diff options
Diffstat (limited to 'src/backend/utils/hash/dynahash.c')
| -rw-r--r-- | src/backend/utils/hash/dynahash.c | 78 |
1 files changed, 37 insertions, 41 deletions
diff --git a/src/backend/utils/hash/dynahash.c b/src/backend/utils/hash/dynahash.c index 66be64a4e56..292673ac26a 100644 --- a/src/backend/utils/hash/dynahash.c +++ b/src/backend/utils/hash/dynahash.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/hash/dynahash.c,v 1.64 2005/08/20 23:26:24 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/hash/dynahash.c,v 1.65 2005/10/15 02:49:33 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -115,14 +115,14 @@ hash_create(const char *tabname, long nelem, HASHCTL *info, int flags) HASHHDR *hctl; /* - * For shared hash tables, we have a local hash header (HTAB struct) - * that we allocate in TopMemoryContext; all else is in shared memory. + * For shared hash tables, we have a local hash header (HTAB struct) that + * we allocate in TopMemoryContext; all else is in shared memory. * - * For non-shared hash tables, everything including the hash header - * is in a memory context created specially for the hash table --- - * this makes hash_destroy very simple. The memory context is made - * a child of either a context specified by the caller, or - * TopMemoryContext if nothing is specified. + * For non-shared hash tables, everything including the hash header is in a + * memory context created specially for the hash table --- this makes + * hash_destroy very simple. The memory context is made a child of either + * a context specified by the caller, or TopMemoryContext if nothing is + * specified. */ if (flags & HASH_SHARED_MEM) { @@ -144,7 +144,7 @@ hash_create(const char *tabname, long nelem, HASHCTL *info, int flags) } /* Initialize the hash header, plus a copy of the table name */ - hashp = (HTAB *) DynaHashAlloc(sizeof(HTAB) + strlen(tabname) + 1); + hashp = (HTAB *) DynaHashAlloc(sizeof(HTAB) + strlen(tabname) +1); MemSet(hashp, 0, sizeof(HTAB)); hashp->tabname = (char *) (hashp + 1); @@ -156,10 +156,9 @@ hash_create(const char *tabname, long nelem, HASHCTL *info, int flags) hashp->hash = string_hash; /* default hash function */ /* - * If you don't specify a match function, it defaults to strncmp() if - * you used string_hash (either explicitly or by default) and to - * memcmp() otherwise. (Prior to PostgreSQL 7.4, memcmp() was always - * used.) + * If you don't specify a match function, it defaults to strncmp() if you + * used string_hash (either explicitly or by default) and to memcmp() + * otherwise. (Prior to PostgreSQL 7.4, memcmp() was always used.) */ if (flags & HASH_COMPARE) hashp->match = info->match; @@ -186,8 +185,8 @@ hash_create(const char *tabname, long nelem, HASHCTL *info, int flags) if (flags & HASH_SHARED_MEM) { /* - * ctl structure is preallocated for shared memory tables. Note - * that HASH_DIRSIZE and HASH_ALLOC had better be set as well. + * ctl structure is preallocated for shared memory tables. Note that + * HASH_DIRSIZE and HASH_ALLOC had better be set as well. */ hashp->hctl = info->hctl; hashp->dir = info->dir; @@ -243,8 +242,8 @@ hash_create(const char *tabname, long nelem, HASHCTL *info, int flags) } /* - * hash table now allocates space for key and data but you have to say - * how much space to allocate + * hash table now allocates space for key and data but you have to say how + * much space to allocate */ if (flags & HASH_ELEM) { @@ -318,8 +317,8 @@ init_htab(HTAB *hashp, long nelem) /* * Divide number of elements by the fill factor to determine a desired - * number of buckets. Allocate space for the next greater power of - * two number of buckets + * number of buckets. Allocate space for the next greater power of two + * number of buckets */ lnbuckets = (nelem - 1) / hctl->ffactor + 1; @@ -329,15 +328,14 @@ init_htab(HTAB *hashp, long nelem) hctl->high_mask = (nbuckets << 1) - 1; /* - * Figure number of directory segments needed, round up to a power of - * 2 + * Figure number of directory segments needed, round up to a power of 2 */ nsegs = (nbuckets - 1) / hctl->ssize + 