LogExtentCollection LogExtentCollection LogExtentCollection LogExtentCollection Class

Definizione

Rappresenta la raccolta di oggetti LogExtent associati a un oggetto LogStore.Represents the collection of LogExtent objects associated with a LogStore.

public ref class LogExtentCollection sealed : System::Collections::Generic::IEnumerable<System::IO::Log::LogExtent ^>
public sealed class LogExtentCollection : System.Collections.Generic.IEnumerable<System.IO.Log.LogExtent>
type LogExtentCollection = class
    interface seq<LogExtent>
    interface IEnumerable
Public NotInheritable Class LogExtentCollection
Implements IEnumerable(Of LogExtent)
Ereditarietà
LogExtentCollectionLogExtentCollectionLogExtentCollectionLogExtentCollection
Implementazioni

Esempi

In questo esempio viene illustrato come utilizzare le classi LogExtent e LogExtentCollection per aggiungere ed emulare extent in una sequenza del log.This example shows how to use the LogExtent and LogExtentCollection classes to add and emulate extents in a log sequence.

using System;
using System.IO;
using System.Collections.Generic;
using System.Text;
using System.IO.Log;

namespace MyLogRecordSequence
{
    public class MyLog
    {
        string logName = "test.log";
        string logContainer = "MyExtent0";
        int containerSize = 32 * 1024;
        LogRecordSequence sequence = null;
        bool delete = true;

        // These are used in the TailPinned event handler.
        public static LogRecordSequence MySequence = null;
        public static bool AdvanceBase = true;

        public MyLog()
        {
            // Create a LogRecordSequence.
            sequence = new LogRecordSequence(this.logName,
                                              FileMode.CreateNew,
                                              FileAccess.ReadWrite,
                                              FileShare.None);

            // At least one container/extent must be added for Log Record Sequence.
            sequence.LogStore.Extents.Add(this.logContainer, this.containerSize);
     
            MySequence = sequence;

        }

        public void AddExtents()
        {
            // Add two additional extents. The extents are 
            // of the same size as the first extent.
            sequence.LogStore.Extents.Add("MyExtent1");
            sequence.LogStore.Extents.Add("MyExtent2");
        }

        public void EnumerateExtents()
        {
            LogStore store = sequence.LogStore;

            Console.WriteLine("Enumerating Log Extents...");
            Console.WriteLine("    Extent Count: {0} extents", store.Extents.Count);
            Console.WriteLine("    Extents Are...");
            foreach (LogExtent extent in store.Extents)
            {
                Console.WriteLine("      {0} ({1}, {2})",
                                  Path.GetFileName(extent.Path),
                                  extent.Size,
                                  extent.State);
            }
            Console.WriteLine("    Free Extents: {0} Free", store.Extents.FreeCount);   
        }

        public void SetLogPolicy()
        {
            Console.WriteLine();
            Console.WriteLine("Setting current log policy...");

            // SET LOG POLICY

            LogPolicy policy = sequence.LogStore.Policy;

            // Set AutoGrow policy. This enables the log to automatically grow
            // when the existing extents are full. New extents are added until
            // we reach the MaximumExtentCount extents.
            // AutoGrow policy is supported only in Windows Vista and not available in R2.
            
            //policy.AutoGrow = true;

            // Set the Growth Rate in terms of extents. This policy specifies
            // "how much" the log should grow. 
            policy.GrowthRate = new PolicyUnit(2, PolicyUnitType.Extents);

            // Set the AutoShrink policy. This enables the log to automatically
            // shrink if the available free space exceeds the shrink percentage. 
            // AutoGrow/shrink policy is supported only in Windows Vista and not available in R2.
            
            //policy.AutoShrinkPercentage = new PolicyUnit(30, PolicyUnitType.Percentage);

            // Set the PinnedTailThreshold policy.
            // A tail pinned event is triggered when there is no
            // log space available and log space may be freed by advancing the base.
            // The user must handle the tail pinned event by advancing the base of the log. 
            // If the user is not able to move the base of the log, the user should report with exception in
            // the tail pinned handler.
            // PinnedTailThreashold policy dictates the amount of space that the TailPinned event requests 
            // for advancing the base of the log. The amount of space can be in percentage or in terms of bytes 
            // which is rounded off to the nearest containers in CLFS. The default is 35 percent.

