diff options
Diffstat (limited to 'src/include/access/hash.h')
| -rw-r--r-- | src/include/access/hash.h | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/src/include/access/hash.h b/src/include/access/hash.h index eb1df57291b..fcc39570367 100644 --- a/src/include/access/hash.h +++ b/src/include/access/hash.h @@ -36,7 +36,7 @@ typedef uint32 Bucket; #define InvalidBucket ((Bucket) 0xFFFFFFFF) #define BUCKET_TO_BLKNO(metap,B) \ - ((BlockNumber) ((B) + ((B) ? (metap)->hashm_spares[_hash_log2((B)+1)-1] : 0)) + 1) + ((BlockNumber) ((B) + ((B) ? (metap)->hashm_spares[_hash_spareindex((B)+1)-1] : 0)) + 1) /* * Special space for hash index pages. @@ -158,7 +158,8 @@ typedef HashScanOpaqueData *HashScanOpaque; #define HASH_METAPAGE 0 /* metapage is always block 0 */ #define HASH_MAGIC 0x6440640 -#define HASH_VERSION 2 /* 2 signifies only hash key value is stored */ +#define HASH_VERSION 3 /* 3 signifies multi-phased bucket allocation + * to reduce doubling */ /* * spares[] holds the number of overflow pages currently allocated at or @@ -176,13 +177,28 @@ typedef HashScanOpaqueData *HashScanOpaque; * * The limitation on the size of spares[] comes from the fact that there's * no point in having more than 2^32 buckets with only uint32 hashcodes. + * (Note: The value of HASH_MAX_SPLITPOINTS which is the size of spares[] is + * adjusted in such a way to accommodate multi phased allocation of buckets + * after HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE). + * * There is no particular upper limit on the size of mapp[], other than * needing to fit into the metapage. (With 8K block size, 128 bitmaps * limit us to 64 GB of overflow space...) */ -#define HASH_MAX_SPLITPOINTS 32 #define HASH_MAX_BITMAPS 128 +#define HASH_SPLITPOINT_PHASE_BITS 2 +#define HASH_SPLITPOINT_PHASES_PER_GRP (1 << HASH_SPLITPOINT_PHASE_BITS) +#define HASH_SPLITPOINT_PHASE_MASK (HASH_SPLITPOINT_PHASES_PER_GRP - 1) +#define HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE 10 + +/* defines max number of splitpoit phases a hash index can have */ +#define HASH_MAX_SPLITPOINT_GROUP 32 +#define HASH_MAX_SPLITPOINTS \ + (((HASH_MAX_SPLITPOINT_GROUP - HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE) * \ + HASH_SPLITPOINT_PHASES_PER_GRP) + \ + HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE) + typedef struct HashMetaPageData { uint32 hashm_magic; /* magic no. for hash tables */ @@ -382,6 +398,8 @@ extern uint32 _hash_datum2hashkey_type(Relation rel, Datum key, Oid keytype); extern Bucket _hash_hashkey2bucket(uint32 hashkey, uint32 maxbucket, uint32 highmask, uint32 lowmask); extern uint32 _hash_log2(uint32 num); +extern uint32 _hash_spareindex(uint32 num_bucket); +extern uint32 _hash_get_totalbuckets(uint32 splitpoint_phase); extern void _hash_checkpage(Relation rel, Buffer buf, int flags); extern uint32 _hash_get_indextuple_hashkey(IndexTuple itup); extern bool _hash_convert_tuple(Relation index, |