Emby.Server.Implementations/Session/SessionManager.cs

@@ -256,7 +256,7 @@ namespace Emby.Server.Implementations.Session
             ArgumentException.ThrowIfNullOrEmpty(deviceId);
 
             var activityDate = DateTime.UtcNow;
-            var session = GetSessionInfo(appName, appVersion, deviceId, deviceName, remoteEndPoint, user);
+            var session = await GetSessionInfo(appName, appVersion, deviceId, deviceName, remoteEndPoint, user).ConfigureAwait(false);
             var lastActivityDate = session.LastActivityDate;
             session.LastActivityDate = activityDate;
 
@@ -491,7 +491,7 @@ namespace Emby.Server.Implementations.Session
         /// <param name="remoteEndPoint">The remote end point.</param>
         /// <param name="user">The user.</param>
         /// <returns>SessionInfo.</returns>
-        private SessionInfo GetSessionInfo(
+        private async Task<SessionInfo> GetSessionInfo(
             string appName,
             string appVersion,
             string deviceId,
@@ -504,7 +504,7 @@ namespace Emby.Server.Implementations.Session
             ArgumentException.ThrowIfNullOrEmpty(deviceId);
 
             var key = GetSessionKey(appName, deviceId, user?.Id ?? Guid.Empty);
-            SessionInfo newSession = CreateSessionInfo(key, appName, appVersion, deviceId, deviceName, remoteEndPoint, user);
+            SessionInfo newSession = await CreateSessionInfo(key, appName, appVersion, deviceId, deviceName, remoteEndPoint, user).ConfigureAwait(false);
             SessionInfo sessionInfo = _activeConnections.GetOrAdd(key, newSession);
             if (ReferenceEquals(newSession, sessionInfo))
             {
@@ -532,7 +532,7 @@ namespace Emby.Server.Implementations.Session
             return sessionInfo;
         }
 
-        private SessionInfo CreateSessionInfo(
+        private async Task<SessionInfo> CreateSessionInfo(
             string key,
             string appName,
             string appVersion,
@@ -562,7 +562,7 @@ namespace Emby.Server.Implementations.Session
                 deviceName = "Network Device";
             }
 
-            var deviceOptions = _deviceManager.GetDeviceOptions(deviceId) ?? new()
+            var deviceOptions = await _deviceManager.GetDeviceOptions(deviceId).ConfigureAwait(false) ?? new()
             {
                 DeviceId = deviceId
             };
@@ -1768,12 +1768,12 @@ namespace Emby.Server.Implementations.Session
             // This should be validated above, but if it isn't don't delete all tokens.
             ArgumentException.ThrowIfNullOrEmpty(deviceId);
 
-            var existing = _deviceManager.GetDevices(
+            var existing = (await _deviceManager.GetDevices(
                 new DeviceQuery
                 {
                     DeviceId = deviceId,
                     UserId = user.Id
-                }).Items;
+                }).ConfigureAwait(false)).Items;
 
             foreach (var auth in existing)
             {
@@ -1801,12 +1801,12 @@ namespace Emby.Server.Implementations.Session
 
             ArgumentException.ThrowIfNullOrEmpty(accessToken);
 
-            var existing = _deviceManager.GetDevices(
+            var existing = (await _deviceManager.GetDevices(
                 new DeviceQuery
                 {
                     Limit = 1,
                     AccessToken = accessToken
-                }).Items;
+                }).ConfigureAwait(false)).Items;
 
             if (existing.Count > 0)
             {
@@ -1845,10 +1845,10 @@ namespace Emby.Server.Implementations.Session
         {
             CheckDisposed();
 
-            var existing = _deviceManager.GetDevices(new DeviceQuery
+            var existing = await _deviceManager.GetDevices(new DeviceQuery
             {
                 UserId = userId
-            });
+            }).ConfigureAwait(false);
 
             foreach (var info in existing.Items)
             {
@@ -2045,11 +2045,11 @@ namespace Emby.Server.Implementations.Session
         /// <inheritdoc />
         public async Task<SessionInfo> GetSessionByAuthenticationToken(string token, string deviceId, string remoteEndpoint)
         {
-            var items = _deviceManager.GetDevices(new DeviceQuery
+            var items = (await _deviceManager.GetDevices(new DeviceQuery
             {
                 AccessToken = token,
                 Limit = 1
-            }).Items;
+            }).ConfigureAwait(false)).Items;
 
