dynahash.c File Reference

#include "postgres.h"
#include <limits.h>
#include "access/xact.h"
#include "common/hashfn.h"
#include "port/pg_bitutils.h"
#include "storage/shmem.h"
#include "storage/spin.h"
#include "utils/dynahash.h"
#include "utils/memutils.h"

Include dependency graph for dynahash.c:

Go to the source code of this file.

Data Structures
struct	FreeListData
struct	HASHHDR
struct	HTAB

Macros
#define	DEF_SEGSIZE   256
#define	DEF_SEGSIZE_SHIFT   8 /* must be log2(DEF_SEGSIZE) */
#define	DEF_DIRSIZE   256
#define	NUM_FREELISTS   32
#define	IS_PARTITIONED(hctl)   ((hctl)->num_partitions != 0)
#define	FREELIST_IDX(hctl, hashcode)    (IS_PARTITIONED(hctl) ? (hashcode) % NUM_FREELISTS : 0)
#define	ELEMENTKEY(helem)   (((char *)(helem)) + MAXALIGN(sizeof(HASHELEMENT)))
#define	ELEMENT_FROM_KEY(key)    ((HASHELEMENT *) (((char *) (key)) - MAXALIGN(sizeof(HASHELEMENT))))
#define	MOD(x, y)   ((x) & ((y)-1))
#define	MAX_SEQ_SCANS   100

Typedefs
typedef HASHELEMENT *	HASHBUCKET
typedef HASHBUCKET *	HASHSEGMENT

Functions
static void *	DynaHashAlloc (Size size)
static HASHSEGMENT	seg_alloc (HTAB *hashp)
static bool	element_alloc (HTAB *hashp, int nelem, int freelist_idx)
static bool	dir_realloc (HTAB *hashp)
static bool	expand_table (HTAB *hashp)
static HASHBUCKET	get_hash_entry (HTAB *hashp, int freelist_idx)
static void	hdefault (HTAB *hashp)
static int	choose_nelem_alloc (Size entrysize)
static bool	init_htab (HTAB *hashp, long nelem)
static void	hash_corrupted (HTAB *hashp)
static long	next_pow2_long (long num)
static int	next_pow2_int (long num)
static void	register_seq_scan (HTAB *hashp)
static void	deregister_seq_scan (HTAB *hashp)
static bool	has_seq_scans (HTAB *hashp)
static int	string_compare (const char *key1, const char *key2, Size keysize)
HTAB *	hash_create (const char *tabname, long nelem, const HASHCTL *info, int flags)
Size	hash_estimate_size (long num_entries, Size entrysize)
long	hash_select_dirsize (long num_entries)
Size	hash_get_shared_size (HASHCTL *info, int flags)
void	hash_destroy (HTAB *hashp)
void	hash_stats (const char *where, HTAB *hashp)
uint32	get_hash_value (HTAB *hashp, const void *keyPtr)
static uint32	calc_bucket (HASHHDR *hctl, uint32 hash_val)
void *	hash_search (HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
void *	hash_search_with_hash_value (HTAB *hashp, const void *keyPtr, uint32 hashvalue, HASHACTION action, bool *foundPtr)
bool	hash_update_hash_key (HTAB *hashp, void *existingEntry, const void *newKeyPtr)
long	hash_get_num_entries (HTAB *hashp)
void	hash_seq_init (HASH_SEQ_STATUS *status, HTAB *hashp)
void *	hash_seq_search (HASH_SEQ_STATUS *status)
void	hash_seq_term (HASH_SEQ_STATUS *status)
void	hash_freeze (HTAB *hashp)
int	my_log2 (long num)
void	AtEOXact_HashTables (bool isCommit)
void	AtEOSubXact_HashTables (bool isCommit, int nestDepth)

Variables
static MemoryContext	CurrentDynaHashCxt = NULL
static HTAB *	seq_scan_tables [MAX_SEQ_SCANS]
static int	seq_scan_level [MAX_SEQ_SCANS]
static int	num_seq_scans = 0

Macro Definition Documentation

DEF_DIRSIZE

#define DEF_DIRSIZE   256

Definition at line 125 of file dynahash.c.

DEF_SEGSIZE

#define DEF_SEGSIZE   256

Definition at line 123 of file dynahash.c.

DEF_SEGSIZE_SHIFT

#define DEF_SEGSIZE_SHIFT   8 /* must be log2(DEF_SEGSIZE) */

Definition at line 124 of file dynahash.c.

ELEMENT_FROM_KEY

#define ELEMENT_FROM_KEY

(

key

)

((HASHELEMENT *) (((char *) (key)) - MAXALIGN(sizeof(HASHELEMENT))))

Definition at line 249 of file dynahash.c.

ELEMENTKEY

#define ELEMENTKEY

(

helem

)

(((char *)(helem)) + MAXALIGN(sizeof(HASHELEMENT)))

Definition at line 244 of file dynahash.c.

FREELIST_IDX

#define FREELIST_IDX	(		hctl,
			hashcode
	)		(IS_PARTITIONED(hctl) ? (hashcode) % NUM_FREELISTS : 0)

Definition at line 212 of file dynahash.c.

IS_PARTITIONED

#define IS_PARTITIONED

(

hctl

)

((hctl)->num_partitions != 0)

Definition at line 210 of file dynahash.c.

MAX_SEQ_SCANS

#define MAX_SEQ_SCANS   100

Definition at line 1822 of file dynahash.c.

MOD

#define MOD	(		x,
			y
	)		((x) & ((y)-1))

Definition at line 255 of file dynahash.c.

NUM_FREELISTS

#define NUM_FREELISTS   32

Definition at line 128 of file dynahash.c.

Typedef Documentation

HASHBUCKET

typedef HASHELEMENT* HASHBUCKET

Definition at line 131 of file dynahash.c.

HASHSEGMENT

typedef HASHBUCKET* HASHSEGMENT

Definition at line 134 of file dynahash.c.

Function Documentation

AtEOSubXact_HashTables()

void AtEOSubXact_HashTables	(	bool	isCommit,
		int	nestDepth
	)

Definition at line 1904 of file dynahash.c.

{
    int         i;
 
    /*
     * Search backward to make cleanup easy.  Note we must check all entries,
     * not only those at the end of the array, because deletion technique
     * doesn't keep them in order.
     */
    for (i = num_seq_scans - 1; i >= 0; i--)
    {
        if (seq_scan_level[i] >= nestDepth)
        {
            if (isCommit)
                elog(WARNING, "leaked hash_seq_search scan for hash table %p",
                     seq_scan_tables[i]);
            seq_scan_tables[i] = seq_scan_tables[num_seq_scans - 1];
            seq_scan_level[i] = seq_scan_level[num_seq_scans - 1];
            num_seq_scans--;
        }
    }
}

References elog(), i, num_seq_scans, seq_scan_level, seq_scan_tables, and WARNING.

Referenced by AbortSubTransaction(), and CommitSubTransaction().

AtEOXact_HashTables()

void AtEOXact_HashTables

(

bool

isCommit

)

Definition at line 1878 of file dynahash.c.

{
    /*
     * During abort cleanup, open scans are expected; just silently clean 'em
     * out.  An open scan at commit means someone forgot a hash_seq_term()
     * call, so complain.
     *
     * Note: it's tempting to try to print the tabname here, but refrain for
     * fear of touching deallocated memory.  This isn't a user-facing message
     * anyway, so it needn't be pretty.
     */
    if (isCommit)
    {
        int         i;
 
        for (i = 0; i < num_seq_scans; i++)
        {
            elog(WARNING, "leaked hash_seq_search scan for hash table %p",
                 seq_scan_tables[i]);
        }
    }
    num_seq_scans = 0;
}

References elog(), i, num_seq_scans, seq_scan_tables, and WARNING.

Referenced by AbortTransaction(), AutoVacLauncherMain(), BackgroundWriterMain(), CheckpointerMain(), CommitTransaction(), PrepareTransaction(), and WalWriterMain().

calc_bucket()

static uint32 calc_bucket ( HASHHDR *  hctl, uint32  hash_val  )

inlinestatic

Definition at line 916 of file dynahash.c.

{
    uint32      bucket;
 
    bucket = hash_val & hctl->high_mask;
    if (bucket > hctl->max_bucket)
        bucket = bucket & hctl->low_mask;
 
    return bucket;
}

References HASHHDR::high_mask, HASHHDR::low_mask, and HASHHDR::max_bucket.

Referenced by expand_table(), hash_search_with_hash_value(), and hash_update_hash_key().

choose_nelem_alloc()

static int choose_nelem_alloc ( Size  entrysize )

static

Definition at line 654 of file dynahash.c.

{
    int         nelem_alloc;
    Size        elementSize;
    Size        allocSize;
 
    /* Each element has a HASHELEMENT header plus user data. */
    /* NB: this had better match element_alloc() */
    elementSize = MAXALIGN(sizeof(HASHELEMENT)) + MAXALIGN(entrysize);
 
    /*
     * The idea here is to choose nelem_alloc at least 32, but round up so
     * that the allocation request will be a power of 2 or just less. This
     * makes little difference for hash tables in shared memory, but for hash
     * tables managed by palloc, the allocation request will be rounded up to
     * a power of 2 anyway.  If we fail to take this into account, we'll waste
     * as much as half the allocated space.
     */
    allocSize = 32 * 4;         /* assume elementSize at least 8 */
    do
    {
        allocSize <<= 1;
        nelem_alloc = allocSize / elementSize;
    } while (nelem_alloc < 32);
 
    return nelem_alloc;
}

References MAXALIGN.

Referenced by hash_estimate_size(), and init_htab().

deregister_seq_scan()

static void deregister_seq_scan ( HTAB *  hashp )

static

Definition at line 1843 of file dynahash.c.

