PostgreSQL Source Code  git master
dynahash.c File Reference
#include "postgres.h"
#include <limits.h>
#include "access/xact.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 DEF_FFACTOR   1 /* default fill factor */
 
#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 HASHELEMENTHASHBUCKET
 
typedef HASHBUCKETHASHSEGMENT
 

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)
 
HTABhash_create (const char *tabname, long nelem, 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 HTABseq_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 112 of file dynahash.c.

Referenced by hash_estimate_size(), hash_select_dirsize(), and hdefault().

◆ DEF_FFACTOR

#define DEF_FFACTOR   1 /* default fill factor */

Definition at line 113 of file dynahash.c.

Referenced by hash_estimate_size(), hash_select_dirsize(), and hdefault().

◆ DEF_SEGSIZE

#define DEF_SEGSIZE   256

Definition at line 110 of file dynahash.c.

Referenced by hash_estimate_size(), hash_select_dirsize(), and hdefault().

◆ DEF_SEGSIZE_SHIFT

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

Definition at line 111 of file dynahash.c.

Referenced by hdefault().

◆ ELEMENT_FROM_KEY

#define ELEMENT_FROM_KEY (   key)    ((HASHELEMENT *) (((char *) (key)) - MAXALIGN(sizeof(HASHELEMENT))))

Definition at line 238 of file dynahash.c.

Referenced by hash_update_hash_key().

◆ ELEMENTKEY

#define ELEMENTKEY (   helem)    (((char *)(helem)) + MAXALIGN(sizeof(HASHELEMENT)))

Definition at line 233 of file dynahash.c.

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

◆ FREELIST_IDX

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

Definition at line 201 of file dynahash.c.

Referenced by hash_search_with_hash_value().

◆ IS_PARTITIONED

#define IS_PARTITIONED (   hctl)    ((hctl)->num_partitions != 0)

◆ MAX_SEQ_SCANS

#define MAX_SEQ_SCANS   100

Definition at line 1774 of file dynahash.c.

Referenced by register_seq_scan().

◆ MOD

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

◆ NUM_FREELISTS

#define NUM_FREELISTS   32

Definition at line 116 of file dynahash.c.

Referenced by get_hash_entry(), hash_create(), hash_get_num_entries(), and init_htab().

Typedef Documentation

◆ HASHBUCKET

Definition at line 119 of file dynahash.c.

◆ HASHSEGMENT

Definition at line 122 of file dynahash.c.

Function Documentation

◆ AtEOSubXact_HashTables()

void AtEOSubXact_HashTables ( bool  isCommit,
int  nestDepth 
)

Definition at line 1856 of file dynahash.c.

References elog, i, num_seq_scans, seq_scan_level, and WARNING.

Referenced by AbortSubTransaction(), and CommitSubTransaction().

1857 {
1858  int i;
1859 
1860  /*
1861  * Search backward to make cleanup easy. Note we must check all entries,
1862  * not only those at the end of the array, because deletion technique
1863  * doesn't keep them in order.
1864  */
1865  for (i = num_seq_scans - 1; i >= 0; i--)
1866  {
1867  if (seq_scan_level[i] >= nestDepth)
1868  {
1869  if (isCommit)
1870  elog(WARNING, "leaked hash_seq_search scan for hash table %p",
1871  seq_scan_tables[i]);
1874  num_seq_scans--;
1875  }
1876  }
1877 }
static int seq_scan_level[MAX_SEQ_SCANS]
Definition: dynahash.c:1777
#define WARNING
Definition: elog.h:40
static int num_seq_scans
Definition: dynahash.c:1778
static HTAB * seq_scan_tables[MAX_SEQ_SCANS]
Definition: dynahash.c:1776
int i
#define elog
Definition: elog.h:219

◆ AtEOXact_HashTables()

void AtEOXact_HashTables ( bool  isCommit)

Definition at line 1830 of file dynahash.c.

References elog, i, num_seq_scans, and WARNING.

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

1831 {
1832  /*
1833  * During abort cleanup, open scans are expected; just silently clean 'em
1834  * out. An open scan at commit means someone forgot a hash_seq_term()
1835  * call, so complain.
1836  *
1837  * Note: it's tempting to try to print the tabname here, but refrain for
1838  * fear of touching deallocated memory. This isn't a user-facing message
1839  * anyway, so it needn't be pretty.
1840  */
1841  if (isCommit)
1842  {
1843  int i;
1844 
1845  for (i = 0; i < num_seq_scans; i++)
1846  {
1847  elog(WARNING, "leaked hash_seq_search scan for hash table %p",
1848  seq_scan_tables[i]);
1849  }
1850  }
1851  num_seq_scans = 0;
1852 }
#define WARNING
Definition: elog.h:40
static int num_seq_scans
Definition: dynahash.c:1778
static HTAB * seq_scan_tables[MAX_SEQ_SCANS]
Definition: dynahash.c:1776
int i
#define elog
Definition: elog.h:219

◆ calc_bucket()

static uint32 calc_bucket ( HASHHDR hctl,
uint32  hash_val 
)
inlinestatic

Definition at line 863 of file dynahash.c.

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().

864 {
865  uint32 bucket;
866 
867  bucket = hash_val & hctl->high_mask;
868  if (bucket > hctl->max_bucket)
869  bucket = bucket & hctl->low_mask;
870 
871  return bucket;
872 }
uint32 max_bucket
Definition: dynahash.c:174
uint32 low_mask
Definition: dynahash.c:176
unsigned int uint32
Definition: c.h:296
uint32 high_mask
Definition: dynahash.c:175

◆ choose_nelem_alloc()

static int choose_nelem_alloc ( Size  entrysize)
static

Definition at line 599 of file dynahash.c.

References MAXALIGN, and HASHHDR::nelem_alloc.

Referenced by hash_estimate_size(), and init_htab().

600 {
601  int nelem_alloc;
602  Size elementSize;
603  Size allocSize;
604 
605  /* Each element has a HASHELEMENT header plus user data. */
606  /* NB: this had better match element_alloc() */
607  elementSize = MAXALIGN(sizeof(HASHELEMENT)) + MAXALIGN(entrysize);
608 
609  /*
610  * The idea here is to choose nelem_alloc at least 32, but round up so
611  * that the allocation request will be a power of 2 or just less. This
612  * makes little difference for hash tables in shared memory, but for hash
613  * tables managed by palloc, the allocation request will be rounded up to
614  * a power of 2 anyway. If we fail to take this into account, we'll waste
615  * as much as half the allocated space.
616  */
617  allocSize = 32 * 4; /* assume elementSize at least 8 */
618  do
619  {
620  allocSize <<= 1;
621  nelem_alloc = allocSize / elementSize;
622  } while (nelem_alloc < 32);
623 
624  return nelem_alloc;
625 }
size_t Size
Definition: c.h:404
#define MAXALIGN(LEN)
Definition: c.h:623

◆ deregister_seq_scan()

static void deregister_seq_scan ( HTAB hashp)
static

Definition at line 1795 of file dynahash.c.

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

Referenced by hash_seq_term().

1796 {
1797  int i;
1798 
1799  /* Search backward since it's most likely at the stack top */
1800  for (i = num_seq_scans - 1; i >= 0; i--)
1801  {
1802  if (seq_scan_tables[i] == hashp)
1803  {
1806  num_seq_scans--;
1807  return;
1808  }
1809  }
1810  elog(ERROR, "no hash_seq_search scan for hash table \"%s\"",
1811  hashp->tabname);
1812 }
static int seq_scan_level[MAX_SEQ_SCANS]
Definition: dynahash.c:1777
#define ERROR
Definition: elog.h:43
static int num_seq_scans
Definition: dynahash.c:1778
static HTAB * seq_scan_tables[MAX_SEQ_SCANS]
Definition: dynahash.c:1776
char * tabname
Definition: dynahash.c:217
int i
#define elog
Definition: elog.h:219

◆ dir_realloc()

static bool dir_realloc ( HTAB hashp)
static

Definition at line 1595 of file dynahash.c.