             if (items.Count == 0)
             {

Jellyfin.Api/Controllers/DevicesController.cs

@@ -50,10 +50,10 @@ public class DevicesController : BaseJellyfinApiController
     /// <returns>An <see cref="OkResult"/> containing the list of devices.</returns>
     [HttpGet]
     [ProducesResponseType(StatusCodes.Status200OK)]
-    public ActionResult<QueryResult<DeviceInfoDto>> GetDevices([FromQuery] Guid? userId)
+    public async Task<ActionResult<QueryResult<DeviceInfoDto>>> GetDevices([FromQuery] Guid? userId)
     {
         userId = RequestHelpers.GetUserId(User, userId);
-        return _deviceManager.GetDevicesForUser(userId);
+        return await _deviceManager.GetDevicesForUser(userId).ConfigureAwait(false);
     }
 
     /// <summary>
@@ -66,9 +66,9 @@ public class DevicesController : BaseJellyfinApiController
     [HttpGet("Info")]
     [ProducesResponseType(StatusCodes.Status200OK)]
     [ProducesResponseType(StatusCodes.Status404NotFound)]
-    public ActionResult<DeviceInfoDto> GetDeviceInfo([FromQuery, Required] string id)
+    public async Task<ActionResult<DeviceInfoDto>> GetDeviceInfo([FromQuery, Required] string id)
     {
-        var deviceInfo = _deviceManager.GetDevice(id);
+        var deviceInfo = await _deviceManager.GetDevice(id).ConfigureAwait(false);
         if (deviceInfo is null)
         {
             return NotFound();
@@ -87,9 +87,9 @@ public class DevicesController : BaseJellyfinApiController
     [HttpGet("Options")]
     [ProducesResponseType(StatusCodes.Status200OK)]
     [ProducesResponseType(StatusCodes.Status404NotFound)]
-    public ActionResult<DeviceOptionsDto> GetDeviceOptions([FromQuery, Required] string id)
+    public async Task<ActionResult<DeviceOptionsDto>> GetDeviceOptions([FromQuery, Required] string id)
     {
-        var deviceInfo = _deviceManager.GetDeviceOptions(id);
+        var deviceInfo = await _deviceManager.GetDeviceOptions(id).ConfigureAwait(false);
         if (deviceInfo is null)
         {
             return NotFound();
@@ -127,7 +127,12 @@ public class DevicesController : BaseJellyfinApiController
     [ProducesResponseType(StatusCodes.Status400BadRequest)]
     public async Task<ActionResult> DeleteDevice([FromQuery] string[] id)
     {
-        var devices = id.Select(_deviceManager.GetDevice).ToArray();
+        var devices = new List<DeviceInfoDto?>(id.Length);
+        foreach (var deviceId in id)
+        {
+            devices.Add(await _deviceManager.GetDevice(deviceId).ConfigureAwait(false));
+        }
+
         if (devices.Any(f => f is null))
         {
             return BadRequest();
@@ -135,7 +140,7 @@ public class DevicesController : BaseJellyfinApiController
 
         foreach (var device in devices)
         {
-            var sessions = _deviceManager.GetDevices(new DeviceQuery { DeviceId = device!.Id });
+            var sessions = await _deviceManager.GetDevices(new DeviceQuery { DeviceId = device!.Id }).ConfigureAwait(false);
 
             foreach (var session in sessions.Items)
             {

Jellyfin.Server.Implementations/Devices/DeviceManager.cs

@@ -31,8 +31,6 @@ namespace Jellyfin.Server.Implementations.Devices
         private readonly IDbContextFactory<JellyfinDbContext> _dbProvider;
         private readonly IUserManager _userManager;
         private readonly ConcurrentDictionary<string, ClientCapabilities> _capabilitiesMap = new();
-        private readonly ConcurrentDictionary<int, Device> _devices;
-        private readonly ConcurrentDictionary<string, DeviceOptions> _deviceOptions;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="DeviceManager"/> class.
@@ -43,23 +41,6 @@ namespace Jellyfin.Server.Implementations.Devices
         {
             _dbProvider = dbProvider;
             _userManager = userManager;
-            _devices = new ConcurrentDictionary<int, Device>();
-            _deviceOptions = new ConcurrentDictionary<string, DeviceOptions>();
-
-            using var dbContext = _dbProvider.CreateDbContext();
-            foreach (var device in dbContext.Devices
-                         .OrderBy(d => d.Id)
-                         .AsEnumerable())
-            {
-                _devices.TryAdd(device.Id, device);
-            }
-
-            foreach (var deviceOption in dbContext.DeviceOptions
-                         .OrderBy(d => d.Id)
-                         .AsEnumerable())
-            {
-                _deviceOptions.TryAdd(deviceOption.DeviceId, deviceOption);
-            }
         }
 