            
            policy.PinnedTailThreshold = new PolicyUnit(10, PolicyUnitType.Percentage);

            // Set the maximum extents the log can have.
            policy.MaximumExtentCount = 6;
            
            // Set the minimum extents the log can have.
            policy.MinimumExtentCount = 2;
            
            // Set the prefix for new containers that are added. 
            // when AutoGrow is enabled.
            //policy.NewExtentPrefix = "MyLogPrefix";
            
            // Set the suffix number for new containers that are added.
            // when AutoGrow is enabled. 
            policy.NextExtentSuffix = 3;

            // Commit the log policy.
            policy.Commit();

            // Refresh updates the IO.Log policy properties with current log policy 
            // set in the log. 
            policy.Refresh();

            // LOG POLICY END
            // 

            //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
            // Setting up IO.Log provided capabilities...
            // 

            // SET RETRY APPEND

            // IO.Log provides a mechanism similar to AutoGrow.
            // If the existing log is full and an append fails, setting RetryAppend
            // invokes the CLFS policy engine to add new extents and re-tries
            // record appends. If MaximumExtent count has been reached, 
            // a SequenceFullException is thrown. 
            // 

            sequence.RetryAppend = true;

            // RETRY APPEND END

            // REGISTER FOR TAILPINNED EVENT NOTIFICATIONS

            // Register for TailPinned Event by passing in an event handler.
            // An event is raised when the log full condition is reached.
            // The user should either advance the base sequence number to the 
            // nearest valid sequence number recommended in the tail pinned event or
            // report a failure that it is not able to advance the base sequence 
            // number. 
            //

            sequence.TailPinned += new EventHandler<TailPinnedEventArgs>(HandleTailPinned);  

            Console.WriteLine("Done...");
        }

        public void ShowLogPolicy()
        {
            Console.WriteLine();
            Console.WriteLine("Showing current log policy...");

            LogPolicy policy = sequence.LogStore.Policy;

            Console.WriteLine("    Minimum extent count:  {0}", policy.MinimumExtentCount);
            Console.WriteLine("    Maximum extent count:  {0}", policy.MaximumExtentCount);
            Console.WriteLine("    Growth rate:           {0}", policy.GrowthRate);
            Console.WriteLine("    Pinned tail threshold: {0}", policy.PinnedTailThreshold);
            Console.WriteLine("    Auto shrink percent:   {0}", policy.AutoShrinkPercentage);
            Console.WriteLine("    Auto grow enabled:     {0}", policy.AutoGrow);
            Console.WriteLine("    New extent prefix:     {0}", policy.NewExtentPrefix);
            Console.WriteLine("    Next extent suffix:    {0}", policy.NextExtentSuffix);

	}

        // Append records. Appending three records.  
        public void AppendRecords()
        {
            Console.WriteLine("Appending Log Records...");
            SequenceNumber previous = SequenceNumber.Invalid;

            previous = sequence.Append(CreateData("Hello World!"), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush);
            previous = sequence.Append(CreateData("This is my first Logging App"), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush);
            previous = sequence.Append(CreateData("Using LogRecordSequence..."), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush);
	    
            Console.WriteLine("Done...");
        }


        // Read the records added to the log. 
        public void ReadRecords()
        {
            Encoding enc = Encoding.Unicode;

            Console.WriteLine();

            Console.WriteLine("Reading Log Records...");
            try
            {
                foreach (LogRecord record in this.sequence.ReadLogRecords(this.sequence.BaseSequenceNumber, LogRecordEnumeratorType.Next))
                {
                    byte[] data = new byte[record.Data.Length];
                    record.Data.Read(data, 0, (int)record.Data.Length);
                    string mystr = enc.GetString(data);
                    Console.WriteLine("    {0}", mystr);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("Exception {0} {1}", e.GetType(), e.Message);
            }

            Console.WriteLine();
        }

        public void FillLog()
        {
            bool append = true;

            while (append)
            {
                try
                {
                    sequence.Append(CreateData(16 * 1024), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush);
                }

                catch (SequenceFullException)
                {
                    Console.WriteLine("Log is Full...");
                    append = false;
                }
            }
        }