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

Referenced by expand_table().

1596 {
1597  HASHSEGMENT *p;
1598  HASHSEGMENT *old_p;
1599  long new_dsize;
1600  long old_dirsize;
1601  long new_dirsize;
1602 
1603  if (hashp->hctl->max_dsize != NO_MAX_DSIZE)
1604  return false;
1605 
1606  /* Reallocate directory */
1607  new_dsize = hashp->hctl->dsize << 1;
1608  old_dirsize = hashp->hctl->dsize * sizeof(HASHSEGMENT);
1609  new_dirsize = new_dsize * sizeof(HASHSEGMENT);
1610 
1611  old_p = hashp->dir;
1612  CurrentDynaHashCxt = hashp->hcxt;
1613  p = (HASHSEGMENT *) hashp->alloc((Size) new_dirsize);
1614 
1615  if (p != NULL)
1616  {
1617  memcpy(p, old_p, old_dirsize);
1618  MemSet(((char *) p) + old_dirsize, 0, new_dirsize - old_dirsize);
1619  hashp->dir = p;
1620  hashp->hctl->dsize = new_dsize;
1621 
1622  /* XXX assume the allocator is palloc, so we know how to free */
1623  Assert(hashp->alloc == DynaHashAlloc);
1624  pfree(old_p);
1625 
1626  return true;
1627  }
1628 
1629  return false;
1630 }
long dsize
Definition: dynahash.c:172
#define NO_MAX_DSIZE
Definition: hsearch.h:100
HashAllocFunc alloc
Definition: dynahash.c:215
#define MemSet(start, val, len)
Definition: c.h:853
void pfree(void *pointer)
Definition: mcxt.c:949
HASHBUCKET * HASHSEGMENT
Definition: dynahash.c:122
long max_dsize
Definition: dynahash.c:183
HASHHDR * hctl
Definition: dynahash.c:210
MemoryContext hcxt
Definition: dynahash.c:216
#define Assert(condition)
Definition: c.h:670
size_t Size
Definition: c.h:404
static void * DynaHashAlloc(Size size)
Definition: dynahash.c:278
static MemoryContext CurrentDynaHashCxt
Definition: dynahash.c:275
HASHSEGMENT * dir
Definition: dynahash.c:211

◆ DynaHashAlloc()

static void * DynaHashAlloc ( Size  size)
static

Definition at line 278 of file dynahash.c.

References Assert, MemoryContextAlloc(), and MemoryContextIsValid.

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

279 {
282 }
#define MemoryContextIsValid(context)
Definition: memnodes.h:97
#define Assert(condition)
Definition: c.h:670
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:706
static MemoryContext CurrentDynaHashCxt
Definition: dynahash.c:275

◆ element_alloc()

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

Definition at line 1653 of file dynahash.c.

References HTAB::alloc, 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().

1654 {
1655  HASHHDR *hctl = hashp->hctl;
1656  Size elementSize;
1657  HASHELEMENT *firstElement;
1658  HASHELEMENT *tmpElement;
1659  HASHELEMENT *prevElement;
1660  int i;
1661 
1662  if (hashp->isfixed)
1663  return false;
1664 
1665  /* Each element has a HASHELEMENT header plus user data. */
1666  elementSize = MAXALIGN(sizeof(HASHELEMENT)) + MAXALIGN(hctl->entrysize);
1667 
1668  CurrentDynaHashCxt = hashp->hcxt;
1669  firstElement = (HASHELEMENT *) hashp->alloc(nelem * elementSize);
1670 
1671  if (!firstElement)
1672  return false;
1673 
1674  /* prepare to link all the new entries into the freelist */
1675  prevElement = NULL;
1676  tmpElement = firstElement;
1677  for (i = 0; i < nelem; i++)
1678  {
1679  tmpElement->link = prevElement;
1680  prevElement = tmpElement;
1681  tmpElement = (HASHELEMENT *) (((char *) tmpElement) + elementSize);
1682  }
1683 
1684  /* if partitioned, must lock to touch freeList */
1685  if (IS_PARTITIONED(hctl))
1686  SpinLockAcquire(&hctl->freeList[freelist_idx].mutex);
1687 
1688  /* freelist could be nonempty if two backends did this concurrently */
1689  firstElement->link = hctl->freeList[freelist_idx].freeList;
1690  hctl->freeList[freelist_idx].freeList = prevElement;
1691 
1692  if (IS_PARTITIONED(hctl))
1693  SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
1694 
1695  return true;
1696 }
Size entrysize
Definition: dynahash.c:180
#define IS_PARTITIONED(hctl)
Definition: dynahash.c:199
HashAllocFunc alloc
Definition: dynahash.c:215
slock_t mutex
Definition: dynahash.c:143
#define SpinLockAcquire(lock)
Definition: spin.h:62
HASHHDR * hctl
Definition: dynahash.c:210
#define SpinLockRelease(lock)
Definition: spin.h:64
FreeListData freeList[NUM_FREELISTS]
Definition: dynahash.c:168
MemoryContext hcxt
Definition: dynahash.c:216
size_t Size
Definition: c.h:404
#define MAXALIGN(LEN)
Definition: c.h:623
bool isfixed
Definition: dynahash.c:219
struct HASHELEMENT * link
Definition: hsearch.h:53
static MemoryContext CurrentDynaHashCxt
Definition: dynahash.c:275
int i
HASHELEMENT * freeList
Definition: dynahash.c:145

◆ expand_table()

static bool expand_table ( HTAB hashp)
static

Definition at line 1498 of file dynahash.c.

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().

1499 {
1500  HASHHDR *hctl = hashp->hctl;
1501  HASHSEGMENT old_seg,
1502  new_seg;
1503  long old_bucket,
1504  new_bucket;
1505  long new_segnum,
1506  new_segndx;
1507  long old_segnum,
1508  old_segndx;
1509  HASHBUCKET *oldlink,
1510  *newlink;
1511  HASHBUCKET currElement,
1512  nextElement;
1513 
1514  Assert(!IS_PARTITIONED(hctl));
1515 
1516 #ifdef HASH_STATISTICS
1517  hash_expansions++;
1518 #endif
1519 
1520  new_bucket = hctl->max_bucket + 1;
1521  new_segnum = new_bucket >> hashp->sshift;
1522  new_segndx = MOD(new_bucket, hashp->ssize);
1523 
1524  if (new_segnum >= hctl->nsegs)
1525  {
1526  /* Allocate new segment if necessary -- could fail if dir full */
1527  if (new_segnum >= hctl->dsize)
1528  if (!dir_realloc(hashp))
1529  return false;
1530  if (!(hashp->dir[new_segnum] = seg_alloc(hashp)))
1531  return false;
1532  hctl->nsegs++;
1533  }
1534 
1535  /* OK, we created a new bucket */
1536  hctl->max_bucket++;
1537 
1538  /*
1539  * *Before* changing masks, find old bucket corresponding to same hash
1540  * values; values in that bucket may need to be relocated to new bucket.
1541  * Note that new_bucket is certainly larger than low_mask at this point,
1542  * so we can skip the first step of the regular hash mask calc.
1543  */
1544  old_bucket = (new_bucket & hctl->low_mask);
1545 
1546  /*
1547  * If we crossed a power of 2, readjust masks.
1548  */
1549  if ((uint32) new_bucket > hctl->high_mask)
1550  {
1551  hctl->low_mask = hctl->high_mask;
1552  hctl->high_mask = (uint32) new_bucket | hctl->low_mask;
1553  }
1554 
1555  /*
1556  * Relocate records to the new bucket. NOTE: because of the way the hash
1557  * masking is done in calc_bucket, only one old bucket can need to be
1558  * split at this point. With a different way of reducing the hash value,
1559  * that might not be true!
1560  */
1561  old_segnum = old_bucket >> hashp->sshift;
1562  old_segndx = MOD(old_bucket, hashp->ssize);
1563 
1564  old_seg = hashp->dir[old_segnum];
1565  new_seg = hashp->dir[new_segnum];
1566 
1567  oldlink = &old_seg[old_segndx];
1568  newlink = &new_seg[new_segndx];
1569 
1570  for (currElement = *oldlink;
1571  currElement != NULL;
1572  currElement = nextElement)
1573  {
1574  nextElement = currElement->link;
1575  if ((long) calc_bucket(hctl, currElement->hashvalue) == old_bucket)
1576  {
1577  *oldlink = currElement;
1578  oldlink = &currElement->link;
1579  }
1580  else
1581  {
1582  *newlink = currElement;
1583  newlink = &currElement->link;
1584  }
1585  }
1586  /* don't forget to terminate the rebuilt hash chains... */
1587  *oldlink = NULL;
1588  *newlink = NULL;
1589 
1590  return true;
1591 }
long dsize
Definition: dynahash.c:172
uint32 max_bucket
Definition: dynahash.c:174
static uint32 calc_bucket(HASHHDR *hctl, uint32 hash_val)
Definition: dynahash.c:863
#define IS_PARTITIONED(hctl)
Definition: dynahash.c:199
uint32 low_mask
Definition: dynahash.c:176
long ssize
Definition: dynahash.c:226
int sshift
Definition: dynahash.c:227
#define MOD(x, y)
Definition: dynahash.c:244
HASHHDR * hctl
Definition: dynahash.c:210
unsigned int uint32
Definition: c.h:296
uint32 high_mask
Definition: dynahash.c:175
#define Assert(condition)
Definition: c.h:670
static HASHSEGMENT seg_alloc(HTAB *hashp)
Definition: dynahash.c:1634
struct HASHELEMENT * link
Definition: hsearch.h:53
HASHSEGMENT * dir
Definition: dynahash.c:211
static bool dir_realloc(HTAB *hashp)
Definition: dynahash.c:1595
uint32 hashvalue
Definition: hsearch.h:54
long nsegs
Definition: dynahash.c:173

