Key/value chunk sizes / alignment?

Hello,

I have two LMDB databases, identical except one has key size 34 bytes and the other key size 33 bytes. (Both have same value sizes and same number of pairs).

How can the file sizes on disk be exactly the same? Is this because of the 2-byte alignment mentioned here? https://github.com/AltSysrq/lmdb-zero/issues/8

I wonder if this 2-byte alignment was documented anywhere.

This doesn't bother me btw. I was just expecting the file sizes to differ (got scared I had a bug in my program until I did an mdb_dump to see the real difference)

Thanks, Samuel