompression ( [Schema] SYSNAME ,[TableName] SYSNAME ,[IndexName] SYSNAME NULL ,[Partition] INT ,[IndexID] INT ,[IndexType] VARCHAR(12) ,[PercentScan] SMALLINT ,[PercentUpdate] SMALLINT ,[RowEstimatePercentOriginal] BIGINT ,[PageEstimatePercentOriginal] BIGINT ,[CompressionTypeRecommendation] VARCHAR(7) ,SizeCurrent BIGINT ,SizeRequested BIGINT ,PercentCompression NUMERIC(10, 2) ); CREATE TABLE ##tmpEstimateRow ( objname SYSNAME ,schname SYSNAME ,indid INT ,partnr INT ,SizeCurrent BIGINT ,SizeRequested BIGINT ,SampleCurrent BIGINT ,SampleRequested BIGINT ); CREATE TABLE ##tmpEstimatePage ( objname SYSNAME ,schname SYSNAME ,indid INT ,partnr INT ,SizeCurrent BIGINT ,SizeRequested BIGINT ,SampleCurrent BIGINT ,SampleRequested BIGINT ); INSERT INTO ##testdbacompression ( [Schema] ,[TableName] ,[IndexName] ,[Partition] ,[IndexID] ,[IndexType] ,[PercentScan] ,[PercentUpdate] ) SELECT s.NAME AS [Schema] ,o.NAME AS [TableName] ,x.NAME AS [IndexName] ,p.partition_number AS [Partition] ,x.Index_ID AS [IndexID] ,x.type_desc AS [IndexType] ,NULL AS [PercentScan] ,NULL AS [PercentUpdate] FROM sys.objects o INNER JOIN sys.schemas s ON o.schema_id = s.schema_id INNER JOIN sys.indexes x ON x.object_id = o.object_id INNER JOIN sys.partitions p ON x.object_id = p.object_id AND x.Index_ID = p.Index_ID WHERE objectproperty(o.object_id, 'IsUserTable') = 1 AND p.data_compression_desc = 'NONE' AND p.rows > 0 ORDER BY [TableName] ASC; DECLARE @schema SYSNAME ,@tbname SYSNAME ,@ixid INT DECLARE cur CURSOR FAST_FORWARD FOR SELECT [Schema] ,[TableName] ,[IndexID] FROM ##testdbacompression OPEN cur FETCH NEXT FROM cur INTO @schema ,@tbname ,@ixid WHILE @@FETCH_STATUS = 0 BEGIN DECLARE @sqlcmd NVARCHAR(500) SET @sqlcmd = 'EXEC sp_estimate_data_compression_savings ''' + @schema + ''', ''' + @tbname + ''', ''' + cast(@ixid AS VARCHAR) + ''', NULL, ''ROW'''; INSERT INTO ##tmpEstimateRow ( objname ,schname ,indid ,partnr ,SizeCurrent ,SizeRequested ,SampleCurrent ,SampleRequested ) EXECUTE sp_executesql @sqlcmd SET @sqlcmd = 'EXEC sp_estimate_data_compression_savings ''' + @schema + ''', ''' + @tbname + ''', ''' + cast(@ixid AS VARCHAR) + ''', NULL, ''PAGE'''; INSERT INTO ##tmpEstimatePage ( objname ,schname ,indid ,partnr ,SizeCurrent ,SizeRequested ,SampleCurrent ,SampleRequested ) EXECUTE sp_executesql @sqlcmd FETCH NEXT FROM cur INTO @schema ,@tbname ,@ixid END CLOSE cur DEALLOCATE cur; --Update usage and partition_number - If database was restore the sys.dm_db_index_operational_stats will be empty until tables have accesses. Executing the sp_estimate_data_compression_savings first will make those entries appear UPDATE ##testdbacompression SET [PercentScan] = i.range_scan_count * 100.0 / NULLIF((i.range_scan_count + i.leaf_insert_count + i.leaf_delete_count + i.leaf_update_count + i.leaf_page_merge_count + i.singleton_lookup_count), 0) ,[PercentUpdate] = i.leaf_update_count * 100.0 / NULLIF((i.range_scan_count + i.leaf_insert_count + i.leaf_delete_count + i.leaf_update_count + i.leaf_page_merge_count + i.singleton_lookup_count), 0) FROM sys.dm_db_index_operational_stats(db_id(), NULL, NULL, NULL) i INNER JOIN ##testdbacompression tmp ON OBJECT_ID(tmp.TableName) = i.