         /// <inheritdoc />
@@ -89,8 +70,6 @@ namespace Jellyfin.Server.Implementations.Devices
                 await dbContext.SaveChangesAsync().ConfigureAwait(false);
             }
 
-            _deviceOptions[deviceId] = deviceOptions;
-
             DeviceOptionsUpdated?.Invoke(this, new GenericEventArgs<Tuple<string, DeviceOptions>>(new Tuple<string, DeviceOptions>(deviceId, deviceOptions)));
         }
 
@@ -102,21 +81,24 @@ namespace Jellyfin.Server.Implementations.Devices
             {
                 dbContext.Devices.Add(device);
                 await dbContext.SaveChangesAsync().ConfigureAwait(false);
-                _devices.TryAdd(device.Id, device);
             }
 
             return device;
         }
 
         /// <inheritdoc />
-        public DeviceOptionsDto? GetDeviceOptions(string deviceId)
+        public async Task<DeviceOptionsDto?> GetDeviceOptions(string deviceId)
         {
-            if (_deviceOptions.TryGetValue(deviceId, out var deviceOptions))
+            var dbContext = await _dbProvider.CreateDbContextAsync().ConfigureAwait(false);
+            await using (dbContext.ConfigureAwait(false))
             {
-                return ToDeviceOptionsDto(deviceOptions);
-            }
+                var deviceOptions = await dbContext.DeviceOptions
+                    .AsNoTracking()
+                    .FirstOrDefaultAsync(dev => dev.DeviceId == deviceId)
+                    .ConfigureAwait(false);
 
-            return null;
+                return deviceOptions is null ? null : ToDeviceOptionsDto(deviceOptions);
+            }
         }
 
         /// <inheritdoc />
@@ -133,43 +115,79 @@ namespace Jellyfin.Server.Implementations.Devices
         }
 
         /// <inheritdoc />
-        public DeviceInfoDto? GetDevice(string id)
+        public async Task<DeviceInfoDto?> GetDevice(string id)
         {
-            var device = _devices.Values.Where(d => d.DeviceId == id).OrderByDescending(d => d.DateLastActivity).FirstOrDefault();
-            _deviceOptions.TryGetValue(id, out var deviceOption);
+            var dbContext = await _dbProvider.CreateDbContextAsync().ConfigureAwait(false);
+            await using (dbContext.ConfigureAwait(false))
+            {
+                var device = await dbContext.Devices
+                    .AsNoTracking()
+                    .Where(d => d.DeviceId == id)
+                    .OrderByDescending(d => d.DateLastActivity)
+                    .FirstOrDefaultAsync()
+                    .ConfigureAwait(false);
 
-            var deviceInfo = device is null ? null : ToDeviceInfo(device, deviceOption);
-            return deviceInfo is null ? null : ToDeviceInfoDto(deviceInfo);
+                if (device is null)
+                {
+                    return null;
+                }
+
+                var deviceOption = await dbContext.DeviceOptions
+                    .AsNoTracking()
+                    .FirstOrDefaultAsync(dev => dev.DeviceId == id)
+                    .ConfigureAwait(false);
+
+                return ToDeviceInfoDto(ToDeviceInfo(device, deviceOption));
+            }
         }
 
         /// <inheritdoc />
-        public QueryResult<Device> GetDevices(DeviceQuery query)
+        public async Task<QueryResult<Device>> GetDevices(DeviceQuery query)
         {
-            IEnumerable<Device> devices = _devices.Values
-                .Where(device => !query.UserId.HasValue || device.UserId.Equals(query.UserId.Value))
-                .Where(device => query.DeviceId is null || device.DeviceId == query.DeviceId)
-                .Where(device => query.AccessToken is null || device.AccessToken == query.AccessToken)
-                .OrderBy(d => d.Id)
-                .ToList();
-            var count = devices.Count();
-
-            if (query.Skip.HasValue)
+            var dbContext = await _dbProvider.CreateDbContextAsync().ConfigureAwait(false);
+            await using (dbContext.ConfigureAwait(false))
             {
-                devices = devices.Skip(query.Skip.Value);
-            }
+                IQueryable<Device> filtered = dbContext.Devices.AsNoTracking();
 