{
    int         i;
 
    /* Search backward since it's most likely at the stack top */
    for (i = num_seq_scans - 1; i >= 0; i--)
    {
        if (seq_scan_tables[i] == hashp)
        {
            seq_scan_tables[i] = seq_scan_tables[num_seq_scans - 1];
            seq_scan_level[i] = seq_scan_level[num_seq_scans - 1];
            num_seq_scans--;
            return;
        }
    }
    elog(ERROR, "no hash_seq_search scan for hash table \"%s\"",
         hashp->tabname);
}

References elog(), ERROR, i, num_seq_scans, seq_scan_level, seq_scan_tables, and HTAB::tabname.

Referenced by hash_seq_term().

dir_realloc()

static bool dir_realloc ( HTAB *  hashp )

static

Definition at line 1641 of file dynahash.c.

{
    HASHSEGMENT *p;
    HASHSEGMENT *old_p;
    long        new_dsize;
    long        old_dirsize;
    long        new_dirsize;
 
    if (hashp->hctl->max_dsize != NO_MAX_DSIZE)
        return false;
 
    /* Reallocate directory */
    new_dsize = hashp->hctl->dsize << 1;
    old_dirsize = hashp->hctl->dsize * sizeof(HASHSEGMENT);
    new_dirsize = new_dsize * sizeof(HASHSEGMENT);
 
    old_p = hashp->dir;
    CurrentDynaHashCxt = hashp->hcxt;
    p = (HASHSEGMENT *) hashp->alloc((Size) new_dirsize);
 
    if (p != NULL)
    {
        memcpy(p, old_p, old_dirsize);
        MemSet(((char *) p) + old_dirsize, 0, new_dirsize - old_dirsize);
        hashp->dir = p;
        hashp->hctl->dsize = new_dsize;
 
        /* XXX assume the allocator is palloc, so we know how to free */
        Assert(hashp->alloc == DynaHashAlloc);
        pfree(old_p);
 
        return true;
    }
 
    return false;
}

References HTAB::alloc, Assert(), CurrentDynaHashCxt, HTAB::dir, HASHHDR::dsize, DynaHashAlloc(), HTAB::hctl, HTAB::hcxt, HASHHDR::max_dsize, MemSet, NO_MAX_DSIZE, and pfree().

Referenced by expand_table().

DynaHashAlloc()

static void * DynaHashAlloc ( Size  size )

static

Definition at line 289 of file dynahash.c.

{
    Assert(MemoryContextIsValid(CurrentDynaHashCxt));
    return MemoryContextAllocExtended(CurrentDynaHashCxt, size,
                                      MCXT_ALLOC_NO_OOM);
}

References Assert(), CurrentDynaHashCxt, MCXT_ALLOC_NO_OOM, MemoryContextAllocExtended(), and MemoryContextIsValid.

Referenced by dir_realloc(), hash_create(), and hash_destroy().

element_alloc()

static bool element_alloc ( HTAB *  hashp, int  nelem, int  freelist_idx  )

static

Definition at line 1699 of file dynahash.c.

{
    HASHHDR    *hctl = hashp->hctl;
    Size        elementSize;
    HASHELEMENT *firstElement;
    HASHELEMENT *tmpElement;
    HASHELEMENT *prevElement;
    int         i;
 
    if (hashp->isfixed)
        return false;
 
    /* Each element has a HASHELEMENT header plus user data. */
    elementSize = MAXALIGN(sizeof(HASHELEMENT)) + MAXALIGN(hctl->entrysize);
 
    CurrentDynaHashCxt = hashp->hcxt;
    firstElement = (HASHELEMENT *) hashp->alloc(nelem * elementSize);
 
    if (!firstElement)
        return false;
 
    /* prepare to link all the new entries into the freelist */
    prevElement = NULL;
    tmpElement = firstElement;
    for (i = 0; i < nelem; i++)
    {
        tmpElement->link = prevElement;
        prevElement = tmpElement;
        tmpElement = (HASHELEMENT *) (((char *) tmpElement) + elementSize);
    }
 
    /* if partitioned, must lock to touch freeList */
    if (IS_PARTITIONED(hctl))
        SpinLockAcquire(&hctl->freeList[freelist_idx].mutex);
 
    /* freelist could be nonempty if two backends did this concurrently */
    firstElement->link = hctl->freeList[freelist_idx].freeList;
    hctl->freeList[freelist_idx].freeList = prevElement;
 
    if (IS_PARTITIONED(hctl))
        SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
 
    return true;
}

References HTAB::alloc, CurrentDynaHashCxt, HASHHDR::entrysize, FreeListData::freeList, HASHHDR::freeList, HTAB::hctl, HTAB::hcxt, i, IS_PARTITIONED, HTAB::isfixed, HASHELEMENT::link, MAXALIGN, FreeListData::mutex, SpinLockAcquire, and SpinLockRelease.

Referenced by get_hash_entry(), and hash_create().

expand_table()

static bool expand_table ( HTAB *  hashp )

static

Definition at line 1544 of file dynahash.c.

{
    HASHHDR    *hctl = hashp->hctl;
    HASHSEGMENT old_seg,
                new_seg;
    long        old_bucket,
                new_bucket;
    long        new_segnum,
                new_segndx;
    long        old_segnum,
                old_segndx;
    HASHBUCKET *oldlink,
               *newlink;
    HASHBUCKET  currElement,
                nextElement;
 
    Assert(!IS_PARTITIONED(hctl));
 
#ifdef HASH_STATISTICS
    hash_expansions++;
#endif
 
    new_bucket = hctl->max_bucket + 1;
    new_segnum = new_bucket >> hashp->sshift;
    new_segndx = MOD(new_bucket, hashp->ssize);
 
    if (new_segnum >= hctl->nsegs)
    {
        /* Allocate new segment if necessary -- could fail if dir full */
        if (new_segnum >= hctl->dsize)
            if (!dir_realloc(hashp))
                return false;
        if (!(hashp->dir[new_segnum] = seg_alloc(hashp)))
            return false;
        hctl->nsegs++;
    }
 
    /* OK, we created a new bucket */
    hctl->max_bucket++;
 
    /*
     * *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.
     */
    old_bucket = (new_bucket & hctl->low_mask);
 
    /*
     * If we crossed a power of 2, readjust masks.
     */
    if ((uint32) new_bucket > hctl->high_mask)
    {
        hctl->low_mask = hctl->high_mask;
        hctl->high_mask = (uint32) new_bucket | hctl->low_mask;
    }
 
    /*
     * 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 >> hashp->sshift;
    old_segndx = MOD(old_bucket, hashp->ssize);
 
    old_seg = hashp->dir[old_segnum];
    new_seg = hashp->dir[new_segnum];
 
    oldlink = &old_seg[old_segndx];
    newlink = &new_seg[new_segndx];
 
    for (currElement = *oldlink;
         currElement != NULL;
         currElement = nextElement)
    {
        nextElement = currElement->link;
        if ((long) calc_bucket(hctl, currElement->hashvalue) == old_bucket)
        {
            *oldlink = currElement;
            oldlink = &currElement->link;
        }
        else
        {
            *newlink = currElement;
            newlink = &currElement->link;
        }
    }
    /* don't forget to terminate the rebuilt hash chains... */
    *oldlink = NULL;
    *newlink = NULL;
 
    return true;
}

References Assert(), calc_bucket(), HTAB::dir, dir_realloc(), HASHHDR::dsize, HASHELEMENT::hashvalue, HTAB::hctl, HASHHDR::high_mask, IS_PARTITIONED, HASHELEMENT::link, HASHHDR::low_mask, HASHHDR::max_bucket, MOD, HASHHDR::nsegs, seg_alloc(), HTAB::sshift, and HTAB::ssize.

Referenced by hash_search_with_hash_value().

get_hash_entry()

static HASHBUCKET get_hash_entry ( HTAB *  hashp, int  freelist_idx  )

static

Definition at line 1292 of file dynahash.c.

{
    HASHHDR    *hctl = hashp->hctl;
    HASHBUCKET  newElement;
 
    for (;;)
    {
        /* if partitioned, must lock to touch nentries and freeList */
        if (IS_PARTITIONED(hctl))
            SpinLockAcquire(&hctl->freeList[freelist_idx].mutex);
 
        /* try to get an entry from the freelist */
        newElement = hctl->freeList[freelist_idx].freeList;
 
        if (newElement != NULL)
            break;
 
        if (IS_PARTITIONED(hctl))
            SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
 
        /*
         * No free elements in this freelist.  In a partitioned table, there
         * might be entries in other freelists, but to reduce contention we
         * prefer to first try to get another chunk of buckets from the main
         * shmem allocator.  If that fails, though, we *MUST* root through all
         * the other freelists before giving up.  There are multiple callers
         * that assume that they can allocate every element in the initially
         * requested table size, or that deleting an element guarantees they
         * can insert a new element, even if shared memory is entirely full.
         * Failing because the needed element is in a different freelist is
         * not acceptable.
         */
        if (!element_alloc(hashp, hctl->nelem_alloc, freelist_idx))
        {
            int         borrow_from_idx;
 
            if (!IS_PARTITIONED(hctl))
                return NULL;    /* out of memory */
 
            /* try to borrow element from another freelist */
            borrow_from_idx = freelist_idx;
            for (;;)
            {
                borrow_from_idx = (borrow_from_idx + 1) % NUM_FREELISTS;
                if (borrow_from_idx == freelist_idx)
                    break;      /* examined all freelists, fail */
 
                SpinLockAcquire(&(hctl->freeList[borrow_from_idx].mutex));
                newElement = hctl->freeList[borrow_from_idx].freeList;
 
                if (newElement != NULL)
                {
                    hctl->freeList[borrow_from_idx].freeList = newElement->link;
                    SpinLockRelease(&(hctl->freeList[borrow_from_idx].mutex));
 
                    /* careful: count the new element in its proper freelist */
                    SpinLockAcquire(&hctl->freeList[freelist_idx].mutex);
                    hctl->freeList[freelist_idx].nentries++;
                    SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
 
                    return newElement;
                }
 
                SpinLockRelease(&(hctl->freeList[borrow_from_idx].mutex));
            }
 
            /* no elements available to borrow either, so out of memory */
            return NULL;
        }
    }
 
    /* remove entry from freelist, bump nentries */
    hctl->freeList[freelist_idx].freeList = newElement->link;
    hctl->freeList[freelist_idx].nentries++;
 
    if (IS_PARTITIONED(hctl))
        SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
 
    return newElement;
}

References element_alloc(), FreeListData::freeList, HASHHDR::freeList, HTAB::hctl, IS_PARTITIONED, HASHELEMENT::link, FreeListData::mutex, HASHHDR::nelem_alloc, FreeListData::nentries, NUM_FREELISTS, SpinLockAcquire, and SpinLockRelease.