[object_id] AND tmp.IndexID = i.index_id; WITH tmp_cte ( objname ,schname ,indid ,pct_of_orig_row ,pct_of_orig_page ,SizeCurrent ,SizeRequested ) AS ( SELECT tr.objname ,tr.schname ,tr.indid ,(tr.SampleRequested * 100) / CASE WHEN tr.SampleCurrent = 0 THEN 1 ELSE tr.SampleCurrent END AS pct_of_orig_row ,(tp.SampleRequested * 100) / CASE WHEN tp.SampleCurrent = 0 THEN 1 ELSE tp.SampleCurrent END AS pct_of_orig_page ,tr.SizeCurrent ,tr.SizeRequested FROM ##tmpestimaterow tr INNER JOIN ##tmpestimatepage tp ON tr.objname = tp.objname AND tr.schname = tp.schname AND tr.indid = tp.indid AND tr.partnr = tp.partnr ) UPDATE ##testdbacompression SET [RowEstimatePercentOriginal] = tcte.pct_of_orig_row ,[PageEstimatePercentOriginal] = tcte.pct_of_orig_page ,SizeCurrent = tcte.SizeCurrent ,SizeRequested = tcte.SizeRequested ,PercentCompression = 100 - (cast(tcte.[SizeRequested] AS NUMERIC(21, 2)) * 100 / (tcte.[SizeCurrent] - ABS(SIGN(tcte.[SizeCurrent])) + 1)) FROM tmp_cte tcte ,##testdbacompression tcomp WHERE tcte.objname = tcomp.TableName AND tcte.schname = tcomp.[schema] AND tcte.indid = tcomp.IndexID; WITH tmp_cte2 ( TableName ,[schema] ,IndexID ,[CompressionTypeRecommendation] ) AS ( SELECT TableName ,[schema] ,IndexID ,CASE WHEN [RowEstimatePercentOriginal] >= 100 AND [PageEstimatePercentOriginal] >= 100 THEN 'NO_GAIN' WHEN [PercentUpdate] >= 10 THEN 'ROW' WHEN [PercentScan] <= 1 AND [PercentUpdate] <= 1 AND [RowEstimatePercentOriginal] < [PageEstimatePercentOriginal] THEN 'ROW' WHEN [PercentScan] <= 1 AND [PercentUpdate] <= 1 AND [RowEstimatePercentOriginal] > [PageEstimatePercentOriginal] THEN 'PAGE' WHEN [PercentScan] >= 60 AND [PercentUpdate] <= 5 THEN 'PAGE' WHEN [PercentScan] <= 35 AND [PercentUpdate] <= 5 THEN '?' ELSE 'ROW' END FROM ##testdbacompression ) UPDATE ##testdbacompression SET [CompressionTypeRecommendation] = tcte2.[CompressionTypeRecommendation] FROM tmp_cte2 tcte2 ,##testdbacompression tcomp2 WHERE tcte2.TableName = tcomp2.TableName AND tcte2.[schema] = tcomp2.[schema] AND tcte2.IndexID = tcomp2.IndexID; SET NOCOUNT ON; SELECT DBName = DB_Name() ,[Schema] ,[TableName] ,[IndexName] ,[Partition] ,[IndexID] ,[IndexType] ,[PercentScan] ,[PercentUpdate] ,[RowEstimatePercentOriginal] ,[PageEstimatePercentOriginal] ,[CompressionTypeRecommendation] ,SizeCurrentKB = [SizeCurrent] ,SizeRequestedKB = [SizeRequested] ,PercentCompression FROM ##testdbacompression; IF OBJECT_ID('tempdb..##setdbacompression', 'U') IS NOT NULL DROP TABLE ##testdbacompression IF OBJECT_ID('tempdb..##tmpEstimateRow', 'U') IS NOT NULL DROP TABLE ##tmpEstimateRow IF OBJECT_ID('tempdb..