fix(log): address remaining CodeRabbit suggestions for log database switch and migrations

docs/superpowers/plans/2026-08-08-log-database-decoupling.md

@@ -2250,6 +2250,10 @@ func (h *LogDBSwitchHandler) Execute(ctx context.Context, payload []byte) (*task
     }
     defer func() { _ = setMigrationFlag(ctx, "") }() // 失败也清除，保持源库可写
 
+    if err := drainLogWriters(ctx); err != nil {
+        return nil, fmt.Errorf("排空日志写入队列失败: %w", err)
+    }
+
     src, err := logstore.Active(ctx)
     if err != nil {
         return nil, err

internal/apps/openflare/tasks/log_db_switch.go

@@ -88,12 +88,7 @@ func (h *LogDBSwitchHandler) Execute(ctx context.Context, payload []byte) (*task
 	}
 	task.AppendLog(ctx, "开始切换日志数据库：%s -> %s", source, p.Target)
 
-	// 冻结前先排空在途批次（chwriter + 用户访问日志 writer），避免迁移期间积压丢失；
+	// 设置迁移冻结标记（置位后由 ensureWritable 拒绝新写入）。
-	// 只等 flush 完成，不停止 writer（置位后由 ensureWritable 拒绝新写入）。
-	if err := drainLogWriters(ctx); err != nil {
-		return nil, fmt.Errorf("排空日志写入队列失败: %w", err)
-	}
-
 	if err := setMigrationFlag(ctx, "migrating"); err != nil {
 		return nil, err
 	}
@@ -104,6 +99,12 @@ func (h *LogDBSwitchHandler) Execute(ctx context.Context, payload []byte) (*task
 		}
 	}()
 
+	// 冻结标记置位后再排空在途批次（chwriter + 用户访问日志 writer），
+	// 保证排空完成后不再有新批次进入源库。
+	if err := drainLogWriters(ctx); err != nil {
+		return nil, fmt.Errorf("排空日志写入队列失败: %w", err)
+	}
+
 	src, err := logstore.Active(ctx)
 	if err != nil {
 		return nil, err

internal/infra/persistence/migrator/goose/postgres/202608080003_drop_database_cleanup_schedule.sql

@@ -11,7 +11,8 @@ FROM w_schedules_backup_of_database_auto_cleanup
 ON CONFLICT (id) DO NOTHING;
 
 INSERT INTO w_schedules (id, name, task_type, cron, payload, is_active, created_at, updated_at)
-VALUES (102, 'OpenFlare 可观测数据自动清理', 'of_database_auto_cleanup', '0 3 * * *', '{}', TRUE, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
+SELECT 102, 'OpenFlare 可观测数据自动清理', 'of_database_auto_cleanup', '0 3 * * *', '{}', TRUE, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP
+WHERE NOT EXISTS (SELECT 1 FROM w_schedules WHERE task_type = 'of_database_auto_cleanup')
 ON CONFLICT (id) DO NOTHING;
 
 DROP TABLE IF EXISTS w_schedules_backup_of_database_auto_cleanup;

internal/infra/persistence/migrator/goose/sqlite/202608080003_drop_database_cleanup_schedule.sql

@@ -10,7 +10,8 @@ SELECT id, name, task_type, cron, payload, is_active, created_at, updated_at
 FROM w_schedules_backup_of_database_auto_cleanup;
 
 INSERT OR IGNORE INTO w_schedules (id, name, task_type, cron, payload, is_active, created_at, updated_at)
-VALUES (102, 'OpenFlare 可观测数据自动清理', 'of_database_auto_cleanup', '0 3 * * *', '{}', 1, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP);
+SELECT 102, 'OpenFlare 可观测数据自动清理', 'of_database_auto_cleanup', '0 3 * * *', '{}', 1, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP
+WHERE NOT EXISTS (SELECT 1 FROM w_schedules WHERE task_type = 'of_database_auto_cleanup');
 
 DROP TABLE IF EXISTS w_schedules_backup_of_database_auto_cleanup;
 

internal/repository/logstore/cleanup.go

@@ -5,11 +5,13 @@ package logstore
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"strconv"
 	"time"
 
 	"github.com/Rain-kl/Wavelet/internal/model"
+	"github.com/Rain-kl/Wavelet/pkg/logger"
 )
 
 // CleanupSummary 汇总本次清理结果。
@@ -39,10 +41,14 @@ func retentionDaysForDatabase(ctx context.Context, dbName string) int {
 	}
 	v, err := getConfig(ctx, key)
 	if err != nil {
+		if !errors.Is(err, errConfigReaderNotWired) {
+			logger.ErrorF(ctx, "读取日志保留天数配置失败(key=%s)，回退默认 %d 天: %v", key, defaultLogRetentionDays, err)
+		}
 		return defaultLogRetentionDays
 	}
 	days, perr := strconv.Atoi(v)
 	if perr != nil || days <= 0 {
+		logger.ErrorF(ctx, "日志保留天数配置非法(key=%s, value=%q)，回退默认 %d 天", key, v, defaultLogRetentionDays)
 		return defaultLogRetentionDays
 	}
 	return days