Referenced by hash_search_with_hash_value().

get_hash_value()

uint32 get_hash_value	(	HTAB *	hashp,
		const void *	keyPtr
	)

Definition at line 909 of file dynahash.c.

{
    return hashp->hash(keyPtr, hashp->keysize);
}

References HTAB::hash, and HTAB::keysize.

Referenced by BufTableHashCode(), and LockTagHashCode().

has_seq_scans()

static bool has_seq_scans ( HTAB *  hashp )

static

Definition at line 1864 of file dynahash.c.

{
    int         i;
 
    for (i = 0; i < num_seq_scans; i++)
    {
        if (seq_scan_tables[i] == hashp)
            return true;
    }
    return false;
}

References i, num_seq_scans, and seq_scan_tables.

Referenced by hash_freeze(), and hash_search_with_hash_value().

hash_corrupted()

static void hash_corrupted ( HTAB *  hashp )

static

Definition at line 1746 of file dynahash.c.

{
    /*
     * If the corruption is in a shared hashtable, we'd better force a
     * systemwide restart.  Otherwise, just shut down this one backend.
     */
    if (hashp->isshared)
        elog(PANIC, "hash table \"%s\" corrupted", hashp->tabname);
    else
        elog(FATAL, "hash table \"%s\" corrupted", hashp->tabname);
}

References elog(), FATAL, HTAB::isshared, PANIC, and HTAB::tabname.

Referenced by hash_search_with_hash_value(), and hash_update_hash_key().

hash_create()

HTAB* hash_create	(	const char *	tabname,
		long	nelem,
		const HASHCTL *	info,
		int	flags
	)

Definition at line 350 of file dynahash.c.

{
    HTAB       *hashp;
    HASHHDR    *hctl;
 
    /*
     * Hash tables now allocate space for key and data, but you have to say
     * how much space to allocate.
     */
    Assert(flags & HASH_ELEM);
    Assert(info->keysize > 0);
    Assert(info->entrysize >= info->keysize);
 
    /*
     * 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.
     */
    if (flags & HASH_SHARED_MEM)
    {
        /* Set up to allocate the hash header */
        CurrentDynaHashCxt = TopMemoryContext;
    }
    else
    {
        /* Create the hash table's private memory context */
        if (flags & HASH_CONTEXT)
            CurrentDynaHashCxt = info->hcxt;
        else
            CurrentDynaHashCxt = TopMemoryContext;
        CurrentDynaHashCxt = AllocSetContextCreate(CurrentDynaHashCxt,
                                                   "dynahash",
                                                   ALLOCSET_DEFAULT_SIZES);
    }
 
    /* Initialize the hash header, plus a copy of the table name */
    hashp = (HTAB *) DynaHashAlloc(sizeof(HTAB) + strlen(tabname) + 1);
    MemSet(hashp, 0, sizeof(HTAB));
 
    hashp->tabname = (char *) (hashp + 1);
    strcpy(hashp->tabname, tabname);
 
    /* If we have a private context, label it with hashtable's name */
    if (!(flags & HASH_SHARED_MEM))
        MemoryContextSetIdentifier(CurrentDynaHashCxt, hashp->tabname);
 
    /*
     * Select the appropriate hash function (see comments at head of file).
     */
    if (flags & HASH_FUNCTION)
    {
        Assert(!(flags & (HASH_BLOBS | HASH_STRINGS)));
        hashp->hash = info->hash;
    }
    else if (flags & HASH_BLOBS)
    {
        Assert(!(flags & HASH_STRINGS));
        /* We can optimize hashing for common key sizes */
        if (info->keysize == sizeof(uint32))
            hashp->hash = uint32_hash;
        else
            hashp->hash = tag_hash;
    }
    else
    {
        /*
         * string_hash used to be considered the default hash method, and in a
         * non-assert build it effectively still is.  But we now consider it
         * an assertion error to not say HASH_STRINGS explicitly.  To help
         * catch mistaken usage of HASH_STRINGS, we also insist on a
         * reasonably long string length: if the keysize is only 4 or 8 bytes,
         * it's almost certainly an integer or pointer not a string.
         */
        Assert(flags & HASH_STRINGS);
        Assert(info->keysize > 8);
 
        hashp->hash = string_hash;
    }
 
    /*
     * If you don't specify a match function, it defaults to string_compare if
     * you used string_hash, and to memcmp otherwise.
     *
     * Note: explicitly specifying string_hash is deprecated, because this
     * might not work for callers in loadable modules on some platforms due to
     * referencing a trampoline instead of the string_hash function proper.
     * Specify HASH_STRINGS instead.
     */
    if (flags & HASH_COMPARE)
        hashp->match = info->match;
    else if (hashp->hash == string_hash)
        hashp->match = (HashCompareFunc) string_compare;
    else
        hashp->match = memcmp;
 
    /*
     * Similarly, the key-copying function defaults to strlcpy or memcpy.
     */
    if (flags & HASH_KEYCOPY)
        hashp->keycopy = info->keycopy;
    else if (hashp->hash == string_hash)
    {
        /*
         * The signature of keycopy is meant for memcpy(), which returns
         * void*, but strlcpy() returns size_t.  Since we never use the return
         * value of keycopy, and size_t is pretty much always the same size as
         * void *, this should be safe.  The extra cast in the middle is to
         * avoid warnings from -Wcast-function-type.
         */
        hashp->keycopy = (HashCopyFunc) (pg_funcptr_t) strlcpy;
    }
    else
        hashp->keycopy = memcpy;
 
    /* And select the entry allocation function, too. */
    if (flags & HASH_ALLOC)
        hashp->alloc = info->alloc;
    else
        hashp->alloc = DynaHashAlloc;
 
    if (flags & HASH_SHARED_MEM)
    {
        /*
         * ctl structure and directory are preallocated for shared memory
         * tables.  Note that HASH_DIRSIZE and HASH_ALLOC had better be set as
         * well.
         */
        hashp->hctl = info->hctl;
        hashp->dir = (HASHSEGMENT *) (((char *) info->hctl) + sizeof(HASHHDR));
        hashp->hcxt = NULL;
        hashp->isshared = true;
 
        /* hash table already exists, we're just attaching to it */
        if (flags & HASH_ATTACH)
        {
            /* make local copies of some heavily-used values */
            hctl = hashp->hctl;
            hashp->keysize = hctl->keysize;
            hashp->ssize = hctl->ssize;
            hashp->sshift = hctl->sshift;
 
            return hashp;
        }
    }
    else
    {
        /* setup hash table defaults */
        hashp->hctl = NULL;
        hashp->dir = NULL;
        hashp->hcxt = CurrentDynaHashCxt;
        hashp->isshared = false;
    }
 
    if (!hashp->hctl)
    {
        hashp->hctl = (HASHHDR *) hashp->alloc(sizeof(HASHHDR));
        if (!hashp->hctl)
            ereport(ERROR,
                    (errcode(ERRCODE_OUT_OF_MEMORY),
                     errmsg("out of memory")));
    }
 
    hashp->frozen = false;
 
    hdefault(hashp);
 
    hctl = hashp->hctl;
 
    if (flags & HASH_PARTITION)
    {
        /* Doesn't make sense to partition a local hash table */
        Assert(flags & HASH_SHARED_MEM);
 
        /*
         * The number of partitions had better be a power of 2. Also, it must
         * be less than INT_MAX (see init_htab()), so call the int version of
         * next_pow2.
         */
        Assert(info->num_partitions == next_pow2_int(info->num_partitions));
 
        hctl->num_partitions = info->num_partitions;
    }
 
    if (flags & HASH_SEGMENT)
    {
        hctl->ssize = info->ssize;
        hctl->sshift = my_log2(info->ssize);
        /* ssize had better be a power of 2 */
        Assert(hctl->ssize == (1L << hctl->sshift));
    }
 
    /*
     * SHM hash tables have fixed directory size passed by the caller.
     */
    if (flags & HASH_DIRSIZE)
    {
        hctl->max_dsize = info->max_dsize;
        hctl->dsize = info->dsize;
    }
 
    /* remember the entry sizes, too */
    hctl->keysize = info->keysize;
    hctl->entrysize = info->entrysize;
 
    /* make local copies of heavily-used constant fields */
    hashp->keysize = hctl->keysize;
    hashp->ssize = hctl->ssize;
    hashp->sshift = hctl->sshift;
 
    /* Build the hash directory structure */
    if (!init_htab(hashp, nelem))
        elog(ERROR, "failed to initialize hash table \"%s\"", hashp->tabname);
 
