Re: [HACKERS] alpha/64bit weirdness
Thomas Lockhart <lockhart@alumni.caltech.edu>
From: "Thomas G. Lockhart" <lockhart@alumni.caltech.edu>
To: Brett McCormick <brett@work.chicken.org>
Cc: Bruce Momjian <maillist@candle.pha.pa.us>, pgsql-hackers@hub.org
Date: 1998-03-05T03:47:25Z
Lists: pgsql-hackers
> Why would the atttypmod affect anything before it in the struct? I
> have verified that everything is shifted over for bytes, but that
> would lead be to beleive that somewhere the length of the first
> attribute (Oid) is being miscalculated? Where would the code write to
> this data structure without using a pointer to actual struct for
> obtaining the correct memory structure? I checked for offsetof macro
> calls that might cause this effect, to no avail.
Just speculating here, but I do know that the Alpha will force alignment
within structures. So, if the structure is filled by reading a byte stream
from a file, rather than filled field-by-field, it will misalign if it has
integers < 4 bytes. During the initialization phase, the backend probably does
not go through the file manager, but does some brute-force reading of each
file on disk.
- Tom