-            if (query.Limit.HasValue && query.Limit.Value > 0)
-            {
-                devices = devices.Take(query.Limit.Value);
-            }
+                if (query.UserId.HasValue)
+                {
+                    filtered = filtered.Where(device => device.UserId.Equals(query.UserId.Value));
+                }
 
-            return new QueryResult<Device>(query.Skip, count, devices.ToList());
+                if (query.DeviceId is not null)
+                {
+                    filtered = filtered.Where(device => device.DeviceId == query.DeviceId);
+                }
+
+                if (query.AccessToken is not null)
+                {
+                    filtered = filtered.Where(device => device.AccessToken == query.AccessToken);
+                }
+
+                // Every filter is an exact match on an indexed column and the table holds one row per
+                // user and device, so paging the materialised set costs less than a second round trip.
+                var matched = await filtered.OrderBy(d => d.Id).ToListAsync().ConfigureAwait(false);
+
+                IEnumerable<Device> devices = matched;
+
+                if (query.Skip.HasValue)
+                {
+                    devices = devices.Skip(query.Skip.Value);
+                }
+
+                if (query.Limit.HasValue && query.Limit.Value > 0)
+                {
+                    devices = devices.Take(query.Limit.Value);
+                }
+
+                return new QueryResult<Device>(query.Skip, matched.Count, devices.ToList());
+            }
         }
 
         /// <inheritdoc />
-        public QueryResult<DeviceInfo> GetDeviceInfos(DeviceQuery query)
+        public async Task<QueryResult<DeviceInfo>> GetDeviceInfos(DeviceQuery query)
         {
-            var devices = GetDevices(query);
+            var devices = await GetDevices(query).ConfigureAwait(false);
 
             return new QueryResult<DeviceInfo>(
                 devices.StartIndex,
@@ -178,38 +196,49 @@ namespace Jellyfin.Server.Implementations.Devices
         }
 
         /// <inheritdoc />
-        public QueryResult<DeviceInfoDto> GetDevicesForUser(Guid? userId)
+        public async Task<QueryResult<DeviceInfoDto>> GetDevicesForUser(Guid? userId)
         {
-            IEnumerable<Device> devices = _devices.Values
-                .OrderByDescending(d => d.DateLastActivity)
-                .ThenBy(d => d.DeviceId);
-
-            if (!userId.IsNullOrEmpty())
+            var dbContext = await _dbProvider.CreateDbContextAsync().ConfigureAwait(false);
+            await using (dbContext.ConfigureAwait(false))
             {
-                var user = _userManager.GetUserById(userId.Value);
-                if (user is null)
+                IEnumerable<Device> devices = await dbContext.Devices
+                    .AsNoTracking()
+                    .OrderByDescending(d => d.DateLastActivity)
+                    .ThenBy(d => d.DeviceId)
+                    .ToListAsync()
+                    .ConfigureAwait(false);
+
+                if (!userId.IsNullOrEmpty())
                 {
-                    throw new ResourceNotFoundException();
+                    var user = _userManager.GetUserById(userId.Value);
+                    if (user is null)
+                    {
+                        throw new ResourceNotFoundException();
+                    }
+
+                    devices = devices.Where(i => CanAccessDevice(user, i.DeviceId));
                 }
 
-                devices = devices.Where(i => CanAccessDevice(user, i.DeviceId));
+                var options = await dbContext.DeviceOptions
+                    .AsNoTracking()
+                    .ToDictionaryAsync(dev => dev.DeviceId)
+                    .ConfigureAwait(false);
+
+                var array = devices.Select(device =>
+                    {
+                        options.TryGetValue(device.DeviceId, out var option);
+                        return ToDeviceInfo(device, option);
+                    })
+                    .Select(ToDeviceInfoDto)
+                    .ToArray();
+
+                return new QueryResult<DeviceInfoDto>(array);
             }
-
-            var array = devices.Select(device =>
-                {
-                    _deviceOptions.TryGetValue(device.DeviceId, out var option);
-                    return ToDeviceInfo(device, option);
-                })
-                .Select(ToDeviceInfoDto)
-                .ToArray();
-
-            return new QueryResult<DeviceInfoDto>(array);
         }
 
         /// <inheritdoc />
         public async Task DeleteDevice(Device device)
         {
-            _devices.TryRemove(device.Id, out _);
             var dbContext = await _dbProvider.CreateDbContextAsync().ConfigureAwait(false);
             await using (dbContext.ConfigureAwait(false))
             {
@@ -229,8 +258,6 @@ namespace Jellyfin.Server.Implementations.Devices
                 dbContext.Devices.Update(device);
                 await dbContext.SaveChangesAsync().ConfigureAwait(false);
             }
-
-            _devices[device.Id] = device;
         }
 