    /*
     * For a shared hash table, preallocate the requested number of elements.
     * This reduces problems with run-time out-of-shared-memory conditions.
     *
     * For a non-shared hash table, preallocate the requested number of
     * elements if it's less than our chosen nelem_alloc.  This avoids wasting
     * space if the caller correctly estimates a small table size.
     */
    if ((flags & HASH_SHARED_MEM) ||
        nelem < hctl->nelem_alloc)
    {
        int         i,
                    freelist_partitions,
                    nelem_alloc,
                    nelem_alloc_first;
 
        /*
         * If hash table is partitioned, give each freelist an equal share of
         * the initial allocation.  Otherwise only freeList[0] is used.
         */
        if (IS_PARTITIONED(hashp->hctl))
            freelist_partitions = NUM_FREELISTS;
        else
            freelist_partitions = 1;
 
        nelem_alloc = nelem / freelist_partitions;
        if (nelem_alloc <= 0)
            nelem_alloc = 1;
 
        /*
         * Make sure we'll allocate all the requested elements; freeList[0]
         * gets the excess if the request isn't divisible by NUM_FREELISTS.
         */
        if (nelem_alloc * freelist_partitions < nelem)
            nelem_alloc_first =
                nelem - nelem_alloc * (freelist_partitions - 1);
        else
            nelem_alloc_first = nelem_alloc;
 
        for (i = 0; i < freelist_partitions; i++)
        {
            int         temp = (i == 0) ? nelem_alloc_first : nelem_alloc;
 
            if (!element_alloc(hashp, temp, i))
                ereport(ERROR,
                        (errcode(ERRCODE_OUT_OF_MEMORY),
                         errmsg("out of memory")));
        }
    }
 
    if (flags & HASH_FIXED_SIZE)
        hashp->isfixed = true;
    return hashp;
}

References HTAB::alloc, HASHCTL::alloc, ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, Assert(), CurrentDynaHashCxt, HTAB::dir, HASHHDR::dsize, HASHCTL::dsize, DynaHashAlloc(), element_alloc(), elog(), HASHHDR::entrysize, HASHCTL::entrysize, ereport, errcode(), errmsg(), ERROR, HTAB::frozen, HTAB::hash, HASHCTL::hash, HASH_ALLOC, HASH_ATTACH, HASH_BLOBS, HASH_COMPARE, HASH_CONTEXT, HASH_DIRSIZE, HASH_ELEM, HASH_FIXED_SIZE, HASH_FUNCTION, HASH_KEYCOPY, HASH_PARTITION, HASH_SEGMENT, HASH_SHARED_MEM, HASH_STRINGS, HTAB::hctl, HASHCTL::hctl, HTAB::hcxt, HASHCTL::hcxt, hdefault(), i, init_htab(), IS_PARTITIONED, HTAB::isfixed, HTAB::isshared, HTAB::keycopy, HASHCTL::keycopy, HASHHDR::keysize, HTAB::keysize, HASHCTL::keysize, HTAB::match, HASHCTL::match, HASHHDR::max_dsize, HASHCTL::max_dsize, MemoryContextSetIdentifier(), MemSet, my_log2(), next_pow2_int(), NUM_FREELISTS, HASHHDR::num_partitions, HASHCTL::num_partitions, HASHHDR::sshift, HTAB::sshift, HASHHDR::ssize, HTAB::ssize, HASHCTL::ssize, string_compare(), string_hash(), strlcpy(), HTAB::tabname, tag_hash(), TopMemoryContext, and uint32_hash().

Referenced by _hash_finish_split(), _PG_init(), AddEventToPendingNotifies(), AddPendingSync(), assign_record_type_typmod(), begin_heap_rewrite(), build_guc_variables(), build_join_rel_hash(), BuildEventTriggerCache(), CheckForSessionAndXactLocks(), CompactCheckpointerRequestQueue(), compute_array_stats(), compute_tsvector_stats(), create_seq_hashtable(), createConnHash(), CreateLocalPredicateLockHash(), CreatePartitionDirectory(), do_autovacuum(), EnablePortalManager(), ExecInitModifyTable(), ExecuteTruncateGuts(), find_all_inheritors(), find_oper_cache_entry(), find_rendezvous_variable(), get_json_object_as_hash(), GetComboCommandId(), GetConnection(), gistInitBuildBuffers(), gistInitParentMap(), init_procedure_caches(), init_rel_sync_cache(), init_timezone_hashtable(), init_ts_config_cache(), init_uncommitted_enums(), InitBufferPoolAccess(), InitializeAttoptCache(), InitializeRelfilenumberMap(), InitializeShippableCache(), InitializeTableSpaceCache(), InitLocalBuffers(), InitLocks(), InitQueryHashTable(), InitRecoveryTransactionEnvironment(), InitSync(), load_categories_hash(), log_invalid_page(), logical_begin_heap_rewrite(), logicalrep_partmap_init(), logicalrep_relmap_init(), lookup_collation_cache(), lookup_proof_cache(), lookup_ts_dictionary_cache(), lookup_ts_parser_cache(), lookup_type_cache(), LookupOpclassInfo(), pa_allocate_worker(), plpgsql_estate_setup(), plpgsql_HashTableInit(), PLy_add_exceptions(), populate_recordset_object_start(), process_syncing_tables_for_apply(), rebuild_database_list(), record_C_func(), RegisterExtensibleNodeEntry(), RelationCacheInitialize(), ReorderBufferAllocate(), ReorderBufferBuildTupleCidHash(), ReorderBufferToastInitHash(), ResetUnloggedRelationsInDbspaceDir(), ri_InitHashTables(), select_perl_context(), SerializePendingSyncs(), set_rtable_names(), ShmemInitHash(), smgropen(), transformGraph(), and XLogPrefetcherAllocate().

hash_destroy()

void hash_destroy

(

HTAB *

hashp

)

Definition at line 863 of file dynahash.c.

{
    if (hashp != NULL)
    {
        /* allocation method must be one we know how to free, too */
        Assert(hashp->alloc == DynaHashAlloc);
        /* so this hashtable must have its own context */
        Assert(hashp->hcxt != NULL);
 
        hash_stats("destroy", hashp);
 
        /*
         * Free everything by destroying the hash table's memory context.
         */
        MemoryContextDelete(hashp->hcxt);
    }
}

References HTAB::alloc, Assert(), DynaHashAlloc(), hash_stats(), HTAB::hcxt, and MemoryContextDelete().

Referenced by _hash_finish_split(), CheckForSessionAndXactLocks(), CompactCheckpointerRequestQueue(), ExecuteTruncateGuts(), find_all_inheritors(), InitLocks(), pgoutput_shutdown(), populate_recordset_object_end(), PostPrepare_PredicateLocks(), process_syncing_tables_for_apply(), ReleasePredicateLocksLocal(), ReorderBufferReturnTXN(), ReorderBufferToastReset(), ReorderBufferTruncateTXN(), ResetSequenceCaches(), ResetUnloggedRelationsInDbspaceDir(), SerializePendingSyncs(), set_rtable_names(), ShutdownRecoveryTransactionEnvironment(), XLogCheckInvalidPages(), and XLogPrefetcherFree().

hash_estimate_size()

Size hash_estimate_size	(	long	num_entries,
		Size	entrysize
	)

Definition at line 781 of file dynahash.c.

{
    Size        size;
    long        nBuckets,
                nSegments,
                nDirEntries,
                nElementAllocs,
                elementSize,
                elementAllocCnt;
 
    /* estimate number of buckets wanted */
    nBuckets = next_pow2_long(num_entries);
    /* # of segments needed for nBuckets */
    nSegments = next_pow2_long((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(HASHHDR));   /* but not HTAB, per above */
    /* directory */
    size = add_size(size, mul_size(nDirEntries, sizeof(HASHSEGMENT)));
    /* segments */
    size = add_size(size, mul_size(nSegments,
                                   MAXALIGN(DEF_SEGSIZE * sizeof(HASHBUCKET))));
    /* elements --- allocated in groups of choose_nelem_alloc() entries */
    elementAllocCnt = choose_nelem_alloc(entrysize);
    nElementAllocs = (num_entries - 1) / elementAllocCnt + 1;
    elementSize = MAXALIGN(sizeof(HASHELEMENT)) + MAXALIGN(entrysize);
    size = add_size(size,
                    mul_size(nElementAllocs,
                             mul_size(elementAllocCnt, elementSize)));
 
    return size;
}

References add_size(), choose_nelem_alloc(), DEF_DIRSIZE, DEF_SEGSIZE, MAXALIGN, mul_size(), and next_pow2_long().

Referenced by BufTableShmemSize(), CalculateShmemSize(), LockShmemSize(), pgss_memsize(), and PredicateLockShmemSize().

hash_freeze()

void hash_freeze

(

HTAB *

hashp

)

Definition at line 1527 of file dynahash.c.

{
    if (hashp->isshared)
        elog(ERROR, "cannot freeze shared hashtable \"%s\"", hashp->tabname);
    if (!hashp->frozen && has_seq_scans(hashp))
        elog(ERROR, "cannot freeze hashtable \"%s\" because it has active scans",
             hashp->tabname);
    hashp->frozen = true;
}

References elog(), ERROR, HTAB::frozen, has_seq_scans(), HTAB::isshared, and HTAB::tabname.

hash_get_num_entries()

long hash_get_num_entries

(

HTAB *

hashp

)

Definition at line 1377 of file dynahash.c.