1; nsegs = 1 << my_log2(nsegs); /* - * Make sure directory is big enough. If pre-allocated directory is - * too small, choke (caller screwed up). + * Make sure directory is big enough. If pre-allocated directory is too + * small, choke (caller screwed up). */ if (nsegs > hctl->dsize) { @@ -418,7 +416,7 @@ hash_estimate_size(long num_entries, Size entrysize) size = add_size(size, mul_size(nDirEntries, sizeof(HASHSEGMENT))); /* segments */ size = add_size(size, mul_size(nSegments, - MAXALIGN(DEF_SEGSIZE * sizeof(HASHBUCKET)))); + MAXALIGN(DEF_SEGSIZE * sizeof(HASHBUCKET)))); /* elements --- allocated in groups of up to HASHELEMENT_ALLOC_MAX */ elementSize = MAXALIGN(sizeof(HASHELEMENT)) + MAXALIGN(entrysize); elementAllocCnt = Min(num_entries, HASHELEMENT_ALLOC_MAX); @@ -528,7 +526,7 @@ calc_bucket(HASHHDR *hctl, uint32 hash_val) * the result is a dangling pointer that shouldn't be dereferenced!) * * HASH_ENTER will normally ereport a generic "out of memory" error if - * it is unable to create a new entry. The HASH_ENTER_NULL operation is + * it is unable to create a new entry. The HASH_ENTER_NULL operation is * the same except it will return NULL if out of memory. Note that * HASH_ENTER_NULL cannot be used with the default palloc-based allocator, * since palloc internally ereports on out-of-memory. @@ -623,8 +621,8 @@ hash_search(HTAB *hashp, /* * better hope the caller is synchronizing access to this - * element, because someone else is going to reuse it the - * next time something is added to the table + * element, because someone else is going to reuse it the next + * time something is added to the table */ return (void *) ELEMENTKEY(currBucket); } @@ -680,9 +678,8 @@ hash_search(HTAB *hashp, if (++hctl->nentries / (long) (hctl->max_bucket + 1) >= hctl->ffactor) { /* - * NOTE: failure to expand table is not a fatal error, it - * just means we have to run at higher fill factor than we - * wanted. + * NOTE: failure to expand table is not a fatal error, it just + * means we have to run at higher fill factor than we wanted. */ expand_table(hashp); } @@ -731,7 +728,7 @@ hash_seq_search(HASH_SEQ_STATUS *status) { /* Continuing scan of curBucket... */ status->curEntry = curElem->link; - if (status->curEntry == NULL) /* end of this bucket */ + if (status->curEntry == NULL) /* end of this bucket */ ++status->curBucket; return (void *) ELEMENTKEY(curElem); } @@ -746,7 +743,7 @@ hash_seq_search(HASH_SEQ_STATUS *status) max_bucket = hctl->max_bucket; if (curBucket > max_bucket) - return NULL; /* search is done */ + return NULL; /* search is done */ /* * first find the right segment in the table directory. @@ -768,7 +765,7 @@ hash_seq_search(HASH_SEQ_STATUS *status) if (++curBucket > max_bucket) { status->curBucket = curBucket; - return NULL; /* search is done */ + return NULL; /* search is done */ } if (++segment_ndx >= ssize) { @@ -833,10 +830,9 @@ expand_table(HTAB *hashp) /* * *Before* changing masks, find old bucket corresponding to same hash - * values; values in that bucket may need to be relocated to new - * bucket. Note that new_bucket is certainly larger than low_mask at - * this point, so we can skip the first step of the regular hash mask - * calc. + * values; values in that bucket may need to be relocated to new bucket. + * Note that new_bucket is certainly larger than low_mask at this point, + * so we can skip the first step of the regular hash mask calc. */ old_bucket = (new_bucket & hctl->low_mask); @@ -850,10 +846,10 @@ expand_table(HTAB *hashp) } /* - * Relocate records to the new bucket. NOTE: because of the way the - * hash masking is done in calc_bucket, only one old bucket can need - * to be split at this point. With a different way of reducing the - * hash value, that might not be true! + * Relocate records to the new bucket. NOTE: because of the way the hash + * masking is done in calc_bucket, only one old bucket can need to be + * split at this point. With a different way of reducing the hash value, + * that might not be true! */ old_segnum = old_bucket >> hctl->sshift; old_segndx = MOD(old_bucket, hctl->ssize); |