Re: [HACKERS] Page OpaqueData

Patch applied. Thanks.

---------------------------------------------------------------------------

Manfred Koizar wrote:
> On Mon, 24 Jun 2002 12:53:42 -0400, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >the extra level of struct naming for pd_opaque has no obvious
> >usefulness.
> >
> >> [...] should I post a patch that puts pagesize directly into
> >> PageHeaderData?
> >
> >If you're so inclined. Given that pd_opaque is hidden in those macros,
> >there wouldn't be much of any gain in readability either, so I haven't
> >worried about changing the declaration.
>
> Thanks for the clarification. Here is the patch. Not much gain, but at
> least it saves the next junior hacker from scratching his head ...
>
> Cordialmente
> Manfredinho :-)
>
> PS: Please do not apply before "Page access" patch from 2002-06-20.
>
> diff -ru ../base/src/backend/access/hash/hashutil.c src/backend/access/hash/hashutil.c
> --- ../base/src/backend/access/hash/hashutil.c 2002-05-21 11:54:11.000000000 +0200
> +++ src/backend/access/hash/hashutil.c 2002-06-21 16:43:24.000000000 +0200
> @@ -131,13 +131,13 @@
> HashPageOpaque opaque;
>
> Assert(page);
> - Assert(((PageHeader) (page))->pd_lower >= (sizeof(PageHeaderData) - sizeof(ItemIdData)));
> + Assert(((PageHeader) (page))->pd_lower >= SizeOfPageHeaderData);
> #if 1
> Assert(((PageHeader) (page))->pd_upper <=
> (BLCKSZ - MAXALIGN(sizeof(HashPageOpaqueData))));
> Assert(((PageHeader) (page))->pd_special ==
> (BLCKSZ - MAXALIGN(sizeof(HashPageOpaqueData))));
> - Assert(((PageHeader) (page))->pd_opaque.od_pagesize == BLCKSZ);
> + Assert(PageGetPageSize(page) == BLCKSZ);
> #endif
> if (flags)
> {
> diff -ru ../base/src/include/storage/bufpage.h src/include/storage/bufpage.h
> --- ../base/src/include/storage/bufpage.h 2002-06-20 12:22:21.000000000 +0200
> +++ src/include/storage/bufpage.h 2002-06-21 16:38:17.000000000 +0200
> @@ -65,8 +65,7 @@
> * byte-offset position, tuples can be physically shuffled on a page
> * whenever the need arises.
> *
> - * AM-generic per-page information is kept in the pd_opaque field of
> - * the PageHeaderData. (Currently, only the page size is kept here.)
> + * AM-generic per-page information is kept in PageHeaderData.
> *
> * AM-specific per-page data (if any) is kept in the area marked "special
> * space"; each AM has an "opaque" structure defined somewhere that is
> @@ -92,25 +91,18 @@
>
>
> /*
> + * disk page organization
> * space management information generic to any page
> *
> - * od_pagesize - size in bytes.
> - * Minimum possible page size is perhaps 64B to fit
> - * page header, opaque space and a minimal tuple;
> - * of course, in reality you want it much bigger.
> - * On the high end, we can only support pages up
> - * to 32KB because lp_off/lp_len are 15 bits.
> - */
> -typedef struct OpaqueData
> -{
> - uint16 od_pagesize;
> -} OpaqueData;
> -
> -typedef OpaqueData *Opaque;
> -
> -
> -/*
> - * disk page organization
> + * pd_lower - offset to start of free space.
> + * pd_upper - offset to end of free space.
> + * pd_special - offset to start of special space.
> + * pd_pagesize - size in bytes.
> + * Minimum possible page size is perhaps 64B to fit
> + * page header, opaque space and a minimal tuple;
> + * of course, in reality you want it much bigger.
> + * On the high end, we can only support pages up
> + * to 32KB because lp_off/lp_len are 15 bits.
> */
> typedef struct PageHeaderData
> {
> @@ -124,7 +116,7 @@
> LocationIndex pd_lower; /* offset to start of free space */
> LocationIndex pd_upper; /* offset to end of free space */
> LocationIndex pd_special; /* offset to start of special space */
> - OpaqueData pd_opaque; /* AM-generic information */
> + uint16 pd_pagesize;
> ItemIdData pd_linp[1]; /* beginning of line pointer array */
> } PageHeaderData;
>
> @@ -216,14 +208,14 @@
> * however, it can be called on a page for which there is no buffer.
> */
> #define PageGetPageSize(page) \
> - ((Size) ((PageHeader) (page))->pd_opaque.od_pagesize)
> + ((Size) ((PageHeader) (page))->pd_pagesize)
>
> /*
> * PageSetPageSize
> * Sets the page size of a page.
> */
> #define PageSetPageSize(page, size) \
> - (((PageHeader) (page))->pd_opaque.od_pagesize = (size))
> + (((PageHeader) (page))->pd_pagesize = (size))
>
> /* ----------------
> * page special data macros
>
> Servus
> Manfred
>
>
>
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