duplicati/Duplicati/Library/Main/Database/LocalDatabase.cs

// Copyright (C) 2025, The Duplicati Team
// https://duplicati.com, hello@duplicati.com
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

#nullable enable

using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using Duplicati.Library.Modules.Builtin.ResultSerialization;
using Duplicati.Library.Utility;
using Duplicati.Library.Interface;
using Microsoft.Data.Sqlite;

// Expose internal classes to UnitTests, so that Database classes can be tested
[assembly: InternalsVisibleTo("Duplicati.UnitTest")]

namespace Duplicati.Library.Main.Database
{
    internal class LocalDatabase : IDisposable
    {
        /// <summary>
        /// The tag used for logging
        /// </summary>
        private static readonly string LOGTAG = Logging.Log.LogTagFromType(typeof(LocalDatabase));

        /// <summary>
        /// The chunk size for batch operations
        /// </summary>
        /// <remarks>SQLite has a limit of 999 parameters in a single statement</remarks>
        public const int CHUNK_SIZE = 128;

        protected readonly SqliteConnection m_connection;
        protected readonly long m_operationid = -1;
        protected readonly long m_pagecachesize;
        private bool m_hasExecutedVacuum;

        private readonly SqliteCommand m_updateremotevolumeCommand;
        private readonly SqliteCommand m_selectremotevolumesCommand;
        private readonly SqliteCommand m_selectremotevolumeCommand;
        private readonly SqliteCommand m_removeremotevolumeCommand;
        private readonly SqliteCommand m_removedeletedremotevolumeCommand;
        private readonly SqliteCommand m_selectremotevolumeIdCommand;
        private readonly SqliteCommand m_createremotevolumeCommand;
        private readonly SqliteCommand m_selectduplicateRemoteVolumesCommand;

        private readonly SqliteCommand m_insertlogCommand;
        private readonly SqliteCommand m_insertremotelogCommand;
        private readonly SqliteCommand m_insertIndexBlockLink;

        private readonly SqliteCommand m_findpathprefixCommand;
        private readonly SqliteCommand m_insertpathprefixCommand;

        public const long FOLDER_BLOCKSET_ID = -100;
        public const long SYMLINK_BLOCKSET_ID = -200;

        public DateTime OperationTimestamp { get; private set; }

        internal SqliteConnection Connection { get { return m_connection; } }

        public bool IsDisposed { get; private set; }

        public bool ShouldCloseConnection { get; set; }

        protected static async Task<SqliteConnection> CreateConnection(string path, long pagecachesize)
        {
            path = Path.GetFullPath(path);
            if (!Directory.Exists(Path.GetDirectoryName(path)))
                Directory.CreateDirectory(Path.GetDirectoryName(path) ?? throw new DirectoryNotFoundException("Path was a root folder."));

            var c = await SQLiteHelper.SQLiteLoader.LoadConnection(path, pagecachesize);

            try
            {
                SQLiteHelper.DatabaseUpgrader.UpgradeDatabase(c, path, typeof(DatabaseSchemaMarker));
            }
            catch
            {
                //Don't leak database connections when something goes wrong
                await c.DisposeAsync();
                throw;
            }

            return c;
        }

        /// <summary>
        /// Formats the string using the invariant culture
        /// </summary>
        /// <param name="formattable">The formattable string</param>
        /// <returns>The formatted string</returns>
        public static string FormatInvariant(FormattableString formattable)
            => Library.Utility.Utility.FormatInvariant(formattable);

        public static bool Exists(string path)
        {
            return File.Exists(path);
        }

        /// <summary>
        /// Creates a new database instance and starts a new operation
        /// </summary>
        /// <param name="path">The path to the database</param>
        /// <param name="operation">The name of the operation. If null, continues last operation</param>
        /// <param name="shouldclose">Should the connection be closed when this object is disposed</param>
        /// <param name="pagecachesize">The page cache size</param>
        public LocalDatabase(string path, string operation, bool shouldclose, long pagecachesize)
            : this(CreateConnection(path, pagecachesize).Await(), operation)
        {
            ShouldCloseConnection = shouldclose;
            m_pagecachesize = pagecachesize;
        }

        /// <summary>
        /// Creates a new database instance and starts a new operation
        /// </summary>
        public LocalDatabase(LocalDatabase db)
            : this(db.m_connection)
        {
            OperationTimestamp = db.OperationTimestamp;
            m_connection = db.m_connection;
            m_operationid = db.m_operationid;
            m_pagecachesize = db.m_pagecachesize;
        }

        /// <summary>
        /// Creates a new database instance and starts a new operation
        /// </summary>
        /// <param name="operation">The name of the operation. If null, continues last operation</param>
        public LocalDatabase(SqliteConnection connection, string operation)
            : this(connection)
        {
            OperationTimestamp = DateTime.UtcNow;
            m_connection = connection;

            if (m_connection.State != ConnectionState.Open)
                m_connection.Open();

            if (operation != null)
            {
                using var cmd = m_connection.CreateCommand();
                using var transaction = m_connection.BeginTransaction();
                cmd.Transaction = transaction;
                cmd.CommandText = @"INSERT INTO ""Operation"" (""Description"", ""Timestamp"") VALUES (@Description, @Timestamp); SELECT last_insert_rowid();";
                cmd.SetParameterValue("@Description", operation);
                cmd.SetParameterValue("@Timestamp", Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(OperationTimestamp));
                m_operationid = cmd.ExecuteScalarInt64Async(-1).Await();
            }
            else
            {
                // Get last operation
                using var cmd = m_connection.CreateCommand();
                cmd.CommandText = @"SELECT ""ID"", ""Timestamp"" FROM ""Operation"" ORDER BY ""Timestamp"" DESC LIMIT 1";
                using var rd = cmd.ExecuteReader(@"SELECT ""ID"", ""Timestamp"" FROM ""Operation"" ORDER BY ""Timestamp"" DESC LIMIT 1");
                if (!rd.Read())
                    throw new Exception("LocalDatabase does not contain a previous operation.");

                m_operationid = rd.ConvertValueToInt64(0);
                OperationTimestamp = ParseFromEpochSeconds(rd.ConvertValueToInt64(1));
            }
        }

        private LocalDatabase(SqliteConnection connection)
        {
            m_connection = connection;
            m_insertlogCommand = connection.CreateCommand(@"INSERT INTO ""LogData"" (""OperationID"", ""Timestamp"", ""Type"", ""Message"", ""Exception"") VALUES (@OperationID, @Timestamp, @Type, @Message, @Exception)");
            m_insertremotelogCommand = connection.CreateCommand(@"INSERT INTO ""RemoteOperation"" (""OperationID"", ""Timestamp"", ""Operation"", ""Path"", ""Data"") VALUES (@OperationID, @Timestamp, @Operation, @Path, @Data)");
            m_updateremotevolumeCommand = connection.CreateCommand(@"UPDATE ""Remotevolume"" SET ""OperationID"" = @OperationID, ""State"" = @State, ""Hash"" = @Hash, ""Size"" = @Size WHERE ""Name"" = @Name");
            m_selectremotevolumesCommand = connection.CreateCommand(@"SELECT ""ID"", ""Name"", ""Type"", ""Size"", ""Hash"", ""State"", ""DeleteGraceTime"", ""ArchiveTime"" FROM ""Remotevolume""");
            m_selectremotevolumeCommand = connection.CreateCommand(m_selectremotevolumesCommand.CommandText + @" WHERE ""Name"" = @Name");
            m_selectduplicateRemoteVolumesCommand = connection.CreateCommand(FormatInvariant($@"SELECT DISTINCT ""Name"", ""State"" FROM ""Remotevolume"" WHERE ""Name"" IN (SELECT ""Name"" FROM ""Remotevolume"" WHERE ""State"" IN ('{RemoteVolumeState.Deleted.ToString()}', '{RemoteVolumeState.Deleting.ToString()}')) AND NOT ""State"" IN ('{RemoteVolumeState.Deleted.ToString()}', '{RemoteVolumeState.Deleting.ToString()}')"));
            m_removeremotevolumeCommand = connection.CreateCommand(@"DELETE FROM ""Remotevolume"" WHERE ""Name"" = @Name AND (""DeleteGraceTime"" < @Now OR ""State"" != @State)");
            m_removedeletedremotevolumeCommand = connection.CreateCommand(FormatInvariant($@"DELETE FROM ""Remotevolume"" WHERE ""State"" == '{RemoteVolumeState.Deleted.ToString()}' AND (""DeleteGraceTime"" < @Now OR LENGTH(""DeleteGraceTime"") > 12) ")); // >12 is to handle removal of old records that were in ticks
            m_selectremotevolumeIdCommand = connection.CreateCommand(@"SELECT ""ID"" FROM ""Remotevolume"" WHERE ""Name"" = @Name");
            m_createremotevolumeCommand = connection.CreateCommand(@"INSERT INTO ""Remotevolume"" (""OperationID"", ""Name"", ""Type"", ""State"", ""Size"", ""VerificationCount"", ""DeleteGraceTime"", ""ArchiveTime"") VALUES (@OperationID, @Name, @Type, @State, @Size, @VerificationCount, @DeleteGraceTime, @ArchiveTime); SELECT last_insert_rowid();");
            m_insertIndexBlockLink = connection.CreateCommand(@"INSERT INTO ""IndexBlockLink"" (""IndexVolumeID"", ""BlockVolumeID"") VALUES (@IndexVolumeId, @BlockVolumeId)");
            m_findpathprefixCommand = connection.CreateCommand(@"SELECT ""ID"" FROM ""PathPrefix"" WHERE ""Prefix"" = @Prefix");
            m_insertpathprefixCommand = connection.CreateCommand(@"INSERT INTO ""PathPrefix"" (""Prefix"") VALUES (@Prefix); SELECT last_insert_rowid(); ");
        }

