FIX (mysql): Detect supported compression levels

backend/internal/features/backups/backups/usecases/mysql/create_backup_uc.go

@@ -118,7 +118,7 @@ func (uc *CreateMysqlBackupUsecase) buildMysqldumpArgs(my *mysqltypes.MysqlDatab
 		args = append(args, "--events")
 	}
 
-	args = append(args, uc.getNetworkCompressionArgs(my.Version)...)
+	args = append(args, uc.getNetworkCompressionArgs(my)...)
 
 	if !config.GetEnv().IsCloud {
 		args = append(args, "--max-allowed-packet=1G")
@@ -135,15 +135,21 @@ func (uc *CreateMysqlBackupUsecase) buildMysqldumpArgs(my *mysqltypes.MysqlDatab
 	return args
 }
 
-func (uc *CreateMysqlBackupUsecase) getNetworkCompressionArgs(version tools.MysqlVersion) []string {
+func (uc *CreateMysqlBackupUsecase) getNetworkCompressionArgs(
+	my *mysqltypes.MysqlDatabase,
+) []string {
 	const zstdCompressionLevel = 5
 
-	switch version {
+	switch my.Version {
 	case tools.MysqlVersion80, tools.MysqlVersion84, tools.MysqlVersion9:
-		return []string{
-			"--compression-algorithms=zstd",
-			fmt.Sprintf("--zstd-compression-level=%d", zstdCompressionLevel),
+		if my.IsZstdSupported {
+			return []string{
+				"--compression-algorithms=zstd",
+				fmt.Sprintf("--zstd-compression-level=%d", zstdCompressionLevel),
+			}
 		}
+
+		return []string{"--compress"}
 	case tools.MysqlVersion57:
 		return []string{"--compress"}
 	default:
@@ -589,6 +595,15 @@ func (uc *CreateMysqlBackupUsecase) handleConnectionErrors(stderrStr string) err
 		)
 	}
 
+	if containsIgnoreCase(stderrStr, "compression algorithm") ||
+		containsIgnoreCase(stderrStr, "2066") {
+		return fmt.Errorf(
+			"MySQL connection failed due to unsupported compression algorithm. "+
+				"Try re-saving the database connection to re-detect compression support. stderr: %s",
+			stderrStr,
+		)
+	}
+
 	if containsIgnoreCase(stderrStr, "unknown database") {
 		return fmt.Errorf(
 			"MySQL database does not exist. stderr: %s",

backend/internal/features/databases/databases/mysql/model.go

@@ -25,13 +25,14 @@ type MysqlDatabase struct {
 
 	Version tools.MysqlVersion `json:"version" gorm:"type:text;not null"`
 
-	Host       string  `json:"host"       gorm:"type:text;not null"`
-	Port       int     `json:"port"       gorm:"type:int;not null"`
-	Username   string  `json:"username"   gorm:"type:text;not null"`
-	Password   string  `json:"password"   gorm:"type:text;not null"`
-	Database   *string `json:"database"   gorm:"type:text"`
-	IsHttps    bool    `json:"isHttps"    gorm:"type:boolean;default:false"`
-	Privileges string  `json:"privileges" gorm:"column:privileges;type:text;not null;default:''"`
+	Host            string  `json:"host"            gorm:"type:text;not null"`
+	Port            int     `json:"port"            gorm:"type:int;not null"`
+	Username        string  `json:"username"        gorm:"type:text;not null"`
+	Password        string  `json:"password"        gorm:"type:text;not null"`
+	Database        *string `json:"database"        gorm:"type:text"`
+	IsHttps         bool    `json:"isHttps"         gorm:"type:boolean;default:false"`
+	Privileges      string  `json:"privileges"      gorm:"column:privileges;type:text;not null;default:''"`
+	IsZstdSupported bool    `json:"isZstdSupported" gorm:"column:is_zstd_supported;type:boolean;not null;default:true"`
 }
 
