Обсуждение: Custom Type Alignment

Simple question on CREATE TYPE (I hope):

When using the "alignment" option, and setting it to "double", what
ends up double aligned? VARDATA()? The whole thing datum (so that the
alignment of VARDATA() is actually conditioned on the size of
VARHDRSZ) ?

Thanks,

Paul

"Paul Ramsey" <pramsey@cleverelephant.ca> writes:
> Simple question on CREATE TYPE (I hope):
> When using the "alignment" option, and setting it to "double", what
> ends up double aligned? VARDATA()? The whole thing datum (so that the
> alignment of VARDATA() is actually conditioned on the size of
> VARHDRSZ) ?

No, the value as a whole.  If you're talking about a varlena-format
value then the length word will start on a double boundary, and you'll
have to waste a word of alignment padding if the data payload has to
start on a double boundary.

            regards, tom lane