        /// <summary>
        /// Creates a DateTime instance by adding the specified number of seconds to the EPOCH value
        /// </summary>
        public static DateTime ParseFromEpochSeconds(long seconds)
        {
            return Library.Utility.Utility.EPOCH.AddSeconds(seconds);
        }

        public async Task UpdateRemoteVolume(string name, RemoteVolumeState state, long size, string? hash, SqliteTransaction transaction)
        {
            await UpdateRemoteVolume(name, state, size, hash, false, transaction);
        }

        public async Task UpdateRemoteVolume(string name, RemoteVolumeState state, long size, string? hash, bool suppressCleanup, SqliteTransaction transaction)
        {
            await UpdateRemoteVolume(name, state, size, hash, suppressCleanup, new TimeSpan(0), null, transaction);
        }

        public async Task UpdateRemoteVolume(string name, RemoteVolumeState state, long size, string? hash, bool suppressCleanup, TimeSpan deleteGraceTime, bool? setArchived, SqliteTransaction transaction)
        {
            m_updateremotevolumeCommand.Transaction = transaction;
            m_updateremotevolumeCommand.SetParameterValue("@OperationID", m_operationid);
            m_updateremotevolumeCommand.SetParameterValue("@State", state.ToString());
            m_updateremotevolumeCommand.SetParameterValue("@Hash", hash);
            m_updateremotevolumeCommand.SetParameterValue("@Size", size);
            m_updateremotevolumeCommand.SetParameterValue("@Name", name);
            var c = await m_updateremotevolumeCommand.ExecuteNonQueryAsync();

            if (c != 1)
            {
                throw new Exception($"Unexpected number of remote volumes detected: {c}!");
            }

            if (deleteGraceTime.Ticks > 0)
            {
                using var cmd = m_connection.CreateCommand();
                cmd.CommandText = @"UPDATE ""RemoteVolume"" SET ""DeleteGraceTime"" = @DeleteGraceTime WHERE ""Name"" = @Name ";
                cmd.Transaction = transaction;
                cmd.SetParameterValue("@DeleteGraceTime", Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(DateTime.UtcNow + deleteGraceTime));
                cmd.SetParameterValue("@Name", name);
                c = await cmd.ExecuteNonQueryAsync();

                if (c != 1)
                    throw new Exception($"Unexpected number of updates when recording remote volume updates: {c}!");
            }

            if (setArchived.HasValue)
            {
                using var cmd = m_connection.CreateCommand();
                cmd.CommandText = @"UPDATE ""RemoteVolume"" SET ""ArchiveTime"" = @ArchiveTime WHERE ""Name"" = @Name ";
                cmd.Transaction = transaction;
                cmd.SetParameterValue("@ArchiveTime", setArchived.Value ? Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(DateTime.UtcNow) : 0);
                cmd.SetParameterValue("@Name", name);
                c = await cmd.ExecuteNonQueryAsync();

                if (c != 1)
                    throw new Exception($"Unexpected number of updates when recording remote volume archive-time updates: {c}!");
            }

            if (!suppressCleanup && state == RemoteVolumeState.Deleted)
            {
                await RemoveRemoteVolume(name, transaction);
            }
        }

        public async IAsyncEnumerable<KeyValuePair<long, DateTime>> FilesetTimes()
        {
            using var cmd = m_connection.CreateCommand();
            cmd.CommandText = @"SELECT ""ID"", ""Timestamp"" FROM ""Fileset"" ORDER BY ""Timestamp"" DESC";
            using var rd = await cmd.ExecuteReaderAsync();
            while (rd.Read())
                yield return new KeyValuePair<long, DateTime>(rd.ConvertValueToInt64(0), ParseFromEpochSeconds(rd.ConvertValueToInt64(1)).ToLocalTime());
        }

        public async Task<(string Query, Dictionary<string, object?> Values)> GetFilelistWhereClause(DateTime time, long[] versions, IEnumerable<KeyValuePair<long, DateTime>>? filesetslist = null, bool singleTimeMatch = false)
        {
            KeyValuePair<long, DateTime>[] filesets;
            if (filesetslist != null)
                filesets = [.. filesetslist];
            else
                filesets = await FilesetTimes().ToArrayAsync();
            var query = new StringBuilder();
            var args = new Dictionary<string, object?>();
            if (time.Ticks > 0 || (versions != null && versions.Length > 0))
            {
                var hasTime = false;
                if (time.Ticks > 0)
                {
                    if (time.Kind == DateTimeKind.Unspecified)
                        throw new Exception("Invalid DateTime given, must be either local or UTC");

                    query.Append(singleTimeMatch ? @" ""Timestamp"" = @Timestamp" : @" ""Timestamp"" <= @Timestamp");
                    // Make sure the resolution is the same (i.e. no milliseconds)
                    args.Add("@Timestamp", Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(time));
                    hasTime = true;
                }

                if (versions != null && versions.Length > 0)
                {
                    var qs = new StringBuilder();
                    foreach (var v in versions)
                    {
                        if (v >= 0 && v < filesets.Length)
                        {
                            var argName = "@Fileset" + v;
                            args.Add(argName, filesets[v].Key);
                            qs.Append(argName);
                            qs.Append(',');
                        }
                        else
                            Logging.Log.WriteWarningMessage(LOGTAG, "SkipInvalidVersion", null, "Skipping invalid version: {0}", v);
                    }

                    if (qs.Length > 0)
                    {
                        if (hasTime)
                            query.Append(" OR ");

                        query.Append(@" ""ID"" IN (" + qs.ToString(0, qs.Length - 1) + ")");
                    }
                }

                if (query.Length > 0)
                {
                    query.Insert(0, " WHERE ");
                }
            }

            return (query.ToString(), args);
        }

        public async Task<long> GetRemoteVolumeID(string file, SqliteTransaction? transaction = null)
        {
            m_selectremotevolumeIdCommand.Transaction = transaction;
            m_selectremotevolumeIdCommand.SetParameterValue("@Name", file);
            return await m_selectremotevolumeIdCommand.ExecuteScalarInt64Async(-1);
        }

        public async IAsyncEnumerable<KeyValuePair<string, long>> GetRemoteVolumeIDs(IEnumerable<string> files, SqliteTransaction? transaction = null)
        {
            using var cmd = m_connection.CreateCommand(@"SELECT ""Name"", ""ID"" FROM ""RemoteVolume"" WHERE ""Name"" IN (@Name)");
            cmd.Transaction = transaction;
            using var tmptable = new TemporaryDbValueList(m_connection, transaction, files);
            cmd.ExpandInClauseParameter("@Name", tmptable);

            using var rd = await cmd.ExecuteReaderAsync();
            while (await rd.ReadAsync())
                yield return new KeyValuePair<string, long>(rd.ConvertValueToString(0) ?? "", rd.ConvertValueToInt64(1));
        }

        public async Task<RemoteVolumeEntry> GetRemoteVolume(string file, SqliteTransaction? transaction = null)
        {
            m_selectremotevolumeCommand.Transaction = transaction;
            m_selectremotevolumeCommand.SetParameterValue("@Name", file);
            using (var rd = await m_selectremotevolumeCommand.ExecuteReaderAsync())
                if (await rd.ReadAsync())
                    return new RemoteVolumeEntry(
                        rd.ConvertValueToInt64(0),
                        rd.ConvertValueToString(1),
                        rd.ConvertValueToString(4),
                        rd.ConvertValueToInt64(3, -1),
                        (RemoteVolumeType)Enum.Parse(typeof(RemoteVolumeType), rd.ConvertValueToString(2) ?? ""),
                        (RemoteVolumeState)Enum.Parse(typeof(RemoteVolumeState), rd.ConvertValueToString(5) ?? ""),
                        ParseFromEpochSeconds(rd.ConvertValueToInt64(6, 0)),
                        ParseFromEpochSeconds(rd.ConvertValueToInt64(7, 0))
                    );

            return RemoteVolumeEntry.Empty;
        }

        public async IAsyncEnumerable<KeyValuePair<string, RemoteVolumeState>> DuplicateRemoteVolumes(SqliteTransaction? transaction)
        {
            m_selectduplicateRemoteVolumesCommand.Transaction = transaction;
            await foreach (var rd in m_selectduplicateRemoteVolumesCommand.ExecuteReaderEnumerableAsync())
            {
                yield return new KeyValuePair<string, RemoteVolumeState>(
                    rd.ConvertValueToString(0) ?? throw new Exception("Name was null"),
                    (RemoteVolumeState)Enum.Parse(typeof(RemoteVolumeState), rd.ConvertValueToString(1) ?? "")
                );
            }
        }

        public async IAsyncEnumerable<RemoteVolumeEntry> GetRemoteVolumes(SqliteTransaction? transaction = null)
        {
            m_selectremotevolumesCommand.Transaction = transaction;
            using var rd = await m_selectremotevolumesCommand.ExecuteReaderAsync();
            while (await rd.ReadAsync())
            {
                yield return new RemoteVolumeEntry(
                    rd.ConvertValueToInt64(0),
                    rd.ConvertValueToString(1),
                    rd.ConvertValueToString(4),
                    rd.ConvertValueToInt64(3, -1),
                    (RemoteVolumeType)Enum.Parse(typeof(RemoteVolumeType), rd.ConvertValueToString(2) ?? ""),
                    (RemoteVolumeState)Enum.Parse(typeof(RemoteVolumeState), rd.ConvertValueToString(5) ?? ""),
                    ParseFromEpochSeconds(rd.ConvertValueToInt64(6, 0)),
                    ParseFromEpochSeconds(rd.ConvertValueToInt64(7, 0))
                );
            }
        }

        /// <summary>
        /// Log an operation performed on the remote backend
        /// </summary>
        /// <param name="operation">The operation performed</param>
        /// <param name="path">The path involved</param>
        /// <param name="data">Any data relating to the operation</param>
        public async Task LogRemoteOperation(string operation, string path, string? data, SqliteTransaction? transaction)
        {
            m_insertremotelogCommand.Transaction = transaction;
            m_insertremotelogCommand.SetParameterValue("@OperationID", m_operationid);
            m_insertremotelogCommand.SetParameterValue("@Timestamp", Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(DateTime.UtcNow));
            m_insertremotelogCommand.SetParameterValue("@Operation", operation);
            m_insertremotelogCommand.SetParameterValue("@Path", path);
            m_insertremotelogCommand.SetParameterValue("@Data", data);
            await m_insertremotelogCommand.ExecuteNonQueryAsync();
        }

        /// <summary>
        /// Log a debug message
        /// </summary>
        /// <param name="type">The message type</param>
        /// <param name="message">The message</param>
        /// <param name="exception">An optional exception</param>
        public async Task LogMessage(string type, string message, Exception? exception, SqliteTransaction? transaction)
        {
            m_insertlogCommand.Transaction = transaction;
            m_insertlogCommand.SetParameterValue("@OperationID", m_operationid);
            m_insertlogCommand.SetParameterValue("@Timestamp", Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(DateTime.UtcNow));
            m_insertlogCommand.SetParameterValue("@Type", type);
            m_insertlogCommand.SetParameterValue("@Message", message);
            m_insertlogCommand.SetParameterValue("@Exception", exception?.ToString());
            await m_insertlogCommand.ExecuteNonQueryAsync();
        }

        public async Task UnlinkRemoteVolume(string name, RemoteVolumeState state, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand(@"DELETE FROM ""RemoteVolume"" WHERE ""Name"" = @Name AND ""State"" = @State ");
            cmd.Transaction = transaction;
            cmd.SetParameterValue("@Name", name);
            cmd.SetParameterValue("@State", state.ToString());
            var c = await cmd.ExecuteNonQueryAsync();

            if (c != 1)
                throw new Exception($"Unexpected number of remote volumes deleted: {c}, expected {1}");

            await transaction.CommitAsync();
        }

        public async Task RemoveRemoteVolume(string name, SqliteTransaction transaction)
        {
            await RemoveRemoteVolumes([name], transaction);
        }

        public async Task RemoveRemoteVolumes(IEnumerable<string> names, SqliteTransaction transaction)
        {
            if (names == null || !names.Any()) return;

            using var deletecmd = m_connection.CreateCommand();
            string temptransguid = Library.Utility.Utility.ByteArrayAsHexString(Guid.NewGuid().ToByteArray());
            var volidstable = "DelVolSetIds-" + temptransguid;
            var blocksetidstable = "DelBlockSetIds-" + temptransguid;
            var filesetidstable = "DelFilesetIds-" + temptransguid;

