diff options
Diffstat (limited to 'src/backend/access/hash/hashutil.c')
| -rw-r--r-- | src/backend/access/hash/hashutil.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/src/backend/access/hash/hashutil.c b/src/backend/access/hash/hashutil.c index 2e9971920bc..d679cf0aed9 100644 --- a/src/backend/access/hash/hashutil.c +++ b/src/backend/access/hash/hashutil.c @@ -150,6 +150,71 @@ _hash_log2(uint32 num) } /* + * _hash_spareindex -- returns spare index / global splitpoint phase of the + * bucket + */ +uint32 +_hash_spareindex(uint32 num_bucket) +{ + uint32 splitpoint_group; + uint32 splitpoint_phases; + + splitpoint_group = _hash_log2(num_bucket); + + if (splitpoint_group < HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE) + return splitpoint_group; + + /* account for single-phase groups */ + splitpoint_phases = HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE; + + /* account for multi-phase groups before splitpoint_group */ + splitpoint_phases += + ((splitpoint_group - HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE) << + HASH_SPLITPOINT_PHASE_BITS); + + /* account for phases within current group */ + splitpoint_phases += + (((num_bucket - 1) >> (HASH_SPLITPOINT_PHASE_BITS + 1)) & + HASH_SPLITPOINT_PHASE_MASK); /* to 0-based value. */ + + return splitpoint_phases; +} + +/* + * _hash_get_totalbuckets -- returns total number of buckets allocated till + * the given splitpoint phase. + */ +uint32 +_hash_get_totalbuckets(uint32 splitpoint_phase) +{ + uint32 splitpoint_group; + uint32 total_buckets; + uint32 phases_within_splitpoint_group; + + if (splitpoint_phase < HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE) + return (1 << splitpoint_phase); + + /* get splitpoint's group */ + splitpoint_group = HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE; + splitpoint_group += + ((splitpoint_phase - HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE) >> + HASH_SPLITPOINT_PHASE_BITS); + + /* account for buckets before splitpoint_group */ + total_buckets = (1 << (splitpoint_group - 1)); + + /* account for buckets within splitpoint_group */ + phases_within_splitpoint_group = + (((splitpoint_phase - HASH_SPLITPOINT_GROUPS_WITH_ONE_PHASE) & + HASH_SPLITPOINT_PHASE_MASK) + 1); /* from 0-based to 1-based */ + total_buckets += + (((1 << (splitpoint_group - 1)) >> HASH_SPLITPOINT_PHASE_BITS) * + phases_within_splitpoint_group); + + return total_buckets; +} + +/* * _hash_checkpage -- sanity checks on the format of all hash pages * * If flags is not zero, it is a bitwise OR of the acceptable values of |