◆ get_hash_entry()

static HASHBUCKET get_hash_entry ( HTAB hashp,
int  freelist_idx 
)
static

Definition at line 1246 of file dynahash.c.

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().

1247 {
1248  HASHHDR *hctl = hashp->hctl;
1249  HASHBUCKET newElement;
1250 
1251  for (;;)
1252  {
1253  /* if partitioned, must lock to touch nentries and freeList */
1254  if (IS_PARTITIONED(hctl))
1255  SpinLockAcquire(&hctl->freeList[freelist_idx].mutex);
1256 
1257  /* try to get an entry from the freelist */
1258  newElement = hctl->freeList[freelist_idx].freeList;
1259 
1260  if (newElement != NULL)
1261  break;
1262 
1263  if (IS_PARTITIONED(hctl))
1264  SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
1265 
1266  /*
1267  * No free elements in this freelist. In a partitioned table, there
1268  * might be entries in other freelists, but to reduce contention we
1269  * prefer to first try to get another chunk of buckets from the main
1270  * shmem allocator. If that fails, though, we *MUST* root through all
1271  * the other freelists before giving up. There are multiple callers
1272  * that assume that they can allocate every element in the initially
1273  * requested table size, or that deleting an element guarantees they
1274  * can insert a new element, even if shared memory is entirely full.
1275  * Failing because the needed element is in a different freelist is
1276  * not acceptable.
1277  */
1278  if (!element_alloc(hashp, hctl->nelem_alloc, freelist_idx))
1279  {
1280  int borrow_from_idx;
1281 
1282  if (!IS_PARTITIONED(hctl))
1283  return NULL; /* out of memory */
1284 
1285  /* try to borrow element from another freelist */
1286  borrow_from_idx = freelist_idx;
1287  for (;;)
1288  {
1289  borrow_from_idx = (borrow_from_idx + 1) % NUM_FREELISTS;
1290  if (borrow_from_idx == freelist_idx)
1291  break; /* examined all freelists, fail */
1292 
1293  SpinLockAcquire(&(hctl->freeList[borrow_from_idx].mutex));
1294  newElement = hctl->freeList[borrow_from_idx].freeList;
1295 
1296  if (newElement != NULL)
1297  {
1298  hctl->freeList[borrow_from_idx].freeList = newElement->link;
1299  SpinLockRelease(&(hctl->freeList[borrow_from_idx].mutex));
1300 
1301  /* careful: count the new element in its proper freelist */
1302  SpinLockAcquire(&hctl->freeList[freelist_idx].mutex);
1303  hctl->freeList[freelist_idx].nentries++;
1304  SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
1305 
1306  return newElement;
1307  }
1308 
1309  SpinLockRelease(&(hctl->freeList[borrow_from_idx].mutex));
1310  }
1311 
1312  /* no elements available to borrow either, so out of memory */
1313  return NULL;
1314  }
1315  }
1316 
1317  /* remove entry from freelist, bump nentries */
1318  hctl->freeList[freelist_idx].freeList = newElement->link;
1319  hctl->freeList[freelist_idx].nentries++;
1320 
1321  if (IS_PARTITIONED(hctl))
1322  SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
1323 
1324  return newElement;
1325 }
#define IS_PARTITIONED(hctl)
Definition: dynahash.c:199
#define NUM_FREELISTS
Definition: dynahash.c:116
slock_t mutex
Definition: dynahash.c:143
#define SpinLockAcquire(lock)
Definition: spin.h:62
HASHHDR * hctl
Definition: dynahash.c:210
long nentries
Definition: dynahash.c:144
#define SpinLockRelease(lock)
Definition: spin.h:64
FreeListData freeList[NUM_FREELISTS]
Definition: dynahash.c:168
int nelem_alloc
Definition: dynahash.c:186
struct HASHELEMENT * link
Definition: hsearch.h:53
HASHELEMENT * freeList
Definition: dynahash.c:145
static bool element_alloc(HTAB *hashp, int nelem, int freelist_idx)
Definition: dynahash.c:1653

◆ get_hash_value()

uint32 get_hash_value ( HTAB hashp,
const void *  keyPtr 
)

Definition at line 856 of file dynahash.c.

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

Referenced by BufTableHashCode(), and LockTagHashCode().

857 {
858  return hashp->hash(keyPtr, hashp->keysize);
859 }
Size keysize
Definition: dynahash.c:225
HashValueFunc hash
Definition: dynahash.c:212

◆ has_seq_scans()

static bool has_seq_scans ( HTAB hashp)
static

Definition at line 1816 of file dynahash.c.

References i, and num_seq_scans.

Referenced by hash_freeze(), and hash_search_with_hash_value().

1817 {
1818  int i;
1819 
1820  for (i = 0; i < num_seq_scans; i++)
1821  {
1822  if (seq_scan_tables[i] == hashp)
1823  return true;
1824  }
1825  return false;
1826 }
static int num_seq_scans
Definition: dynahash.c:1778
static HTAB * seq_scan_tables[MAX_SEQ_SCANS]
Definition: dynahash.c:1776
int i

◆ hash_corrupted()

static void hash_corrupted ( HTAB hashp)
static

Definition at line 1700 of file dynahash.c.

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

Referenced by hash_search_with_hash_value(), and hash_update_hash_key().

1701 {
1702  /*
1703  * If the corruption is in a shared hashtable, we'd better force a
1704  * systemwide restart. Otherwise, just shut down this one backend.
1705  */
1706  if (hashp->isshared)
1707  elog(PANIC, "hash table \"%s\" corrupted", hashp->tabname);
1708  else
1709  elog(FATAL, "hash table \"%s\" corrupted", hashp->tabname);
1710 }
#define PANIC
Definition: elog.h:53
#define FATAL
Definition: elog.h:52
bool isshared
Definition: dynahash.c:218
char * tabname
Definition: dynahash.c:217
#define elog
Definition: elog.h:219

◆ hash_create()

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

Definition at line 316 of file dynahash.c.