            // Create and fill a temp table with the volids to delete. We avoid using too many parameters that way.
            deletecmd.ExecuteNonQuery(FormatInvariant($@"CREATE TEMP TABLE ""{volidstable}"" (""ID"" INTEGER PRIMARY KEY)"));
            deletecmd.SetCommandAndParameters(FormatInvariant($@"INSERT OR IGNORE INTO ""{volidstable}"" SELECT ""ID"" FROM ""RemoteVolume"" WHERE ""Name"" IN (@VolumeNames)"))
                .ExpandInClauseParameter("@VolumeNames", names.ToArray())
                .ExecuteNonQuery();

            var volIdsSubQuery = FormatInvariant($@"SELECT ""ID"" FROM ""{volidstable}"" ");
            deletecmd.Parameters.Clear();

            var bsIdsSubQuery = FormatInvariant(@$"
SELECT DISTINCT ""BlocksetEntry"".""BlocksetID"" FROM ""BlocksetEntry"", ""Block""
WHERE ""BlocksetEntry"".""BlockID"" = ""Block"".""ID"" AND ""Block"".""VolumeID"" IN ({volIdsSubQuery})
UNION ALL
SELECT DISTINCT ""BlocksetID"" FROM ""BlocklistHash""
WHERE ""Hash"" IN (SELECT ""Hash"" FROM ""Block"" WHERE ""VolumeID"" IN ({volIdsSubQuery}))");

            // Create a temporary table to cache subquery result, as it might take long (SQLite does not cache at all).
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"CREATE TEMP TABLE ""{blocksetidstable}"" (""ID"" INTEGER PRIMARY KEY)"));
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"INSERT OR IGNORE INTO ""{blocksetidstable}"" (""ID"") {bsIdsSubQuery}"));
            bsIdsSubQuery = FormatInvariant($@"SELECT DISTINCT ""ID"" FROM ""{blocksetidstable}"" ");
            deletecmd.Parameters.Clear();

            // Create a temp table to associate metadata that is being deleted to a fileset
            var metadataFilesetQuery = FormatInvariant($@"SELECT Metadataset.ID, FilesetEntry.FilesetID
FROM Metadataset
INNER JOIN FileLookup ON FileLookup.MetadataID = Metadataset.ID
INNER JOIN FilesetEntry ON FilesetEntry.FileID = FileLookup.ID
WHERE Metadataset.BlocksetID IN ({bsIdsSubQuery})
OR Metadataset.ID IN (SELECT MetadataID FROM FileLookup WHERE BlocksetID IN ({bsIdsSubQuery}))");

            var metadataFilesetTable = @"DelMetadataFilesetIds-" + temptransguid;
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"CREATE TEMP TABLE ""{metadataFilesetTable}"" (MetadataID INTEGER PRIMARY KEY, FilesetID INTEGER)"));
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"INSERT OR IGNORE INTO ""{metadataFilesetTable}"" (MetadataID, FilesetID) {metadataFilesetQuery}"));

            // Delete FilesetEntry rows that had their metadata deleted
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"DELETE FROM FilesetEntry
WHERE FilesetEntry.FilesetID IN (SELECT DISTINCT FilesetID FROM ""{metadataFilesetTable}"")
AND FilesetEntry.FileID IN (
	SELECT FilesetEntry.FileID
	FROM FilesetEntry
	INNER JOIN FileLookup ON FileLookup.ID = FilesetEntry.FileID
	WHERE FileLookup.MetadataID IN (SELECT MetadataID FROM ""{metadataFilesetTable}""))"));

            // Delete FilesetEntry rows that had their blocks deleted
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"DELETE FROM FilesetEntry WHERE FilesetEntry.FileID IN (
SELECT ID FROM FileLookup
WHERE FileLookup.BlocksetID IN ({bsIdsSubQuery}))"));
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"DELETE FROM FileLookup WHERE FileLookup.MetadataID IN (SELECT MetadataID FROM ""{metadataFilesetTable}"")"));

            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"DELETE FROM ""Metadataset"" WHERE ""BlocksetID"" IN ({bsIdsSubQuery})"));
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"DELETE FROM ""FileLookup"" WHERE ""BlocksetID"" IN ({bsIdsSubQuery})"));
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"DELETE FROM ""Blockset"" WHERE ""ID"" IN ({bsIdsSubQuery})"));
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"DELETE FROM ""BlocksetEntry"" WHERE ""BlocksetID"" IN ({bsIdsSubQuery})"));
            await deletecmd.ExecuteNonQueryAsync(FormatInvariant($@"DELETE FROM ""BlocklistHash"" WHERE ""BlocklistHash"".""BlocksetID"" IN ({bsIdsSubQuery})"));

            // If the volume is a block or index volume, this will update the crosslink table, otherwise nothing will happen
            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM ""IndexBlockLink"" WHERE ""BlockVolumeID"" IN ({volIdsSubQuery}) OR ""IndexVolumeID"" IN ({volIdsSubQuery})"));
            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM ""Block"" WHERE ""VolumeID"" IN ({volIdsSubQuery})"));
            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM ""DeletedBlock"" WHERE ""VolumeID"" IN ({volIdsSubQuery})"));
            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM ""ChangeJournalData"" WHERE ""FilesetID"" IN (SELECT ""ID"" FROM ""Fileset"" WHERE ""VolumeID"" IN ({volIdsSubQuery}))"));
            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM FilesetEntry WHERE FilesetID IN (SELECT ID FROM Fileset WHERE VolumeID IN ({volIdsSubQuery}))"));

            deletecmd.ExecuteNonQuery(FormatInvariant($@"CREATE TABLE ""{filesetidstable}"" (""ID"" INTEGER PRIMARY KEY)"));
            deletecmd.ExecuteNonQuery(FormatInvariant($@"INSERT OR IGNORE INTO ""{filesetidstable}"" SELECT ""ID"" FROM ""Fileset"" WHERE ""VolumeID"" IN ({volIdsSubQuery})"));
            // Delete from Fileset if FilesetEntry rows were deleted by related metadata and there are no references in FilesetEntry anymore
            deletecmd.ExecuteNonQuery(FormatInvariant($@"INSERT OR IGNORE INTO ""{filesetidstable}"" SELECT ""ID"" FROM ""Fileset"" WHERE ""Fileset"".""ID"" IN
(SELECT DISTINCT ""FilesetID"" FROM ""{metadataFilesetTable}"")
AND ""Fileset"".""ID"" NOT IN
    (SELECT DISTINCT ""FilesetID"" FROM FilesetEntry)"));

            // Since we are deleting the fileset, we also need to mark the remote volume as deleting so it will be cleaned up later
            deletecmd.SetCommandAndParameters(FormatInvariant($@"UPDATE ""RemoteVolume"" SET ""State"" = @NewState WHERE ""ID"" IN (SELECT DISTINCT ""VolumeID"" FROM ""Fileset"" WHERE ""Fileset"".""ID"" IN (SELECT ""ID"" FROM ""{filesetidstable}"")) AND ""State"" IN (@AllowedStates)"))
                .SetParameterValue("@NewState", RemoteVolumeState.Deleting.ToString())
                .ExpandInClauseParameter("@AllowedStates", [RemoteVolumeState.Uploading.ToString(), RemoteVolumeState.Uploaded.ToString(), RemoteVolumeState.Verified.ToString(), RemoteVolumeState.Temporary.ToString()])
                .ExecuteNonQuery();

            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM ""Fileset"" WHERE ""ID"" IN (SELECT ""ID"" FROM ""{filesetidstable}"")"));


            // Clean up temp tables for subqueries. We truncate content and then try to delete.
            // Drop in try-block, as it fails in nested transactions (SQLite problem)
            // SQLite.SQLiteException (0x80004005): database table is locked
            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM ""{blocksetidstable}"" "));
            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM ""{volidstable}"" "));
            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM ""{metadataFilesetTable}"" "));
            deletecmd.ExecuteNonQuery(FormatInvariant($@"DELETE FROM ""{filesetidstable}"" "));
            try
            {
                deletecmd.CommandTimeout = 2;
                deletecmd.ExecuteNonQuery(FormatInvariant($@"DROP TABLE IF EXISTS ""{blocksetidstable}"" "));
                deletecmd.ExecuteNonQuery(FormatInvariant($@"DROP TABLE IF EXISTS ""{volidstable}"" "));
                deletecmd.ExecuteNonQuery(FormatInvariant($@"DROP TABLE IF EXISTS ""{metadataFilesetTable}"" "));
                deletecmd.ExecuteNonQuery(FormatInvariant($@"DROP TABLE IF EXISTS ""{filesetidstable}"" "));
            }
            catch { /* Ignore, will be deleted on close anyway. */ }

            m_removeremotevolumeCommand.Transaction = transaction;
            m_removeremotevolumeCommand.SetParameterValue("@Now", Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(DateTime.UtcNow));
            m_removeremotevolumeCommand.SetParameterValue("@State", RemoteVolumeState.Deleted.ToString());
            foreach (var name in names)
            {
                m_removeremotevolumeCommand.SetParameterValue("@Name", name);
                await m_removeremotevolumeCommand.ExecuteNonQueryAsync();
            }

            // Validate before commiting changes
            var nonAttachedFiles = await deletecmd.ExecuteScalarInt64Async(@"SELECT COUNT(*) FROM ""FilesetEntry"" WHERE ""FileID"" NOT IN (SELECT ""ID"" FROM ""FileLookup"")");
            if (nonAttachedFiles > 0)
                throw new ConstraintException($"Detected {nonAttachedFiles} file(s) in FilesetEntry without corresponding FileLookup entry");

            await transaction.CommitAsync();
        }

        public async Task Vacuum()
        {
            m_hasExecutedVacuum = true;
            using var cmd = m_connection.CreateCommand();
            await cmd.ExecuteNonQueryAsync("VACUUM");
        }

        public async Task<long> RegisterRemoteVolume(string name, RemoteVolumeType type, long size, RemoteVolumeState state)
        {
            var transaction = m_connection.BeginTransaction();
            return await RegisterRemoteVolume(name, type, state, size, new TimeSpan(0), transaction);
        }

        public async Task<long> RegisterRemoteVolume(string name, RemoteVolumeType type, RemoteVolumeState state, SqliteTransaction transaction)
        {
            return await RegisterRemoteVolume(name, type, state, new TimeSpan(0), transaction);
        }

        public async Task<long> RegisterRemoteVolume(string name, RemoteVolumeType type, RemoteVolumeState state, TimeSpan deleteGraceTime, SqliteTransaction transaction)
        {
            return await RegisterRemoteVolume(name, type, state, -1, deleteGraceTime, transaction);
        }

        public async Task<long> RegisterRemoteVolume(string name, RemoteVolumeType type, RemoteVolumeState state, long size, TimeSpan deleteGraceTime, SqliteTransaction transaction)
        {
            m_createremotevolumeCommand.Transaction = transaction;
            m_createremotevolumeCommand.SetParameterValue("@OperationId", m_operationid);
            m_createremotevolumeCommand.SetParameterValue("@Name", name);
            m_createremotevolumeCommand.SetParameterValue("@Type", type.ToString());
            m_createremotevolumeCommand.SetParameterValue("@State", state.ToString());
            m_createremotevolumeCommand.SetParameterValue("@Size", size);
            m_createremotevolumeCommand.SetParameterValue("@VerificationCount", 0);
            m_createremotevolumeCommand.SetParameterValue("@DeleteGraceTime", deleteGraceTime.Ticks <= 0 ? 0 : (DateTime.UtcNow + deleteGraceTime).Ticks);
            m_createremotevolumeCommand.SetParameterValue("@ArchiveTime", 0);
            var r = await m_createremotevolumeCommand.ExecuteScalarInt64Async();

            await transaction.CommitAsync();

            return r;
        }

        public async Task<IEnumerable<long>> GetFilesetIDs(DateTime restoretime, long[] versions, bool singleTimeMatch = false)
        {
            if (restoretime.Kind == DateTimeKind.Unspecified)
                throw new Exception("Invalid DateTime given, must be either local or UTC");

