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Repair some pretty serious problems in dynahash.c and

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shared memory space allocation.  It's a wonder we have not seen bug
reports traceable to this area ... it's quite clear that the routine
dir_realloc() has never worked correctly, for example.
This commit is contained in:
Tom Lane
1999-02-22 06:16:57 +00:00
parent ceb233ed11
commit bcfdc9df04
7 changed files with 176 additions and 171 deletions
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33
src/include/utils/hsearch.h
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@@ -6,7 +6,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: hsearch.h,v 1.10 1999/02/13 23:22:22 momjian Exp $
* $Id: hsearch.h,v 1.11 1999/02/22 06:16:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -16,16 +16,23 @@
/*
* 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.
*/
#define DEF_BUCKET_SIZE 256
#define DEF_BUCKET_SHIFT 8/* log2(BUCKET) */
#define DEF_SEGSIZE 256
#define DEF_SEGSIZE_SHIFT 8 /* log2(SEGSIZE) */
#define DEF_SEGSIZE_SHIFT 8 /* log2(SEGSIZE) */
#define DEF_DIRSIZE 256
#define PRIME1 37
#define DEF_FFACTOR 1 /* default fill factor */
#define PRIME1 37 /* for the hash function */
#define PRIME2 1048583
#define DEF_FFACTOR 1
#define SPLTMAX 8
/*
@@ -46,10 +53,8 @@ typedef unsigned long SEG_OFFSET;
typedef struct hashhdr
{
long bsize; /* Bucket/Page Size */
long bshift; /* Bucket shift */
long dsize; /* Directory Size */
long ssize; /* Segment Size */
long ssize; /* Segment Size --- must be power of 2 */
long sshift; /* Segment shift */
long max_bucket; /* ID of Maximum bucket in use */
long high_mask; /* Mask to modulo into entire table */
@@ -59,8 +64,7 @@ typedef struct hashhdr
long nsegs; /* Number of allocated segments */
long keysize; /* hash key length in bytes */
long datasize; /* elem data length in bytes */
long max_dsize; /* 'dsize' limit if directory is fixed
* size */
long max_dsize; /* 'dsize' limit if directory is fixed size */
BUCKET_INDEX freeBucketIndex;
/* index of first free bucket */
#ifdef HASH_STATISTICS
@@ -83,14 +87,13 @@ typedef struct htab
typedef struct hashctl
{
long bsize; /* Bucket Size */
long ssize; /* Segment Size */
long dsize; /* Dirsize Size */
long ffactor; /* Fill factor */
long (*hash) (); /* Hash Function */
long keysize; /* hash key length in bytes */
long datasize; /* elem data length in bytes */
long max_size; /* limit to dsize if directory size is
long max_dsize; /* limit to dsize if directory size is
* limited */
long *segbase; /* base for calculating bucket + seg ptrs */
long *(*alloc) (); /* memory allocation function */
@@ -100,7 +103,6 @@ typedef struct hashctl
} HASHCTL;
/* Flags to indicate action for hctl */
#define HASH_BUCKET 0x001 /* Setting bucket size */
#define HASH_SEGMENT 0x002 /* Setting segment size */
#define HASH_DIRSIZE 0x004 /* Setting directory size */
#define HASH_FFACTOR 0x008 /* Setting fill factor */
@@ -136,6 +138,7 @@ extern void hash_stats(char *where, HTAB *hashp);
extern long *hash_search(HTAB *hashp, char *keyPtr, HASHACTION action,
bool *foundPtr);
extern long *hash_seq(HTAB *hashp);
extern long hash_estimate_size(long num_entries, long keysize, long datasize);
/*
* prototypes from functions in hashfn.c