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

Referenced by _hash_finish_split(), _PG_init(), assign_record_type_typmod(), begin_heap_rewrite(), build_join_rel_hash(), BuildEventTriggerCache(), CompactCheckpointerRequestQueue(), compute_array_stats(), compute_tsvector_stats(), create_seq_hashtable(), createConnHash(), do_autovacuum(), EnablePortalManager(), find_all_inheritors(), find_oper_cache_entry(), find_rendezvous_variable(), get_json_object_as_hash(), get_tabstat_entry(), GetComboCommandId(), GetConnection(), GetSerializableTransactionSnapshotInt(), gistInitBuildBuffers(), gistInitParentMap(), init_procedure_caches(), init_rel_sync_cache(), init_timezone_hashtable(), init_ts_config_cache(), InitBufferPoolAccess(), InitializeAttoptCache(), InitializeRelfilenodeMap(), InitializeShippableCache(), InitializeTableSpaceCache(), InitLocalBuffers(), InitLocks(), InitQueryHashTable(), load_categories_hash(), log_invalid_page(), logical_begin_heap_rewrite(), logicalrep_relmap_init(), lookup_collation_cache(), lookup_proof_cache(), lookup_ts_dictionary_cache(), lookup_ts_parser_cache(), lookup_type_cache(), LookupOpclassInfo(), mdinit(), pgstat_collect_oids(), pgstat_init_function_usage(), pgstat_read_statsfiles(), 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(), reset_dbentry_counters(), ResetUnloggedRelationsInDbspaceDir(), ri_InitHashTables(), select_perl_context(), set_rtable_names(), ShmemInitHash(), smgropen(), and transformGraph().

