diff options
Diffstat (limited to 'src/include/utils/hsearch.h')
| -rw-r--r-- | src/include/utils/hsearch.h | 98 |
1 files changed, 22 insertions, 76 deletions
diff --git a/src/include/utils/hsearch.h b/src/include/utils/hsearch.h index a89be514d90..c682cf03295 100644 --- a/src/include/utils/hsearch.h +++ b/src/include/utils/hsearch.h @@ -1,13 +1,13 @@ /*------------------------------------------------------------------------- * * hsearch.h - * for hash tables, particularly hash tables in shared memory + * exported definitions for utils/hash/dynahash.c; see notes therein * * * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/utils/hsearch.h,v 1.43 2006/06/25 18:29:49 tgl Exp $ + * $PostgreSQL: pgsql/src/include/utils/hsearch.h,v 1.44 2006/07/22 23:04:39 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -44,27 +44,6 @@ typedef void *(*HashCopyFunc) (void *dest, const void *src, Size keysize); typedef void *(*HashAllocFunc) (Size request); /* - * Constants - * - * A hash table has a top-level "directory", each of whose entries points - * to a "segment" of ssize bucket headers. The maximum number of hash - * buckets is thus dsize * ssize (but dsize may be expansible). Of course, - * the number of records in the table can be larger, but we don't want a - * whole lot of records per bucket or performance goes down. - * - * In a hash table allocated in shared memory, the directory cannot be - * expanded because it must stay at a fixed address. The directory size - * should be selected using hash_select_dirsize (and you'd better have - * a good idea of the maximum number of entries!). For non-shared hash - * tables, the initial directory size can be left at the default. - */ -#define DEF_SEGSIZE 256 -#define DEF_SEGSIZE_SHIFT 8 /* must be log2(DEF_SEGSIZE) */ -#define DEF_DIRSIZE 256 -#define DEF_FFACTOR 1 /* default fill factor */ - - -/* * HASHELEMENT is the private part of a hashtable entry. The caller's data * follows the HASHELEMENT structure (on a MAXALIGN'd boundary). The hash key * is expected to be at the start of the caller's hash entry data structure. @@ -75,81 +54,42 @@ typedef struct HASHELEMENT uint32 hashvalue; /* hash function result for this entry */ } HASHELEMENT; -/* A hash bucket is a linked list of HASHELEMENTs */ -typedef HASHELEMENT *HASHBUCKET; +/* Hash table header struct is an opaque type known only within dynahash.c */ +typedef struct HASHHDR HASHHDR; -/* A hash segment is an array of bucket headers */ -typedef HASHBUCKET *HASHSEGMENT; - -/* Header structure for a hash table --- contains all changeable info */ -typedef struct HASHHDR -{ - long dsize; /* Directory Size */ - long ssize; /* Segment Size --- must be power of 2 */ - int sshift; /* Segment shift = log2(ssize) */ - uint32 max_bucket; /* ID of Maximum bucket in use */ - uint32 high_mask; /* Mask to modulo into entire table */ - uint32 low_mask; /* Mask to modulo into lower half of table */ - long ffactor; /* Fill factor */ - long nentries; /* Number of entries in hash table */ - long nsegs; /* Number of allocated segments */ - Size keysize; /* hash key length in bytes */ - Size entrysize; /* total user element size in bytes */ - long max_dsize; /* 'dsize' limit if directory is fixed size */ - int nelem_alloc; /* number of entries to allocate at once */ - HASHELEMENT *freeList; /* linked list of free elements */ -#ifdef HASH_STATISTICS - long accesses; - long collisions; -#endif -} HASHHDR; - -/* - * Top control structure for a hashtable --- need not be shared, since - * no fields change at runtime - */ -typedef struct HTAB -{ - HASHHDR *hctl; /* shared control information */ - HASHSEGMENT *dir; /* directory of segment starts */ - HashValueFunc hash; /* hash function */ - HashCompareFunc match; /* key comparison function */ - HashCopyFunc keycopy; /* key copying function */ - HashAllocFunc alloc; /* memory allocator */ - MemoryContext hcxt; /* memory context if default allocator used */ - char *tabname; /* table name (for error messages) */ - bool isshared; /* true if table is in shared memory */ -} HTAB; +/* Hash table control struct is an opaque type known only within dynahash.c */ +typedef struct HTAB HTAB; /* Parameter data structure for hash_create */ /* Only those fields indicated by hash_flags need be set */ typedef struct HASHCTL { - long ssize; /* Segment Size */ - long dsize; /* (initial) Directory Size */ - long max_dsize; /* limit to dsize if directory size is limited */ - long ffactor; /* Fill factor */ + long num_partitions; /* # partitions (must be power of 2) */ + long ssize; /* segment size */ + long dsize; /* (initial) directory size */ + long max_dsize; /* limit to dsize if dir size is limited */ + long ffactor; /* fill factor */ Size keysize; /* hash key length in bytes */ Size entrysize; /* total user element size in bytes */ HashValueFunc hash; /* hash function */ HashCompareFunc match; /* key comparison function */ HashCopyFunc keycopy; /* key copying function */ HashAllocFunc alloc; /* memory allocator */ - HASHSEGMENT *dir; /* directory of segment starts */ - HASHHDR *hctl; /* location of header in shared mem */ MemoryContext hcxt; /* memory context to use for allocations */ + HASHHDR *hctl; /* location of header in shared mem */ } HASHCTL; /* Flags to indicate which parameters are supplied */ +#define HASH_PARTITION 0x001 /* Hashtable is used w/partitioned locking */ #define HASH_SEGMENT 0x002 /* Set segment size */ -#define HASH_DIRSIZE 0x004 /* Set directory size */ +#define HASH_DIRSIZE 0x004 /* Set directory size (initial and max) */ #define HASH_FFACTOR 0x008 /* Set fill factor */ #define HASH_FUNCTION 0x010 /* Set user defined hash function */ -#define HASH_ELEM 0x020 /* Set key/entry size */ +#define HASH_ELEM 0x020 /* Set keysize and entrysize */ #define HASH_SHARED_MEM 0x040 /* Hashtable is in shared memory */ #define HASH_ATTACH 0x080 /* Do not initialize hctl */ #define HASH_ALLOC 0x100 /* Set memory allocator */ -#define HASH_CONTEXT 0x200 /* Set explicit memory context */ +#define HASH_CONTEXT 0x200 /* Set memory allocation context */ #define HASH_COMPARE 0x400 /* Set user defined comparison function */ #define HASH_KEYCOPY 0x800 /* Set user defined key-copying function */ @@ -183,10 +123,16 @@ extern void hash_destroy(HTAB *hashp); extern void hash_stats(const char *where, HTAB *hashp); extern void *hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr); +extern uint32 get_hash_value(HTAB *hashp, const void *keyPtr); +extern void *hash_search_with_hash_value(HTAB *hashp, const void *keyPtr, + uint32 hashvalue, HASHACTION action, + bool *foundPtr); +extern long hash_get_num_entries(HTAB *hashp); extern void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp); extern void *hash_seq_search(HASH_SEQ_STATUS *status); extern Size hash_estimate_size(long num_entries, Size entrysize); extern long hash_select_dirsize(long num_entries); +extern Size hash_get_shared_size(HASHCTL *info, int flags); /* * prototypes for functions in hashfn.c |