Tom Lane wrote:
Scott Bailey <artacus@xxxxxxxxxxx> writes:
I'm trying to better understand the internals of Postgres, and I'm
looking at the enum type. The docs say that an enum value is stored on
disk as 4 bytes. But enum_send() returns a bytea representing the actual
text of the value and not the index of that value. So what step am I
missing here?
The wire format isn't necessarily the on-disk format. In this case
we concluded that the internal OID value wouldn't be of any use to
clients.
Also, is there a way to see the raw data for the tuple on a page?
Try contrib/pageinspect, and read
http://developer.postgresql.org/pgdocs/postgres/storage-page-layout.html
regards, tom lane
Thanks Tom that did the trick. The only I/O functions I'm aware of are
send, recv, in and out. What controls converting from/to wire and
on-disk formats? And why is wire format little endian and disk big endian?
And for posterity, here's how to get to the raw tuple data.
SELECT substring(page, lp_off + t_hoff + 1, lp_len - t_hoff) AS tuple_data,
sub.*
FROM (
SELECT (heap_page_items(page)).*, page
FROM (
SELECT get_raw_page('test', 0) page
) s
) sub
--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general
