Reading the code, I have a hard time understanding the various ways NULLs
are represented in the DB for non-aligned format.

I see comments in the code suggesting that nullable columns have the first
value byte representing if the value is null, but I also see special cases
all over the place that take care of null as being totally absent cells.

The former method (adding a first byte indicating a null) having
consequences on predicate push down -> need to re-do predicate evaluation
at trafodion layer to deal with null semantic.



But I am not sure why we have this special situation of coding null with a
byte, instead of always dealing with nulls as being “absent” cell? I am
sure there is a reason, but I just could not figure it out…

Someone can help?

Eric

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