            (var query, var values) = await GetFilelistWhereClause(restoretime, versions, singleTimeMatch: singleTimeMatch);
            var res = new List<long>();
            using var cmd = m_connection.CreateCommand();
            using (var rd = await cmd.ExecuteReaderAsync($@"SELECT ""ID"" FROM ""Fileset"" {query} ORDER BY ""Timestamp"" DESC", values))
                while (await rd.ReadAsync())
                    res.Add(rd.ConvertValueToInt64(0));

            if (res.Count == 0)
            {
                cmd.Parameters.Clear();
                using (var rd = await cmd.ExecuteReaderAsync(@"SELECT ""ID"" FROM ""Fileset"" ORDER BY ""Timestamp"" DESC "))
                    while (await rd.ReadAsync())
                        res.Add(rd.ConvertValueToInt64(0));

                if (res.Count == 0)
                    throw new Duplicati.Library.Interface.UserInformationException("No backup at the specified date", "NoBackupAtDate");
                else
                    Logging.Log.WriteWarningMessage(LOGTAG, "RestoreTimeNoMatch", null, "Restore time or version did not match any existing backups, selecting newest backup");
            }

            return res;
        }

        public async Task<IEnumerable<long>> FindMatchingFilesets(DateTime restoretime, long[] versions)
        {
            if (restoretime.Kind == DateTimeKind.Unspecified)
                throw new Exception("Invalid DateTime given, must be either local or UTC");

            var (query, args) = await GetFilelistWhereClause(restoretime, versions, singleTimeMatch: true);

            var res = new List<long>();
            using (var cmd = m_connection.CreateCommand())
            using (var rd = await cmd.ExecuteReaderAsync(@"SELECT ""ID"" FROM ""Fileset"" " + query + @" ORDER BY ""Timestamp"" DESC", args))
                while (await rd.ReadAsync())
                    res.Add(rd.ConvertValueToInt64(0));

            return res;
        }

        public async Task<bool> IsFilesetFullBackup(DateTime filesetTime, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            cmd.SetCommandAndParameters($@"SELECT ""IsFullBackup"" FROM ""Fileset"" WHERE ""Timestamp"" = @Timestamp");
            cmd.SetParameterValue("@Timestamp", Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(filesetTime));
            using var rd = await cmd.ExecuteReaderAsync();
            if (!await rd.ReadAsync())
                return false;
            var isFullBackup = rd.GetInt32(0);
            return isFullBackup == BackupType.FULL_BACKUP;
        }

        // TODO: Remove this
        public IDbTransaction BeginTransaction()
        {
            return m_connection.BeginTransactionSafe();
        }

        protected class TemporaryTransactionWrapper : IDisposable
        {
            private readonly IDbTransaction m_parent;
            private readonly bool m_isTemporary;

            public TemporaryTransactionWrapper(IDbConnection connection, IDbTransaction? transaction)
            {
                if (transaction != null)
                {
                    m_parent = transaction;
                    m_isTemporary = false;
                }
                else
                {
                    m_parent = connection.BeginTransactionSafe();
                    m_isTemporary = true;
                }
            }

            public void Commit()
            {
                if (m_isTemporary)
                    m_parent.Commit();
            }

            public void Dispose()
            {
                if (m_isTemporary)
                    m_parent.Dispose();
            }

            public IDbTransaction Parent { get { return m_parent; } }
        }

        private IEnumerable<KeyValuePair<string, string>> GetDbOptionList(IDbTransaction? transaction = null)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            using var rd = await cmd.ExecuteReaderAsync(@"SELECT ""Key"", ""Value"" FROM ""Configuration"" ");
            while (await rd.ReadAsync())
                yield return new KeyValuePair<string, string>(rd.ConvertValueToString(0) ?? "", rd.ConvertValueToString(1) ?? "");
        }

        public async Task<IDictionary<string, string>> GetDbOptions(SqliteTransaction? transaction)
        {
            var t = transaction ?? m_connection.BeginTransaction();
            var res = await GetDbOptionList(t).ToDictionaryAsync(x => x.Key, x => x.Value);
            if (transaction == null)
                await t.CommitAsync();
            return res;
        }

        /// <summary>
        /// Updates a database option
        /// </summary>
        /// <param name="key">The key to update</param>
        /// <param name="value">The value to set</param>
        private async Task UpdateDbOption(string key, bool value)
        {
            var transaction = m_connection.BeginTransaction();
            var opts = await GetDbOptions(transaction);

            if (value)
                opts[key] = "true";
            else
                opts.Remove(key);

            await SetDbOptions(opts, transaction);
            await transaction.CommitAsync();
        }

        /// <summary>
        /// Flag indicating if a repair is in progress
        /// </summary>
        public bool RepairInProgress
        {
            get => GetDbOptions(null).Await().ContainsKey("repair-in-progress");
            set => UpdateDbOption("repair-in-progress", value).Await();
        }

        /// <summary>
        /// Flag indicating if a repair is in progress
        /// </summary>
        public bool PartiallyRecreated
        {
            get => GetDbOptions(null).Await().ContainsKey("partially-recreated");
            set => UpdateDbOption("partially-recreated", value).Await();
        }

        /// <summary>
        /// Flag indicating if the database can contain partial uploads
        /// </summary>
        public bool TerminatedWithActiveUploads
        {
            get => GetDbOptions(null).Await().ContainsKey("terminated-with-active-uploads");
            set => UpdateDbOption("terminated-with-active-uploads", value).Await();
        }

        /// <summary>
        /// Sets the database options
        /// </summary>
        /// <param name="options">The options to set</param>
        /// <param name="transaction">An optional transaction</param>
        public async Task SetDbOptions(IDictionary<string, string> options, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            await cmd.ExecuteNonQueryAsync(@"DELETE FROM ""Configuration"" ");

            foreach (var kp in options)
            {
                cmd.SetCommandAndParameters(@"INSERT INTO ""Configuration"" (""Key"", ""Value"") VALUES (@Key, @Value) ");
                cmd.SetParameterValue("@Key", kp.Key);
                cmd.SetParameterValue("@Value", kp.Value);
                await cmd.ExecuteNonQueryAsync();
            }

            await transaction.CommitAsync();
        }

        public async Task<long> GetBlocksLargerThan(long fhblocksize)
        {
            using var cmd = m_connection.CreateCommand(@"SELECT COUNT(*) FROM ""Block"" WHERE ""Size"" > @Size");
            cmd.SetParameterValue("@Size", fhblocksize);
            return await cmd.ExecuteScalarInt64Async(-1);
        }

        /// <summary>
        /// Verifies the consistency of the database
        /// </summary>
        /// <param name="blocksize">The block size in bytes</param>
        /// <param name="hashsize">The hash size in byts</param>
        /// <param name="verifyfilelists">Also verify filelists (can be slow)</param>
        /// <param name="transaction">The transaction to run in</param>
        public async Task VerifyConsistency(long blocksize, long hashsize, bool verifyfilelists, SqliteTransaction transaction)
            => await VerifyConsistencyInner(blocksize, hashsize, verifyfilelists, false, transaction);

        /// <summary>
        /// Verifies the consistency of the database prior to repair
        /// </summary>
        /// <param name="blocksize">The block size in bytes</param>
        /// <param name="hashsize">The hash size in byts</param>
        /// <param name="verifyfilelists">Also verify filelists (can be slow)</param>
        /// <param name="transaction">The transaction to run in</param>
        public async Task VerifyConsistencyForRepair(long blocksize, long hashsize, bool verifyfilelists, SqliteTransaction transaction)
            => await VerifyConsistencyInner(blocksize, hashsize, verifyfilelists, true, transaction);

        /// <summary>
        /// Verifies the consistency of the database
        /// </summary>
        /// <param name="blocksize">The block size in bytes</param>
        /// <param name="hashsize">The hash size in byts</param>
        /// <param name="verifyfilelists">Also verify filelists (can be slow)</param>
        /// <param name="laxVerifyForRepair">Disable verify for errors that will be fixed by repair</param>
        /// <param name="transaction">The transaction to run in</param>
        private async Task VerifyConsistencyInner(long blocksize, long hashsize, bool verifyfilelists, bool laxVerifyForRepair, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            // Calculate the lengths for each blockset
            var combinedLengths = @"
SELECT
    ""A"".""ID"" AS ""BlocksetID"",
    IFNULL(""B"".""CalcLen"", 0) AS ""CalcLen"",
    ""A"".""Length""
FROM
    ""Blockset"" A
LEFT OUTER JOIN
    (
        SELECT
            ""BlocksetEntry"".""BlocksetID"",
            SUM(""Block"".""Size"") AS ""CalcLen""
        FROM
            ""BlocksetEntry""
        LEFT OUTER JOIN
            ""Block""
        ON
            ""Block"".""ID"" = ""BlocksetEntry"".""BlockID""
        GROUP BY ""BlocksetEntry"".""BlocksetID""
    ) B
ON
    ""A"".""ID"" = ""B"".""BlocksetID""

";
            // For each blockset with wrong lengths, fetch the file path
            var reportDetails = @"SELECT ""CalcLen"", ""Length"", ""A"".""BlocksetID"", ""File"".""Path"" FROM (" + combinedLengths + @") A, ""File"" WHERE ""A"".""BlocksetID"" = ""File"".""BlocksetID"" AND ""A"".""CalcLen"" != ""A"".""Length"" ";

            using (var rd = await cmd.ExecuteReaderAsync(reportDetails))
                if (await rd.ReadAsync())
                {
                    var sb = new StringBuilder();
                    sb.AppendLine("Found inconsistency in the following files while validating database: ");
                    var c = 0;
                    do
                    {
                        if (c < 5)
                            sb.AppendFormat("{0}, actual size {1}, dbsize {2}, blocksetid: {3}{4}", rd.GetValue(3), rd.GetValue(1), rd.GetValue(0), rd.GetValue(2), Environment.NewLine);
                        c++;
                    } while (await rd.ReadAsync());

                    c -= 5;
                    if (c > 0)
                        sb.AppendFormat("... and {0} more", c);

                    sb.Append(". Run repair to fix it.");
                    throw new DatabaseInconsistencyException(sb.ToString());
                }

            var real_count = await cmd.ExecuteScalarInt64Async(@"SELECT Count(*) FROM ""BlocklistHash""", 0);
            var unique_count = await cmd.ExecuteScalarInt64Async(@"SELECT Count(*) FROM (SELECT DISTINCT ""BlocksetID"", ""Index"" FROM ""BlocklistHash"")", 0);

            if (real_count != unique_count)
                throw new DatabaseInconsistencyException($"Found {real_count} blocklist hashes, but there should be {unique_count}. Run repair to fix it.");

