may be a code bug

[jerousrb]

in the file db/column_family.cc ,the destructor of ColumnFamilySet, deleting cfd directly after dereferencing by call cfd->Unref();

I think we can delete cfd only when the cfd->Unref()== true, others we no need to delete!

ColumnFamilySet::~ColumnFamilySet() {
while (column_family_data_.size() > 0) {
// cfd destructor will delete itself from column_family_data_
auto cfd = column_family_data_.begin()->second;
cfd->Unref();
delete cfd; // this should do it when cfd->Unref()==true ?
}
dummy_cfd_->Unref();
delete dummy_cfd_;
}

[ajkr]

Interesting question. The ColumnFamilySet is deleted only when the DB is destroyed, so maybe this lets us avoid memory leak in case there are CFD referrers that forget to call Unref(). Want to try fixing it as you suggested and see if valgrind/ASAN pass?

[yiwu-arbug]

I think an assert is more appropriate since cfd is not suppose to outlive the DB. I'll send a patch.