317 {
318  HTAB *hashp;
319  HASHHDR *hctl;
320 
321  /*
322  * For shared hash tables, we have a local hash header (HTAB struct) that
323  * we allocate in TopMemoryContext; all else is in shared memory.
324  *
325  * For non-shared hash tables, everything including the hash header is in
326  * a memory context created specially for the hash table --- this makes
327  * hash_destroy very simple. The memory context is made a child of either
328  * a context specified by the caller, or TopMemoryContext if nothing is
329  * specified.
330  */
331  if (flags & HASH_SHARED_MEM)
332  {
333  /* Set up to allocate the hash header */
335  }
336  else
337  {
338  /* Create the hash table's private memory context */
339  if (flags & HASH_CONTEXT)
340  CurrentDynaHashCxt = info->hcxt;
341  else
344  tabname,
346  }
347 
348  /* Initialize the hash header, plus a copy of the table name */
349  hashp = (HTAB *) DynaHashAlloc(sizeof(HTAB) + strlen(tabname) + 1);
350  MemSet(hashp, 0, sizeof(HTAB));
351 
352  hashp->tabname = (char *) (hashp + 1);
353  strcpy(hashp->tabname, tabname);
354 
355  /*
356  * Select the appropriate hash function (see comments at head of file).
357  */
358  if (flags & HASH_FUNCTION)
359  hashp->hash = info->hash;
360  else if (flags & HASH_BLOBS)
361  {
362  /* We can optimize hashing for common key sizes */
363  Assert(flags & HASH_ELEM);
364  if (info->keysize == sizeof(uint32))
365  hashp->hash = uint32_hash;
366  else
367  hashp->hash = tag_hash;
368  }
369  else
370  hashp->hash = string_hash; /* default hash function */
371 
372  /*
373  * If you don't specify a match function, it defaults to string_compare if
374  * you used string_hash (either explicitly or by default) and to memcmp
375  * otherwise.
376  *
377  * Note: explicitly specifying string_hash is deprecated, because this
378  * might not work for callers in loadable modules on some platforms due to
379  * referencing a trampoline instead of the string_hash function proper.
380  * Just let it default, eh?
381  */
382  if (flags & HASH_COMPARE)
383  hashp->match = info->match;
384  else if (hashp->hash == string_hash)
386  else
387  hashp->match = memcmp;
388 
389  /*
390  * Similarly, the key-copying function defaults to strlcpy or memcpy.
391  */
392  if (flags & HASH_KEYCOPY)
393  hashp->keycopy = info->keycopy;
394  else if (hashp->hash == string_hash)
395  hashp->keycopy = (HashCopyFunc) strlcpy;
396  else
397  hashp->keycopy = memcpy;
398 
399  /* And select the entry allocation function, too. */
400  if (flags & HASH_ALLOC)
401  hashp->alloc = info->alloc;
402  else
403  hashp->alloc = DynaHashAlloc;
404 
405  if (flags & HASH_SHARED_MEM)
406  {
407  /*
408  * ctl structure and directory are preallocated for shared memory
409  * tables. Note that HASH_DIRSIZE and HASH_ALLOC had better be set as
410  * well.
411  */
412  hashp->hctl = info->hctl;
413  hashp->dir = (HASHSEGMENT *) (((char *) info->hctl) + sizeof(HASHHDR));
414  hashp->hcxt = NULL;
415  hashp->isshared = true;
416 
417  /* hash table already exists, we're just attaching to it */
418  if (flags & HASH_ATTACH)
419  {
420  /* make local copies of some heavily-used values */
421  hctl = hashp->hctl;
422  hashp->keysize = hctl->keysize;
423  hashp->ssize = hctl->ssize;
424  hashp->sshift = hctl->sshift;
425 
426  return hashp;
427  }
428  }
429  else
430  {
431  /* setup hash table defaults */
432  hashp->hctl = NULL;
433  hashp->dir = NULL;
434  hashp->hcxt = CurrentDynaHashCxt;
435  hashp->isshared = false;
436  }
437 
438  if (!hashp->hctl)
439  {
440  hashp->hctl = (HASHHDR *) hashp->alloc(sizeof(HASHHDR));
441  if (!hashp->hctl)
442  ereport(ERROR,
443  (errcode(ERRCODE_OUT_OF_MEMORY),
444  errmsg("out of memory")));
445  }
446 
447  hashp->frozen = false;
448 
449  hdefault(hashp);
450 
451  hctl = hashp->hctl;
452 
453  if (flags & HASH_PARTITION)
454  {
455  /* Doesn't make sense to partition a local hash table */
456  Assert(flags & HASH_SHARED_MEM);
457 
458  /*
459  * The number of partitions had better be a power of 2. Also, it must
460  * be less than INT_MAX (see init_htab()), so call the int version of
461  * next_pow2.
462  */
464 
465  hctl->num_partitions = info->num_partitions;
466  }
467 
468  if (flags & HASH_SEGMENT)
469  {
470  hctl->ssize = info->ssize;
471  hctl->sshift = my_log2(info->ssize);
472  /* ssize had better be a power of 2 */
473  Assert(hctl->ssize == (1L << hctl->sshift));
474  }
475  if (flags & HASH_FFACTOR)
476  hctl->ffactor = info->ffactor;
477 
478  /*
479  * SHM hash tables have fixed directory size passed by the caller.
480  */
481  if (flags & HASH_DIRSIZE)
482  {
483  hctl->max_dsize = info->max_dsize;
484  hctl->dsize = info->dsize;
485  }
486 
487  /*
488  * hash table now allocates space for key and data but you have to say how
489  * much space to allocate
490  */
491  if (flags & HASH_ELEM)
492  {
493  Assert(info->entrysize >= info->keysize);
494  hctl->keysize = info->keysize;
495  hctl->entrysize = info->entrysize;
496  }
497 
498  /* make local copies of heavily-used constant fields */
499  hashp->keysize = hctl->keysize;
500  hashp->ssize = hctl->ssize;
501  hashp->sshift = hctl->sshift;
502 
503  /* Build the hash directory structure */
504  if (!init_htab(hashp, nelem))
505  elog(ERROR, "failed to initialize hash table \"%s\"", hashp->tabname);
506 
507  /*
508  * For a shared hash table, preallocate the requested number of elements.
509  * This reduces problems with run-time out-of-shared-memory conditions.
510  *
511  * For a non-shared hash table, preallocate the requested number of
512  * elements if it's less than our chosen nelem_alloc. This avoids wasting
513  * space if the caller correctly estimates a small table size.
514  */
515  if ((flags & HASH_SHARED_MEM) ||
516  nelem < hctl->nelem_alloc)
517  {
518  int i,
519  freelist_partitions,
520  nelem_alloc,
521  nelem_alloc_first;
522 
523  /*
524  * If hash table is partitioned, give each freelist an equal share of
525  * the initial allocation. Otherwise only freeList[0] is used.
526  */
527  if (IS_PARTITIONED(hashp->hctl))
528  freelist_partitions = NUM_FREELISTS;
529  else
530  freelist_partitions = 1;
531 
532  nelem_alloc = nelem / freelist_partitions;
533  if (nelem_alloc <= 0)
534  nelem_alloc = 1;
535 
536  /*
537  * Make sure we'll allocate all the requested elements; freeList[0]
538  * gets the excess if the request isn't divisible by NUM_FREELISTS.
539  */
540  if (nelem_alloc * freelist_partitions < nelem)
541  nelem_alloc_first =
542  nelem - nelem_alloc * (freelist_partitions - 1);
543  else
544  nelem_alloc_first = nelem_alloc;
545 
546  for (i = 0; i < freelist_partitions; i++)
547  {
548  int temp = (i == 0) ? nelem_alloc_first : nelem_alloc;
549 
550  if (!element_alloc(hashp, temp, i))
551  ereport(ERROR,
552  (errcode(ERRCODE_OUT_OF_MEMORY),
553  errmsg("out of memory")));
554  }
555  }
556 
557  if (flags & HASH_FIXED_SIZE)
558  hashp->isfixed = true;
559  return hashp;
560 }
int(* HashCompareFunc)(const void *key1, const void *key2, Size keysize)
Definition: hsearch.h:29
Size keysize
Definition: dynahash.c:179
Size keysize
Definition: dynahash.c:225
long dsize
Definition: dynahash.c:172
#define HASH_CONTEXT
Definition: hsearch.h:93
#define HASH_ELEM
Definition: hsearch.h:87
MemoryContext hcxt
Definition: hsearch.h:78
long ssize
Definition: hsearch.h:68
HashCopyFunc keycopy
Definition: hsearch.h:76
Size entrysize
Definition: dynahash.c:180
#define IS_PARTITIONED(hctl)
Definition: dynahash.c:199
uint32 string_hash(const void *key, Size keysize)
Definition: hashfn.c:34
long num_partitions
Definition: dynahash.c:181
Size entrysize
Definition: hsearch.h:73
#define NUM_FREELISTS
Definition: dynahash.c:116
int errcode(int sqlerrcode)
Definition: elog.c:575
HashAllocFunc alloc
Definition: dynahash.c:215
#define MemSet(start, val, len)
Definition: c.h:853
#define HASH_SHARED_MEM
Definition: hsearch.h:94
static int string_compare(const char *key1, const char *key2, Size keysize)
Definition: dynahash.c:293
long dsize
Definition: hsearch.h:69
uint32 uint32_hash(const void *key, Size keysize)
Definition: hashfn.c:64
#define HASH_PARTITION
Definition: hsearch.h:83
#define HASH_ATTACH
Definition: hsearch.h:95
long ffactor
Definition: dynahash.c:182
HashValueFunc hash
Definition: dynahash.c:212
Definition: dynahash.c:208
long max_dsize
Definition: hsearch.h:70
long ssize
Definition: dynahash.c:226
#define ERROR
Definition: elog.h:43
long num_partitions
Definition: hsearch.h:67
int sshift
Definition: dynahash.c:227
#define ALLOCSET_DEFAULT_SIZES
Definition: memutils.h:165
HashAllocFunc alloc
Definition: hsearch.h:77
#define HASH_KEYCOPY
Definition: hsearch.h:91
long max_dsize
Definition: dynahash.c:183
static void hdefault(HTAB *hashp)
Definition: dynahash.c:566
HASHHDR * hctl
Definition: dynahash.c:210
unsigned int uint32
Definition: c.h:296
static bool init_htab(HTAB *hashp, long nelem)
Definition: dynahash.c:632
#define ereport(elevel, rest)
Definition: elog.h:122
MemoryContext TopMemoryContext
Definition: mcxt.c:43
int my_log2(long num)
Definition: dynahash.c:1714
HashCompareFunc match
Definition: dynahash.c:213
static int next_pow2_int(long num)
Definition: dynahash.c:1738
bool isshared
Definition: dynahash.c:218
#define HASH_BLOBS
Definition: hsearch.h:88
bool frozen
Definition: dynahash.c:222
MemoryContext AllocSetContextCreate(MemoryContext parent, const char *name, Size minContextSize, Size initBlockSize, Size maxBlockSize)
Definition: aset.c:322
uint32 tag_hash(const void *key, Size keysize)
Definition: hashfn.c:52
long ssize
Definition: dynahash.c:184
Size keysize
Definition: hsearch.h:72
void *(* HashCopyFunc)(void *dest, const void *src, Size keysize)
Definition: hsearch.h:37
HashCompareFunc match
Definition: hsearch.h:75
MemoryContext hcxt
Definition: dynahash.c:216
HashCopyFunc keycopy
Definition: dynahash.c:214
#define HASH_SEGMENT
Definition: hsearch.h:84
size_t strlcpy(char *dst, const char *src, size_t siz)
Definition: strlcpy.c:45
#define Assert(condition)
Definition: c.h:670
#define HASH_COMPARE
Definition: hsearch.h:90
HASHHDR * hctl
Definition: hsearch.h:79
long ffactor
Definition: hsearch.h:71
char * tabname
Definition: dynahash.c:217
#define HASH_FIXED_SIZE
Definition: hsearch.h:96
bool isfixed
Definition: dynahash.c:219
#define HASH_FFACTOR
Definition: hsearch.h:86
static void * DynaHashAlloc(Size size)
Definition: dynahash.c:278
#define HASH_DIRSIZE
Definition: hsearch.h:85
int errmsg(const char *fmt,...)
Definition: elog.c:797
static MemoryContext CurrentDynaHashCxt
Definition: dynahash.c:275
int i
#define HASH_ALLOC
Definition: hsearch.h:92
HASHSEGMENT * dir
Definition: dynahash.c:211
#define elog
Definition: elog.h:219
static bool element_alloc(HTAB *hashp, int nelem, int freelist_idx)
Definition: dynahash.c:1653
int sshift
Definition: dynahash.c:185
HashValueFunc hash
Definition: hsearch.h:74
#define HASH_FUNCTION
Definition: hsearch.h:89

◆ hash_destroy()

void hash_destroy ( HTAB hashp)

Definition at line 810 of file dynahash.c.

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

Referenced by _hash_finish_split(), clear_external_function_hash(), CompactCheckpointerRequestQueue(), find_all_inheritors(), InitLocks(), pgoutput_shutdown(), pgstat_recv_dropdb(), pgstat_recv_resetcounter(), pgstat_report_stat(), pgstat_vacuum_stat(), populate_recordset_object_end(), PostPrepare_PredicateLocks(), process_syncing_tables_for_apply(), ReleasePredicateLocks(), ReorderBufferReturnTXN(), ReorderBufferToastReset(), ResetSequenceCaches(), ResetUnloggedRelationsInDbspaceDir(), set_rtable_names(), SetForwardFsyncRequests(), and XLogCheckInvalidPages().