            var itemswithnoblocklisthash = await cmd.ExecuteScalarInt64Async(FormatInvariant($@"SELECT COUNT(*) FROM (SELECT * FROM (SELECT ""N"".""BlocksetID"", ((""N"".""BlockCount"" + {blocksize / hashsize} - 1) / {blocksize / hashsize}) AS ""BlocklistHashCountExpected"", CASE WHEN ""G"".""BlocklistHashCount"" IS NULL THEN 0 ELSE ""G"".""BlocklistHashCount"" END AS ""BlocklistHashCountActual"" FROM (SELECT ""BlocksetID"", COUNT(*) AS ""BlockCount"" FROM ""BlocksetEntry"" GROUP BY ""BlocksetID"") ""N"" LEFT OUTER JOIN (SELECT ""BlocksetID"", COUNT(*) AS ""BlocklistHashCount"" FROM ""BlocklistHash"" GROUP BY ""BlocksetID"") ""G"" ON ""N"".""BlocksetID"" = ""G"".""BlocksetID"" WHERE ""N"".""BlockCount"" > 1) WHERE ""BlocklistHashCountExpected"" != ""BlocklistHashCountActual"")"), 0);
            if (itemswithnoblocklisthash != 0)
                throw new DatabaseInconsistencyException($"Found {itemswithnoblocklisthash} file(s) with missing blocklist hashes");

            if (await cmd.ExecuteScalarInt64Async(@"SELECT COUNT(*) FROM ""Blockset"" WHERE ""Length"" > 0 AND ""ID"" NOT IN (SELECT ""BlocksetId"" FROM ""BlocksetEntry"")") != 0)
                throw new DatabaseInconsistencyException("Detected non-empty blocksets with no associated blocks!");

            cmd.SetCommandAndParameters(@"SELECT COUNT(*) FROM ""FileLookup"" WHERE ""BlocksetID"" != @FolderBlocksetId AND ""BlocksetID"" != @SymlinkBlocksetId AND NOT ""BlocksetID"" IN (SELECT ""ID"" FROM ""Blockset"")");
            cmd.SetParameterValue("@FolderBlocksetId", FOLDER_BLOCKSET_ID);
            cmd.SetParameterValue("@SymlinkBlocksetId", SYMLINK_BLOCKSET_ID);
            if (await cmd.ExecuteScalarInt64Async(0) != 0)
                throw new DatabaseInconsistencyException("Detected files associated with non-existing blocksets!");

            if (!laxVerifyForRepair)
            {
                cmd.SetCommandAndParameters(@"SELECT COUNT(*) FROM ""Fileset"" WHERE ""VolumeID"" NOT IN (SELECT ""ID"" FROM ""RemoteVolume"" WHERE ""Type"" = @Type AND ""State"" != @State)");
                cmd.SetParameterValue("@Type", RemoteVolumeType.Files.ToString());
                cmd.SetParameterValue("@State", RemoteVolumeState.Deleted.ToString());
                var filesetsMissingVolumes = await cmd.ExecuteScalarInt64Async(0);

                if (filesetsMissingVolumes != 0)
                {
                    if (filesetsMissingVolumes == 1)
                    {
                        cmd.SetCommandAndParameters(@"SELECT ""ID"", ""Timestamp"", ""VolumeID"" FROM ""Fileset"" WHERE ""VolumeID"" NOT IN (SELECT ""ID"" FROM ""RemoteVolume"" WHERE ""Type"" = @Type AND ""State"" != @State)");
                        cmd.SetParameterValue("@Type", RemoteVolumeType.Files.ToString());
                        cmd.SetParameterValue("@State", RemoteVolumeState.Deleted.ToString());
                        using var reader = await cmd.ExecuteReaderAsync();
                        if (await reader.ReadAsync())
                            throw new DatabaseInconsistencyException($"Detected 1 fileset with missing volume: FilesetId = {reader.ConvertValueToInt64(0)}, Time = ({ParseFromEpochSeconds(reader.ConvertValueToInt64(1))}), unmatched VolumeID {reader.ConvertValueToInt64(2)}");
                    }

                    throw new DatabaseInconsistencyException($"Detected {filesetsMissingVolumes} filesets with missing volumes");
                }

                cmd.SetCommandAndParameters(@"SELECT COUNT(*) FROM ""RemoteVolume"" WHERE ""Type"" = @Type AND ""State"" != @State AND ""ID"" NOT IN (SELECT ""VolumeID"" FROM ""Fileset"")");
                cmd.SetParameterValue("@Type", RemoteVolumeType.Files.ToString());
                cmd.SetParameterValue("@State", RemoteVolumeState.Deleted.ToString());
                var volumesMissingFilests = await cmd.ExecuteScalarInt64Async(0);
                if (volumesMissingFilests != 0)
                {
                    if (volumesMissingFilests == 1)
                    {
                        cmd.SetCommandAndParameters(@"SELECT ""ID"", ""Name"", ""State"" FROM ""RemoteVolume"" WHERE ""Type"" = @Type AND ""State"" != @State AND ""ID"" NOT IN (SELECT ""VolumeID"" FROM ""Fileset"")");
                        cmd.SetParameterValue("@Type", RemoteVolumeType.Files.ToString());
                        cmd.SetParameterValue("@State", RemoteVolumeState.Deleted.ToString());
                        using var reader = await cmd.ExecuteReaderAsync();
                        if (await reader.ReadAsync())
                            throw new DatabaseInconsistencyException($"Detected 1 volume with missing filesets: VolumeId = {reader.ConvertValueToInt64(0)}, Name = {reader.ConvertValueToString(1)}, State = {reader.ConvertValueToString(2)}");
                    }

                    throw new DatabaseInconsistencyException($"Detected {volumesMissingFilests} volumes with missing filesets");
                }
            }

            var nonAttachedFiles = await cmd.ExecuteScalarInt64Async(@"SELECT COUNT(*) FROM ""FilesetEntry"" WHERE ""FileID"" NOT IN (SELECT ""ID"" FROM ""FileLookup"")");
            if (nonAttachedFiles != 0)
            {
                // Attempt to create a better error message by finding the first 10 fileset ids with the issue
                using var filesetIdReader = await cmd.ExecuteReaderAsync(@"SELECT DISTINCT(FilesetID) FROM ""FilesetEntry"" WHERE ""FileID"" NOT IN (SELECT ""ID"" FROM ""FileLookup"") LIMIT 11");
                var filesetIds = new HashSet<long>();
                var overflow = false;
                while (await filesetIdReader.ReadAsync())
                {
                    if (filesetIds.Count >= 10)
                    {
                        overflow = true;
                        break;
                    }
                    filesetIds.Add(filesetIdReader.ConvertValueToInt64(0));
                }

                var pairs = FilesetTimes()
                    .Select((x, i) => new { FilesetId = x.Key, Version = i, Time = x.Value })
                    .Where(x => filesetIds.Contains(x.FilesetId))
                    .Select(x => $"Fileset {x.Version}: {x.Time} (id = {x.FilesetId})");

                // Fall back to a generic error message if we can't find the fileset ids
                if (!await pairs.AnyAsync())
                    throw new DatabaseInconsistencyException($"Detected {nonAttachedFiles} file(s) in FilesetEntry without corresponding FileLookup entry");

                if (overflow)
                    pairs = pairs.Append("... and more");

                throw new DatabaseInconsistencyException($"Detected {nonAttachedFiles} file(s) in FilesetEntry without corresponding FileLookup entry in the following filesets:{Environment.NewLine}{string.Join(Environment.NewLine, pairs)}");
            }

            if (verifyfilelists)
            {
                var anyError = new List<string>();
                using (var cmd2 = m_connection.CreateCommand())
                {
                    cmd2.Transaction = transaction;
                    await foreach (var filesetid in cmd.ExecuteReaderEnumerableAsync(@"SELECT ""ID"" FROM ""Fileset"" ").Select(x => x.ConvertValueToInt64(0, -1)))
                    {
                        var expandedCmd = FormatInvariant($@"SELECT COUNT(*) FROM (SELECT DISTINCT ""Path"" FROM ({LocalDatabase.LIST_FILESETS}) UNION SELECT DISTINCT ""Path"" FROM ({LocalDatabase.LIST_FOLDERS_AND_SYMLINKS}))");
                        cmd2.SetCommandAndParameters(expandedCmd);
                        cmd2.SetParameterValue("@FilesetId", filesetid);
                        cmd2.SetParameterValue("@FolderBlocksetId", FOLDER_BLOCKSET_ID);
                        cmd2.SetParameterValue("@SymlinkBlocksetId", SYMLINK_BLOCKSET_ID);
                        var expandedlist = await cmd.ExecuteScalarInt64Async(0);
                        //var storedfilelist = cmd2.ExecuteScalarInt64(FormatInvariant(@"SELECT COUNT(*) FROM ""FilesetEntry"", ""FileLookup"" WHERE ""FilesetEntry"".""FilesetID"" = @FilesetId AND ""FileLookup"".""ID"" = ""FilesetEntry"".""FileID"" AND ""FileLookup"".""BlocksetID"" != @FolderBlocksetId AND ""FileLookup"".""BlocksetID"" != @SymlinkBlocksetId"), 0, filesetid, FOLDER_BLOCKSET_ID, SYMLINK_BLOCKSET_ID);
                        cmd2.SetCommandAndParameters(@"SELECT COUNT(*) FROM ""FilesetEntry"" WHERE ""FilesetEntry"".""FilesetID"" = @FilesetId");
                        cmd2.SetParameterValue("@FilesetId", filesetid);
                        var storedlist = await cmd2.ExecuteScalarInt64Async(0);

                        if (expandedlist != storedlist)
                        {
                            var filesetname = filesetid.ToString();
                            var fileset = await FilesetTimes().Zip(AsyncEnumerable.Range(0, await FilesetTimes().CountAsync()), (a, b) => new Tuple<long, long, DateTime>(b, a.Key, a.Value)).FirstOrDefaultAsync(x => x.Item2 == filesetid);
                            if (fileset != null)
                                filesetname = $"version {fileset.Item1}: {fileset.Item3} (database id: {fileset.Item2})";
                            anyError.Add($"Unexpected difference in fileset {filesetname}, found {expandedlist} entries, but expected {storedlist}");
                        }
                    }
                }

                if (anyError.Any())
                {
                    throw new DatabaseInconsistencyException(string.Join("\n\r", anyError), "FilesetDifferences");
                }
            }
        }

        public interface IBlock
        {
            string Hash { get; }
            long Size { get; }
        }

        internal class Block(string hash, long size) : IBlock
        {
            public string Hash { get; private set; } = hash;
            public long Size { get; private set; } = size;
        }

        public async IAsyncEnumerable<IBlock> GetBlocks(long volumeid, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand(@"SELECT DISTINCT ""Hash"", ""Size"" FROM ""Block"" WHERE ""VolumeID"" = @VolumeId");
            cmd.Transaction = transaction;
            cmd.SetParameterValue("@VolumeId", volumeid);
            using var rd = await cmd.ExecuteReaderAsync();
            while (await rd.ReadAsync())
                yield return new Block(rd.ConvertValueToString(0) ?? throw new Exception("Hash is null"), rd.ConvertValueToInt64(1));
        }

