Chainstate Bitcoin Core 0.15

Question

Recently updated my LevelDB parser to work with the new LevelDB 0.15 internal structure. However, I'm wondering about two small changes I found:

• The prefix for transactions was changed from b'c' to b'C'.

• The nVersion field was dropped from the database.

Is there any specific reason for changing the prefix?

On the other hand, and regarding the version field, it was always set to the same value for every entry (can't recall if 1 or 0), so dropping it seems the right thing to do but, why was it included in first place?

Answer 1

• The prefix for transactions was changed from b'c' to b'C'.

Is there any specific reason for changing the prefix?

The entry changed to a new data structure. However in order to be able to upgrade previous database versions to the new one, we need to be able to identify which entry corresponds to the old structure and which corresponds to the new structure. So a different prefix is used.

• The nVersion field was dropped from the database.

On the other hand, and regarding the version field, it was always set to the same value for every entry (can't recall if 1 or 0), so dropping it seems the right thing to do but, why was it included in first place?

nVersion is the transaction version. It should have been either 1 or 2 as those are the only transaction versions used on the network with version 1 being the most common.