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A few further tweaks to shared memory space estimation.

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This change brings the default size of the main shmem block back under 1MB,
which is a fairly popular value for the kernel's SHMMAX parameter.
This commit is contained in:
Tom Lane
1999-03-06 21:17:56 +00:00
parent 03842eb03b
commit 731603a92b
5 changed files with 42 additions and 27 deletions
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26
src/backend/utils/hash/dynahash.c
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@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/hash/dynahash.c,v 1.19 1999/02/22 06:16:47 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/hash/dynahash.c,v 1.20 1999/03/06 21:17:56 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -373,18 +373,23 @@ hash_estimate_size(long num_entries, long keysize, long datasize)
long size = 0;
long nBuckets,
nSegments,
nDirEntries,
nRecordAllocs,
recordSize;
/* estimate number of buckets wanted */
nBuckets = 1L << my_log2((num_entries - 1) / DEF_FFACTOR + 1);
/* # of segments needed for nBuckets */
nSegments = (nBuckets - 1) / DEF_SEGSIZE + 1;
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 */
/* fixed control info */
size += MAXALIGN(sizeof(HHDR)); /* but not HTAB, per above */
/* directory, assumed to be of size DEF_DIRSIZE */
size += MAXALIGN(DEF_DIRSIZE * sizeof(SEG_OFFSET));
/* directory */
size += MAXALIGN(nDirEntries * sizeof(SEG_OFFSET));
/* segments */
size += nSegments * MAXALIGN(DEF_SEGSIZE * sizeof(BUCKET_INDEX));
/* records --- allocated in groups of BUCKET_ALLOC_INCR */
@@ -408,9 +413,6 @@ hash_estimate_size(long num_entries, long keysize, long datasize)
void
hash_destroy(HTAB *hashp)
{
/* cannot destroy a shared memory hash table */
Assert(!hashp->segbase);
if (hashp != NULL)
{
SEG_OFFSET segNum;
@@ -422,6 +424,13 @@ hash_destroy(HTAB *hashp)
q;
ELEMENT *curr;
/* cannot destroy a shared memory hash table */
Assert(!hashp->segbase);
/* allocation method must be one we know how to free, too */
Assert(hashp->alloc == (dhalloc_ptr) MEM_ALLOC);
hash_stats("destroy", hashp);
for (segNum = 0; nsegs > 0; nsegs--, segNum++)
{
@@ -435,11 +444,10 @@ hash_destroy(HTAB *hashp)
MEM_FREE((char *) curr);
}
}
free((char *) segp);
MEM_FREE((char *) segp);
}
MEM_FREE((char *) hashp->dir);
MEM_FREE((char *) hashp->hctl);
hash_stats("destroy", hashp);
MEM_FREE((char *) hashp);
}
}