Re: Fixed length data types issue

Tom Lane wrote:
> Mark Dilger <pgsql@markdilger.com> writes:
>> int1 works perfectly, as far as I can tell.  int3 works great in memory, 
>> but can't be stored to a table.  The problem seems to be that 
>> store_att_byval allows data of size 1 byte but not size 3 bytes, forcing 
>> me to pass int3 by reference.  But when I pass either of these types by 
>> reference the backend exits when trying to store to a table.
> 
> Please provide a stack trace --- AFAIK there shouldn't be any reason why
> a pass-by-ref 3-byte type wouldn't work.  I'm wondering though what
> alignment you expect it to have.  You'd need some pretty ugly code to
> pick up an unaligned 3-byte integer portably ... but if you align it,
> the space savings probably goes out the window.
> 
>             regards, tom lane

Program received signal SIGSEGV, Segmentation fault.
0xb7e01d45 in memcpy () from /lib/libc.so.6
(gdb) bt
#0  0xb7e01d45 in memcpy () from /lib/libc.so.6
#1  0x08077ece in heap_fill_tuple (tupleDesc=0x83c2ef7, 
values=0x83c2e84, isnull=0x83c2e98 "", data=0x83c2ef4 "", 
infomask=0x83c2ef0, bit=0x0)    at heaptuple.c:181
#2  0x08078b0d in heap_form_tuple (tupleDescriptor=0x83c2d78, 
values=0x83c2e84, isnull=0x83c2e98 "") at heaptuple.c:749
#3  0x0815d2d9 in ExecCopySlotTuple (slot=0x83c26f4) at execTuples.c:558
#4  0x0815d393 in ExecMaterializeSlot (slot=0x83c26f4) at execTuples.c:639
#5  0x081560ca in ExecutorRun (queryDesc=0x83c2834, 
direction=ForwardScanDirection, count=0) at execMain.c:1401
#6  0x081e78e4 in ProcessQuery (parsetree=0x83c2240, plan=0x83b837c, 
params=0x3, dest=0x83b8290, completionTag=0xbfedffa0 "") at pquery.c:174
#7  0x081e89f9 in PortalRun (portal=0x83c0064, count=2147483647, 
dest=0x83b8290, altdest=0x83b8290, completionTag=0xbfedffa0 "") at 
pquery.c:1076
#8  0x081e4060 in exec_simple_query (query_string=0x83b7bbc "insert into 
test (a) values (3::int3);") at postgres.c:1004
#9  0x081e6074 in PostgresMain (argc=4, argv=0x836fab4, 
username=0x836fa8c "mark") at postgres.c:3219
#10 0x081b89b3 in ServerLoop () at postmaster.c:2854
#11 0x081ba21b in PostmasterMain (argc=1, argv=0x836d9f8) at 
postmaster.c:941
#12 0x081764a8 in main (argc=1, argv=0x836d9f8) at main.c:265