{
    int         i;
    long        sum = hashp->hctl->freeList[0].nentries;
 
    /*
     * We currently don't bother with acquiring the mutexes; it's only
     * sensible to call this function if you've got lock on all partitions of
     * the table.
     */
    if (IS_PARTITIONED(hashp->hctl))
    {
        for (i = 1; i < NUM_FREELISTS; i++)
            sum += hashp->hctl->freeList[i].nentries;
    }
 
    return sum;
}

References HASHHDR::freeList, HTAB::hctl, i, IS_PARTITIONED, FreeListData::nentries, and NUM_FREELISTS.

Referenced by build_guc_variables(), compute_array_stats(), compute_tsvector_stats(), entry_alloc(), entry_dealloc(), entry_reset(), EstimatePendingSyncsSpace(), EstimateUncommittedEnumsSpace(), get_crosstab_tuplestore(), get_explain_guc_options(), get_guc_variables(), GetLockStatusData(), GetPredicateLockStatusData(), GetRunningTransactionLocks(), hash_stats(), pgss_shmem_shutdown(), ResetUnloggedRelationsInDbspaceDir(), SerializePendingSyncs(), transformGraph(), and XLogHaveInvalidPages().

hash_get_shared_size()

Size hash_get_shared_size	(	HASHCTL *	info,
		int	flags
	)

Definition at line 852 of file dynahash.c.

{
    Assert(flags & HASH_DIRSIZE);
    Assert(info->dsize == info->max_dsize);
    return sizeof(HASHHDR) + info->dsize * sizeof(HASHSEGMENT);
}

References Assert(), HASHCTL::dsize, HASH_DIRSIZE, and HASHCTL::max_dsize.

Referenced by ShmemInitHash().

hash_search()

void* hash_search	(	HTAB *	hashp,
		const void *	keyPtr,
		HASHACTION	action,
		bool *	foundPtr
	)

Definition at line 953 of file dynahash.c.

{
    return hash_search_with_hash_value(hashp,
                                       keyPtr,
                                       hashp->hash(keyPtr, hashp->keysize),
                                       action,
                                       foundPtr);
}

References generate_unaccent_rules::action, HTAB::hash, hash_search_with_hash_value(), and HTAB::keysize.

Referenced by _hash_finish_split(), _hash_splitbucket(), add_guc_variable(), add_join_rel(), AddEnumLabel(), AddEventToPendingNotifies(), AddPendingSync(), ApplyLogicalMappingFile(), assign_record_type_typmod(), AsyncExistsPendingNotify(), AtEOSubXact_RelationCache(), AtEOXact_RelationCache(), build_guc_variables(), build_join_rel_hash(), BuildEventTriggerCache(), CheckAndPromotePredicateLockRequest(), CheckForSerializableConflictOut(), CheckForSessionAndXactLocks(), CompactCheckpointerRequestQueue(), compile_plperl_function(), compile_pltcl_function(), compute_array_stats(), compute_tsvector_stats(), createNewConnection(), define_custom_variable(), deleteConnection(), do_autovacuum(), DropAllPredicateLocksFromTable(), DropAllPreparedStatements(), DropPreparedStatement(), DropRelationAllLocalBuffers(), DropRelationLocalBuffers(), entry_alloc(), entry_dealloc(), entry_reset(), EnumUncommitted(), EventCacheLookup(), ExecInitModifyTable(), ExecLookupResultRelByOid(), ExecuteTruncateGuts(), FetchPreparedStatement(), find_all_inheritors(), find_join_rel(), find_oper_cache_entry(), find_option(), find_rendezvous_variable(), forget_invalid_pages(), forget_invalid_pages_db(), ForgetPrivateRefCountEntry(), get_attribute_options(), get_cast_hashentry(), get_rel_sync_entry(), get_tablespace(), GetComboCommandId(), GetConnection(), getConnectionByName(), GetExtensibleNodeEntry(), GetPrivateRefCountEntry(), getState(), gistGetNodeBuffer(), gistGetParent(), gistMemorizeParent(), gistRelocateBuildBuffersOnSplit(), hash_object_field_end(), init_sequence(), InitPredicateLocks(), InvalidateAttoptCacheCallback(), InvalidateOprCacheCallBack(), InvalidateShippableCacheCallback(), InvalidateTableSpaceCacheCallback(), is_shippable(), JsObjectGetField(), LocalBufferAlloc(), LockAcquireExtended(), LockHasWaiters(), LockHeldByMe(), LockRelease(), log_invalid_page(), logical_rewrite_log_mapping(), logicalrep_partition_open(), logicalrep_rel_open(), logicalrep_relmap_update(), lookup_C_func(), lookup_collation_cache(), lookup_proof_cache(), lookup_ts_config_cache(), lookup_ts_dictionary_cache(), lookup_ts_parser_cache(), lookup_type_cache(), LookupOpclassInfo(), make_oper_cache_entry(), MarkGUCPrefixReserved(), pa_allocate_worker(), pa_find_worker(), pa_free_worker(), PartitionDirectoryLookup(), pg_tzset(), pgss_store(), plperl_spi_exec_prepared(), plperl_spi_freeplan(), plperl_spi_prepare(), plperl_spi_query_prepared(), plpgsql_HashTableDelete(), plpgsql_HashTableInsert(), plpgsql_HashTableLookup(), pltcl_fetch_interp(), PLy_commit(), PLy_generate_spi_exceptions(), PLy_procedure_get(), PLy_rollback(), PLy_spi_subtransaction_abort(), populate_recordset_object_field_end(), predicatelock_twophase_recover(), PredicateLockExists(), PredicateLockTwoPhaseFinish(), PrefetchLocalBuffer(), process_syncing_tables_for_apply(), ProcessSyncRequests(), prune_element_hashtable(), prune_lexemes_hashtable(), rebuild_database_list(), record_C_func(), RegisterExtensibleNodeEntry(), RegisterPredicateLockingXid(), rel_sync_cache_relation_cb(), RelationPreTruncate(), ReleaseOneSerializableXact(), RelFileLocatorSkippingWAL(), RelfilenumberMapInvalidateCallback(), RelidByRelfilenumber(), RememberSyncRequest(), RemoveLocalLock(), ReorderBufferBuildTupleCidHash(), ReorderBufferCleanupTXN(), ReorderBufferToastAppendChunk(), ReorderBufferToastReplace(), ReorderBufferTXNByXid(), ReservePrivateRefCountEntry(), ResetUnloggedRelationsInDbspaceDir(), ResolveCminCmaxDuringDecoding(), RestoreUncommittedEnums(), rewrite_heap_dead_tuple(), rewrite_heap_tuple(), ri_FetchPreparedPlan(), ri_HashCompareOp(), ri_HashPreparedPlan(), ri_LoadConstraintInfo(), select_perl_context(), SerializePendingSyncs(), set_rtable_names(), ShmemInitStruct(), smgrclose(), smgrcloserellocator(), smgrDoPendingSyncs(), smgropen(), StandbyAcquireAccessExclusiveLock(), StandbyReleaseAllLocks(), StandbyReleaseLocks(), StandbyReleaseOldLocks(), StandbyReleaseXidEntryLocks(), StorePreparedStatement(), table_recheck_autovac(), XLogPrefetcherAddFilter(), XLogPrefetcherCompleteFilters(), and XLogPrefetcherIsFiltered().

hash_search_with_hash_value()

void* hash_search_with_hash_value	(	HTAB *	hashp,
		const void *	keyPtr,
		uint32	hashvalue,
		HASHACTION	action,
		bool *	foundPtr
	)

Definition at line 966 of file dynahash.c.

{
    HASHHDR    *hctl = hashp->hctl;
    int         freelist_idx = FREELIST_IDX(hctl, hashvalue);
    Size        keysize;
    uint32      bucket;
    long        segment_num;
    long        segment_ndx;
    HASHSEGMENT segp;
    HASHBUCKET  currBucket;
    HASHBUCKET *prevBucketPtr;
    HashCompareFunc match;
 
#ifdef HASH_STATISTICS
    hash_accesses++;
    hctl->accesses++;
#endif
 
    /*
     * If inserting, check if it is time to split a bucket.
     *
     * NOTE: failure to expand table is not a fatal error, it just means we
     * have to run at higher fill factor than we wanted.  However, if we're
     * using the palloc allocator then it will throw error anyway on
     * out-of-memory, so we must do this before modifying the table.
     */
    if (action == HASH_ENTER || action == HASH_ENTER_NULL)
    {
        /*
         * Can't split if running in partitioned mode, nor if frozen, nor if
         * table is the subject of any active hash_seq_search scans.
         */
        if (hctl->freeList[0].nentries > (long) hctl->max_bucket &&
            !IS_PARTITIONED(hctl) && !hashp->frozen &&
            !has_seq_scans(hashp))
            (void) expand_table(hashp);
    }
 
    /*
     * Do the initial lookup
     */
    bucket = calc_bucket(hctl, hashvalue);
 
    segment_num = bucket >> hashp->sshift;
    segment_ndx = MOD(bucket, hashp->ssize);
 
    segp = hashp->dir[segment_num];
 
    if (segp == NULL)
        hash_corrupted(hashp);
 
    prevBucketPtr = &segp[segment_ndx];
    currBucket = *prevBucketPtr;
 
    /*
     * Follow collision chain looking for matching key
     */
    match = hashp->match;       /* save one fetch in inner loop */
    keysize = hashp->keysize;   /* ditto */
 
    while (currBucket != NULL)
    {
        if (currBucket->hashvalue == hashvalue &&
            match(ELEMENTKEY(currBucket), keyPtr, keysize) == 0)
            break;
        prevBucketPtr = &(currBucket->link);
        currBucket = *prevBucketPtr;
#ifdef HASH_STATISTICS
        hash_collisions++;
        hctl->collisions++;
#endif
    }
 
    if (foundPtr)
        *foundPtr = (bool) (currBucket != NULL);
 