         /// <inheritdoc />

Jellyfin.Server.Implementations/Security/AuthorizationContext.cs

@@ -126,95 +126,95 @@ namespace Jellyfin.Server.Implementations.Security
                 return authInfo;
             }
 
+            var device = (await _deviceManager.GetDevices(
+                new DeviceQuery { AccessToken = token }).ConfigureAwait(false)).Items.FirstOrDefault();
+
+            if (device is not null)
+            {
+                authInfo.IsAuthenticated = true;
+                var updateToken = false;
+
+                // TODO: Remove these checks for IsNullOrWhiteSpace
+                if (string.IsNullOrWhiteSpace(authInfo.Client))
+                {
+                    authInfo.Client = device.AppName;
+                }
+
+                if (string.IsNullOrWhiteSpace(authInfo.DeviceId))
+                {
+                    authInfo.DeviceId = device.DeviceId;
+                }
+
+                // Temporary. TODO - allow clients to specify that the token has been shared with a casting device
+                var allowTokenInfoUpdate = !authInfo.Client.Contains("chromecast", StringComparison.OrdinalIgnoreCase);
+
+                if (string.IsNullOrWhiteSpace(authInfo.Device))
+                {
+                    authInfo.Device = device.DeviceName;
+                }
+                else if (!string.Equals(authInfo.Device, device.DeviceName, StringComparison.OrdinalIgnoreCase))
+                {
+                    if (allowTokenInfoUpdate)
+                    {
+                        updateToken = true;
+                        device.DeviceName = authInfo.Device;
+                    }
+                }
+
+                if (string.IsNullOrWhiteSpace(authInfo.Version))
+                {
+                    authInfo.Version = device.AppVersion;
+                }
+                else if (!string.Equals(authInfo.Version, device.AppVersion, StringComparison.OrdinalIgnoreCase))
+                {
+                    if (allowTokenInfoUpdate)
+                    {
+                        updateToken = true;
+                        device.AppVersion = authInfo.Version;
+                    }
+                }
+
+                if ((DateTime.UtcNow - device.DateLastActivity).TotalMinutes > 3)
+                {
+                    device.DateLastActivity = DateTime.UtcNow;
+                    updateToken = true;
+                }
+
+                authInfo.User = _userManager.GetUserById(device.UserId);
+
+                if (updateToken)
+                {
+                    await _deviceManager.UpdateDevice(device).ConfigureAwait(false);
+                }
+
+                return authInfo;
+            }
+
             var dbContext = await _jellyfinDbProvider.CreateDbContextAsync().ConfigureAwait(false);
             await using (dbContext.ConfigureAwait(false))
             {
-                var device = _deviceManager.GetDevices(
-                    new DeviceQuery { AccessToken = token }).Items.FirstOrDefault();
-
-                if (device is not null)
+                var key = await dbContext.ApiKeys.FirstOrDefaultAsync(apiKey => apiKey.AccessToken == token).ConfigureAwait(false);
+                if (key is not null)
                 {
                     authInfo.IsAuthenticated = true;
-                    var updateToken = false;
-
-                    // TODO: Remove these checks for IsNullOrWhiteSpace
-                    if (string.IsNullOrWhiteSpace(authInfo.Client))
-                    {
-                        authInfo.Client = device.AppName;
-                    }
-
+                    authInfo.Client = key.Name;
+                    authInfo.Token = key.AccessToken;
                     if (string.IsNullOrWhiteSpace(authInfo.DeviceId))
                     {
-                        authInfo.DeviceId = device.DeviceId;
+                        authInfo.DeviceId = _serverApplicationHost.SystemId;
                     }
 
-                    // Temporary. TODO - allow clients to specify that the token has been shared with a casting device
-                    var allowTokenInfoUpdate = !authInfo.Client.Contains("chromecast", StringComparison.OrdinalIgnoreCase);
-
                     if (string.IsNullOrWhiteSpace(authInfo.Device))
                     {
-                        authInfo.Device = device.DeviceName;
-                    }
-                    else if (!string.Equals(authInfo.Device, device.DeviceName, StringComparison.OrdinalIgnoreCase))
-                    {
-                        if (allowTokenInfoUpdate)
-                        {
-                            updateToken = true;
-                            device.DeviceName = authInfo.Device;
-                        }
+                        authInfo.Device = _serverApplicationHost.Name;
                     }
 
                     if (string.IsNullOrWhiteSpace(authInfo.Version))
                     {
-                        authInfo.Version = device.AppVersion;
-                    }
-                    else if (!string.Equals(authInfo.Version, device.AppVersion, StringComparison.OrdinalIgnoreCase))
-                    {
-                        if (allowTokenInfoUpdate)
-                        {
-                            updateToken = true;
-                            device.AppVersion = authInfo.Version;
-                        }
+                        authInfo.Version = _serverApplicationHost.ApplicationVersionString;
                     }
 