        // TODO: Replace this with an enumerable method
        private class BlocklistHashEnumerable : IEnumerable<string>
        {
            private class BlocklistHashEnumerator : IEnumerator<string>
            {
                private readonly SqliteDataReader m_reader;
                private readonly BlocklistHashEnumerable m_parent;
                private string? m_path = null;
                private bool m_first = true;
                private string? m_current = null;

                public BlocklistHashEnumerator(BlocklistHashEnumerable parent, SqliteDataReader reader)
                {
                    m_reader = reader;
                    m_parent = parent;
                }

                public string Current { get { return m_current!; } }

                public void Dispose()
                {
                }

                object System.Collections.IEnumerator.Current { get { return Current; } }

                public bool MoveNext()
                {
                    m_first = false;

                    if (m_path == null)
                    {
                        m_path = m_reader.ConvertValueToString(0);
                        m_current = m_reader.ConvertValueToString(6);
                        return true;
                    }
                    else
                    {
                        if (m_current == null)
                            return false;

                        if (!m_reader.ReadAsync().Await())
                        {
                            m_current = null;
                            m_parent.MoreData = false;
                            return false;
                        }

                        var np = m_reader.ConvertValueToString(0);
                        if (m_path != np)
                        {
                            m_current = null;
                            return false;
                        }

                        m_current = m_reader.ConvertValueToString(6);
                        return true;
                    }
                }

                public void Reset()
                {
                    if (!m_first)
                        throw new Exception("Iterator reset not supported");

                    m_first = false;
                }
            }

            private readonly SqliteDataReader m_reader;

            public BlocklistHashEnumerable(SqliteDataReader reader)
            {
                m_reader = reader;
                MoreData = true;
            }

            public bool MoreData { get; protected set; }

            public IEnumerator<string> GetEnumerator()
            {
                return new BlocklistHashEnumerator(this, m_reader);
            }

            System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
            {
                return GetEnumerator();
            }
        }

        public const string LIST_FILESETS = @"
SELECT
    ""L"".""Path"",
    ""L"".""Lastmodified"",
    ""L"".""Filelength"",
    ""L"".""Filehash"",
    ""L"".""Metahash"",
    ""L"".""Metalength"",
    ""L"".""BlocklistHash"",
    ""L"".""FirstBlockHash"",
    ""L"".""FirstBlockSize"",
    ""L"".""FirstMetaBlockHash"",
    ""L"".""FirstMetaBlockSize"",
    ""M"".""Hash"" AS ""MetaBlocklistHash""
FROM
    (
    SELECT
        ""J"".""Path"",
        ""J"".""Lastmodified"",
        ""J"".""Filelength"",
        ""J"".""Filehash"",
        ""J"".""Metahash"",
        ""J"".""Metalength"",
        ""K"".""Hash"" AS ""BlocklistHash"",
        ""J"".""FirstBlockHash"",
        ""J"".""FirstBlockSize"",
        ""J"".""FirstMetaBlockHash"",
        ""J"".""FirstMetaBlockSize"",
        ""J"".""MetablocksetID""
    FROM
        (
        SELECT
	        ""A"".""Path"" AS ""Path"",
	        ""D"".""Lastmodified"" AS ""Lastmodified"",
	        ""B"".""Length"" AS ""Filelength"",
	        ""B"".""FullHash"" AS ""Filehash"",
	        ""E"".""FullHash"" AS ""Metahash"",
	        ""E"".""Length"" AS ""Metalength"",
	        ""A"".""BlocksetID"" AS ""BlocksetID"",
	        ""F"".""Hash"" AS ""FirstBlockHash"",
	        ""F"".""Size"" AS ""FirstBlockSize"",
	        ""H"".""Hash"" AS ""FirstMetaBlockHash"",
	        ""H"".""Size"" AS ""FirstMetaBlockSize"",
	        ""C"".""BlocksetID"" AS ""MetablocksetID""
        FROM
	        ""File"" A
        LEFT JOIN ""Blockset"" B
          ON ""A"".""BlocksetID"" = ""B"".""ID""
        LEFT JOIN ""Metadataset"" C
          ON ""A"".""MetadataID"" = ""C"".""ID""
        LEFT JOIN ""FilesetEntry"" D
          ON ""A"".""ID"" = ""D"".""FileID""
        LEFT JOIN ""Blockset"" E
          ON ""E"".""ID"" = ""C"".""BlocksetID""
        LEFT JOIN ""BlocksetEntry"" G
          ON ""B"".""ID"" = ""G"".""BlocksetID""
        LEFT JOIN ""Block"" F
          ON ""G"".""BlockID"" = ""F"".""ID""
        LEFT JOIN ""BlocksetEntry"" I
          ON ""E"".""ID"" = ""I"".""BlocksetID""
        LEFT JOIN ""Block"" H
          ON ""I"".""BlockID"" = ""H"".""ID""
        WHERE
          ""A"".""BlocksetId"" >= 0 AND
          ""D"".""FilesetID"" = @FilesetId AND
          (""I"".""Index"" = 0 OR ""I"".""Index"" IS NULL) AND
          (""G"".""Index"" = 0 OR ""G"".""Index"" IS NULL)
        ) J
    LEFT OUTER JOIN
        ""BlocklistHash"" K
    ON
        ""K"".""BlocksetID"" = ""J"".""BlocksetID""
    ORDER BY ""J"".""Path"", ""K"".""Index""
    ) L

LEFT OUTER JOIN
    ""BlocklistHash"" M
ON
    ""M"".""BlocksetID"" = ""L"".""MetablocksetID""
";

        public const string LIST_FOLDERS_AND_SYMLINKS = @"
SELECT
    ""G"".""BlocksetID"",
    ""G"".""ID"",
    ""G"".""Path"",
    ""G"".""Length"",
    ""G"".""FullHash"",
    ""G"".""Lastmodified"",
    ""G"".""FirstMetaBlockHash"",
    ""H"".""Hash"" AS ""MetablocklistHash""
FROM
    (
    SELECT
        ""B"".""BlocksetID"",
        ""B"".""ID"",
        ""B"".""Path"",
        ""D"".""Length"",
        ""D"".""FullHash"",
        ""A"".""Lastmodified"",
        ""F"".""Hash"" AS ""FirstMetaBlockHash"",
        ""C"".""BlocksetID"" AS ""MetaBlocksetID""
    FROM
        ""FilesetEntry"" A,
        ""File"" B,
        ""Metadataset"" C,
        ""Blockset"" D,
        ""BlocksetEntry"" E,
        ""Block"" F
    WHERE
        ""A"".""FileID"" = ""B"".""ID""
        AND ""B"".""MetadataID"" = ""C"".""ID""
        AND ""C"".""BlocksetID"" = ""D"".""ID""
        AND ""E"".""BlocksetID"" = ""C"".""BlocksetID""
        AND ""E"".""BlockID"" = ""F"".""ID""
        AND ""E"".""Index"" = 0
        AND (""B"".""BlocksetID"" = @FolderBlocksetId OR ""B"".""BlocksetID"" = @SymlinkBlocksetId)
        AND ""A"".""FilesetID"" = @FilesetId
    ) G
LEFT OUTER JOIN
   ""BlocklistHash"" H
ON
   ""H"".""BlocksetID"" = ""G"".""MetaBlocksetID""
ORDER BY
   ""G"".""Path"", ""H"".""Index""

";

        public async Task WriteFileset(Volumes.FilesetVolumeWriter filesetvolume, long filesetId, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            cmd.SetCommandAndParameters(LIST_FOLDERS_AND_SYMLINKS);
            cmd.SetParameterValue("@FilesetId", filesetId);
            cmd.SetParameterValue("@FolderBlocksetId", FOLDER_BLOCKSET_ID);
            cmd.SetParameterValue("@SymlinkBlocksetId", SYMLINK_BLOCKSET_ID);

            string? lastpath = null;
            using (var rd = await cmd.ExecuteReaderAsync())
                while (await rd.ReadAsync())
                {
                    var blocksetID = rd.ConvertValueToInt64(0, -1);
                    var path = rd.ConvertValueToString(2);
                    var metalength = rd.ConvertValueToInt64(3, -1);
                    var metahash = rd.ConvertValueToString(4);
                    var metablockhash = rd.ConvertValueToString(6);
                    var metablocklisthash = rd.ConvertValueToString(7);

                    if (path == lastpath)
                        Logging.Log.WriteWarningMessage(LOGTAG, "DuplicatePathFound", null, "Duplicate path detected: {0}", path);

                    lastpath = path;

                    if (blocksetID == FOLDER_BLOCKSET_ID)
                        filesetvolume.AddDirectory(path, metahash, metalength, metablockhash, string.IsNullOrWhiteSpace(metablocklisthash) ? null : new string[] { metablocklisthash });
                    else if (blocksetID == SYMLINK_BLOCKSET_ID)
                        filesetvolume.AddSymlink(path, metahash, metalength, metablockhash, string.IsNullOrWhiteSpace(metablocklisthash) ? null : new string[] { metablocklisthash });
                }

            // TODO: Perhaps run the above query after recreate and compare count(*) with count(*) from filesetentry where id = x

            cmd.SetCommandAndParameters(LIST_FILESETS);
            cmd.SetParameterValue("@FilesetId", filesetId);

            using (var rd = await cmd.ExecuteReaderAsync())
                if (await rd.ReadAsync())
                {
                    var more = false;
                    do
                    {
                        var path = rd.ConvertValueToString(0);
                        var filehash = rd.ConvertValueToString(3);
                        var size = rd.ConvertValueToInt64(2);
                        var lastmodified = new DateTime(rd.ConvertValueToInt64(1, 0), DateTimeKind.Utc);
                        var metahash = rd.ConvertValueToString(4);
                        var metasize = rd.ConvertValueToInt64(5, -1);
                        var p = rd.GetValue(6);
                        var blrd = (p == null || p == DBNull.Value) ? null : new BlocklistHashEnumerable(rd);
                        var blockhash = rd.ConvertValueToString(7);
                        var blocksize = rd.ConvertValueToInt64(8, -1);
                        var metablockhash = rd.ConvertValueToString(9);
                        //var metablocksize = rd.ConvertValueToInt64(10, -1);
                        var metablocklisthash = rd.ConvertValueToString(11);

                        if (blockhash == filehash)
                            blockhash = null;

                        if (metablockhash == metahash)
                            metablockhash = null;

                        filesetvolume.AddFile(path, filehash, size, lastmodified, metahash, metasize, metablockhash, blockhash, blocksize, blrd, string.IsNullOrWhiteSpace(metablocklisthash) ? null : new string[] { metablocklisthash });
                        if (blrd == null)
                            more = await rd.ReadAsync();
                        else
                            more = blrd.MoreData;