        // Dispose the record sequence and delete the log file. 
        public void Cleanup()
        {
            // Dispose the sequence
            sequence.Dispose();

            // Delete the log file.
            if (delete)
            {
                try
                {
                    // This deletes the base log file and all the extents associated with the log.
                    LogStore.Delete(this.logName);
                }
                catch (Exception e)
                {
                    Console.WriteLine("Exception {0} {1}", e.GetType(), e.Message);
                }
            }
        }

        // Converts the given data to an Array of ArraySegment<byte> 
        public static IList<ArraySegment<byte>> CreateData(string str)
        {
            Encoding enc = Encoding.Unicode;

            byte[] array = enc.GetBytes(str);

            ArraySegment<byte>[] segments = new ArraySegment<byte>[1];
            segments[0] = new ArraySegment<byte>(array);

            return Array.AsReadOnly<ArraySegment<byte>>(segments);
        }

        public static IList<ArraySegment<byte>> CreateData(int size)
        {
            byte[] array = new byte[size];

            Random rnd = new Random();
            rnd.NextBytes(array);

            ArraySegment<byte>[] segments = new ArraySegment<byte>[1];
            segments[0] = new ArraySegment<byte>(array);

            return Array.AsReadOnly<ArraySegment<byte>>(segments);
        }

        public static SequenceNumber GetAdvanceBaseSeqNumber(SequenceNumber recTargetSeqNum)
        {
            SequenceNumber targetSequenceNumber = SequenceNumber.Invalid;

            Console.WriteLine("Getting actual target sequence number...");
            
            // 
            // Implement the logic for returning a valid sequence number closer to
            // recommended target sequence number. 
            //

            return targetSequenceNumber;
        }

        public static void HandleTailPinned(object arg, TailPinnedEventArgs tailPinnedEventArgs)
        {
            Console.WriteLine("TailPinned has fired");

            // Based on the implementation of a logging application, the log base can be moved
            // to free up more log space and if it is not possible to move the 
            // base, the application should report by throwing an exception.

            if(MyLog.AdvanceBase)
            {
                try
                {
                    // TailPnnedEventArgs has the recommended sequence number and its generated 
                    // based on PinnedTailThreshold policy. 
                    // This does not map to an actual sequence number in the record sequence
                    // but an approximation and potentially frees up the threshold % log space
                    // when the log base is advanced to a valid sequence number closer to the 
                    // recommended sequence number. 
                    // The user should use this sequence number to locate a closest valid sequence
                    // number to advance the base of the log.

                    SequenceNumber recommendedTargetSeqNum = tailPinnedEventArgs.TargetSequenceNumber; 
                    
                    // Get the actual Target sequence number.
                    SequenceNumber actualTargetSeqNum = MyLog.GetAdvanceBaseSeqNumber(recommendedTargetSeqNum);

                    MySequence.AdvanceBaseSequenceNumber(actualTargetSeqNum);
                }
                catch (Exception e)
                {
                    Console.WriteLine("Exception thrown {0} {1}", e.GetType(), e.Message);
                }
            }
            else
            {
                // Report back Error if under some conditions the log cannot
                // advance the base sequence number.

                Console.WriteLine("Reporting Error! Unable to move the base sequence number!");
                throw new IOException();
            }
        }
    }

    class LogSample
    {
        static void Main(string[] args)
        {
            // Create log record sequence.
            MyLog log = new MyLog();

            // Add additional extents.
            log.AddExtents();

            // Enumerate the current log extents.
            log.EnumerateExtents();

            // Set log policies and register for TailPinned event notifications. 
            log.SetLogPolicy();

            log.ShowLogPolicy();
            
            // Append a few records and read the appended records. 
            log.AppendRecords();
            log.ReadRecords();

            // Fill the Log to trigger log growth...and subsequent TailPinned notifications.
            log.FillLog();

            log.EnumerateExtents();

            log.Cleanup();
        }
    }
}


Imports System
Imports System.IO
Imports System.Collections.Generic
Imports System.Text
Imports System.IO.Log

Namespace MyLogRecordSequence
	Public Class MyLog
		Private logName As String = "test.log"
		Private logContainer As String = "MyExtent0"
		Private containerSize As Integer = 32 * 1024
		Private sequence As LogRecordSequence = Nothing
		Private delete As Boolean = True