 func (m *MysqlDatabase) TableName() string {
@@ -102,6 +103,7 @@ func (m *MysqlDatabase) TestConnection(
 		return err
 	}
 	m.Privileges = privileges
+	m.IsZstdSupported = detectZstdSupport(ctx, db)
 
 	if err := checkBackupPermissions(m.Privileges); err != nil {
 		return err
@@ -125,6 +127,7 @@ func (m *MysqlDatabase) Update(incoming *MysqlDatabase) {
 	m.Database = incoming.Database
 	m.IsHttps = incoming.IsHttps
 	m.Privileges = incoming.Privileges
+	m.IsZstdSupported = incoming.IsZstdSupported
 
 	if incoming.Password != "" {
 		m.Password = incoming.Password
@@ -185,6 +188,7 @@ func (m *MysqlDatabase) PopulateDbData(
 		return err
 	}
 	m.Privileges = privileges
+	m.IsZstdSupported = detectZstdSupport(ctx, db)
 
 	return nil
 }
@@ -223,6 +227,7 @@ func (m *MysqlDatabase) PopulateVersion(
 		return err
 	}
 	m.Version = detectedVersion
+	m.IsZstdSupported = detectZstdSupport(ctx, db)
 
 	return nil
 }
@@ -575,6 +580,22 @@ func checkBackupPermissions(privileges string) error {
 	return nil
 }
 
+// detectZstdSupport checks if the MySQL server supports zstd network compression.
+// The protocol_compression_algorithms variable was introduced in MySQL 8.0.18.
+// Managed MySQL providers (e.g. PlanetScale) may not support zstd even on 8.0+.
+func detectZstdSupport(ctx context.Context, db *sql.DB) bool {
+	var varName, value string
+
+	err := db.QueryRowContext(ctx,
+		"SHOW VARIABLES LIKE 'protocol_compression_algorithms'",
+	).Scan(&varName, &value)
+	if err != nil {
+		return false
+	}
+
+	return strings.Contains(strings.ToLower(value), "zstd")
+}
+
 func decryptPasswordIfNeeded(
 	password string,
 	encryptor encryption.FieldEncryptor,

backend/internal/features/databases/databases/mysql/model_test.go

@@ -177,6 +177,38 @@ func Test_TestConnection_SufficientPermissions_Success(t *testing.T) {
 	}
 }
 
+func Test_TestConnection_DetectsZstdSupport(t *testing.T) {
+	env := config.GetEnv()
+	cases := []struct {
+		name         string
+		version      tools.MysqlVersion
+		port         string
+		isExpectZstd bool
+	}{
+		{"MySQL 5.7", tools.MysqlVersion57, env.TestMysql57Port, false},
+		{"MySQL 8.0", tools.MysqlVersion80, env.TestMysql80Port, true},
+		{"MySQL 8.4", tools.MysqlVersion84, env.TestMysql84Port, true},
+		{"MySQL 9", tools.MysqlVersion9, env.TestMysql90Port, true},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			container := connectToMysqlContainer(t, tc.port, tc.version)
+			defer container.DB.Close()
+
+			mysqlModel := createMysqlModel(container)
+			logger := slog.New(slog.NewTextHandler(os.Stdout, nil))
+
+			err := mysqlModel.TestConnection(logger, nil, uuid.New())
+			assert.NoError(t, err)
+			assert.Equal(t, tc.isExpectZstd, mysqlModel.IsZstdSupported,
+				"IsZstdSupported mismatch for %s", tc.name)
+		})
+	}
+}
+
 func Test_IsUserReadOnly_AdminUser_ReturnsFalse(t *testing.T) {
 	env := config.GetEnv()
 	cases := []struct {

backend/migrations/20260311094356_add_is_zstd_supported_to_mysql.sql

@@ -0,0 +1,11 @@
+-- +goose Up
+-- +goose StatementBegin
+ALTER TABLE mysql_databases
+    ADD COLUMN is_zstd_supported BOOLEAN NOT NULL DEFAULT TRUE;
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+ALTER TABLE mysql_databases
+    DROP COLUMN is_zstd_supported;
+-- +goose StatementEnd