Note that getLastError() doesn't work if you run multiple queries with runQueries(). It doesn't return any error, even if one or several (or all) of the queries failed.
(PECL sphinx >= 0.1.0)
SphinxClient::getLastError — Get the last error message
Returns string with the last error message. If there were no errors during the previous API call, empty string is returned. This method doesn't reset the error message, so you can safely call it several times.
This function has no parameters.
Returns the last error message or an empty string if there were no errors.