static void verify_or_upgrade_db_descriptor(DB *db, const Descriptor &descriptor,
const bool hot_index) {
const DBT *desc = &db->cmp_descriptor->dbt;
verify(desc->data != NULL && desc->size >= 4);
if (desc->size == 4) {
// existing descriptor is from before descriptors were even versioned.
// it's only an ordering. make sure it matches, then upgrade.
const Ordering &ordering(*reinterpret_cast<const Ordering *>(desc->data));
const Ordering &expected(descriptor.ordering());
verify(memcmp(&ordering, &expected, 4) == 0);
set_db_descriptor(db, descriptor, hot_index);
} else {
const Descriptor existing(reinterpret_cast<const char *>(desc->data), desc->size);
if (existing.version() < descriptor.version()) {
// existing descriptor is out-dated. upgrade to the current version.
set_db_descriptor(db, descriptor, hot_index);
} else if (existing.version() > descriptor.version()) {
problem() << "Detected a \"dictionary descriptor\" version that is too new: "
<< existing.version() << ". The highest known version is " << descriptor.version()
<< "This data may have already been upgraded by a newer version of "
<< "TokuMX and is now no longer usable by this version."
<< endl << endl
<< "The assertion failure you are about to see is intentional."
<< endl;
verify(false);
} else {
// same version, ensure the contents of the descriptor are correct
verify(existing == descriptor);
}
}
}
