I was looking into HOT updates, and trying to get the page info:
db=# SELECT * FROM heap_page_items(get_raw_page('foo', 0)); ERROR: function get_raw_page(unknown, integer) does not exist LINE 1: SELECT * FROM heap_page_items(get_raw_page('foo', 0)); ^ HINT: No function matches the given name and argument types. You might need to add explicit type casts.
The documentation seemed pretty clear, and no doubt the experienced DBAs have spotted the unforced error…
pageinspectmodule provides functions…
It’s a module, and needs to be loaded
CREATE EXTENSION pageinspect;