发布课表投影改为数据库端删除旧数据、每 2,000 条分批写入并及时释放 EF 跟踪对象，避免大规模发布时内存持续增长。

为“空闲教室/预约占用”新增 学期 + 周次 + 星期 + 节次 + 场地 查询索引；新发布课表的该查询已优先走课次明细投影。

src/Jiaowu.Api/Infrastructure/Persistence/Migrations/MySql/20260809080519_OptimizePublishedTimetableOccurrenceLookup.cs

@@ -0,0 +1,27 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Jiaowu.Api.Infrastructure.Persistence.Migrations.MySql
+{
+    /// <inheritdoc />
+    public partial class OptimizePublishedTimetableOccurrenceLookup : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateIndex(
+                name: "IX_PublishedScheduleOccurrences_AcademicTermId_Week_DayOfWeek_S~",
+                table: "PublishedScheduleOccurrences",
+                columns: new[] { "AcademicTermId", "Week", "DayOfWeek", "StartPeriod", "ClassroomId" });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "IX_PublishedScheduleOccurrences_AcademicTermId_Week_DayOfWeek_S~",
+                table: "PublishedScheduleOccurrences");
+        }
+    }
+}

src/Jiaowu.Api/Infrastructure/Persistence/Migrations/MySql/AppDbContextModelSnapshot.cs

@@ -3552,6 +3552,8 @@ namespace Jiaowu.Api.Infrastructure.Persistence.Migrations.MySql
 
                     b.HasIndex("AcademicTermId", "TeachingTaskId", "Week");
 
+                    b.HasIndex("AcademicTermId", "Week", "DayOfWeek", "StartPeriod", "ClassroomId");
+
                     b.HasIndex("SchedulePlanId", "ClassroomId", "Week", "DayOfWeek", "StartPeriod");
 
                     b.ToTable("PublishedScheduleOccurrences");