Re: pageinspect and hash indexes

>>>> Thanks for reviewing my patch. I have removed the extra white space.
>>>> Attached are both the patches.
>>>
>>> Sorry, I have mistakenly attached wrong patch. Here are the correct
>>> set of patches.
>>
>> The latest version of patches looks fine to me.
>
> I don't really like 0002.  What about this, instead?
>
> --- a/contrib/pageinspect/hashfuncs.c
> +++ b/contrib/pageinspect/hashfuncs.c
> @@ -80,7 +80,8 @@ verify_hash_page(bytea *raw_page, int flags)
>      /* Check that page type is sane. */
>      pagetype = pageopaque->hasho_flag & LH_PAGE_TYPE;
>      if (pagetype != LH_OVERFLOW_PAGE && pagetype != LH_BUCKET_PAGE &&
> -        pagetype != LH_BITMAP_PAGE && pagetype != LH_META_PAGE)
> +        pagetype != LH_BITMAP_PAGE && pagetype != LH_META_PAGE &&
> +        pagetype != LH_UNUSED_PAGE)
>          ereport(ERROR,
>                  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
>                   errmsg("invalid hash page type %08x", pagetype)));
>
> The advantage of that is (1) it won't get confused if in the future we
> have an unused page that has some flag bit not in LH_PAGE_TYPE set,
> and (2) if in the future we want to add any other checks to this
> function which should apply to unused pages also, they won't get
> bypassed by an early return statement.

Agreed. Moreover, previous approach might even change the current
behaviour of functions like hash_page_items() and hash_page_stats()
basically when we pass UNUSED pages to these functions. Attached is
the newer version of patch.