speed optimizations

internal/bsdaily/verify.go

@@ -19,7 +19,7 @@ func VerifyOutput(path string) error {
 
 	slog.Info("verifying SQL content")
 	catCmd := exec.Command("zstdcat", path)
-	headCmd := exec.Command("head", "-20")
+	headCmd := exec.Command("head", fmt.Sprintf("-%d", verificationHeadLines))
 
 	pipe, err := catCmd.StdoutPipe()
 	if err != nil {
@@ -30,16 +30,23 @@ func VerifyOutput(path string) error {
 	var headOut strings.Builder
 	headCmd.Stdout = &headOut
 
-	if err := headCmd.Start(); err != nil {
-		return fmt.Errorf("starting head: %w", err)
-	}
 	if err := catCmd.Start(); err != nil {
 		return fmt.Errorf("starting zstdcat: %w", err)
 	}
+	if err := headCmd.Start(); err != nil {
+		catCmd.Process.Kill() // Clean up if head fails to start
+		return fmt.Errorf("starting head: %w", err)
+	}
 
-	// head closes pipe early, zstdcat gets SIGPIPE - expected
-	_ = headCmd.Wait()
-	_ = catCmd.Wait()
+	// Wait for head first (it will exit when it has enough lines)
+	if err := headCmd.Wait(); err != nil {
+		catCmd.Process.Kill()
+		return fmt.Errorf("head command failed: %w", err)
+	}
+
+	// Kill zstdcat since head closed the pipe (expected SIGPIPE)
+	catCmd.Process.Kill()
+	_ = catCmd.Wait() // Reap the process
 
 	content := headOut.String()
 	if len(content) == 0 {
@@ -53,9 +60,10 @@ func VerifyOutput(path string) error {
 			break
 		}
 	}
+	const verificationSampleBytes = 200
 	if !hasSQLMarker {
-		return fmt.Errorf("decompressed content does not look like SQL; first 200 bytes: %s",
-			content[:min(200, len(content))])
+		return fmt.Errorf("decompressed content does not look like SQL; first %d bytes: %s",
+			verificationSampleBytes, content[:min(verificationSampleBytes, len(content))])
 	}
 
 	slog.Info("SQL content verification passed")