-                    if ((DateTime.UtcNow - device.DateLastActivity).TotalMinutes > 3)
-                    {
-                        device.DateLastActivity = DateTime.UtcNow;
-                        updateToken = true;
-                    }
-
-                    authInfo.User = _userManager.GetUserById(device.UserId);
-
-                    if (updateToken)
-                    {
-                        await _deviceManager.UpdateDevice(device).ConfigureAwait(false);
-                    }
-                }
-                else
-                {
-                    var key = await dbContext.ApiKeys.FirstOrDefaultAsync(apiKey => apiKey.AccessToken == token).ConfigureAwait(false);
-                    if (key is not null)
-                    {
-                        authInfo.IsAuthenticated = true;
-                        authInfo.Client = key.Name;
-                        authInfo.Token = key.AccessToken;
-                        if (string.IsNullOrWhiteSpace(authInfo.DeviceId))
-                        {
-                            authInfo.DeviceId = _serverApplicationHost.SystemId;
-                        }
-
-                        if (string.IsNullOrWhiteSpace(authInfo.Device))
-                        {
-                            authInfo.Device = _serverApplicationHost.Name;
-                        }
-
-                        if (string.IsNullOrWhiteSpace(authInfo.Version))
-                        {
-                            authInfo.Version = _serverApplicationHost.ApplicationVersionString;
-                        }
-
-                        authInfo.IsApiKey = true;
-                    }
+                    authInfo.IsApiKey = true;
                 }
 
                 return authInfo;

Jellyfin.Server.Implementations/Users/DeviceAccessHost.cs

@@ -61,10 +61,10 @@ public sealed class DeviceAccessHost : IHostedService
 
     private async Task UpdateDeviceAccess(User user)
     {
-        var existing = _deviceManager.GetDevices(new DeviceQuery
+        var existing = (await _deviceManager.GetDevices(new DeviceQuery
         {
             UserId = user.Id
-        }).Items;
+        }).ConfigureAwait(false)).Items;
 
         foreach (var device in existing)
         {

MediaBrowser.Controller/Devices/IDeviceManager.cs

@@ -47,29 +47,29 @@ public interface IDeviceManager
     /// Gets the device information.
     /// </summary>
     /// <param name="id">The identifier.</param>
-    /// <returns>DeviceInfoDto.</returns>
-    DeviceInfoDto? GetDevice(string id);
+    /// <returns>A <see cref="Task"/> representing the retrieval of the device information.</returns>
+    Task<DeviceInfoDto?> GetDevice(string id);
 
     /// <summary>
     /// Gets devices based on the provided query.
     /// </summary>
     /// <param name="query">The device query.</param>
     /// <returns>A <see cref="Task{QueryResult}"/> representing the retrieval of the devices.</returns>
-    QueryResult<Device> GetDevices(DeviceQuery query);
+    Task<QueryResult<Device>> GetDevices(DeviceQuery query);
 
     /// <summary>
     /// Gets device information based on the provided query.
     /// </summary>
     /// <param name="query">The device query.</param>
     /// <returns>A <see cref="Task{QueryResult}"/> representing the retrieval of the device information.</returns>
-    QueryResult<DeviceInfo> GetDeviceInfos(DeviceQuery query);
+    Task<QueryResult<DeviceInfo>> GetDeviceInfos(DeviceQuery query);
 
     /// <summary>
     /// Gets the device information.
     /// </summary>
     /// <param name="userId">The user's id, or <c>null</c>.</param>
-    /// <returns>IEnumerable&lt;DeviceInfoDto&gt;.</returns>
-    QueryResult<DeviceInfoDto> GetDevicesForUser(Guid? userId);
+    /// <returns>A <see cref="Task{QueryResult}"/> representing the retrieval of the device information.</returns>
+    Task<QueryResult<DeviceInfoDto>> GetDevicesForUser(Guid? userId);
 