		' These are used in the TailPinned event handler.
		Public Shared MySequence As LogRecordSequence = Nothing
		Public Shared AdvanceBase As Boolean = True

		Public Sub New()
			' Create a LogRecordSequence.
			sequence = New LogRecordSequence(Me.logName, FileMode.CreateNew, FileAccess.ReadWrite, FileShare.None)

			' At least one container/extent must be added for Log Record Sequence.
			sequence.LogStore.Extents.Add(Me.logContainer, Me.containerSize)

			MySequence = sequence

		End Sub

		Public Sub AddExtents()
			' Add two additional extents. The extents are 
			' of the same size as the first extent.
			sequence.LogStore.Extents.Add("MyExtent1")
			sequence.LogStore.Extents.Add("MyExtent2")
		End Sub

		Public Sub EnumerateExtents()
			Dim store As LogStore = sequence.LogStore

			Console.WriteLine("Enumerating Log Extents...")
			Console.WriteLine("    Extent Count: {0} extents", store.Extents.Count)
			Console.WriteLine("    Extents Are...")
            For Each extent In store.Extents
                Console.WriteLine("      {0} ({1}, {2})", Path.GetFileName(extent.Path), extent.Size, extent.State)
            Next extent
			Console.WriteLine("    Free Extents: {0} Free", store.Extents.FreeCount)
		End Sub

		Public Sub SetLogPolicy()
			Console.WriteLine()
			Console.WriteLine("Setting current log policy...")

			' SET LOG POLICY

			Dim policy As LogPolicy = sequence.LogStore.Policy

			' Set AutoGrow policy. This enables the log to automatically grow
			' when the existing extents are full. New extents are added until
			' we reach the MaximumExtentCount extents.
			' AutoGrow policy is supported only in Windows Vista and not available in R2.

			'policy.AutoGrow = true;

			' Set the Growth Rate in terms of extents. This policy specifies
			' "how much" the log should grow. 
			policy.GrowthRate = New PolicyUnit(2, PolicyUnitType.Extents)

			' Set the AutoShrink policy. This enables the log to automatically
			' shrink if the available free space exceeds the shrink percentage. 
			' AutoGrow/shrink policy is supported only in Windows Vista and not available in R2.

			'policy.AutoShrinkPercentage = new PolicyUnit(30, PolicyUnitType.Percentage);

			' Set the PinnedTailThreshold policy.
			' A tail pinned event is triggered when there is no
			' log space available and log space may be freed by advancing the base.
			' The user must handle the tail pinned event by advancing the base of the log. 
			' If the user is not able to move the base of the log, the user should report with exception in
			' the tail pinned handler.
			' PinnedTailThreashold policy dictates the amount of space that the TailPinned event requests 
			' for advancing the base of the log. The amount of space can be in percentage or in terms of bytes 
			' which is rounded off to the nearest containers in CLFS. The default is 35 percent.


			policy.PinnedTailThreshold = New PolicyUnit(10, PolicyUnitType.Percentage)

			' Set the maximum extents the log can have.
			policy.MaximumExtentCount = 6

			' Set the minimum extents the log can have.
			policy.MinimumExtentCount = 2

			' Set the prefix for new containers that are added. 
			' when AutoGrow is enabled.
			'policy.NewExtentPrefix = "MyLogPrefix";

			' Set the suffix number for new containers that are added.
			' when AutoGrow is enabled. 
			policy.NextExtentSuffix = 3

			' Commit the log policy.
			policy.Commit()

			' Refresh updates the IO.Log policy properties with current log policy 
			' set in the log. 
			policy.Refresh()

			' LOG POLICY END
			' 

			'+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
			' Setting up IO.Log provided capabilities...
			' 

			' SET RETRY APPEND

			' IO.Log provides a mechanism similar to AutoGrow.
			' If the existing log is full and an append fails, setting RetryAppend
			' invokes the CLFS policy engine to add new extents and re-tries
			' record appends. If MaximumExtent count has been reached, 
			' a SequenceFullException is thrown. 
			' 

			sequence.RetryAppend = True

			' RETRY APPEND END

			' REGISTER FOR TAILPINNED EVENT NOTIFICATIONS

			' Register for TailPinned Event by passing in an event handler.
			' An event is raised when the log full condition is reached.
			' The user should either advance the base sequence number to the 
			' nearest valid sequence number recommended in the tail pinned event or
			' report a failure that it is not able to advance the base sequence 
			' number. 
			'

			AddHandler sequence.TailPinned, AddressOf HandleTailPinned

			Console.WriteLine("Done...")
		End Sub

		Public Sub ShowLogPolicy()
			Console.WriteLine()
			Console.WriteLine("Showing current log policy...")

