Nettoyage d'assembly inutilisé

Article
05/07/2013

L'exemple AssemblyCleanup contient une procédure stockée .NET qui nettoie les assemblys inutilisés de la base de données actuelle en interrogeant les catalogues de métadonnées. Son seul paramètre, visible_assemblies, est utilisé pour spécifier si les assemblys visibles inutilisés doivent être supprimés ou pas. La valeur « false » signifie par défaut que seuls les assemblys invisibles inutilisés seront supprimés ; sinon, tous les assemblys inutilisés le seront. L'ensemble des assemblys inutilisés sont les assemblys qui n'ont pas de points d'entrée définis (routines / types et agrégats) et qui ne sont référencés directement ou indirectement par aucun assembly utilisé.

Configuration préalable requise

Pour créer et exécuter ce projet, les logiciels suivants doivent être installés :

SQL Server ou SQL Server Express. Vous pouvez vous procurer gratuitement SQL Server Express à partir du site Web SQL Server Express Documentation and Samples (en anglais)
Base de données AdventureWorks qui est disponible sur le site Web du Centre pour les développeurs SQL Server
Le Kit de développement logiciel .NET Framework SDK 2.0 ou version ultérieure, ou Microsoft Visual Studio 2005 ou version ultérieure. Vous pouvez vous procurer gratuitement le Kit de développement logiciel .NET Framework SDK.
De plus, les conditions suivantes doivent être réunies :
L'intégration du CLR doit être activée sur l'instance SQL Server que vous utilisez.
Pour activer l'intégration du CLR, effectuez les étapes suivantes :

Activation de l'intégration du CLR
- Exécutez les commandes Transact-SQL suivantes :
sp_configure 'clr enabled', 1

GO

RECONFIGURE

GO

[!REMARQUE]

Pour activer l'intégration du CLR, vous devez disposer de l'autorisation de niveau serveur ALTER SETTINGS qui est attribuée implicitement aux membres des rôles serveur fixes sysadmin et serveradmin.
La base de données AdventureWorks doit être installée sur l'instance SQL Server que vous utilisez.
Si vous n'êtes pas administrateur de l'instance SQL Server utilisée, vous devez demander à un administrateur de vous accorder l'autorisation CreateAssembly pour terminer l'installation.

Génération de l'exemple

Créez et exécutez l'exemple à l'aide des instructions suivantes :

Ouvrez une invite de commandes Visual Studio ou .NET Framework.
Si nécessaire, créez un répertoire pour votre exemple. Pour cet exemple, nous utiliserons C:\MySample.
Dans c:\MySample, créez AssemblyCleanup.vb (pour l'exemple Visual Basic) ou AssemblyCleanup.cs (pour l'exemple C#) et copiez l'exemple de code Visual Basic ou C# approprié (ci-dessous) dans le fichier.
Compilez l'exemple de code à partir de l'invite de ligne de commande en exécutant l'un des éléments suivants, selon le langage choisi.
- Vbc /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll,C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll,C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Transactions.dll,C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Xml.dll /target:library AssemblyCleanup.vb
- Csc /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.XML.dll /target:library AssemblyCleanup.cs
Copiez le code d'installation Transact-SQL dans un fichier et enregistrez-le sous Install.sql dans le répertoire d'exemple.
Si l'exemple est installé dans un répertoire autre que C:\MySample\, modifiez le fichier Install.sql comme indiqué pour pointer sur cet emplacement.
Déployez l'assembly et la procédure stockée en exécutant
- sqlcmd -E -I -i install.sql
Copiez le script de la commande de test Transact-SQL dans un fichier et enregistrez-le sous test.sql dans le répertoire d'exemple.
Exécutez le script de test avec la commande suivante
- sqlcmd -E -I -i test.sql
Copiez le script de nettoyage Transact-SQL dans un fichier et enregistrez-le sous cleanup.sql dans le répertoire d'exemple.
Exécutez le script avec la commande suivante
- sqlcmd -E -I -i cleanup.sql

Exemple de code

Voici les listes de code pour cet exemple.

using System;
using System.Text;
using System.Diagnostics;
using System.Data.SqlClient;
using System.Collections.Generic;
using System.Globalization;
using Microsoft.SqlServer.Server;


