diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/storage/ipc/shmem.c | 16 | ||||
| -rw-r--r-- | src/backend/utils/hash/dynahash.c | 35 |
2 files changed, 39 insertions, 12 deletions
diff --git a/src/backend/storage/ipc/shmem.c b/src/backend/storage/ipc/shmem.c index 28298dda742..1a4d8127553 100644 --- a/src/backend/storage/ipc/shmem.c +++ b/src/backend/storage/ipc/shmem.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.48 2000/01/26 05:56:58 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.49 2000/02/26 05:25:55 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -332,7 +332,7 @@ ShmemIsValid(unsigned long addr) HTAB * ShmemInitHash(char *name, /* table string name for shmem index */ long init_size, /* initial table size */ - long max_size, /* max size of the table (NOT USED) */ + long max_size, /* max size of the table */ HASHCTL *infoP, /* info about key and bucket size */ int hash_flags) /* info about infoP */ { @@ -340,19 +340,21 @@ ShmemInitHash(char *name, /* table string name for shmem index */ long *location; /* - * Hash tables allocated in shared memory have a fixed directory; it - * can't grow or other backends wouldn't be able to find it. The - * segbase is for calculating pointer values. The shared memory + * Hash tables allocated in shared memory have a fixed directory; + * it can't grow or other backends wouldn't be able to find it. + * So, make sure we make it big enough to start with. + * + * The segbase is for calculating pointer values. The shared memory * allocator must be specified too. */ - infoP->dsize = infoP->max_dsize = DEF_DIRSIZE; + infoP->dsize = infoP->max_dsize = hash_select_dirsize(max_size); infoP->segbase = (long *) ShmemBase; infoP->alloc = ShmemAlloc; hash_flags |= HASH_SHARED_MEM | HASH_DIRSIZE; /* look it up in the shmem index */ location = ShmemInitStruct(name, - sizeof(HHDR) + DEF_DIRSIZE * sizeof(SEG_OFFSET), + sizeof(HHDR) + infoP->dsize * sizeof(SEG_OFFSET), &found); /* diff --git a/src/backend/utils/hash/dynahash.c b/src/backend/utils/hash/dynahash.c index 0cb235b62bc..341e6027a12 100644 --- a/src/backend/utils/hash/dynahash.c +++ b/src/backend/utils/hash/dynahash.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/hash/dynahash.c,v 1.28 2000/01/26 05:57:24 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/hash/dynahash.c,v 1.29 2000/02/26 05:25:54 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -328,10 +328,7 @@ init_htab(HTAB *hashp, int nelem) { *segp = seg_alloc(hashp); if (*segp == (SEG_OFFSET) 0) - { - hash_destroy(hashp); - return 0; - } + return -1; } #if HASH_DEBUG @@ -392,6 +389,34 @@ hash_estimate_size(long num_entries, long keysize, long datasize) return size; } +/* + * Select an appropriate directory size for a hashtable with the given + * maximum number of entries. + * This is only needed for hashtables in shared memory, whose directories + * cannot be expanded dynamically. + * NB: assumes that all hash structure parameters have default values! + * + * XXX this had better agree with the behavior of init_htab()... + */ +long +hash_select_dirsize(long num_entries) +{ + long nBuckets, + nSegments, + nDirEntries; + + /* estimate number of buckets wanted */ + nBuckets = 1L << my_log2((num_entries - 1) / DEF_FFACTOR + 1); + /* # of segments needed for nBuckets */ + nSegments = 1L << my_log2((nBuckets - 1) / DEF_SEGSIZE + 1); + /* directory entries */ + nDirEntries = DEF_DIRSIZE; + while (nDirEntries < nSegments) + nDirEntries <<= 1; /* dir_alloc doubles dsize at each call */ + + return nDirEntries; +} + /********************** DESTROY ROUTINES ************************/ |