Re: Re: Call for platforms

-----BEGIN PGP SIGNED MESSAGE-----

On 26 Mar 2001, at 23:14, Tom Lane wrote:

> "Mark Knox" <segfault(at)hardline(dot)org> writes:
> > On 25 Mar 2001, at 16:07, Tom Lane wrote:
> >> Does that database have any user-created relations in it, or is it
> >> just a virgin database?
>
> > Totally virgin. I created it just for that select you wanted.
>
> Okay. Would you create a couple of random tables in it and do the
> select again? I want to see what ctid looks like in a user-created
> table.

Sure. I created two tables called 'test1' and 'test2'. Test1 has a
single field 'field1' of type int4. Test2 has two fields 'field1' and
'field2' of types char(200) and int4 respectively.

Here are the results:

postgres=> select
p1.oid,attrelid,relname,attname,attlen,attalign,attbyval from
pg_attribute p1, pg_class p2 where atttypid = 27 and p2.oid =
attrelid order by 1;
oid|attrelid|relname |attname|attlen|attalign|attbyval
- -----+--------+--------------+-------+------+--------+--------
16401| 1247|pg_type |ctid | 6|i |f
16415| 1262|pg_database |ctid | 6|i |f
16439| 1255|pg_proc |ctid | 6|i |f
16454| 1260|pg_shadow |ctid | 6|i |f
16464| 1261|pg_group |ctid | 6|i |f
16486| 1249|pg_attribute |ctid | 6|i |f
16515| 1259|pg_class |ctid | 6|i |f
16526| 1215|pg_attrdef |ctid | 6|i |f
16537| 1216|pg_relcheck |ctid | 6|i |f
16557| 1219|pg_trigger |ctid | 6|i |f
16572| 16567|pg_inherits |ctid | 8|i |f
16593| 16579|pg_index |ctid | 8|i |f
16610| 16600|pg_statistic |ctid | 8|i |f
16635| 16617|pg_operator |ctid | 8|i |f
16646| 16642|pg_opclass |ctid | 8|i |f
16678| 16653|pg_am |ctid | 8|i |f
16691| 16685|pg_amop |ctid | 8|i |f
16873| 16867|pg_amproc |ctid | 8|i |f
16941| 16934|pg_language |ctid | 8|i |f
16953| 16948|pg_largeobject|ctid | 8|i |f
16970| 16960|pg_aggregate |ctid | 8|i |f
17038| 17033|pg_ipl |ctid | 8|i |f
17051| 17045|pg_inheritproc|ctid | 8|i |f
17067| 17058|pg_rewrite |ctid | 8|i |f
17079| 17074|pg_listener |ctid | 8|i |f
17090| 17086|pg_description|ctid | 8|i |f
17206| 17201|pg_toast_1215 |ctid | 8|i |f
17221| 17216|pg_toast_17086|ctid | 8|i |f
17236| 17231|pg_toast_1255 |ctid | 8|i |f
17251| 17246|pg_toast_1216 |ctid | 8|i |f
17266| 17261|pg_toast_17058|ctid | 8|i |f
17281| 17276|pg_toast_16600|ctid | 8|i |f
17301| 17291|pg_user |ctid | 8|i |f
17314| 17309|pg_rules |ctid | 8|i |f
17327| 17322|pg_views |ctid | 8|i |f
17342| 17335|pg_tables |ctid | 8|i |f
17355| 17350|pg_indexes |ctid | 8|i |f
18724| 18721|test1 |ctid | 8|i |f
18735| 18731|test2 |ctid | 8|i |f
(39 rows)

> > I suspect it might be an alignment problem
>
> Sort of. I am suspicious that sizeof(ItemPointerData) is returning 8
> rather than 6 as one might expect.

Maybe it's padding the structure to a dword boundary? ARM is
notorious for such things.. I will rebuild it with
__attribute__((packed)) on the struct and see if the size changes..

-----BEGIN PGP SIGNATURE-----
Version: N/A

iQCVAwUBOsFDJP+IdJuhyV9xAQEKxQP/YJXTxZppLd7ECk4BSwDZaStP4+bE6acc
StT//i/drdPC53DDWqiXLGA0bS384EXxyjvvaO1bTXzVFU/3+X/pY6YN/G3HMoah
dbCXRli2Y57yansf1WaVmK1lhiAqLy3iGYFp2nZvO1Sl1u+ba89HtV+G+iaKZSTr
U+HWTU3nnOM=
=vkY+
-----END PGP SIGNATURE-----