     /// <summary>
     /// Deletes a device.
@@ -105,8 +105,8 @@ public interface IDeviceManager
     /// Gets the options of a device.
     /// </summary>
     /// <param name="deviceId">The device id.</param>
-    /// <returns><see cref="DeviceOptions"/> of the device.</returns>
-    DeviceOptionsDto? GetDeviceOptions(string deviceId);
+    /// <returns>A <see cref="Task"/> representing the retrieval of the <see cref="DeviceOptions"/> of the device.</returns>
+    Task<DeviceOptionsDto?> GetDeviceOptions(string deviceId);
 
     /// <summary>
     /// Gets the dto for client capabilities.

tests/Jellyfin.Server.Tests/Devices/DeviceManagerReplicaTests.cs

@@ -0,0 +1,197 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Jellyfin.Data.Queries;
+using Jellyfin.Database.Implementations;
+using Jellyfin.Database.Implementations.DbConfiguration;
+using Jellyfin.Database.Implementations.Entities;
+using Jellyfin.Database.Implementations.Entities.Security;
+using Jellyfin.Database.Implementations.Locking;
+using Jellyfin.Database.Providers.PostgreSQL;
+using Jellyfin.Server.Implementations.Devices;
+using Jellyfin.Server.Tests.Migrations;
+using MediaBrowser.Controller.Library;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using Npgsql;
+using Xunit;
+
+namespace Jellyfin.Server.Tests.Devices;
+
+/// <summary>
+/// Two independently constructed <see cref="DeviceManager"/> instances over one PostgreSQL database are the
+/// in-process stand-in for two replicas sharing one database: what either of them writes, the other has to
+/// see on its very next read.
+/// </summary>
+[Trait("Category", "RequiresDocker")]
+public sealed class DeviceManagerReplicaTests : IAsyncLifetime
+{
+    private PostgreSqlTestServer _server = null!;
+
+    /// <inheritdoc/>
+    public async ValueTask InitializeAsync()
+    {
+        _server = await PostgreSqlTestServer.StartAsync().ConfigureAwait(false);
+    }
+
+    /// <inheritdoc/>
+    public async ValueTask DisposeAsync()
+    {
+        await _server.DisposeAsync().ConfigureAwait(false);
+    }
+
+    /// <summary>
+    /// A client that logs in against one replica has to be authenticated by every other replica that was
+    /// already running when the token was minted - a rolling update or a scale-up must not 401 it.
+    /// </summary>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [Fact]
+    public async Task TokenMintedOnOneReplica_IsValidOnAnother()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var connectionString = await _server.CreateDatabaseAsync("device_replica_create", cancellationToken);
+
+        await using var dataSource = new NpgsqlDataSourceBuilder(connectionString).Build();
+        var user = await CreateSchemaWithUserAsync(dataSource, cancellationToken);
+
+        // Both replicas start before the login, so neither has the device in hand when it is created.
+        var replicaA = CreateManager(dataSource, user);
+        var replicaB = CreateManager(dataSource, user);
+
+        var device = await replicaA.CreateDevice(new Device(user.Id, "Jellyfin Web", "1.0.0", "Living Room TV", "device-1"));
+
+        var seenByB = await replicaB.GetDevices(new DeviceQuery { AccessToken = device.AccessToken });
+
+        Assert.Equal(device.Id, Assert.Single(seenByB.Items).Id);
+        Assert.Equal(user.Id, seenByB.Items[0].UserId);
+    }
+
+    /// <summary>
+    /// Revocation has to propagate at least as fast as creation: a token logged out on one replica must not
+    /// still authenticate on another.
+    /// </summary>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [Fact]
+    public async Task TokenRevokedOnOneReplica_IsInvalidOnAnother()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var connectionString = await _server.CreateDatabaseAsync("device_replica_revoke", cancellationToken);
+
+        await using var dataSource = new NpgsqlDataSourceBuilder(connectionString).Build();
+        var user = await CreateSchemaWithUserAsync(dataSource, cancellationToken);
+
+        var replicaA = CreateManager(dataSource, user);
+        var device = await replicaA.CreateDevice(new Device(user.Id, "Jellyfin Web", "1.0.0", "Living Room TV", "device-1"));
+
+        // Replica B comes up after the login, so it starts out agreeing that the token is valid.
+        var replicaB = CreateManager(dataSource, user);
+        Assert.Single((await replicaB.GetDevices(new DeviceQuery { AccessToken = device.AccessToken })).Items);
+
+        await replicaA.DeleteDevice(device);
+
