Method getVersion

backend/plugin/db/pg/pg.go:357–378

getVersion gets the version of Postgres server.

(ctx context.Context)

// getVersion gets the version of Postgres server.
func (d *Driver) getVersion(ctx context.Context) (string, error) {
	// SHOW server_version_num returns an integer such as 100005, which means 10.0.5.
	// It is more convenient to use SHOW server_version to get the version string.
	// PostgreSQL supports it since 8.2.
	// https://www.postgresql.org/docs/current/functions-info.html
	query := "SHOW server_version_num"
	var version string
	if err := d.db.QueryRowContext(ctx, query).Scan(&version); err != nil {
		if err == sql.ErrNoRows {
			return "", common.FormatDBErrorEmptyRowWithQuery(query)
		}
		return "", util.FormatErrorWithQuery(err, query)
	}
	versionNum, err := strconv.Atoi(version)
	if err != nil {
		return "", err
	}
	// https://www.postgresql.org/docs/current/libpq-status.html#LIBPQ-PQSERVERVERSION
	// Convert to semantic version.
	major, minor, patch := versionNum/1_00_00, (versionNum/100)%100, versionNum%100
	return fmt.Sprintf("%d.%d.%d", major, minor, patch), nil
}

// Execute will execute the statement. For CREATE DATABASE statement, some types of databases such as Postgres
// will not use transactions to execute the statement but will still use transactions to execute the rest of statements.