Bruce Momjian <[EMAIL PROTECTED]> writes:
> But if you are walking through attributes, how do you know to look at
> the next byte or the next aligned byte?  We have to force zeros in
> there?

Yup: pad bytes must be zeroes (they are already) and a 1-byte-header
can't be a zero (easily done if its length includes itself).  So the
tuple-walking code would do something like

        if (looking-at-a-zero && not-at-4-byte-boundary)
                advance to next 4-byte boundary;
        check current byte to determine if 1-byte or 4-byte header;

                        regards, tom lane

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