    /// <summary>
    /// Defines a CLR user defined function CleanupUnusedAssemblies that drops 
    /// all the invisible assemblies with no references.
    /// </summary>
    public sealed class AssemblyCleanup
    {
        private SqlTransaction transaction;

        internal class AssemblySet
        {
            private Dictionary<int, object> m_dictionary;

            /// <summary>
            /// Initialize internal structures
            /// </summary>
            /// <returns></returns>
            public AssemblySet()
            {
                m_dictionary = new Dictionary<int, object>();
            }

            /// <summary>
            /// Adds an assembly id into the current AssemblySet if it is not 
            /// already part of it.
            /// </summary>
            /// <returns></returns>
            public void Add(int assemblyId)
            {
                if (!m_dictionary.ContainsKey(assemblyId))
                {
                    m_dictionary.Add(assemblyId, null);
                }
            }

            /// <summary>
            /// Number of assembly ids stored in this instance
            /// </summary>
            /// <returns></returns>
            public int Count
            {
                get
                {
                    return m_dictionary.Count;
                }
            }

            /// <summary>
            /// Returns the comma-separated list of assembly ids contained in this instance
            /// </summary>
            /// <returns>string value that represents a comma-seperated list 
            /// of assembly ids</returns>
            public string ToCommaSeperatedList()
            {
                StringBuilder sb = new StringBuilder();

                if (m_dictionary.Count > 0)
                {
                    foreach (KeyValuePair<int, object> kv in m_dictionary)
                    {
                        sb.Append(kv.Key);
                        sb.Append(",");
                    }

                    sb.Length--; // remove the trailing comma
                }

                return sb.ToString();
            }
        }

        /// <summary>
        /// Initializes an instance of AssemblyCleanup with a SqlTransaction
        /// </summary>
        /// <returns></returns>
        private AssemblyCleanup(SqlTransaction transaction)
        {
            this.transaction = transaction;
        }

        /// <summary>
        /// Helper function that creates a SqlCommand object as part of the current 
        /// transaction
        /// </summary>
        /// <returns></returns>
        private SqlCommand CreateCommandInTransaction()
        {
            SqlCommand cmd = this.transaction.Connection.CreateCommand();

            cmd.Transaction = this.transaction;

            return cmd;
        }

        /// <summary>
        /// Helper function that constructs an AssemblySet instance using the 
        /// first column of the resultset resulting from the query that was passed in.
        /// </summary>
        /// <param name="query"></param>
        /// <returns></returns>
        private AssemblySet GetAssemblySetFromQuery(string query)
        {
            SqlCommand cmd = CreateCommandInTransaction();

            AssemblySet set = new AssemblySet();

            cmd.CommandText = query;
            using (SqlDataReader rd = cmd.ExecuteReader())
            {
                while (rd.Read())
                {
                    set.Add(rd.GetInt32(0));
                }
            }

            return set;
        }

        /// <summary>
        /// Constructs a DROP ASSEMBLY T-SQL statement using the AssemblySet 
        /// passed in as a parameter.
        /// </summary>
        /// <param name="set"></param>
        /// <returns></returns>
        private void DropAssemblies(AssemblySet unusedAssemblySet)
        {
            if (unusedAssemblySet.Count > 0)
            {
                StringBuilder assemblyNamesToDrop = new StringBuilder();

                // Gather the list of assembly names we will drop later
                SqlCommand cmd = CreateCommandInTransaction();

                cmd.CommandText = String.Format(CultureInfo.InvariantCulture,
                    "SELECT name FROM sys.assemblies WHERE assembly_id IN ({0});",
                    unusedAssemblySet.ToCommaSeperatedList());
                using (SqlDataReader rd = cmd.ExecuteReader())
                {
                    while (rd.Read())
                    {
                        assemblyNamesToDrop.Append("[");
                        assemblyNamesToDrop.Append(rd.GetString(0));
                        assemblyNamesToDrop.Append("],");
                    }
                }

                // Remove trailing comma
                assemblyNamesToDrop.Length--;

                // Drop all assemblies at the same time
                cmd.CommandText = String.Format(CultureInfo.InvariantCulture,
                    "DROP ASSEMBLY {0}", assemblyNamesToDrop.ToString());
                cmd.ExecuteNonQuery();
            }
        }