811 {
812  if (hashp != NULL)
813  {
814  /* allocation method must be one we know how to free, too */
815  Assert(hashp->alloc == DynaHashAlloc);
816  /* so this hashtable must have it's own context */
817  Assert(hashp->hcxt != NULL);
818 
819  hash_stats("destroy", hashp);
820 
821  /*
822  * Free everything by destroying the hash table's memory context.
823  */
824  MemoryContextDelete(hashp->hcxt);
825  }
826 }
void MemoryContextDelete(MemoryContext context)
Definition: mcxt.c:200
void hash_stats(const char *where, HTAB *hashp)
Definition: dynahash.c:829
HashAllocFunc alloc
Definition: dynahash.c:215
MemoryContext hcxt
Definition: dynahash.c:216
#define Assert(condition)
Definition: c.h:670
static void * DynaHashAlloc(Size size)
Definition: dynahash.c:278

◆ hash_estimate_size()

Size hash_estimate_size ( long  num_entries,
Size  entrysize 
)

Definition at line 728 of file dynahash.c.

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

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

729 {
730  Size size;
731  long nBuckets,
732  nSegments,
733  nDirEntries,
734  nElementAllocs,
735  elementSize,
736  elementAllocCnt;
737 
738  /* estimate number of buckets wanted */
739  nBuckets = next_pow2_long((num_entries - 1) / DEF_FFACTOR + 1);
740  /* # of segments needed for nBuckets */
741  nSegments = next_pow2_long((nBuckets - 1) / DEF_SEGSIZE + 1);
742  /* directory entries */
743  nDirEntries = DEF_DIRSIZE;
744  while (nDirEntries < nSegments)
745  nDirEntries <<= 1; /* dir_alloc doubles dsize at each call */
746 
747  /* fixed control info */
748  size = MAXALIGN(sizeof(HASHHDR)); /* but not HTAB, per above */
749  /* directory */
750  size = add_size(size, mul_size(nDirEntries, sizeof(HASHSEGMENT)));
751  /* segments */
752  size = add_size(size, mul_size(nSegments,
753  MAXALIGN(DEF_SEGSIZE * sizeof(HASHBUCKET))));
754  /* elements --- allocated in groups of choose_nelem_alloc() entries */
755  elementAllocCnt = choose_nelem_alloc(entrysize);
756  nElementAllocs = (num_entries - 1) / elementAllocCnt + 1;
757  elementSize = MAXALIGN(sizeof(HASHELEMENT)) + MAXALIGN(entrysize);
758  size = add_size(size,
759  mul_size(nElementAllocs,
760  mul_size(elementAllocCnt, elementSize)));
761 
762  return size;
763 }
static long next_pow2_long(long num)
Definition: dynahash.c:1730
Size mul_size(Size s1, Size s2)
Definition: shmem.c:492
Size add_size(Size s1, Size s2)
Definition: shmem.c:475
size_t Size
Definition: c.h:404
#define MAXALIGN(LEN)
Definition: c.h:623
static int choose_nelem_alloc(Size entrysize)
Definition: dynahash.c:599
#define DEF_FFACTOR
Definition: dynahash.c:113
#define DEF_SEGSIZE
Definition: dynahash.c:110
#define DEF_DIRSIZE
Definition: dynahash.c:112

◆ hash_freeze()

void hash_freeze ( HTAB hashp)

Definition at line 1481 of file dynahash.c.

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

1482 {
1483  if (hashp->isshared)
1484  elog(ERROR, "cannot freeze shared hashtable \"%s\"", hashp->tabname);
1485  if (!hashp->frozen && has_seq_scans(hashp))
1486  elog(ERROR, "cannot freeze hashtable \"%s\" because it has active scans",
1487  hashp->tabname);
1488  hashp->frozen = true;
1489 }
#define ERROR
Definition: elog.h:43
static bool has_seq_scans(HTAB *hashp)
Definition: dynahash.c:1816
bool isshared
Definition: dynahash.c:218
bool frozen
Definition: dynahash.c:222
char * tabname
Definition: dynahash.c:217
#define elog
Definition: elog.h:219

◆ hash_get_num_entries()

long hash_get_num_entries ( HTAB hashp)

Definition at line 1331 of file dynahash.c.

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

Referenced by compute_array_stats(), compute_tsvector_stats(), entry_alloc(), entry_dealloc(), get_crosstab_tuplestore(), GetLockStatusData(), GetPredicateLockStatusData(), GetRunningTransactionLocks(), hash_stats(), pgss_shmem_shutdown(), pgstat_vacuum_stat(), ResetUnloggedRelationsInDbspaceDir(), transformGraph(), and XLogHaveInvalidPages().

1332 {
1333  int i;
1334  long sum = hashp->hctl->freeList[0].nentries;
1335 
1336  /*
1337  * We currently don't bother with acquiring the mutexes; it's only
1338  * sensible to call this function if you've got lock on all partitions of
1339  * the table.
1340  */
1341  if (IS_PARTITIONED(hashp->hctl))
1342  {
1343  for (i = 1; i < NUM_FREELISTS; i++)
1344  sum += hashp->hctl->freeList[i].nentries;
1345  }
1346 
1347  return sum;
1348 }
#define IS_PARTITIONED(hctl)
Definition: dynahash.c:199
#define NUM_FREELISTS
Definition: dynahash.c:116
HASHHDR * hctl
Definition: dynahash.c:210
long nentries
Definition: dynahash.c:144
FreeListData freeList[NUM_FREELISTS]
Definition: dynahash.c:168
int i

◆ hash_get_shared_size()

Size hash_get_shared_size ( HASHCTL info,
int  flags 
)

Definition at line 799 of file dynahash.c.

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

Referenced by ShmemInitHash().

800 {
801  Assert(flags & HASH_DIRSIZE);
802  Assert(info->dsize == info->max_dsize);
803  return sizeof(HASHHDR) + info->dsize * sizeof(HASHSEGMENT);
804 }
long dsize
Definition: hsearch.h:69
long max_dsize
Definition: hsearch.h:70
struct HASHHDR HASHHDR
Definition: hsearch.h:58
#define Assert(condition)
Definition: c.h:670
#define HASH_DIRSIZE
Definition: hsearch.h:85

◆ hash_search()

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

Definition at line 902 of file dynahash.c.

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

Referenced by _hash_finish_split(), _hash_splitbucket(), add_join_rel(), ApplyLogicalMappingFile(), assign_record_type_typmod(), AtEOSubXact_RelationCache(), AtEOXact_RelationCache(), build_join_rel_hash(), BuildEventTriggerCache(), CheckAndPromotePredicateLockRequest(), CheckForSerializableConflictOut(), CompactCheckpointerRequestQueue(), compile_plperl_function(), compile_pltcl_function(), compute_array_stats(), compute_tsvector_stats(), createNewConnection(), deleteConnection(), do_autovacuum(), DropAllPredicateLocksFromTable(), DropAllPreparedStatements(), DropPreparedStatement(), DropRelFileNodeAllLocalBuffers(), DropRelFileNodeLocalBuffers(), entry_alloc(), entry_dealloc(), entry_reset(), EventCacheLookup(), FetchPreparedStatement(), find_all_inheritors(), find_funcstat_entry(), find_join_rel(), find_oper_cache_entry(), find_rendezvous_variable(), find_tabstat_entry(), forget_invalid_pages(), forget_invalid_pages_db(), ForgetPrivateRefCountEntry(), get_attribute_options(), get_cast_hashentry(), get_pgstat_tabentry_relid(), get_rel_sync_entry(), get_tablespace(), get_tabstat_entry(), 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(), LocalPrefetchBuffer(), LockAcquireExtended(), LockHasWaiters(), LockRelease(), log_invalid_page(), logical_rewrite_log_mapping(), logicalrep_rel_open(), logicalrep_relmap_update(), logicalrep_typmap_getid(), logicalrep_typmap_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(), mdsync(), pg_tzset(), pgss_store(), pgstat_collect_oids(), pgstat_fetch_stat_dbentry(), pgstat_fetch_stat_funcentry(), pgstat_fetch_stat_tabentry(), pgstat_get_db_entry(), pgstat_get_tab_entry(), pgstat_init_function_usage(), pgstat_read_db_statsfile(), pgstat_read_statsfiles(), pgstat_recv_dropdb(), pgstat_recv_funcpurge(), pgstat_recv_funcstat(), pgstat_recv_resetsinglecounter(), pgstat_recv_tabpurge(), pgstat_recv_tabstat(), pgstat_vacuum_stat(), plperl_spi_exec_prepared(), plperl_spi_freeplan(), plperl_spi_prepare(), plperl_spi_query_prepared(), plpgsql_HashTableDelete(), plpgsql_HashTableInsert(), plpgsql_HashTableLookup(), pltcl_fetch_interp(), PLy_generate_spi_exceptions(), PLy_procedure_get(), PLy_spi_subtransaction_abort(), populate_recordset_object_field_end(), predicatelock_twophase_recover(), PredicateLockExists(), PredicateLockTwoPhaseFinish(), process_syncing_tables_for_apply(), prune_element_hashtable(), prune_lexemes_hashtable(), rebuild_database_list(), record_C_func(), RegisterExtensibleNodeEntry(), RegisterPredicateLockingXid(), rel_sync_cache_relation_cb(), ReleaseOneSerializableXact(), RelfilenodeMapInvalidateCallback(), RelidByRelfilenode(), RememberFsyncRequest(), RemoveLocalLock(), ReorderBufferBuildTupleCidHash(), ReorderBufferCleanupTXN(), ReorderBufferToastAppendChunk(), ReorderBufferToastReplace(), ReorderBufferTXNByXid(), ReservePrivateRefCountEntry(), ResetUnloggedRelationsInDbspaceDir(), ResolveCminCmaxDuringDecoding(), rewrite_heap_dead_tuple(), rewrite_heap_tuple(), ri_FetchPreparedPlan(), ri_HashCompareOp(), ri_HashPreparedPlan(), ri_LoadConstraintInfo(), select_perl_context(), set_rtable_names(), ShmemInitStruct(), smgrclose(), smgrclosenode(), smgropen(), StorePreparedStatement(), and table_recheck_autovac().

