presto-main/src/main/java/io/prestosql/server/PrestoSystemRequirements.java/PrestoSystemRequirements/verifyFileDescriptor
class PrestoSystemRequirements:    private static void verifyFileDescriptor()
    {
        OptionalLong maxFileDescriptorCount = getMaxFileDescriptorCount();
        if (!maxFileDescriptorCount.isPresent()) {
            // This should never happen since we have verified the OS and JVM above
            failRequirement("Cannot read OS file descriptor limit");
        }
        if (maxFileDescriptorCount.getAsLong() < MIN_FILE_DESCRIPTORS) {
            failRequirement("Presto requires at least %s file descriptors (found %s)", MIN_FILE_DESCRIPTORS, maxFileDescriptorCount.getAsLong());
        }
        if (maxFileDescriptorCount.getAsLong() < RECOMMENDED_FILE_DESCRIPTORS) {
            warnRequirement("Current OS file descriptor limit is %s. Presto recommends at least %s", maxFileDescriptorCount.getAsLong(), RECOMMENDED_FILE_DESCRIPTORS);
        }
    }