        /// <summary>
        /// Serves as the stored procedure entry point and drives the process 
        /// of expanding the "assemblies in use" set, negating it, and 
        /// dropping the results
        /// </summary>
        /// <param name="visibleAssemblies">If set to true, will also drop 
        /// unused visible assemblies. Otherwise, will only drop unused invisible 
        /// assemblies.</param>
        /// <returns></returns>
        [Microsoft.SqlServer.Server.SqlProcedure()]
        public static void CleanupUnusedAssemblies(bool visibleAssemblies)
        {
            bool succeeded = false;
            SqlConnection conn;
            SqlTransaction transaction;
            string sqlStatement;
            AssemblySet assembliesToDrop;
            AssemblyCleanup assemblyCleanup;

            conn = new SqlConnection("context connection=true");
            conn.Open();
            transaction = conn.BeginTransaction();

            try
            {
                // Create a set of assemblies in use by looking at 
                // the metadata of the current database
                sqlStatement =
                    "DECLARE @UsedAssembly TABLE (AssemblyID int NOT NULL); " +
                    "DECLARE @RowCount int; " +
                    "INSERT INTO @UsedAssembly " +
                    "SELECT DISTINCT([assembly_id]) " +
                    "FROM sys.assembly_modules " +
                    "UNION " +
                    "SELECT [assembly_id] " +
                    "FROM sys.assembly_types; " +
                    "SET @RowCount = @@ROWCOUNT; " +
                    "WHILE @RowCount > 0 " +
                    "BEGIN " +
                    "INSERT INTO @UsedAssembly " +
                    "SELECT [referenced_assembly_id] " +
                    "FROM sys.assembly_references ar " +
                    "INNER JOIN @UsedAssembly ua " +
                    "ON ar.[assembly_id] = ua.AssemblyID " +
                    "WHERE NOT EXISTS (SELECT * FROM @UsedAssembly WHERE AssemblyID = [referenced_assembly_id]) " +
                    "SET @RowCount = @@ROWCOUNT; " +
                    "END;";

                if (visibleAssemblies)
                {
                    sqlStatement +=
                        "SELECT assembly_id " +
                        "FROM sys.assemblies " +
                        "WHERE assembly_id NOT IN (SELECT AssemblyID FROM @UsedAssembly);";
                }
                else
                {
                    sqlStatement +=
                        "SELECT assembly_id " +
                        "FROM sys.assemblies " +
                        "WHERE assembly_id NOT IN (SELECT AssemblyID FROM @UsedAssembly) " +
                        "    AND is_visible = 0;";
                }

                // This marks the beginning of the transaction
                assemblyCleanup = new AssemblyCleanup(transaction);

                // Assemblies that are currently in use
                assembliesToDrop
                    = assemblyCleanup.GetAssemblySetFromQuery(sqlStatement);

                assemblyCleanup.DropAssemblies(assembliesToDrop);

                // Mark as succeeded
                succeeded = true;
            }
            finally
            {
                // We must guarantee that we explicitly call either Commit() 
                // or Rollback() before we return.
                if (succeeded)
                {
                    transaction.Commit();
                }
                else
                {
                    transaction.Rollback();
                }
                conn.Dispose();
            }
        }
    }

Visual Basic

Imports Microsoft.SqlServer.Server
Imports Microsoft.VisualBasic
Imports System
Imports System.Collections
Imports System.Collections.Generic
Imports System.Data
Imports System.Data.SqlClient
Imports System.Diagnostics
Imports System.Globalization
Imports System.Text
Imports System.Transactions
Public NotInheritable Class AssemblyCleanup
    Private transaction As SqlTransaction

    Friend Class AssemblySet
        Private m_dictionary As Dictionary(Of Integer, Object)

        ''' <summary>
        ''' Initialize internal structures
        ''' </summary>
        ''' <returns></returns>
        Public Sub New()
            m_dictionary = New Dictionary(Of Integer, Object)
        End Sub

        ''' <summary>
        ''' Adds an assembly id into the current AssemblySet if it is not already part of it.
        ''' </summary>
        ''' <returns></returns>
        Public Sub Add(ByVal assemblyId As Integer)
            If Not m_dictionary.ContainsKey(assemblyId) Then
                m_dictionary.Add(assemblyId, Nothing)
            End If
        End Sub

        ''' <summary>
        ''' Number of assembly ids stored in this instance
        ''' </summary>
        ''' <returns></returns>
        Public ReadOnly Property Count() As Integer
            Get
                Return m_dictionary.Count
            End Get
        End Property

