Make the /Persons de-duplication use an index instead of grouping the table

Jellyfin.Server.Implementations/Item/PeopleRepository.cs

@@ -33,6 +33,7 @@ public class PeopleRepository(IDbContextFactory<JellyfinDbContext> dbProvider, I
     {
         using var context = _dbProvider.CreateDbContext();
         var dbQuery = TranslateQuery(context.Peoples.AsNoTracking(), context, filter);
+        int? distinctNameCount = null;
 
         // Include PeopleBaseItemMap
         if (!filter.ItemId.IsEmpty())
@@ -46,17 +47,17 @@ public class PeopleRepository(IDbContextFactory<JellyfinDbContext> dbProvider, I
         {
             // The Peoples table has one row per (Name, PersonType), so the same person can
             // appear multiple times (e.g. as Actor and GuestStar). Collapse to one row per
-            // name so /Persons doesn't return the same BaseItem id repeatedly. Lowercase the
-            // grouping key so case-only duplicates collapse together.
-            var representativeIds = dbQuery
-                .GroupBy(e => e.Name.ToLower())
-                .Select(g => g.Min(e => e.Id));
-            dbQuery = context.Peoples.AsNoTracking()
-                .Where(p => representativeIds.Contains(p.Id))
-                .OrderBy(e => e.Name);
+            // name so /Persons doesn't return the same BaseItem id repeatedly, keeping the
+            // lowest id per lowercased name so case-only duplicates collapse together.
+            var candidates = dbQuery;
+            dbQuery = candidates
+                .Where(p => !candidates.Any(other => other.Name.ToLower() == p.Name.ToLower() && other.Id < p.Id))
+                .OrderBy(e => e.Name.ToLower());
+
+            distinctNameCount = candidates.Select(e => e.Name.ToLower()).Distinct().Count();
         }
 
-        var count = dbQuery.Count();
+        var count = distinctNameCount ?? dbQuery.Count();
         if (filter.StartIndex.HasValue && filter.StartIndex > 0)
         {
             dbQuery = dbQuery.Skip(filter.StartIndex.Value);

src/Jellyfin.Database/Jellyfin.Database.Providers.Sqlite/Migrations/20260728170000_AddPeopleNameLowerIndex.cs

@@ -0,0 +1,25 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Jellyfin.Server.Implementations.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddPeopleNameLowerIndex : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            // Expression index, so it cannot be declared on the entity type. /Persons collapses the
+            // one-row-per-(Name, PersonType) table to one row per lowercased name; without this index
+            // that dedup scans and groups the whole table on every request.
+            migrationBuilder.Sql("CREATE INDEX IF NOT EXISTS \"IX_Peoples_NameLower\" ON \"Peoples\" (lower(\"Name\"));");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql("DROP INDEX IF EXISTS \"IX_Peoples_NameLower\";");
+        }
+    }
+}