			Dim policy As LogPolicy = sequence.LogStore.Policy

			Console.WriteLine("    Minimum extent count:  {0}", policy.MinimumExtentCount)
			Console.WriteLine("    Maximum extent count:  {0}", policy.MaximumExtentCount)
			Console.WriteLine("    Growth rate:           {0}", policy.GrowthRate)
			Console.WriteLine("    Pinned tail threshold: {0}", policy.PinnedTailThreshold)
			Console.WriteLine("    Auto shrink percent:   {0}", policy.AutoShrinkPercentage)
			Console.WriteLine("    Auto grow enabled:     {0}", policy.AutoGrow)
			Console.WriteLine("    New extent prefix:     {0}", policy.NewExtentPrefix)
			Console.WriteLine("    Next extent suffix:    {0}", policy.NextExtentSuffix)

		End Sub

		' Append records. Appending three records.  
		Public Sub AppendRecords()
			Console.WriteLine("Appending Log Records...")
			Dim previous As SequenceNumber = SequenceNumber.Invalid

			previous = sequence.Append(CreateData("Hello World!"), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush)
			previous = sequence.Append(CreateData("This is my first Logging App"), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush)
			previous = sequence.Append(CreateData("Using LogRecordSequence..."), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush)

			Console.WriteLine("Done...")
		End Sub


		' Read the records added to the log. 
		Public Sub ReadRecords()
			Dim enc As Encoding = Encoding.Unicode

			Console.WriteLine()

			Console.WriteLine("Reading Log Records...")
			Try
				For Each record As LogRecord In Me.sequence.ReadLogRecords(Me.sequence.BaseSequenceNumber, LogRecordEnumeratorType.Next)
					Dim data(record.Data.Length - 1) As Byte
					record.Data.Read(data, 0, CInt(Fix(record.Data.Length)))
					Dim mystr As String = enc.GetString(data)
					Console.WriteLine("    {0}", mystr)
				Next record
			Catch e As Exception
				Console.WriteLine("Exception {0} {1}", e.GetType(), e.Message)
			End Try

			Console.WriteLine()
		End Sub

		Public Sub FillLog()
			Dim append As Boolean = True

			Do While append
				Try
					sequence.Append(CreateData(16 * 1024), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush)

				Catch e1 As SequenceFullException
					Console.WriteLine("Log is Full...")
					append = False
				End Try
			Loop
		End Sub

		' Dispose the record sequence and delete the log file. 
		Public Sub Cleanup()
			' Dispose the sequence
			sequence.Dispose()

			' Delete the log file.
			If delete Then
				Try
					' This deletes the base log file and all the extents associated with the log.
					LogStore.Delete(Me.logName)
				Catch e As Exception
					Console.WriteLine("Exception {0} {1}", e.GetType(), e.Message)
				End Try
			End If
		End Sub

		' Converts the given data to an Array of ArraySegment<byte> 
		Public Shared Function CreateData(ByVal str As String) As IList(Of ArraySegment(Of Byte))
			Dim enc As Encoding = Encoding.Unicode

			Dim array() As Byte = enc.GetBytes(str)

			Dim segments(0) As ArraySegment(Of Byte)
			segments(0) = New ArraySegment(Of Byte)(array)

            Return System.Array.AsReadOnly(Of ArraySegment(Of Byte))(segments)
		End Function

		Public Shared Function CreateData(ByVal size As Integer) As IList(Of ArraySegment(Of Byte))
			Dim array(size - 1) As Byte

			Dim rand As New Random()
			rand.NextBytes(array)

			Dim segments(0) As ArraySegment(Of Byte)
			segments(0) = New ArraySegment(Of Byte)(array)

            Return System.Array.AsReadOnly(Of ArraySegment(Of Byte))(segments)
		End Function

		Public Shared Function GetAdvanceBaseSeqNumber(ByVal recTargetSeqNum As SequenceNumber) As SequenceNumber
			Dim targetSequenceNumber As SequenceNumber = SequenceNumber.Invalid

			Console.WriteLine("Getting actual target sequence number...")