+        Assert.Empty((await replicaB.GetDevices(new DeviceQuery { AccessToken = device.AccessToken })).Items);
+    }
+
+    /// <summary>
+    /// A device renamed on one replica has to be reported under its new name by the others, and the rename has
+    /// to survive being read back through a replica that never saw the write.
+    /// </summary>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [Fact]
+    public async Task DeviceOptionsWrittenOnOneReplica_AreReadOnAnother()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var connectionString = await _server.CreateDatabaseAsync("device_replica_options", cancellationToken);
+
+        await using var dataSource = new NpgsqlDataSourceBuilder(connectionString).Build();
+        var user = await CreateSchemaWithUserAsync(dataSource, cancellationToken);
+
+        var replicaA = CreateManager(dataSource, user);
+        var replicaB = CreateManager(dataSource, user);
+
+        await replicaA.CreateDevice(new Device(user.Id, "Jellyfin Web", "1.0.0", "Living Room TV", "device-1"));
+        await replicaA.UpdateDeviceOptions("device-1", "Kitchen TV");
+
+        var options = await replicaB.GetDeviceOptions("device-1");
+        Assert.Equal("Kitchen TV", options?.CustomName);
+
+        var info = await replicaB.GetDevice("device-1");
+        Assert.Equal("Kitchen TV", info?.CustomName);
+    }
+
+    /// <summary>
+    /// Activity written by the replica serving the request has to be visible to the others, because the next
+    /// request from the same client can land anywhere.
+    /// </summary>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [Fact]
+    public async Task DeviceUpdatedOnOneReplica_IsReadOnAnother()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var connectionString = await _server.CreateDatabaseAsync("device_replica_update", cancellationToken);
+
+        await using var dataSource = new NpgsqlDataSourceBuilder(connectionString).Build();
+        var user = await CreateSchemaWithUserAsync(dataSource, cancellationToken);
+
+        var replicaA = CreateManager(dataSource, user);
+        var replicaB = CreateManager(dataSource, user);
+
+        var device = await replicaA.CreateDevice(new Device(user.Id, "Jellyfin Web", "1.0.0", "Living Room TV", "device-1"));
+        device.AppVersion = "2.0.0";
+        await replicaA.UpdateDevice(device);
+
+        var seenByB = Assert.Single((await replicaB.GetDevices(new DeviceQuery { DeviceId = "device-1" })).Items);
+        Assert.Equal("2.0.0", seenByB.AppVersion);
+    }
+
+    private static DeviceManager CreateManager(NpgsqlDataSource dataSource, User user)
+    {
+        var userManager = new Mock<IUserManager>();
+        userManager.Setup(manager => manager.GetUserById(user.Id)).Returns(user);
+        return new DeviceManager(new DataSourceContextFactory(dataSource), userManager.Object);
+    }
+
+    private static async Task<User> CreateSchemaWithUserAsync(NpgsqlDataSource dataSource, CancellationToken cancellationToken)
+    {
+        var context = CreateContext(dataSource);
+        await using (context.ConfigureAwait(false))
+        {
+            await context.Database.EnsureCreatedAsync(cancellationToken).ConfigureAwait(false);
+
+            var user = new User("replica-user", "provider", "provider");
+            context.Users.Add(user);
+            await context.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
+
+            return user;
+        }
+    }
+
+    private static JellyfinDbContext CreateContext(NpgsqlDataSource dataSource)
+    {
+        var optionsBuilder = new DbContextOptionsBuilder<JellyfinDbContext>();
+        var provider = new PostgreSqlDatabaseProvider(dataSource);
+        provider.Initialise(optionsBuilder, new DatabaseConfigurationOptions { DatabaseType = "PostgreSQL" });
+        return new JellyfinDbContext(
+            optionsBuilder.Options,
+            NullLogger<JellyfinDbContext>.Instance,
+            provider,
+            new NoLockBehavior(NullLogger<NoLockBehavior>.Instance));
+    }
+
+    /// <summary>
+    /// Hands every <see cref="DeviceManager"/> its own context over the one shared database, the way the
+    /// pooled factory does in the server.
+    /// </summary>
+    private sealed class DataSourceContextFactory : IDbContextFactory<JellyfinDbContext>
+    {
+        private readonly NpgsqlDataSource _dataSource;
+
+        public DataSourceContextFactory(NpgsqlDataSource dataSource)
+        {
+            _dataSource = dataSource;
+        }
+
+        public JellyfinDbContext CreateDbContext() => CreateContext(_dataSource);
+    }
+}