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Diffstat (limited to 'src/include/access/brin_page.h')
-rw-r--r-- | src/include/access/brin_page.h | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/src/include/access/brin_page.h b/src/include/access/brin_page.h new file mode 100644 index 0000000..75de538 --- /dev/null +++ b/src/include/access/brin_page.h @@ -0,0 +1,96 @@ +/* + * brin_page.h + * Prototypes and definitions for BRIN page layouts + * + * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/include/access/brin_page.h + * + * NOTES + * + * These structs should really be private to specific BRIN files, but it's + * useful to have them here so that they can be used by pageinspect and similar + * tools. + */ +#ifndef BRIN_PAGE_H +#define BRIN_PAGE_H + +#include "storage/block.h" +#include "storage/itemptr.h" + +/* + * Special area of BRIN pages. + * + * We define it in this odd way so that it always occupies the last + * MAXALIGN-sized element of each page. + */ +typedef struct BrinSpecialSpace +{ + uint16 vector[MAXALIGN(1) / sizeof(uint16)]; +} BrinSpecialSpace; + +/* + * Make the page type be the last half-word in the page, for consumption by + * pg_filedump and similar utilities. We don't really care much about the + * position of the "flags" half-word, but it's simpler to apply a consistent + * rule to both. + * + * See comments above GinPageOpaqueData. + */ +#define BrinPageType(page) \ + (((BrinSpecialSpace *) \ + PageGetSpecialPointer(page))->vector[MAXALIGN(1) / sizeof(uint16) - 1]) + +#define BrinPageFlags(page) \ + (((BrinSpecialSpace *) \ + PageGetSpecialPointer(page))->vector[MAXALIGN(1) / sizeof(uint16) - 2]) + +/* special space on all BRIN pages stores a "type" identifier */ +#define BRIN_PAGETYPE_META 0xF091 +#define BRIN_PAGETYPE_REVMAP 0xF092 +#define BRIN_PAGETYPE_REGULAR 0xF093 + +#define BRIN_IS_META_PAGE(page) (BrinPageType(page) == BRIN_PAGETYPE_META) +#define BRIN_IS_REVMAP_PAGE(page) (BrinPageType(page) == BRIN_PAGETYPE_REVMAP) +#define BRIN_IS_REGULAR_PAGE(page) (BrinPageType(page) == BRIN_PAGETYPE_REGULAR) + +/* flags for BrinSpecialSpace */ +#define BRIN_EVACUATE_PAGE (1 << 0) + + +/* Metapage definitions */ +typedef struct BrinMetaPageData +{ + uint32 brinMagic; + uint32 brinVersion; + BlockNumber pagesPerRange; + BlockNumber lastRevmapPage; +} BrinMetaPageData; + +#define BRIN_CURRENT_VERSION 1 +#define BRIN_META_MAGIC 0xA8109CFA + +#define BRIN_METAPAGE_BLKNO 0 + +/* Definitions for revmap pages */ +typedef struct RevmapContents +{ + /* + * This array will fill all available space on the page. It should be + * declared [FLEXIBLE_ARRAY_MEMBER], but for some reason you can't do that + * in an otherwise-empty struct. + */ + ItemPointerData rm_tids[1]; +} RevmapContents; + +#define REVMAP_CONTENT_SIZE \ + (BLCKSZ - MAXALIGN(SizeOfPageHeaderData) - \ + offsetof(RevmapContents, rm_tids) - \ + MAXALIGN(sizeof(BrinSpecialSpace))) +/* max num of items in the array */ +#define REVMAP_PAGE_MAXITEMS \ + (REVMAP_CONTENT_SIZE / sizeof(ItemPointerData)) + +#endif /* BRIN_PAGE_H */ |