			' 
			' Implement the logic for returning a valid sequence number closer to
			' recommended target sequence number. 
			'

			Return targetSequenceNumber
		End Function

		Public Shared Sub HandleTailPinned(ByVal arg As Object, ByVal tailPinnedEventArgs As TailPinnedEventArgs)
			Console.WriteLine("TailPinned has fired")

			' Based on the implementation of a logging application, the log base can be moved
			' to free up more log space and if it is not possible to move the 
			' base, the application should report by throwing an exception.

			If MyLog.AdvanceBase Then
				Try
					' TailPnnedEventArgs has the recommended sequence number and its generated 
					' based on PinnedTailThreshold policy. 
					' This does not map to an actual sequence number in the record sequence
					' but an approximation and potentially frees up the threshold % log space
					' when the log base is advanced to a valid sequence number closer to the 
					' recommended sequence number. 
					' The user should use this sequence number to locate a closest valid sequence
					' number to advance the base of the log.

					Dim recommendedTargetSeqNum As SequenceNumber = tailPinnedEventArgs.TargetSequenceNumber

					' Get the actual Target sequence number.
					Dim actualTargetSeqNum As SequenceNumber = MyLog.GetAdvanceBaseSeqNumber(recommendedTargetSeqNum)

					MySequence.AdvanceBaseSequenceNumber(actualTargetSeqNum)
				Catch e As Exception
					Console.WriteLine("Exception thrown {0} {1}", e.GetType(), e.Message)
				End Try
			Else
				' Report back Error if under some conditions the log cannot
				' advance the base sequence number.

				Console.WriteLine("Reporting Error! Unable to move the base sequence number!")
				Throw New IOException()
			End If
		End Sub
	End Class

	Friend Class LogSample
		Shared Sub Main(ByVal args() As String)
			' Create log record sequence.
			Dim log As New MyLog()

			' Add additional extents.
			log.AddExtents()

			' Enumerate the current log extents.
			log.EnumerateExtents()

			' Set log policies and register for TailPinned event notifications. 
			log.SetLogPolicy()

			log.ShowLogPolicy()

			' Append a few records and read the appended records. 
			log.AppendRecords()
			log.ReadRecords()

			' Fill the Log to trigger log growth...and subsequent TailPinned notifications.
			log.FillLog()

			log.EnumerateExtents()

			log.Cleanup()
		End Sub
	End Class
End Namespace

Commenti

Questa classe contiene una raccolta di oggetti LogExtent associati a LogStore.This class contains a collection of LogExtent objects associated with a LogStore. Un'istanza di LogStore memorizza i relativi dati in una raccolta di extent del disco, rappresentati da istanze LogExtent.A LogStore instance stores its data in a collection of disk extents, represented by LogExtent instances. Una determinata istanza di LogExtent è associata a un'istanza di LogStore e gli oggetti LogExtent inclusi nella stessa istanza di LogStore sono di dimensione identica.A particular LogExtent is associated with one LogStore, and LogExtent objects in the same LogStore are of identical size. Lo spazio viene aggiunto e rimosso da un'istanza LogStore per incrementi di extent.Space is added to and removed from a LogStore instance in extent increments.

Sebbene gli oggetti LogExtent siano rappresentati su disco come file, non devono essere spostati né eliminati come file normali.Although LogExtent objects are represented on disk as files, they should not be moved or deleted as normal files. Per aggiungere ed eliminare direttamente le istanze di LogExtent, al contrario, è opportuno utilizzare i metodi forniti da questa classe.Rather, you should use the methods provided by this class for adding and deleting LogExtent instances directly. Gli extent vengono solitamente rimossi quando non contengono più dati attivi.Extents are usually removed when they no longer contain any active data. Se tuttavia il parametro force contenuto nel metodo Remove è true, viene generata un'eccezione se non è possibile rimuoverli immediatamente.However, if the force parameter in the Remove method is true, an exception is thrown if they cannot be removed immediately.