                    } while (more);
                }
        }

        public async Task LinkFilesetToVolume(long filesetid, long volumeid, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            cmd.SetCommandAndParameters(@"UPDATE ""Fileset"" SET ""VolumeID"" = @VolumeId WHERE ""ID"" = @FilesetId");
            cmd.SetParameterValue("@VolumeId", volumeid);
            cmd.SetParameterValue("@FilesetId", filesetid);
            var c = await cmd.ExecuteNonQueryAsync();

            if (c != 1)
                throw new Exception($"Failed to link filesetid {filesetid} to volumeid {volumeid}");
        }

        public async Task PushTimestampChangesToPreviousVersion(long filesetId, SqliteTransaction transaction)
        {
            var query = @"
UPDATE FilesetEntry AS oldVersion
SET Lastmodified = tempVersion.Lastmodified
FROM FilesetEntry AS tempVersion
WHERE oldVersion.FileID = tempVersion.FileID
AND tempVersion.FilesetID = @FilesetId
AND oldVersion.FilesetID = (SELECT ID FROM Fileset WHERE ID != @FilesetId ORDER BY Timestamp DESC LIMIT 1)";

            using var cmd = m_connection.CreateCommand(query);
            cmd.Transaction = transaction;
            cmd.SetParameterValue("@FilesetId", filesetId);
            await cmd.ExecuteNonQueryAsync();
        }

        /// <summary>
        /// Keeps a list of filenames in a temporary table with a single column Path
        /// </summary>
        public class FilteredFilenameTable : IDisposable
        {
            public string Tablename { get; private set; }
            private readonly SqliteConnection m_connection;

            public FilteredFilenameTable(SqliteConnection connection, IFilter filter, SqliteTransaction transaction)
            {
                m_connection = connection;
                Tablename = "Filenames-" + Library.Utility.Utility.ByteArrayAsHexString(Guid.NewGuid().ToByteArray());
                var type = FilterType.Regexp;
                if (filter is FilterExpression expression)
                    type = expression.Type;

                // Bugfix: SQLite does not handle case-insensitive LIKE with non-ascii characters
                if (type != FilterType.Regexp && !Library.Utility.Utility.IsFSCaseSensitive && filter.ToString()!.Any(x => x > 127))
                    type = FilterType.Regexp;

                if (filter.Empty)
                {
                    using var cmd = m_connection.CreateCommand();
                    cmd.Transaction = transaction;
                    cmd.ExecuteNonQueryAsync(FormatInvariant($@"CREATE TEMPORARY TABLE ""{Tablename}"" AS SELECT DISTINCT ""Path"" FROM ""File"" ")).Await();
                    return;
                }

                if (type == FilterType.Regexp || type == FilterType.Group)
                {
                    using var cmd = m_connection.CreateCommand();
                    cmd.Transaction = transaction;
                    // TODO: Optimize this to not rely on the "File" view, and not instantiate the paths in full
                    cmd.ExecuteNonQueryAsync(FormatInvariant($@"CREATE TEMPORARY TABLE ""{Tablename}"" (""Path"" TEXT NOT NULL)")).Await();
                    cmd.SetCommandAndParameters(FormatInvariant($@"INSERT INTO ""{Tablename}"" (""Path"") VALUES (@Path)"));
                    using (var c2 = m_connection.CreateCommand())
                    using (var rd = c2.ExecuteReaderAsync(@"SELECT DISTINCT ""Path"" FROM ""File"" ").Await())
                        while (rd.ReadAsync().Await())
                        {
                            var p = rd.ConvertValueToString(0);
                            if (FilterExpression.Matches(filter, p))
                            {
                                cmd.SetParameterValue("@Path", p);
                                cmd.ExecuteNonQueryAsync().Await();
                            }
                        }

                    transaction.CommitAsync().Await();
                }
                else
                {
                    var sb = new StringBuilder();
                    var args = new Dictionary<string, object?>();
                    foreach (var f in ((FilterExpression)filter).GetSimpleList())
                    {
                        if (sb.Length != 0)
                            sb.Append(" OR ");

                        var argName = $"@Arg{args.Count}";
                        if (type == FilterType.Wildcard)
                        {
                            sb.Append(FormatInvariant(@$"""Path"" LIKE {argName}"));
                            args.Add(argName, f.Replace('*', '%').Replace('?', '_'));
                        }
                        else
                        {
                            sb.Append(FormatInvariant(@$"""Path"" = {argName}"));
                            args.Add(argName, f);
                        }
                    }

                    using var cmd = m_connection.CreateCommand();
                    cmd.Transaction = transaction;
                    cmd.ExecuteNonQueryAsync(FormatInvariant($@"CREATE TEMPORARY TABLE ""{Tablename}"" (""Path"" TEXT NOT NULL)")).Await();
                    cmd.ExecuteNonQueryAsync(FormatInvariant($@"INSERT INTO ""{Tablename}"" SELECT DISTINCT ""Path"" FROM ""File"" WHERE {sb}"), args).Await();
                    transaction.CommitAsync().Await();
                }
            }

            public void Dispose()
            {
                if (Tablename != null)
                    try
                    {
                        using var cmd = m_connection.CreateCommand();
                        cmd.ExecuteNonQueryAsync(FormatInvariant(@$"DROP TABLE IF EXISTS ""{Tablename}"" ")).Await();
                    }
                    catch { }
                    finally { Tablename = null!; }
            }
        }

        public async Task RenameRemoteFile(string oldname, string newname, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            //Rename the old entry, to preserve ID links
            cmd.SetCommandAndParameters(@"UPDATE ""Remotevolume"" SET ""Name"" = @Newname WHERE ""Name"" = @Oldname");
            cmd.SetParameterValue("@Newname", newname);
            cmd.SetParameterValue("@Oldname", oldname);
            var c = await cmd.ExecuteNonQueryAsync();

            if (c != 1)
                throw new Exception($"Unexpected result from renaming \"{oldname}\" to \"{newname}\", expected {1} got {c}");

            // Grab the type of entry
            cmd.SetCommandAndParameters(@"SELECT ""Type"" FROM ""Remotevolume"" WHERE ""Name"" = @Name");
            cmd.SetParameterValue("@Name", newname);
            var type = (RemoteVolumeType)Enum.Parse(
                typeof(RemoteVolumeType), (await cmd.ExecuteScalarAsync())?.ToString() ?? "",
                true);

            //Create a fake new entry with the old name and mark as deleting
            // as this ensures we will remove it, if it shows up in some later listing
            await RegisterRemoteVolume(oldname, type, RemoteVolumeState.Deleting, transaction);

            await transaction.CommitAsync();
        }

        /// <summary>
        /// Creates a timestamped backup operation to correctly associate the fileset with the time it was created.
        /// </summary>
        /// <param name="volumeid">The ID of the fileset volume to update</param>
        /// <param name="timestamp">The timestamp of the operation to create</param>
        /// <param name="transaction">An optional external transaction</param>
        public virtual async Task<long> CreateFileset(long volumeid, DateTime timestamp, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            cmd.SetCommandAndParameters(@"INSERT INTO ""Fileset"" (""OperationID"", ""Timestamp"", ""VolumeID"", ""IsFullBackup"") VALUES (@OperationId, @Timestamp, @VolumeId, @IsFullBackup); SELECT last_insert_rowid();");
            cmd.SetParameterValue("@OperationId", m_operationid);
            cmd.SetParameterValue("@Timestamp", Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(timestamp));
            cmd.SetParameterValue("@VolumeId", volumeid);
            cmd.SetParameterValue("@IsFullBackup", BackupType.PARTIAL_BACKUP);
            var id = await cmd.ExecuteScalarInt64Async(-1);

            await transaction.CommitAsync();

            return id;
        }

        /// <summary>
        /// Adds a link between an index volume and a block volume.
        /// </summary>
        /// <param name="indexVolumeID">The ID of the index volume.</param>
        /// <param name="blockVolumeID">The ID of the block volume.</param>
        /// <param name="transaction">An optional transaction.</param>
        public async Task AddIndexBlockLink(long indexVolumeID, long blockVolumeID, SqliteTransaction transaction)
        {
            if (indexVolumeID <= 0)
                throw new ArgumentOutOfRangeException(nameof(indexVolumeID), "Index volume ID must be greater than 0.");
            if (blockVolumeID <= 0)
                throw new ArgumentOutOfRangeException(nameof(blockVolumeID), "Block volume ID must be greater than 0.");

            m_insertIndexBlockLink.Transaction = transaction;
            m_insertIndexBlockLink.SetParameterValue("@IndexVolumeId", indexVolumeID);
            m_insertIndexBlockLink.SetParameterValue("@BlockVolumeId", blockVolumeID);
            await m_insertIndexBlockLink.ExecuteNonQueryAsync();
        }

        /// <summary>
        /// Returns all unique blocklists for a given volume
        /// </summary>
        /// <param name="volumeid">The volume ID to get blocklists for</param>
        /// <param name="blocksize">The blocksize</param>
        /// <param name="hashsize">The size of the hash</param>
        /// <param name="transaction">An optional external transaction</param>
        /// <returns>An enumerable of tuples containing the blocklist hash, the blocklist data and the length of the data</returns>
        public async IAsyncEnumerable<Tuple<string, byte[], int>> GetBlocklists(long volumeid, long blocksize, int hashsize, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            // Group subquery by hash to ensure that each blocklist hash appears only once in the result
            var sql = FormatInvariant($@"SELECT ""A"".""Hash"", ""C"".""Hash"" FROM
(SELECT ""BlocklistHash"".""BlocksetID"", ""Block"".""Hash"", ""BlocklistHash"".""Index"" FROM  ""BlocklistHash"",""Block"" WHERE  ""BlocklistHash"".""Hash"" = ""Block"".""Hash"" AND ""Block"".""VolumeID"" = @VolumeId GROUP BY ""Block"".""Hash"", ""Block"".""Size"") A,
 ""BlocksetEntry"" B, ""Block"" C WHERE ""B"".""BlocksetID"" = ""A"".""BlocksetID"" AND
 ""B"".""Index"" >= (""A"".""Index"" * {blocksize / hashsize}) AND ""B"".""Index"" < ((""A"".""Index"" + 1) * {blocksize / hashsize}) AND ""C"".""ID"" = ""B"".""BlockID""
 ORDER BY ""A"".""BlocksetID"", ""B"".""Index""");

            string? curHash = null;
            var count = 0;
            var buffer = new byte[blocksize];

            cmd.SetCommandAndParameters(sql);
            cmd.SetParameterValue("@VolumeId", volumeid);
            using (var rd = await cmd.ExecuteReaderAsync())
                while (await rd.ReadAsync())
                {
                    var blockhash = rd.ConvertValueToString(0);
                    if ((blockhash != curHash && curHash != null) || count + hashsize > buffer.Length)
                    {
                        yield return new Tuple<string, byte[], int>(curHash!, buffer, count);
                        buffer = new byte[blocksize];
                        count = 0;
                    }

                    var hash = Convert.FromBase64String(rd.ConvertValueToString(1) ?? throw new Exception("Hash is null"));
                    Array.Copy(hash, 0, buffer, count, hashsize);
                    curHash = blockhash;
                    count += hashsize;
                }

            if (curHash != null)
                yield return new Tuple<string, byte[], int>(curHash, buffer, count);
        }

