diff options
Diffstat (limited to 'src/include/access/hash.h')
| -rw-r--r-- | src/include/access/hash.h | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/src/include/access/hash.h b/src/include/access/hash.h index fcc39570367..adba224008c 100644 --- a/src/include/access/hash.h +++ b/src/include/access/hash.h @@ -41,13 +41,13 @@ typedef uint32 Bucket; /* * Special space for hash index pages. * - * hasho_flag tells us which type of page we're looking at. For - * example, knowing overflow pages from bucket pages is necessary - * information when you're deleting tuples from a page. If all the - * tuples are deleted from an overflow page, the overflow is made - * available to other buckets by calling _hash_freeovflpage(). If all - * the tuples are deleted from a bucket page, no additional action is - * necessary. + * hasho_flag's LH_PAGE_TYPE bits tell us which type of page we're looking at. + * Additional bits in the flag word are used for more transient purposes. + * + * To test a page's type, do (hasho_flag & LH_PAGE_TYPE) == LH_xxx_PAGE. + * However, we ensure that each used page type has a distinct bit so that + * we can OR together page types for uses such as the allowable-page-types + * argument of _hash_checkpage(). */ #define LH_UNUSED_PAGE (0) #define LH_OVERFLOW_PAGE (1 << 0) @@ -60,7 +60,7 @@ typedef uint32 Bucket; #define LH_PAGE_HAS_DEAD_TUPLES (1 << 7) #define LH_PAGE_TYPE \ - (LH_OVERFLOW_PAGE|LH_BUCKET_PAGE|LH_BITMAP_PAGE|LH_META_PAGE) + (LH_OVERFLOW_PAGE | LH_BUCKET_PAGE | LH_BITMAP_PAGE | LH_META_PAGE) /* * In an overflow page, hasho_prevblkno stores the block number of the previous @@ -78,16 +78,16 @@ typedef struct HashPageOpaqueData BlockNumber hasho_prevblkno; /* see above */ BlockNumber hasho_nextblkno; /* see above */ Bucket hasho_bucket; /* bucket number this pg belongs to */ - uint16 hasho_flag; /* page type code, see above */ + uint16 hasho_flag; /* page type code + flag bits, see above */ uint16 hasho_page_id; /* for identification of hash indexes */ } HashPageOpaqueData; typedef HashPageOpaqueData *HashPageOpaque; -#define H_NEEDS_SPLIT_CLEANUP(opaque) ((opaque)->hasho_flag & LH_BUCKET_NEEDS_SPLIT_CLEANUP) -#define H_BUCKET_BEING_SPLIT(opaque) ((opaque)->hasho_flag & LH_BUCKET_BEING_SPLIT) -#define H_BUCKET_BEING_POPULATED(opaque) ((opaque)->hasho_flag & LH_BUCKET_BEING_POPULATED) -#define H_HAS_DEAD_TUPLES(opaque) ((opaque)->hasho_flag & LH_PAGE_HAS_DEAD_TUPLES) +#define H_NEEDS_SPLIT_CLEANUP(opaque) (((opaque)->hasho_flag & LH_BUCKET_NEEDS_SPLIT_CLEANUP) != 0) +#define H_BUCKET_BEING_SPLIT(opaque) (((opaque)->hasho_flag & LH_BUCKET_BEING_SPLIT) != 0) +#define H_BUCKET_BEING_POPULATED(opaque) (((opaque)->hasho_flag & LH_BUCKET_BEING_POPULATED) != 0) +#define H_HAS_DEAD_TUPLES(opaque) (((opaque)->hasho_flag & LH_PAGE_HAS_DEAD_TUPLES) != 0) /* * The page ID is for the convenience of pg_filedump and similar utilities, |