    /*
     * OK, now what?
     */
    switch (action)
    {
        case HASH_FIND:
            if (currBucket != NULL)
                return (void *) ELEMENTKEY(currBucket);
            return NULL;
 
        case HASH_REMOVE:
            if (currBucket != NULL)
            {
                /* if partitioned, must lock to touch nentries and freeList */
                if (IS_PARTITIONED(hctl))
                    SpinLockAcquire(&(hctl->freeList[freelist_idx].mutex));
 
                /* delete the record from the appropriate nentries counter. */
                Assert(hctl->freeList[freelist_idx].nentries > 0);
                hctl->freeList[freelist_idx].nentries--;
 
                /* remove record from hash bucket's chain. */
                *prevBucketPtr = currBucket->link;
 
                /* add the record to the appropriate freelist. */
                currBucket->link = hctl->freeList[freelist_idx].freeList;
                hctl->freeList[freelist_idx].freeList = currBucket;
 
                if (IS_PARTITIONED(hctl))
                    SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
 
                /*
                 * 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
                 */
                return (void *) ELEMENTKEY(currBucket);
            }
            return NULL;
 
        case HASH_ENTER:
        case HASH_ENTER_NULL:
            /* Return existing element if found, else create one */
            if (currBucket != NULL)
                return (void *) ELEMENTKEY(currBucket);
 
            /* disallow inserts if frozen */
            if (hashp->frozen)
                elog(ERROR, "cannot insert into frozen hashtable \"%s\"",
                     hashp->tabname);
 
            currBucket = get_hash_entry(hashp, freelist_idx);
            if (currBucket == NULL)
            {
                /* out of memory */
                if (action == HASH_ENTER_NULL)
                    return NULL;
                /* report a generic message */
                if (hashp->isshared)
                    ereport(ERROR,
                            (errcode(ERRCODE_OUT_OF_MEMORY),
                             errmsg("out of shared memory")));
                else
                    ereport(ERROR,
                            (errcode(ERRCODE_OUT_OF_MEMORY),
                             errmsg("out of memory")));
            }
 
            /* link into hashbucket chain */
            *prevBucketPtr = currBucket;
            currBucket->link = NULL;
 
            /* copy key into record */
            currBucket->hashvalue = hashvalue;
            hashp->keycopy(ELEMENTKEY(currBucket), keyPtr, keysize);
 
            /*
             * Caller is expected to fill the data field on return.  DO NOT
             * insert any code that could possibly throw error here, as doing
             * so would leave the table entry incomplete and hence corrupt the
             * caller's data structure.
             */
 
            return (void *) ELEMENTKEY(currBucket);
    }
 
    elog(ERROR, "unrecognized hash action code: %d", (int) action);
 
    return NULL;                /* keep compiler quiet */
}

References generate_unaccent_rules::action, Assert(), calc_bucket(), HTAB::dir, ELEMENTKEY, elog(), ereport, errcode(), errmsg(), ERROR, expand_table(), FreeListData::freeList, HASHHDR::freeList, FREELIST_IDX, HTAB::frozen, get_hash_entry(), has_seq_scans(), hash_corrupted(), HASH_ENTER, HASH_ENTER_NULL, HASH_FIND, HASH_REMOVE, HASHELEMENT::hashvalue, HTAB::hctl, IS_PARTITIONED, HTAB::isshared, HTAB::keycopy, HTAB::keysize, HASHELEMENT::link, HTAB::match, HASHHDR::max_bucket, MOD, FreeListData::mutex, FreeListData::nentries, SpinLockAcquire, SpinLockRelease, HTAB::sshift, HTAB::ssize, and HTAB::tabname.

Referenced by BufTableDelete(), BufTableInsert(), BufTableLookup(), CheckTargetForConflictsIn(), CleanUpLock(), ClearOldPredicateLocks(), CreatePredicateLock(), DecrementParentLocks(), DeleteChildTargetLocks(), DeleteLockTarget(), DropAllPredicateLocksFromTable(), FastPathGetRelationLockEntry(), GetLockConflicts(), hash_search(), lock_twophase_recover(), LockAcquireExtended(), LockRefindAndRelease(), LockRelease(), LockWaiterCount(), PageIsPredicateLocked(), PredicateLockAcquire(), ReleaseOneSerializableXact(), RemoveScratchTarget(), RemoveTargetIfNoLongerUsed(), RestoreScratchTarget(), SetupLockInTable(), and TransferPredicateLocksToNewTarget().

hash_select_dirsize()

long hash_select_dirsize

(

long

num_entries

)

Definition at line 828 of file dynahash.c.

{
    long        nBuckets,
                nSegments,
                nDirEntries;
 
    /* estimate number of buckets wanted */
    nBuckets = next_pow2_long(num_entries);
    /* # of segments needed for nBuckets */
    nSegments = next_pow2_long((nBuckets - 1) / DEF_SEGSIZE + 1);
    /* directory entries */
    nDirEntries = DEF_DIRSIZE;
    while (nDirEntries < nSegments)
        nDirEntries <<= 1;      /* dir_alloc doubles dsize at each call */
 
    return nDirEntries;
}

References DEF_DIRSIZE, DEF_SEGSIZE, and next_pow2_long().

Referenced by ShmemInitHash().

hash_seq_init()

void hash_seq_init	(	HASH_SEQ_STATUS *	status,
		HTAB *	hashp
	)

Definition at line 1421 of file dynahash.c.

{
    status->hashp = hashp;
    status->curBucket = 0;
    status->curEntry = NULL;
    if (!hashp->frozen)
        register_seq_scan(hashp);
}

References HTAB::frozen, register_seq_scan(), and status().

Referenced by AtAbort_Portals(), AtCleanup_Portals(), AtEOSubXact_RelationCache(), AtEOXact_RelationCache(), AtPrepare_Locks(), AtSubAbort_Portals(), AtSubCleanup_Portals(), AtSubCommit_Portals(), BeginReportingGUCOptions(), CheckForBufferLeaks(), CheckForSessionAndXactLocks(), CheckTableForSerializableConflictIn(), cleanup_rel_sync_cache(), compute_array_stats(), compute_tsvector_stats(), dblink_get_connections(), DestroyPartitionDirectory(), disconnect_cached_connections(), DropAllPredicateLocksFromTable(), DropAllPreparedStatements(), end_heap_rewrite(), entry_dealloc(), entry_reset(), ExecuteTruncateGuts(), forget_invalid_pages(), forget_invalid_pages_db(), ForgetPortalSnapshots(), gc_qtexts(), get_guc_variables(), GetLockStatusData(), GetPredicateLockStatusData(), GetRunningTransactionLocks(), HoldPinnedPortals(), InitializeGUCOptions(), InvalidateAttoptCacheCallback(), InvalidateOprCacheCallBack(), InvalidateOprProofCacheCallBack(), InvalidateShippableCacheCallback(), InvalidateTableSpaceCacheCallback(), InvalidateTSCacheCallBack(), LockReassignCurrentOwner(), LockReleaseAll(), LockReleaseCurrentOwner(), LockReleaseSession(), logical_end_heap_rewrite(), logical_heap_rewrite_flush_mappings(), logicalrep_partmap_invalidate_cb(), logicalrep_partmap_reset_relmap(), logicalrep_relmap_invalidate_cb(), MarkGUCPrefixReserved(), packGraph(), pg_cursor(), pg_get_shmem_allocations(), pg_prepared_statement(), pg_stat_statements_internal(), pgfdw_inval_callback(), pgfdw_subxact_callback(), pgfdw_xact_callback(), pgss_shmem_shutdown(), plperl_fini(), PortalErrorCleanup(), PortalHashTableDeleteAll(), postgres_fdw_get_connections(), PostPrepare_Locks(), PreCommit_Portals(), ProcessConfigFileInternal(), ProcessSyncRequests(), prune_element_hashtable(), prune_lexemes_hashtable(), rebuild_database_list(), rel_sync_cache_publication_cb(), rel_sync_cache_relation_cb(), RelationCacheInitializePhase3(), RelationCacheInvalidate(), RelfilenumberMapInvalidateCallback(), RememberSyncRequest(), ReorderBufferLargestTXN(), ReorderBufferToastReset(), selectColorTrigrams(), SerializePendingSyncs(), SerializeUncommittedEnums(), smgrcloseall(), smgrDoPendingSyncs(), smgrreleaseall(), StandbyReleaseAllLocks(), StandbyReleaseOldLocks(), ThereAreNoReadyPortals(), TypeCacheOpcCallback(), TypeCacheRelCallback(), TypeCacheTypCallback(), write_relcache_init_file(), and XLogCheckInvalidPages().

hash_seq_search()

void* hash_seq_search

(

HASH_SEQ_STATUS *

status

)

Definition at line 1431 of file dynahash.c.

