Re: pageinspect: Hash index support

Hi,

On 09/23/2016 12:10 AM, Peter Eisentraut wrote:
> On 9/21/16 9:30 AM, Jesper Pedersen wrote:
>> Attached is v5, which add basic page verification.
>
> There are still some things that I found that appear to follow the old
> style (btree) conventions instead the new style (brin, gin) conventions.
>
> - Rename hash_metap to hash_metapage_info.
>

Done.

> - Don't use BuildTupleFromCStrings(). (There is nothing inherently
> wrong with it, but why convert numbers to strings and back again when it
> can be done more directly.)
>

Left as is, since BuildTupleFromCStrings() vs. xyzGetDatum() are equally
readable in this case. But, I can change the patch if needed.

> - Documentation for hash_page_stats still has blkno argument.
>

Fixed.

> - In hash_metap, the magic field could be type bytea, so that it
> displays in hex. Or text like the brin functions.
>

Changed to 'text'.

> Some other comments:
>
> - hash_metap result fields spares and mapp should be arrays of integer.
>

B-tree and BRIN uses a 'text' field as output, so left as is.

> (Incidentally, the comment in hash.h talks about bitmaps[] but I think
> it means hashm_mapp[].)
>
> - As of very recently, we don't need to move pageinspect--1.5.sql to
> pageinspect--1.6.sql anymore. Just add pageinspect--1.5--1.6.sql.
>

We need to rename the pageinspect--1.5.sql file and add the new methods,
right ? Or ?

> - In the documentation for hash_page_stats(), the "+" sign is misaligned.
>

Fixed.

> - In hash_page_items, the fields itemlen, nulls, vars are always 16,
> false, false. So perhaps there is no need for them. Similarly, the
> hash_page_stats in hash_page_stats is always 16.
>

Fixed, by removing them. We can add them back later if needed.

> - The data field could be of type bytea.
>

Left as is, for same reasons as 'spares' and 'mapp'.

> - Add a pointer in the documentation to the relevant header file.
>

Done.

> Bonus:
>
> - Add subsections in the documentation (general functions, B-tree
> functions, etc.)
>

Done.

> - Add tests.
>

Thanks for the review !

Best regards,
Jesper