        ''' <summary>
        ''' Returns the comma-separated list of assembly ids contained in this instance
        ''' </summary>
        ''' <returns>string value that represents a comma-seperated list of assembly ids</returns>
        Public Function ToCommaSeperatedList() As String
            Dim sb As New StringBuilder()

            If m_dictionary.Count > 0 Then
                For Each kv As KeyValuePair(Of Integer, Object) In m_dictionary
                    If (True) Then
                        sb.Append(kv.Key)
                        sb.Append(",")
                    End If
                Next

                sb.Length -= 1 ' remove the trailing comma
            End If

            Return sb.ToString()

        End Function
    End Class

    ''' <summary>
    ''' Initializes an instance of AssemblyCleanup with a SqlTransaction
    ''' </summary>
    ''' <returns></returns>
    Private Sub New(ByVal trans As SqlTransaction)
        Me.transaction = trans
    End Sub

    ''' <summary>
    ''' Helper function that creates a SqlCommand object as part of the 
    ''' current transaction
    ''' </summary>
    ''' <returns></returns>
    Private Function CreateCommandInTransaction() As SqlCommand
        Dim cmd As SqlCommand = transaction.Connection.CreateCommand()

        cmd.Transaction = Me.transaction

        Return cmd
    End Function

    ''' <summary>
    ''' Helper function that constructs an AssemblySet instance using the 
    ''' first column of the resultset resulting from the query that was passed in.
    ''' </summary>
    ''' <param name="query"></param>
    ''' <returns></returns>
    Private Function GetAssemblySetFromQuery(ByVal query As String) As AssemblySet
        Dim cmd As SqlCommand = CreateCommandInTransaction()
        Dim [set] As New AssemblySet()

        cmd.CommandText = query
        Dim rd As SqlDataReader = cmd.ExecuteReader()
        Try
            While rd.Read()
                [set].Add(rd.GetInt32(0))
            End While
        Finally
            rd.Dispose()
        End Try

        Return [set]
    End Function

    ''' <summary>
    ''' Constructs a DROP ASSEMBLY T-SQL statement using the AssemblySet 
    ''' passed in as a parameter.
    ''' </summary>
    ''' <param name="set"></param>
    ''' <returns></returns>
    Private Sub DropAssemblies(ByVal unusedAssemblySet As AssemblySet)
        If unusedAssemblySet.Count > 0 Then
            Dim assemblyNamesToDrop As New StringBuilder()

            ' Gather the list of assembly names we will drop later
            Dim cmd As SqlCommand = CreateCommandInTransaction()


            cmd.CommandText = String.Format(CultureInfo.InvariantCulture, _
                "SELECT name FROM sys.assemblies WHERE assembly_id IN ({0});", _
                unusedAssemblySet.ToCommaSeperatedList())
            Dim rd As SqlDataReader = cmd.ExecuteReader()
            Try
                While rd.Read()
                    assemblyNamesToDrop.Append("[")
                    assemblyNamesToDrop.Append(rd.GetString(0))
                    assemblyNamesToDrop.Append("],")
                End While
            Finally
                rd.Dispose()
            End Try

            ' Remove trailing comma
            assemblyNamesToDrop.Length -= 1

            ' Drop all assemblies at the same time
            cmd.CommandText = String.Format(CultureInfo.InvariantCulture, _
                "DROP ASSEMBLY {0}", assemblyNamesToDrop.ToString())
            cmd.ExecuteNonQuery()
        End If
    End Sub

    ''' <summary>
    ''' Serves as the stored procedure entry point and drives the process of 
    ''' expanding the "assemblies in use" set, negating it, and dropping 
    ''' the results.
    ''' </summary>
    ''' <param name="visibleAssemblies">If set to true, will also drop unused 
    ''' visible assemblies. Otherwise, will only drop unused invisible assemblies.</param>
    ''' <returns></returns>
    <Microsoft.SqlServer.Server.SqlProcedure()> _
    Public Shared Sub CleanupUnusedAssemblies(ByVal visibleAssemblies As Boolean)

        Dim succeeded As Boolean = False
        Dim conn As SqlConnection
        Dim transaction As SqlTransaction
        Dim sqlStatement As String
        Dim assembliesToDrop As AssemblySet
        Dim assemblyCleanup As AssemblyCleanup

        conn = New SqlConnection("context connection=true")
        conn.Open()
        transaction = conn.BeginTransaction()

