Maybe we can remove the type cast in typecache.c

mod_registry->next_typmod, 1); ``` typmod has u32 type, but we cast it to int first. And I also have some confusion about why `NextRecordTypmod` and `TupleDescData.tdtypmod` has type of int32, but `SharedTypmodTableEntry.typmod` has type of uint32. Best

found the document `README.parallel` to be a little bit incorrect

Hi hackers, Recently, I'm looking into the implementation of parallel index building. And I noticed that in `README.parallel` we mentioned that `we allow no writes to the database and no DDL` . But if I understand it correctly, index building as one significant DDL is now supporting paralle