Poiché non è possibile rimuovere l'ultimo extent contenuto in LogExtentCollection, la proprietà Count non può essere zero dopo l'aggiunta di un extent.You cannot remove the last extent in the LogExtentCollection, which means that the Count property cannot be zero after an extent is added.

Proprietà

Count Count Count Count

Ottiene il numero di extent del log contenuti nella raccolta.Gets the number of log extents in the collection.

FreeCount FreeCount FreeCount FreeCount

Ottiene il numero di istanze LogExtent libere contenute nella raccolta, ovvero il numero delle istanze LogExtent che non contengono dati.Gets the number of free LogExtent instances in the collection, that is, the number of LogExtent instances that do not contain any data.

Metodi

Add(String) Add(String) Add(String) Add(String)

Aggiunge un'istanza di LogExtent alla raccolta.Adds a LogExtent instance to the collection.

Add(String, Int64) Add(String, Int64) Add(String, Int64) Add(String, Int64)

Crea un nuovo oggetto LogExtent con la dimensione specificata e lo aggiunge alla raccolta.Creates a new LogExtent with the specified size and adds it to the collection.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determina se l'oggetto specificato è uguale all'oggetto corrente.Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetEnumerator() GetEnumerator() GetEnumerator() GetEnumerator()

Restituisce un enumeratore per le istanze di LogExtent contenute nella raccolta.Gets an enumerator for the LogExtent instances in this collection. Questo metodo non può essere ereditato.This method cannot be inherited.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Funge da funzione hash predefinita.Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Ottiene l'oggetto Type dell'istanza corrente.Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Crea una copia superficiale dell'oggetto Object corrente.Creates a shallow copy of the current Object.

(Inherited from Object)
Remove(LogExtent, Boolean) Remove(LogExtent, Boolean) Remove(LogExtent, Boolean) Remove(LogExtent, Boolean)

Consente di rimuovere dalla raccolta l'istanza di LogExtent specificata.Removes the specified LogExtent instance from the collection.

Remove(String, Boolean) Remove(String, Boolean) Remove(String, Boolean) Remove(String, Boolean)

Rimuove dalla raccolta l'istanza di LogExtent con il percorso specificato.Removes the LogExtent instance with the specified path from the collection.

ToString() ToString() ToString() ToString()

Restituisce una stringa che rappresenta l'oggetto corrente.Returns a string that represents the current object.

(Inherited from Object)

Implementazioni dell'interfaccia esplicita

IEnumerable.GetEnumerator() IEnumerable.GetEnumerator() IEnumerable.GetEnumerator() IEnumerable.GetEnumerator()

Restituisce un enumeratore per le istanze di LogExtent contenute nella raccolta.Gets an enumerator for the LogExtent instances in this collection. Questo metodo non può essere ereditato.This method cannot be inherited.

Metodi di estensione

CopyToDataTable<T>(IEnumerable<T>) CopyToDataTable<T>(IEnumerable<T>) CopyToDataTable<T>(IEnumerable<T>) CopyToDataTable<T>(IEnumerable<T>)

Restituisce un oggetto DataTable che contiene copie degli oggetti DataRow, dato un oggetto IEnumerable<T> di input dove il parametro generico DataRow è T.Returns a DataTable that contains copies of the DataRow objects, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption)

Copia gli oggetti DataRow nell'oggetto DataTable specificato, dato un oggetto IEnumerable<T> di input dove il parametro generico T è DataRow.Copies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler)

Copia gli oggetti DataRow nell'oggetto DataTable specificato, dato un oggetto IEnumerable<T> di input dove il parametro generico T è DataRow.Copies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable)

Esegue il cast degli elementi di un oggetto IEnumerable nel tipo specificato.Casts the elements of an IEnumerable to the specified type.

OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable)

Filtra gli elementi di un oggetto IEnumerable in base a un tipo specificato.Filters the elements of an IEnumerable based on a specified type.

AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable)

Consente la parallelizzazione di una query.Enables parallelization of a query.

AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable)

Converte un oggetto IEnumerable in un oggetto IQueryable.Converts an IEnumerable to an IQueryable.