906 {
907  return hash_search_with_hash_value(hashp,
908  keyPtr,
909  hashp->hash(keyPtr, hashp->keysize),
910  action,
911  foundPtr);
912 }
void * hash_search_with_hash_value(HTAB *hashp, const void *keyPtr, uint32 hashvalue, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:915
Size keysize
Definition: dynahash.c:225
HashValueFunc hash
Definition: dynahash.c:212

◆ 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 915 of file dynahash.c.

References HTAB::alloc, Assert, calc_bucket(), HTAB::dir, DynaHashAlloc(), ELEMENTKEY, elog, ereport, errcode(), errmsg(), ERROR, expand_table(), HASHHDR::ffactor, 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, HASHHDR::keysize, 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().

920 {
921  HASHHDR *hctl = hashp->hctl;
922  int freelist_idx = FREELIST_IDX(hctl, hashvalue);
923  Size keysize;
924  uint32 bucket;
925  long segment_num;
926  long segment_ndx;
927  HASHSEGMENT segp;
928  HASHBUCKET currBucket;
929  HASHBUCKET *prevBucketPtr;
930  HashCompareFunc match;
931 
932 #if HASH_STATISTICS
933  hash_accesses++;
934  hctl->accesses++;
935 #endif
936 
937  /*
938  * If inserting, check if it is time to split a bucket.
939  *
940  * NOTE: failure to expand table is not a fatal error, it just means we
941  * have to run at higher fill factor than we wanted. However, if we're
942  * using the palloc allocator then it will throw error anyway on
943  * out-of-memory, so we must do this before modifying the table.
944  */
946  {
947  /*
948  * Can't split if running in partitioned mode, nor if frozen, nor if
949  * table is the subject of any active hash_seq_search scans. Strange
950  * order of these tests is to try to check cheaper conditions first.
951  */
952  if (!IS_PARTITIONED(hctl) && !hashp->frozen &&
953  hctl->freeList[0].nentries / (long) (hctl->max_bucket + 1) >= hctl->ffactor &&
954  !has_seq_scans(hashp))
955  (void) expand_table(hashp);
956  }
957 
958  /*
959  * Do the initial lookup
960  */
961  bucket = calc_bucket(hctl, hashvalue);
962 
963  segment_num = bucket >> hashp->sshift;
964  segment_ndx = MOD(bucket, hashp->ssize);
965 
966  segp = hashp->dir[segment_num];
967 
968  if (segp == NULL)
969  hash_corrupted(hashp);
970 
971  prevBucketPtr = &segp[segment_ndx];
972  currBucket = *prevBucketPtr;
973 
974  /*
975  * Follow collision chain looking for matching key
976  */
977  match = hashp->match; /* save one fetch in inner loop */
978  keysize = hashp->keysize; /* ditto */
979 
980  while (currBucket != NULL)
981  {
982  if (currBucket->hashvalue == hashvalue &&
983  match(ELEMENTKEY(currBucket), keyPtr, keysize) == 0)
984  break;
985  prevBucketPtr = &(currBucket->link);
986  currBucket = *prevBucketPtr;
987 #if HASH_STATISTICS
988  hash_collisions++;
989  hctl->collisions++;
990 #endif
991  }
992 
993  if (foundPtr)
994  *foundPtr = (bool) (currBucket != NULL);
995 
996  /*
997  * OK, now what?
998  */
999  switch (action)
1000  {
1001  case HASH_FIND:
1002  if (currBucket != NULL)
1003  return (void *) ELEMENTKEY(currBucket);
1004  return NULL;
1005 
1006  case HASH_REMOVE:
1007  if (currBucket != NULL)
1008  {
1009  /* if partitioned, must lock to touch nentries and freeList */
1010  if (IS_PARTITIONED(hctl))
1011  SpinLockAcquire(&(hctl->freeList[freelist_idx].mutex));
1012 
1013  /* delete the record from the appropriate nentries counter. */
1014  Assert(hctl->freeList[freelist_idx].nentries > 0);
1015  hctl->freeList[freelist_idx].nentries--;
1016 
1017  /* remove record from hash bucket's chain. */
1018  *prevBucketPtr = currBucket->link;
1019 
1020  /* add the record to the appropriate freelist. */
1021  currBucket->link = hctl->freeList[freelist_idx].freeList;
1022  hctl->freeList[freelist_idx].freeList = currBucket;
1023 
1024  if (IS_PARTITIONED(hctl))
1025  SpinLockRelease(&hctl->freeList[freelist_idx].mutex);
1026 
1027  /*
1028  * better hope the caller is synchronizing access to this
1029  * element, because someone else is going to reuse it the next
1030  * time something is added to the table
1031  */
1032  return (void *) ELEMENTKEY(currBucket);
1033  }
1034  return NULL;
1035 
1036  case HASH_ENTER_NULL:
1037  /* ENTER_NULL does not work with palloc-based allocator */
1038  Assert(hashp->alloc != DynaHashAlloc);
1039  /* FALL THRU */
1040 
1041  case HASH_ENTER:
1042  /* Return existing element if found, else create one */
1043  if (currBucket != NULL)
1044  return (void *) ELEMENTKEY(currBucket);
1045 
1046  /* disallow inserts if frozen */
1047  if (hashp->frozen)
1048  elog(ERROR, "cannot insert into frozen hashtable \"%s\"",
1049  hashp->tabname);
1050 
1051  currBucket = get_hash_entry(hashp, freelist_idx);
1052  if (currBucket == NULL)
1053  {
1054  /* out of memory */
1055  if (action == HASH_ENTER_NULL)
1056  return NULL;
1057  /* report a generic message */
1058  if (hashp->isshared)
1059  ereport(ERROR,
1060  (errcode(ERRCODE_OUT_OF_MEMORY),
1061  errmsg("out of shared memory")));
1062  else
1063  ereport(ERROR,
1064  (errcode(ERRCODE_OUT_OF_MEMORY),
1065  errmsg("out of memory")));
1066  }
1067 
1068  /* link into hashbucket chain */
1069  *prevBucketPtr = currBucket;
1070  currBucket->link = NULL;
1071 
1072  /* copy key into record */
1073  currBucket->hashvalue = hashvalue;
1074  hashp->keycopy(ELEMENTKEY(currBucket), keyPtr, keysize);
1075 
1076  /*
1077  * Caller is expected to fill the data field on return. DO NOT
1078  * insert any code that could possibly throw error here, as doing
1079  * so would leave the table entry incomplete and hence corrupt the
1080  * caller's data structure.
1081  */
1082 
1083  return (void *) ELEMENTKEY(currBucket);
1084  }
1085 
1086  elog(ERROR, "unrecognized hash action code: %d", (int) action);
1087 
1088  return NULL; /* keep compiler quiet */
1089 }
int(* HashCompareFunc)(const void *key1, const void *key2, Size keysize)
Definition: hsearch.h:29
Size keysize
Definition: dynahash.c:225
uint32 max_bucket
Definition: dynahash.c:174
static uint32 calc_bucket(HASHHDR *hctl, uint32 hash_val)
Definition: dynahash.c:863
#define IS_PARTITIONED(hctl)
Definition: dynahash.c:199
#define ELEMENTKEY(helem)
Definition: dynahash.c:233
int errcode(int sqlerrcode)
Definition: elog.c:575
HashAllocFunc alloc
Definition: dynahash.c:215
slock_t mutex
Definition: dynahash.c:143
static HASHBUCKET get_hash_entry(HTAB *hashp, int freelist_idx)
Definition: dynahash.c:1246
char bool
Definition: c.h:247
long ffactor
Definition: dynahash.c:182
#define SpinLockAcquire(lock)
Definition: spin.h:62
long ssize
Definition: dynahash.c:226
#define ERROR
Definition: elog.h:43
int sshift
Definition: dynahash.c:227
#define MOD(x, y)
Definition: dynahash.c:244
HASHHDR * hctl
Definition: dynahash.c:210
static void hash_corrupted(HTAB *hashp)
Definition: dynahash.c:1700
static bool has_seq_scans(HTAB *hashp)
Definition: dynahash.c:1816
unsigned int uint32
Definition: c.h:296
long nentries
Definition: dynahash.c:144
#define ereport(elevel, rest)
Definition: elog.h:122
HashCompareFunc match
Definition: dynahash.c:213
bool isshared
Definition: dynahash.c:218
#define SpinLockRelease(lock)
Definition: spin.h:64
bool frozen
Definition: dynahash.c:222
FreeListData freeList[NUM_FREELISTS]
Definition: dynahash.c:168
HashCopyFunc keycopy
Definition: dynahash.c:214
#define Assert(condition)
Definition: c.h:670
size_t Size
Definition: c.h:404
static bool expand_table(HTAB *hashp)
Definition: dynahash.c:1498
char * tabname
Definition: dynahash.c:217
static void * DynaHashAlloc(Size size)
Definition: dynahash.c:278
int errmsg(const char *fmt,...)
Definition: elog.c:797
struct HASHELEMENT * link
Definition: hsearch.h:53
HASHELEMENT * freeList
Definition: dynahash.c:145
HASHSEGMENT * dir
Definition: dynahash.c:211
#define elog
Definition: elog.h:219
#define FREELIST_IDX(hctl, hashcode)
Definition: dynahash.c:201
uint32 hashvalue
Definition: hsearch.h:54