        /// <summary>
        /// Update fileset with full backup state
        /// </summary>
        /// <param name="fileSetId">Existing file set to update</param>
        /// <param name="isFullBackup">Full backup state</param>
        /// <param name="transaction">An optional external transaction</param>
        public async Task UpdateFullBackupStateInFileset(long fileSetId, bool isFullBackup, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            cmd.SetCommandAndParameters(@"UPDATE ""Fileset"" SET ""IsFullBackup"" = @IsFullBackup WHERE ""ID"" = @FilesetId;");
            cmd.SetParameterValue("@FilesetId", fileSetId);
            cmd.SetParameterValue("@IsFullBackup", isFullBackup ? BackupType.FULL_BACKUP : BackupType.PARTIAL_BACKUP);
            await cmd.ExecuteNonQueryAsync();

            await transaction.CommitAsync();
        }

        /// <summary>
        /// Removes all entries in the fileset entry table for a given fileset ID
        /// </summary>
        /// <param name="filesetId">The fileset ID to clear</param>
        /// <param name="transaction">The transaction to use</param>
        public async Task ClearFilesetEntries(long filesetId, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            cmd.SetCommandAndParameters(@"DELETE FROM ""FilesetEntry"" WHERE ""FilesetID"" = @FilesetId");
            cmd.SetParameterValue("@FilesetId", filesetId);
            await cmd.ExecuteNonQueryAsync();
        }

        /// <summary>
        /// Gets the last previous fileset that was incomplete
        /// </summary>
        /// <param name="transaction">The transaction to use</param>
        /// <returns>The last incomplete fileset or default</returns>
        public async Task<RemoteVolumeEntry> GetLastIncompleteFilesetVolume(SqliteTransaction transaction)
        {
            var candidates = GetIncompleteFilesets(transaction).OrderBy(x => x.Value);
            if (await candidates.AnyAsync())
                return await GetRemoteVolumeFromFilesetID((await candidates.LastAsync()).Key, transaction);

            return default;
        }

        /// <summary>
        /// Gets a list of incomplete filesets
        /// </summary>
        /// <param name="transaction">An optional transaction</param>
        /// <returns>A list of fileset IDs and timestamps</returns>
        public async IAsyncEnumerable<KeyValuePair<long, DateTime>> GetIncompleteFilesets(SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            using var rd = await cmd.ExecuteReaderAsync(FormatInvariant(@$"SELECT DISTINCT ""Fileset"".""ID"", ""Fileset"".""Timestamp"" FROM ""Fileset"", ""RemoteVolume"" WHERE ""RemoteVolume"".""ID"" = ""Fileset"".""VolumeID"" AND ""Fileset"".""ID"" IN (SELECT ""FilesetID"" FROM ""FilesetEntry"")  AND (""RemoteVolume"".""State"" = '{RemoteVolumeState.Uploading}' OR ""RemoteVolume"".""State"" = '{RemoteVolumeState.Temporary}')"));
            while (await rd.ReadAsync())
            {
                yield return new KeyValuePair<long, DateTime>(
                    rd.ConvertValueToInt64(0),
                    ParseFromEpochSeconds(rd.ConvertValueToInt64(1)).ToLocalTime()
                );
            }
        }

        /// <summary>
        /// Gets the remote volume entry from the fileset ID
        /// </summary>
        /// <param name="filesetID">The fileset ID</param>
        /// <param name="transaction">An optional transaction</param>
        /// <returns>The remote volume entry or default</returns>
        public async Task<RemoteVolumeEntry> GetRemoteVolumeFromFilesetID(long filesetID, SqliteTransaction transaction)
        {
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            cmd.SetCommandAndParameters(@"SELECT ""RemoteVolume"".""ID"", ""Name"", ""Type"", ""Size"", ""Hash"", ""State"", ""DeleteGraceTime"", ""ArchiveTime"" FROM ""RemoteVolume"", ""Fileset"" WHERE ""Fileset"".""VolumeID"" = ""RemoteVolume"".""ID"" AND ""Fileset"".""ID"" = @FilesetId");
            cmd.SetParameterValue("@FilesetId", filesetID);
            using var rd = await cmd.ExecuteReaderAsync();
            if (await rd.ReadAsync())
                return new RemoteVolumeEntry(
                    rd.ConvertValueToInt64(0, -1),
                    rd.ConvertValueToString(1),
                    rd.ConvertValueToString(4),
                    rd.ConvertValueToInt64(3, -1),
                    (RemoteVolumeType)Enum.Parse(typeof(RemoteVolumeType), rd.ConvertValueToString(2) ?? ""),
                    (RemoteVolumeState)Enum.Parse(typeof(RemoteVolumeState), rd.ConvertValueToString(5) ?? ""),
                    ParseFromEpochSeconds(rd.ConvertValueToInt64(6)).ToLocalTime(),
                    ParseFromEpochSeconds(rd.ConvertValueToInt64(7)).ToLocalTime()
                );
            else
                return default(RemoteVolumeEntry);
        }

        public async Task PurgeLogData(DateTime threshold)
        {
            using var transaction = m_connection.BeginTransaction();
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            var t = Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(threshold);
            cmd.SetCommandAndParameters(@"DELETE FROM ""LogData"" WHERE ""Timestamp"" < @Timestamp");
            cmd.SetParameterValue("@Timestamp", t);
            await cmd.ExecuteNonQueryAsync();
            cmd.SetCommandAndParameters(@"DELETE FROM ""RemoteOperation"" WHERE ""Timestamp"" < @Timestamp");
            cmd.SetParameterValue("@Timestamp", t);
            await cmd.ExecuteNonQueryAsync();

            await transaction.CommitAsync();
        }

        public async Task PurgeDeletedVolumes(DateTime threshold)
        {
            using var transaction = m_connection.BeginTransaction();
            using var cmd = m_connection.CreateCommand();
            cmd.Transaction = transaction;
            m_removedeletedremotevolumeCommand.SetParameterValue("@Now", Library.Utility.Utility.NormalizeDateTimeToEpochSeconds(threshold));
            await m_removedeletedremotevolumeCommand.ExecuteNonQueryAsync();

            await transaction.CommitAsync();
        }

        public virtual void Dispose()
        {
            if (IsDisposed)
                return;

            DisposeAllFields<SqliteCommand>(this, false);

            if (ShouldCloseConnection && m_connection != null)
            {
                if (m_connection.State == ConnectionState.Open && !m_hasExecutedVacuum)
                {
                    using (var transaction = m_connection.BeginTransaction())
                    using (var command = m_connection.CreateCommand())
                    {
                        command.Transaction = transaction;
                        // SQLite recommends that PRAGMA optimize is run just before closing each database connection.
                        command.ExecuteNonQueryAsync("PRAGMA optimize").Await();

                        try
                        {
                            transaction.CommitAsync().Await();
                        }
                        catch (Exception ex)
                        {
                            Logging.Log.WriteVerboseMessage(LOGTAG, "FailedToCommitTransaction", ex, "Failed to commit transaction after pragma optimize, usually caused by the a no-op transaction");
                        }
                    }

                    m_connection.CloseAsync().Await();
                }

                m_connection.Dispose();
            }

            IsDisposed = true;
        }

        /// <summary>
        /// Disposes all fields of a certain type, in the instance and its bases
        /// </summary>
        /// <typeparam name="T">The type of fields to find</typeparam>
        /// <param name="item">The item to dispose</param>
        /// <param name="throwExceptions"><c>True</c> if an aggregate exception should be thrown, or <c>false</c> if exceptions are silently captured</param>
        public static void DisposeAllFields<T>(object item, bool throwExceptions)
            where T : IDisposable
        {
            var typechain = new List<Type>();
            var cur = item.GetType();
            var exceptions = new List<Exception>();

            while (cur != null && cur != typeof(object))
            {
                typechain.Add(cur);
                cur = cur.BaseType;
            }

            var fields =
                typechain.SelectMany(x =>
                    x.GetFields(System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.FlattenHierarchy)
                ).Distinct().Where(x => x.FieldType.IsAssignableFrom(typeof(T)));

            foreach (var p in fields)
                try
                {
                    var val = p.GetValue(item);
                    if (val != null)
                        ((T)val).Dispose();
                }
                catch (Exception ex)
                {
                    if (throwExceptions)
                        exceptions.Add(ex);
                }

            if (exceptions.Count > 0)
                throw new AggregateException(exceptions);
        }

        public async Task WriteResults(IBasicResults result)
        {
            if (IsDisposed)
                return;

            if (m_connection != null && result != null)
            {
                if (result is BasicResults basicResults)
                {
                    basicResults.FlushLog(this);
                    if (basicResults.EndTime.Ticks == 0)
                        basicResults.EndTime = DateTime.UtcNow;
                }

                var serializer = new JsonFormatSerializer();
                await LogMessage("Result",
                    serializer.SerializeResults(result),
                    null,
                    null
                );
            }
        }

        /// <summary>
        /// The current index into the path prefix buffer
        /// </summary>
        private int m_pathPrefixIndex = 0;
        /// <summary>
        /// The path prefix lookup list
        /// </summary>
        private readonly KeyValuePair<string, long>[] m_pathPrefixLookup = new KeyValuePair<string, long>[5];

        /// <summary>
        /// Gets the path prefix ID, optionally creating it in the process.
        /// </summary>
        /// <returns>The path prefix ID.</returns>
        /// <param name="prefix">The path to get the prefix for.</param>
        /// <param name="transaction">The transaction to use for insertion, or null for no transaction</param>
        public async Task<long> GetOrCreatePathPrefix(string prefix, SqliteTransaction transaction)
        {
            // Ring-buffer style lookup
            for (var i = 0; i < m_pathPrefixLookup.Length; i++)
            {
                var ix = (i + m_pathPrefixIndex) % m_pathPrefixLookup.Length;
                if (string.Equals(m_pathPrefixLookup[ix].Key, prefix, StringComparison.Ordinal))
                    return m_pathPrefixLookup[ix].Value;
            }

            m_findpathprefixCommand.Transaction = transaction;
            m_findpathprefixCommand.SetParameterValue("@Prefix", prefix);
            var id = await m_findpathprefixCommand.ExecuteScalarInt64Async();

            if (id < 0)
            {
                m_insertpathprefixCommand.SetParameterValue("@Prefix", prefix);
                m_insertpathprefixCommand.Transaction = transaction;
                id = await m_insertpathprefixCommand.ExecuteScalarInt64Async();
            }

            m_pathPrefixIndex = (m_pathPrefixIndex + 1) % m_pathPrefixLookup.Length;
            m_pathPrefixLookup[m_pathPrefixIndex] = new KeyValuePair<string, long>(prefix, id);

            return id;
        }

        /// <summary>
        /// The path separators on this system
        /// </summary>
        private static readonly char[] _pathseparators = [
            Path.DirectorySeparatorChar,
            Path.AltDirectorySeparatorChar,
        ];

        /// <summary>
        /// Helper method that splits a path on the last path separator
        /// </summary>
        /// <returns>The prefix and name.</returns>
        /// <param name="path">The path to split.</param>
        public static KeyValuePair<string, string> SplitIntoPrefixAndName(string path)
        {
            if (string.IsNullOrEmpty(path))
                throw new ArgumentException($"Invalid path: {path}", nameof(path));

            int nLast = path.TrimEnd(_pathseparators).LastIndexOfAny(_pathseparators);
            if (nLast >= 0)
                return new KeyValuePair<string, string>(path.Substring(0, nLast + 1), path.Substring(nLast + 1));

            return new KeyValuePair<string, string>(string.Empty, path);
        }
    }

    /// <summary>
    /// Defines the backups types
    /// </summary>
    public static class BackupType
    {
        public const int PARTIAL_BACKUP = 0;
        public const int FULL_BACKUP = 1;
    }
}