        Try
            ' Create a set of assemblies in use by looking at 
            ' the metadata of the current database
            sqlStatement = "DECLARE @UsedAssembly TABLE (AssemblyID int NOT NULL); " & _
                "DECLARE @RowCount int; " & _
                "INSERT INTO @UsedAssembly " & _
                "SELECT DISTINCT([assembly_id]) " & _
                "FROM sys.assembly_modules " & _
                "UNION " & _
                "SELECT [assembly_id] " & _
                "FROM sys.assembly_types; " & _
                "SET @RowCount = @@ROWCOUNT; " & _
                "WHILE @RowCount > 0 " & _
                "BEGIN " & _
                "INSERT INTO @UsedAssembly " & _
                "SELECT [referenced_assembly_id] " & _
                "FROM sys.assembly_references ar " & _
                "INNER JOIN @UsedAssembly ua " & _
                "ON ar.[assembly_id] = ua.AssemblyID " & _
                "WHERE NOT EXISTS (SELECT * FROM @UsedAssembly WHERE AssemblyID = [referenced_assembly_id]) " & _
                "SET @RowCount = @@ROWCOUNT; " & _
                "END;"

            If visibleAssemblies Then
                sqlStatement += "SELECT assembly_id " & _
                    "FROM sys.assemblies " & _
                    "WHERE assembly_id NOT IN (SELECT AssemblyID FROM @UsedAssembly);"
            Else
                sqlStatement += "SELECT assembly_id " & _
                    "FROM sys.assemblies " & _
                    "WHERE assembly_id NOT IN (SELECT AssemblyID FROM @UsedAssembly) " & _
                    "    AND is_visible = 0;"
            End If

            ' This marks the beginning of the transaction
            assemblyCleanup = New AssemblyCleanup(transaction)

            ' Assemblies that are currently in use
            assembliesToDrop _
                = assemblyCleanup.GetAssemblySetFromQuery(sqlStatement)

            assemblyCleanup.DropAssemblies(assembliesToDrop)

            ' Mark as succeeded
            succeeded = True
        Finally
            ' We must guarantee that we explicitly call either Commit() 
            ' or Rollback() before we return.
            If succeeded Then
                transaction.Commit()
            Else
                transaction.Rollback()
            End If
            conn.Dispose()
        End Try
    End Sub
End Class

Il s'agit du script d'installation Transact-SQL (Install.sql), qui déploie l'assembly et crée la procédure stockée dans la base de données.

USE AdventureWorks;
GO
IF EXISTS (SELECT * FROM sys.objects WHERE name = N'CleanupUnusedAssemblies')
DROP PROCEDURE CleanupUnusedAssemblies;
GO

IF EXISTS (SELECT * FROM sys.assemblies WHERE name = N'AssemblyCleanupUtils') 
DROP ASSEMBLY AssemblyCleanupUtils;
GO
DECLARE @SamplesPath nvarchar(1024)

-- You may need to modify the value of the this variable if you have installed the sample someplace other than the default location.
Set @SamplesPath = 'C:\MySample\'

CREATE ASSEMBLY AssemblyCleanupUtils 
FROM @SamplesPath + 'AssemblyCleanup.dll' 
WITH permission_set = Safe;
GO

CREATE PROCEDURE CleanupUnusedAssemblies (
@visible_assemblies bit
) AS
EXTERNAL NAME [AssemblyCleanupUtils].[AssemblyCleanup].CleanupUnusedAssemblies;
GO

Il s'agit de test.sql, qui teste l'exemple en exécutant la procédure stockée.

USE AdventureWorks;
GO

PRINT 'Before cleanup...'
SELECT [name] FROM sys.assemblies;
GO

-- pass in false, which means the cleanup will only include invisible assemblies
EXEC dbo.CleanupUnusedAssemblies false;
GO

PRINT 'After cleanup'
SELECT [name] FROM sys.assemblies;

Le code Transact-SQL suivant supprime l'assembly et la procédure stockée de la base de données.

USE AdventureWorks;
GO

IF EXISTS (SELECT * FROM sys.objects WHERE name = N'CleanupUnusedAssemblies')
DROP PROCEDURE CleanupUnusedAssemblies;
GO

IF EXISTS (SELECT * FROM sys.assemblies WHERE name = N'AssemblyCleanupUtils') 
DROP ASSEMBLY AssemblyCleanupUtils;
GO

Voir aussi

Concepts

Scénarios et exemples d'utilisation pour l'intégration du CLR (Common Language Runtime)

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