{
    HTAB       *hashp;
    HASHHDR    *hctl;
    uint32      max_bucket;
    long        ssize;
    long        segment_num;
    long        segment_ndx;
    HASHSEGMENT segp;
    uint32      curBucket;
    HASHELEMENT *curElem;
 
    if ((curElem = status->curEntry) != NULL)
    {
        /* Continuing scan of curBucket... */
        status->curEntry = curElem->link;
        if (status->curEntry == NULL)   /* end of this bucket */
            ++status->curBucket;
        return (void *) ELEMENTKEY(curElem);
    }
 
    /*
     * Search for next nonempty bucket starting at curBucket.
     */
    curBucket = status->curBucket;
    hashp = status->hashp;
    hctl = hashp->hctl;
    ssize = hashp->ssize;
    max_bucket = hctl->max_bucket;
 
    if (curBucket > max_bucket)
    {
        hash_seq_term(status);
        return NULL;            /* search is done */
    }
 
    /*
     * first find the right segment in the table directory.
     */
    segment_num = curBucket >> hashp->sshift;
    segment_ndx = MOD(curBucket, ssize);
 
    segp = hashp->dir[segment_num];
 
    /*
     * Pick up the first item in this bucket's chain.  If chain is not empty
     * we can begin searching it.  Otherwise we have to advance to find the
     * next nonempty bucket.  We try to optimize that case since searching a
     * near-empty hashtable has to iterate this loop a lot.
     */
    while ((curElem = segp[segment_ndx]) == NULL)
    {
        /* empty bucket, advance to next */
        if (++curBucket > max_bucket)
        {
            status->curBucket = curBucket;
            hash_seq_term(status);
            return NULL;        /* search is done */
        }
        if (++segment_ndx >= ssize)
        {
            segment_num++;
            segment_ndx = 0;
            segp = hashp->dir[segment_num];
        }
    }
 
    /* Begin scan of curBucket... */
    status->curEntry = curElem->link;
    if (status->curEntry == NULL)   /* end of this bucket */
        ++curBucket;
    status->curBucket = curBucket;
    return (void *) ELEMENTKEY(curElem);
}

References HTAB::dir, ELEMENTKEY, hash_seq_term(), HTAB::hctl, HASHELEMENT::link, HASHHDR::max_bucket, MOD, HTAB::sshift, HTAB::ssize, and status().

Referenced by AtAbort_Portals(), AtCleanup_Portals(), AtEOSubXact_RelationCache(), AtEOXact_RelationCache(), AtPrepare_Locks(), AtSubAbort_Portals(), AtSubCleanup_Portals(), AtSubCommit_Portals(), BeginReportingGUCOptions(), CheckForBufferLeaks(), CheckForSessionAndXactLocks(), CheckTableForSerializableConflictIn(), cleanup_rel_sync_cache(), compute_array_stats(), compute_tsvector_stats(), dblink_get_connections(), DestroyPartitionDirectory(), disconnect_cached_connections(), DropAllPredicateLocksFromTable(), DropAllPreparedStatements(), end_heap_rewrite(), entry_dealloc(), entry_reset(), ExecuteTruncateGuts(), forget_invalid_pages(), forget_invalid_pages_db(), ForgetPortalSnapshots(), gc_qtexts(), get_guc_variables(), GetLockStatusData(), GetPredicateLockStatusData(), GetRunningTransactionLocks(), HoldPinnedPortals(), InitializeGUCOptions(), InvalidateAttoptCacheCallback(), InvalidateOprCacheCallBack(), InvalidateOprProofCacheCallBack(), InvalidateShippableCacheCallback(), InvalidateTableSpaceCacheCallback(), InvalidateTSCacheCallBack(), LockReassignCurrentOwner(), LockReleaseAll(), LockReleaseCurrentOwner(), LockReleaseSession(), logical_end_heap_rewrite(), logical_heap_rewrite_flush_mappings(), logicalrep_partmap_invalidate_cb(), logicalrep_partmap_reset_relmap(), logicalrep_relmap_invalidate_cb(), MarkGUCPrefixReserved(), packGraph(), pg_cursor(), pg_get_shmem_allocations(), pg_prepared_statement(), pg_stat_statements_internal(), pgfdw_inval_callback(), pgfdw_subxact_callback(), pgfdw_xact_callback(), pgss_shmem_shutdown(), plperl_fini(), PortalErrorCleanup(), PortalHashTableDeleteAll(), postgres_fdw_get_connections(), PostPrepare_Locks(), PreCommit_Portals(), ProcessConfigFileInternal(), ProcessSyncRequests(), prune_element_hashtable(), prune_lexemes_hashtable(), rebuild_database_list(), rel_sync_cache_publication_cb(), rel_sync_cache_relation_cb(), RelationCacheInitializePhase3(), RelationCacheInvalidate(), RelfilenumberMapInvalidateCallback(), RememberSyncRequest(), ReorderBufferLargestTXN(), ReorderBufferToastReset(), selectColorTrigrams(), SerializePendingSyncs(), SerializeUncommittedEnums(), smgrcloseall(), smgrDoPendingSyncs(), smgrreleaseall(), StandbyReleaseAllLocks(), StandbyReleaseOldLocks(), ThereAreNoReadyPortals(), TypeCacheOpcCallback(), TypeCacheRelCallback(), TypeCacheTypCallback(), write_relcache_init_file(), and XLogCheckInvalidPages().

hash_seq_term()

void hash_seq_term

(

HASH_SEQ_STATUS *

status

)

Definition at line 1507 of file dynahash.c.

{
    if (!status->hashp->frozen)
        deregister_seq_scan(status->hashp);
}

References deregister_seq_scan(), and status().

Referenced by gc_qtexts(), hash_seq_search(), logicalrep_partmap_invalidate_cb(), logicalrep_relmap_invalidate_cb(), pgss_shmem_shutdown(), PortalHashTableDeleteAll(), PreCommit_Portals(), and RelationCacheInitializePhase3().

hash_stats()

void hash_stats	(	const char *	where,
		HTAB *	hashp
	)

Definition at line 882 of file dynahash.c.

{
#ifdef HASH_STATISTICS
    fprintf(stderr, "%s: this HTAB -- accesses %ld collisions %ld\n",
            where, hashp->hctl->accesses, hashp->hctl->collisions);
 
    fprintf(stderr, "hash_stats: entries %ld keysize %ld maxp %u segmentcount %ld\n",
            hash_get_num_entries(hashp), (long) hashp->hctl->keysize,
            hashp->hctl->max_bucket, hashp->hctl->nsegs);
    fprintf(stderr, "%s: total accesses %ld total collisions %ld\n",
            where, hash_accesses, hash_collisions);
    fprintf(stderr, "hash_stats: total expansions %ld\n",
            hash_expansions);
#endif
}

References fprintf, hash_get_num_entries(), HTAB::hctl, HASHHDR::keysize, HASHHDR::max_bucket, and HASHHDR::nsegs.

Referenced by hash_destroy().

hash_update_hash_key()

bool hash_update_hash_key	(	HTAB *	hashp,
		void *	existingEntry,
		const void *	newKeyPtr
	)

Definition at line 1157 of file dynahash.c.

{
    HASHELEMENT *existingElement = ELEMENT_FROM_KEY(existingEntry);
    HASHHDR    *hctl = hashp->hctl;
    uint32      newhashvalue;
    Size        keysize;
    uint32      bucket;
    uint32      newbucket;
    long        segment_num;
    long        segment_ndx;
    HASHSEGMENT segp;
    HASHBUCKET  currBucket;
    HASHBUCKET *prevBucketPtr;
    HASHBUCKET *oldPrevPtr;
    HashCompareFunc match;
 
#ifdef HASH_STATISTICS
    hash_accesses++;
    hctl->accesses++;
#endif
 
    /* disallow updates if frozen */
    if (hashp->frozen)
        elog(ERROR, "cannot update in frozen hashtable \"%s\"",
             hashp->tabname);
 
    /*
     * Lookup the existing element using its saved hash value.  We need to do
     * this to be able to unlink it from its hash chain, but as a side benefit
     * we can verify the validity of the passed existingEntry pointer.
     */
    bucket = calc_bucket(hctl, existingElement->hashvalue);
 
    segment_num = bucket >> hashp->sshift;
    segment_ndx = MOD(bucket, hashp->ssize);
 
    segp = hashp->dir[segment_num];
 
    if (segp == NULL)
        hash_corrupted(hashp);
 
    prevBucketPtr = &segp[segment_ndx];
    currBucket = *prevBucketPtr;
 
    while (currBucket != NULL)
    {
        if (currBucket == existingElement)
            break;
        prevBucketPtr = &(currBucket->link);
        currBucket = *prevBucketPtr;
    }
 
    if (currBucket == NULL)
        elog(ERROR, "hash_update_hash_key argument is not in hashtable \"%s\"",
             hashp->tabname);
 
    oldPrevPtr = prevBucketPtr;
 
    /*
     * Now perform the equivalent of a HASH_ENTER operation to locate the hash
     * chain we want to put the entry into.
     */
    newhashvalue = hashp->hash(newKeyPtr, hashp->keysize);
 
    newbucket = calc_bucket(hctl, newhashvalue);
 
    segment_num = newbucket >> hashp->sshift;
    segment_ndx = MOD(newbucket, hashp->ssize);
 
    segp = hashp->dir[segment_num];
 
    if (segp == NULL)
        hash_corrupted(hashp);
 
    prevBucketPtr = &segp[segment_ndx];
    currBucket = *prevBucketPtr;
 
    /*
     * Follow collision chain looking for matching key
     */
    match = hashp->match;       /* save one fetch in inner loop */
    keysize = hashp->keysize;   /* ditto */
 
    while (currBucket != NULL)
    {
        if (currBucket->hashvalue == newhashvalue &&
            match(ELEMENTKEY(currBucket), newKeyPtr, keysize) == 0)
            break;
        prevBucketPtr = &(currBucket->link);
        currBucket = *prevBucketPtr;
#ifdef HASH_STATISTICS
        hash_collisions++;
        hctl->collisions++;
#endif
    }
 
    if (currBucket != NULL)
        return false;           /* collision with an existing entry */
 
    currBucket = existingElement;
 
    /*
     * If old and new hash values belong to the same bucket, we need not
     * change any chain links, and indeed should not since this simplistic
     * update will corrupt the list if currBucket is the last element.  (We
     * cannot fall out earlier, however, since we need to scan the bucket to
     * check for duplicate keys.)
     */
    if (bucket != newbucket)
    {
        /* OK to remove record from old hash bucket's chain. */
        *oldPrevPtr = currBucket->link;
 
        /* link into new hashbucket chain */
        *prevBucketPtr = currBucket;
        currBucket->link = NULL;
    }
 
    /* copy new key into record */
    currBucket->hashvalue = newhashvalue;
    hashp->keycopy(ELEMENTKEY(currBucket), newKeyPtr, keysize);
 
    /* rest of record is untouched */
 
    return true;
}

References calc_bucket(), HTAB::dir, ELEMENT_FROM_KEY, ELEMENTKEY, elog(), ERROR, HTAB::frozen, HTAB::hash, hash_corrupted(), HASHELEMENT::hashvalue, HTAB::hctl, HTAB::keycopy, HTAB::keysize, HASHELEMENT::link, HTAB::match, MOD, HTAB::sshift, HTAB::ssize, and HTAB::tabname.