Ancestors<T>(IEnumerable<T>) Ancestors<T>(IEnumerable<T>) Ancestors<T>(IEnumerable<T>) Ancestors<T>(IEnumerable<T>)

Restituisce una raccolta di elementi che contiene i predecessori di ciascun nodo nella raccolta di origine.Returns a collection of elements that contains the ancestors of every node in the source collection.

Ancestors<T>(IEnumerable<T>, XName) Ancestors<T>(IEnumerable<T>, XName) Ancestors<T>(IEnumerable<T>, XName) Ancestors<T>(IEnumerable<T>, XName)

Restituisce una raccolta di elementi filtrati che contiene i predecessori di ciascun nodo nella raccolta di origine.Returns a filtered collection of elements that contains the ancestors of every node in the source collection. Solo gli elementi che hanno un oggetto XName corrispondente vengono inclusi nella raccolta.Only elements that have a matching XName are included in the collection.

DescendantNodes<T>(IEnumerable<T>) DescendantNodes<T>(IEnumerable<T>) DescendantNodes<T>(IEnumerable<T>) DescendantNodes<T>(IEnumerable<T>)

Restituisce una raccolta di nodi discendenti di ciascun documento ed elemento nella raccolta di origine.Returns a collection of the descendant nodes of every document and element in the source collection.

Descendants<T>(IEnumerable<T>) Descendants<T>(IEnumerable<T>) Descendants<T>(IEnumerable<T>) Descendants<T>(IEnumerable<T>)

Restituisce una raccolta di elementi che contiene gli elementi discendenti di ciascun elemento e documento nella raccolta di origine.Returns a collection of elements that contains the descendant elements of every element and document in the source collection.

Descendants<T>(IEnumerable<T>, XName) Descendants<T>(IEnumerable<T>, XName) Descendants<T>(IEnumerable<T>, XName) Descendants<T>(IEnumerable<T>, XName)

Restituisce una raccolta filtrata di elementi che contiene gli elementi discendenti di ciascun elemento e documento nella raccolta di origine.Returns a filtered collection of elements that contains the descendant elements of every element and document in the source collection. Solo gli elementi che hanno un oggetto XName corrispondente vengono inclusi nella raccolta.Only elements that have a matching XName are included in the collection.

Elements<T>(IEnumerable<T>) Elements<T>(IEnumerable<T>) Elements<T>(IEnumerable<T>) Elements<T>(IEnumerable<T>)

Restituisce una raccolta di elementi figlio di ciascun elemento e documento nella raccolta di origine.Returns a collection of the child elements of every element and document in the source collection.

Elements<T>(IEnumerable<T>, XName) Elements<T>(IEnumerable<T>, XName) Elements<T>(IEnumerable<T>, XName) Elements<T>(IEnumerable<T>, XName)

Restituisce una raccolta filtrata degli elementi figlio di ciascun elemento e documento nella raccolta di origine.Returns a filtered collection of the child elements of every element and document in the source collection. Solo gli elementi che hanno un oggetto XName corrispondente vengono inclusi nella raccolta.Only elements that have a matching XName are included in the collection.

InDocumentOrder<T>(IEnumerable<T>) InDocumentOrder<T>(IEnumerable<T>) InDocumentOrder<T>(IEnumerable<T>) InDocumentOrder<T>(IEnumerable<T>)

Restituisce una raccolta di nodi che contiene tutti i nodi nella raccolta di origine ordinati in base all'ordine con cui sono riportati nel documento.Returns a collection of nodes that contains all nodes in the source collection, sorted in document order.

Nodes<T>(IEnumerable<T>) Nodes<T>(IEnumerable<T>) Nodes<T>(IEnumerable<T>) Nodes<T>(IEnumerable<T>)

Restituisce una raccolta di nodi figlio di ciascun documento ed elemento nella raccolta di origine.Returns a collection of the child nodes of every document and element in the source collection.

Remove<T>(IEnumerable<T>) Remove<T>(IEnumerable<T>) Remove<T>(IEnumerable<T>) Remove<T>(IEnumerable<T>)

Rimuove ciascun nodo nella raccolta di origine dal nodo padre.Removes every node in the source collection from its parent node.

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