##tmpEstimatePage', 'U') IS NOT NULL DROP TABLE ##tmpEstimatePage; " } process { foreach ($instance in $SqlInstance) { try { Write-Message -Level VeryVerbose -Message "Connecting to $instance" -Target $instance $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SourceSqlCredential -MinimumVersion 10 } catch { Stop-Function -Message "Failed to process Instance $Instance" -ErrorRecord $_ -Target $instance -Continue } $Server.ConnectionContext.StatementTimeout = 0 [long]$instanceVersionNumber = $($server.VersionString).Replace(".", "") #If SQL Server 2016 SP1 (13.0.4001.0) or higher every version supports compression. if ($Server.EngineEdition -ne "EnterpriseOrDeveloper" -and $instanceVersionNumber -lt 13040010) { Stop-Function -Message "Compresison before SQLServer 2016 SP1 (13.0.4001.0) is only supported by enterprise, developer or evaluation edition. $Server has version $($server.VersionString) and edition is $($Server.EngineEdition)." -Target $db -Continue } #If IncludeSystemDBs is true, include systemdbs #look at all databases, online/offline/accessible/inaccessible and tell user if a db can't be queried. try { $dbs = $server.Databases | Where-Object IsAccessible if ($Database) { $dbs = $dbs | Where-Object { $Database -contains $_.Name -and $_.IsSystemObject -eq 0 } } else { $dbs = $dbs | Where-Object { $_.IsSystemObject -eq 0 } } if (Test-Bound "ExcludeDatabase") { $dbs = $dbs | Where-Object Name -NotIn $ExcludeDatabase } } catch { Stop-Function -Message "Unable to gather list of databases for $instance" -Target $instance -ErrorRecord $_ -Continue } foreach ($db in $dbs) { try { $dbCompatibilityLevel = [int]($db.CompatibilityLevel.ToString().Replace('Version', '')) Write-Message -Level Verbose -Message "Querying $instance - $db" if ($db.status -ne 'Normal' -or $db.IsAccessible -eq $false) { Write-Message -Level Warning -Message "$db is not accessible." -Target $db Continue } if ($dbCompatibilityLevel -lt 100) { Stop-Function -Message "$db has a compatibility level lower than Version100 and will be skipped." -Target $db -Continue Continue } #Execute query against individual database and add to output foreach ($row in ($server.Query($sql, $db.Name))) { [pscustomobject]@{ ComputerName = $server.NetName InstanceName = $server.ServiceName SqlInstance = $server.DomainInstanceName Database = $row.DBName Schema = $row.Schema TableName = $row.TableName IndexName = $row.IndexName Partition = $row.Partition IndexID = $row.IndexID IndexType = $row.IndexType PercentScan = $row.PercentScan PercentUpdate = $row.PercentUpdate RowEstimatePercentOriginal = $row.RowEstimatePercentOriginal PageEstimatePercentOriginal = $row.PageEstimatePercentOriginal CompressionTypeRecommendation = $row.CompressionTypeRecommendation SizeCurrent = [dbasize]($row.SizeCurrentKB * 1024) SizeRequested = [dbasize]($row.SizeRequestedKB * 1024) PercentCompression = $row.PercentCompression } } } catch { Stop-Function -Message "Unable to query $instance - $db" -Target $db -ErrorRecord $_ -Continue } } } } } |