Referenced by PostPrepare_Locks().

hdefault()

static void hdefault ( HTAB *  hashp )

static

Definition at line 627 of file dynahash.c.

{
    HASHHDR    *hctl = hashp->hctl;
 
    MemSet(hctl, 0, sizeof(HASHHDR));
 
    hctl->dsize = DEF_DIRSIZE;
    hctl->nsegs = 0;
 
    hctl->num_partitions = 0;   /* not partitioned */
 
    /* table has no fixed maximum size */
    hctl->max_dsize = NO_MAX_DSIZE;
 
    hctl->ssize = DEF_SEGSIZE;
    hctl->sshift = DEF_SEGSIZE_SHIFT;
 
#ifdef HASH_STATISTICS
    hctl->accesses = hctl->collisions = 0;
#endif
}

References DEF_DIRSIZE, DEF_SEGSIZE, DEF_SEGSIZE_SHIFT, HASHHDR::dsize, HTAB::hctl, HASHHDR::max_dsize, MemSet, NO_MAX_DSIZE, HASHHDR::nsegs, HASHHDR::num_partitions, HASHHDR::sshift, and HASHHDR::ssize.

Referenced by hash_create().

init_htab()

static bool init_htab ( HTAB *  hashp, long  nelem  )

static

Definition at line 687 of file dynahash.c.

{
    HASHHDR    *hctl = hashp->hctl;
    HASHSEGMENT *segp;
    int         nbuckets;
    int         nsegs;
    int         i;
 
    /*
     * initialize mutexes if it's a partitioned table
     */
    if (IS_PARTITIONED(hctl))
        for (i = 0; i < NUM_FREELISTS; i++)
            SpinLockInit(&(hctl->freeList[i].mutex));
 
    /*
     * Allocate space for the next greater power of two number of buckets,
     * assuming a desired maximum load factor of 1.
     */
    nbuckets = next_pow2_int(nelem);
 
    /*
     * In a partitioned table, nbuckets must be at least equal to
     * num_partitions; were it less, keys with apparently different partition
     * numbers would map to the same bucket, breaking partition independence.
     * (Normally nbuckets will be much bigger; this is just a safety check.)
     */
    while (nbuckets < hctl->num_partitions)
        nbuckets <<= 1;
 
    hctl->max_bucket = hctl->low_mask = nbuckets - 1;
    hctl->high_mask = (nbuckets << 1) - 1;
 
    /*
     * Figure number of directory segments needed, round up to a power of 2
     */
    nsegs = (nbuckets - 1) / hctl->ssize + 1;
    nsegs = next_pow2_int(nsegs);
 
    /*
     * Make sure directory is big enough. If pre-allocated directory is too
     * small, choke (caller screwed up).
     */
    if (nsegs > hctl->dsize)
    {
        if (!(hashp->dir))
            hctl->dsize = nsegs;
        else
            return false;
    }
 
    /* Allocate a directory */
    if (!(hashp->dir))
    {
        CurrentDynaHashCxt = hashp->hcxt;
        hashp->dir = (HASHSEGMENT *)
            hashp->alloc(hctl->dsize * sizeof(HASHSEGMENT));
        if (!hashp->dir)
            return false;
    }
 
    /* Allocate initial segments */
    for (segp = hashp->dir; hctl->nsegs < nsegs; hctl->nsegs++, segp++)
    {
        *segp = seg_alloc(hashp);
        if (*segp == NULL)
            return false;
    }
 
    /* Choose number of entries to allocate at a time */
    hctl->nelem_alloc = choose_nelem_alloc(hctl->entrysize);
 
#ifdef HASH_DEBUG
    fprintf(stderr, "init_htab:\n%s%p\n%s%ld\n%s%ld\n%s%d\n%s%ld\n%s%u\n%s%x\n%s%x\n%s%ld\n",
            "TABLE POINTER   ", hashp,
            "DIRECTORY SIZE  ", hctl->dsize,
            "SEGMENT SIZE    ", hctl->ssize,
            "SEGMENT SHIFT   ", hctl->sshift,
            "MAX BUCKET      ", hctl->max_bucket,
            "HIGH MASK       ", hctl->high_mask,
            "LOW  MASK       ", hctl->low_mask,
            "NSEGS           ", hctl->nsegs);
#endif
    return true;
}

References HTAB::alloc, choose_nelem_alloc(), CurrentDynaHashCxt, HTAB::dir, HASHHDR::dsize, HASHHDR::entrysize, fprintf, HASHHDR::freeList, HTAB::hctl, HTAB::hcxt, HASHHDR::high_mask, i, IS_PARTITIONED, HASHHDR::low_mask, HASHHDR::max_bucket, FreeListData::mutex, HASHHDR::nelem_alloc, next_pow2_int(), HASHHDR::nsegs, NUM_FREELISTS, seg_alloc(), SpinLockInit, HASHHDR::sshift, and HASHHDR::ssize.

Referenced by hash_create().

my_log2()

int my_log2

(

long

num

)

Definition at line 1760 of file dynahash.c.

{
    /*
     * guard against too-large input, which would be invalid for
     * pg_ceil_log2_*()
     */
    if (num > LONG_MAX / 2)
        num = LONG_MAX / 2;
 
#if SIZEOF_LONG < 8
    return pg_ceil_log2_32(num);
#else
    return pg_ceil_log2_64(num);
#endif
}

References pg_ceil_log2_32(), and pg_ceil_log2_64().

Referenced by ExecHashTableCreate(), ExecParallelHashTableSetCurrentBatch(), hash_choose_num_partitions(), hash_create(), MultiExecParallelHash(), next_pow2_int(), next_pow2_long(), and subxact_info_read().

next_pow2_int()

static int next_pow2_int ( long  num )

static

Definition at line 1786 of file dynahash.c.

{
    if (num > INT_MAX / 2)
        num = INT_MAX / 2;
    return 1 << my_log2(num);
}

References my_log2().

Referenced by hash_create(), and init_htab().

next_pow2_long()

static long next_pow2_long ( long  num )

static

Definition at line 1778 of file dynahash.c.

{
    /* my_log2's internal range check is sufficient */
    return 1L << my_log2(num);
}

References my_log2().

Referenced by hash_estimate_size(), and hash_select_dirsize().

register_seq_scan()

static void register_seq_scan ( HTAB *  hashp )

static

Definition at line 1831 of file dynahash.c.

{
    if (num_seq_scans >= MAX_SEQ_SCANS)
        elog(ERROR, "too many active hash_seq_search scans, cannot start one on \"%s\"",
             hashp->tabname);
    seq_scan_tables[num_seq_scans] = hashp;
    seq_scan_level[num_seq_scans] = GetCurrentTransactionNestLevel();
    num_seq_scans++;
}

References elog(), ERROR, GetCurrentTransactionNestLevel(), MAX_SEQ_SCANS, num_seq_scans, seq_scan_level, seq_scan_tables, and HTAB::tabname.

Referenced by hash_seq_init().

seg_alloc()

static HASHSEGMENT seg_alloc ( HTAB *  hashp )

static

Definition at line 1680 of file dynahash.c.

{
    HASHSEGMENT segp;
 
    CurrentDynaHashCxt = hashp->hcxt;
    segp = (HASHSEGMENT) hashp->alloc(sizeof(HASHBUCKET) * hashp->ssize);
 
    if (!segp)
        return NULL;
 
    MemSet(segp, 0, sizeof(HASHBUCKET) * hashp->ssize);
 
    return segp;
}

References HTAB::alloc, CurrentDynaHashCxt, HTAB::hcxt, MemSet, and HTAB::ssize.

Referenced by expand_table(), and init_htab().

string_compare()

static int string_compare ( const char *  key1, const char *  key2, Size  keysize  )

static

Definition at line 305 of file dynahash.c.

{
    return strncmp(key1, key2, keysize - 1);
}

Referenced by hash_create().

Variable Documentation

CurrentDynaHashCxt

MemoryContext CurrentDynaHashCxt = NULL

static

Definition at line 286 of file dynahash.c.

Referenced by dir_realloc(), DynaHashAlloc(), element_alloc(), hash_create(), init_htab(), and seg_alloc().

num_seq_scans

int num_seq_scans = 0

static

Definition at line 1826 of file dynahash.c.

Referenced by AtEOSubXact_HashTables(), AtEOXact_HashTables(), deregister_seq_scan(), has_seq_scans(), and register_seq_scan().

seq_scan_level

int seq_scan_level[MAX_SEQ_SCANS]

static

Definition at line 1825 of file dynahash.c.

Referenced by AtEOSubXact_HashTables(), deregister_seq_scan(), and register_seq_scan().

seq_scan_tables

HTAB* seq_scan_tables[MAX_SEQ_SCANS]

static

Definition at line 1824 of file dynahash.c.

Referenced by AtEOSubXact_HashTables(), AtEOXact_HashTables(), deregister_seq_scan(), has_seq_scans(), and register_seq_scan().