Getting "Access is denied" for WAL files in Windows

[primez]

Hello,

First of all, thank you for creating such an interesting database.
I tried to use it in my application on Windows and it keeps throwing errors related to WAL files, e.g:

• level=error db=logs_db msg="failed to delete old segment" baseIndex=1 id=2 err="sync D:\Temp\frostdb\databases\logs_db\wal: Access is denied."
• err="failed initializing meta DB: sync D:\Temp\frostdb\databases\logs_db\wal: Access is denied."

It works just fine in Windows WSL2 though.

Here is an initialization excerpt

      // Create a registry for metrics
	registry := prometheus.NewRegistry()

	// Configure index levels with parquet disk compaction for better performance
	indexConfig := []*index.LevelConfig{
		{
			Level:   index.L0,
			MaxSize: 100 * frostdb.MiB,
			Type:    index.CompactionTypeParquetDisk,
		},
		{
			Level:   index.L1,
			MaxSize: 200 * frostdb.MiB,
			Type:    index.CompactionTypeParquetDisk,
		},
		{
			Level:   index.L2,
			MaxSize: 500 * frostdb.MiB,
		},
	}

	// Create column store with Windows-friendly options
	fmt.Println("Creating column store...")
	var columnstore, err = frostdb.New(
		frostdb.WithLogger(logger),
		frostdb.WithWAL(),
		frostdb.WithStoragePath(storagePathDir),
		frostdb.WithActiveMemorySize(100*frostdb.MiB),
		frostdb.WithRegistry(registry),
		frostdb.WithIndexConfig(indexConfig),
		frostdb.WithSnapshotTriggerSize(100*frostdb.MiB),
	)
	if err != nil {
		log.Fatalf("Failed to create column store: %v", err)
	}

	// Defer close and handle potential errors
	defer func() {
		if closeErr := columnstore.Close(); closeErr != nil {
			log.Printf("Warning: Error during column store close: %v", closeErr)
		}
	}()

[asubiotto]

Hi, unfortunately we don't offer any guarantees re Windows compatibility. It seems likely that the process somehow doesn't have the correct permissions to read/write from disk.

[primez]

Hi Alfonso,

The process had admin permission while running.
I've done a small research and it seems that Windows keeps a lock on file after the program is done working with it for some additional milliseconds.
This means that the fix is to wait before deleting/changing those files again or just do additional retries if it fails for the first time.