Re: GIN pageinspect functions

On 11/20/2014 05:52 AM, Michael Paquier wrote:

On Wed, Nov 19, 2014 at 7:01 AM, Peter Geoghegan <pg@heroku.com> wrote:

On Tue, Nov 4, 2014 at 7:26 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:

1. Documentation seems to be missing, other API's exposed
via pageinspect are documented at:
http://www.postgresql.org/docs/devel/static/pageinspect.html

Done.

2.
+CREATE FUNCTION gin_metapage(IN page bytea,
+    OUT pending_head bigint,
+    OUT pending_tail bigint,
+    OUT version int4)
+AS 'MODULE_PATHNAME', 'gin_metapage'
+LANGUAGE C STRICT;
a. Isn't it better to name the function as gin_metap(..) similar to
existing function bt_metap(..)?

I actually liked more gin_metapage_info, a name similar to the
newly-introduced brin indexes.

b. Can this function have a similar signature as bt_metap() which means
it should take input as relname?

That's mostly a matter of taste but I think we should definitely pass
a raw page to it as it is now. This has the advantage to add an extra
check if the page passed is really a meta page of not, something
useful for development.

3. Can gin_dataleafpage() API have similar name and signature as
API bt_page_items() exposed for btree?

What about gin_leafpage_items then?

The signature of bt_page_items() isn't a good example to follow. It existed before the get_raw_page() function, and the other functions that are designed to work with that, was added. gin_leafpage_items() name seems fine to me.