◆ hash_select_dirsize()

long hash_select_dirsize ( long  num_entries)

Definition at line 775 of file dynahash.c.

References DEF_DIRSIZE, DEF_FFACTOR, DEF_SEGSIZE, and next_pow2_long().

Referenced by ShmemInitHash().

776 {
777  long nBuckets,
778  nSegments,
779  nDirEntries;
780 
781  /* estimate number of buckets wanted */
782  nBuckets = next_pow2_long((num_entries - 1) / DEF_FFACTOR + 1);
783  /* # of segments needed for nBuckets */
784  nSegments = next_pow2_long((nBuckets - 1) / DEF_SEGSIZE + 1);
785  /* directory entries */
786  nDirEntries = DEF_DIRSIZE;
787  while (nDirEntries < nSegments)
788  nDirEntries <<= 1; /* dir_alloc doubles dsize at each call */
789 
790  return nDirEntries;
791 }
static long next_pow2_long(long num)
Definition: dynahash.c:1730
#define DEF_FFACTOR
Definition: dynahash.c:113
#define DEF_SEGSIZE
Definition: dynahash.c:110
#define DEF_DIRSIZE
Definition: dynahash.c:112

◆ hash_seq_init()

void hash_seq_init ( HASH_SEQ_STATUS status,
HTAB hashp 
)

Definition at line 1375 of file dynahash.c.

References HASH_SEQ_STATUS::curBucket, HASH_SEQ_STATUS::curEntry, HTAB::frozen, HASH_SEQ_STATUS::hashp, and register_seq_scan().

Referenced by AtAbort_Portals(), AtCleanup_Portals(), AtEOSubXact_RelationCache(), AtEOXact_RelationCache(), AtPrepare_Locks(), AtSubAbort_Portals(), AtSubCleanup_Portals(), AtSubCommit_Portals(), CheckForBufferLeaks(), CheckTableForSerializableConflictIn(), compute_array_stats(), compute_tsvector_stats(), dblink_get_connections(), DropAllPredicateLocksFromTable(), DropAllPreparedStatements(), end_heap_rewrite(), entry_dealloc(), entry_reset(), forget_invalid_pages(), forget_invalid_pages_db(), gc_qtexts(), GetLockmodeName(), GetLockStatusData(), GetPredicateLockStatusData(), GetRunningTransactionLocks(), InvalidateAttoptCacheCallback(), InvalidateOprCacheCallBack(), InvalidateOprProofCacheCallBack(), InvalidateShippableCacheCallback(), InvalidateTableSpaceCacheCallback(), InvalidateTSCacheCallBack(), LockReassignCurrentOwner(), LockReleaseAll(), LockReleaseCurrentOwner(), LockReleaseSession(), logical_end_heap_rewrite(), logical_heap_rewrite_flush_mappings(), logicalrep_relmap_invalidate_cb(), logicalrep_typmap_invalidate_cb(), mdsync(), packArcInfoCmp(), packGraph(), pg_cursor(), pg_prepared_statement(), pg_stat_statements_internal(), pgfdw_inval_callback(), pgfdw_subxact_callback(), pgfdw_xact_callback(), pgss_shmem_shutdown(), pgstat_send_funcstats(), pgstat_vacuum_stat(), pgstat_write_db_statsfile(), pgstat_write_statsfiles(), plperl_fini(), PortalHashTableDeleteAll(), PostPrepare_Locks(), PreCommit_Portals(), prune_element_hashtable(), prune_lexemes_hashtable(), rebuild_database_list(), rel_sync_cache_publication_cb(), RelationCacheInitializePhase3(), RelationCacheInvalidate(), RelfilenodeMapInvalidateCallback(), RememberFsyncRequest(), ReorderBufferToastReset(), selectColorTrigrams(), smgrcloseall(), ThereAreNoReadyPortals(), TypeCacheOpcCallback(), TypeCacheRelCallback(), write_relcache_init_file(), and XLogCheckInvalidPages().

1376 {
1377  status->hashp = hashp;
1378  status->curBucket = 0;
1379  status->curEntry = NULL;
1380  if (!hashp->frozen)
1381  register_seq_scan(hashp);
1382 }
uint32 curBucket
Definition: hsearch.h:115
HASHELEMENT * curEntry
Definition: hsearch.h:116
HTAB * hashp
Definition: hsearch.h:114
bool frozen
Definition: dynahash.c:222
static void register_seq_scan(HTAB *hashp)
Definition: dynahash.c:1783

◆ hash_seq_search()

void* hash_seq_search ( HASH_SEQ_STATUS status)

Definition at line 1385 of file dynahash.c.

References HASH_SEQ_STATUS::curBucket, HASH_SEQ_STATUS::curEntry, HTAB::dir, ELEMENTKEY, hash_seq_term(), HASH_SEQ_STATUS::hashp, HTAB::hctl, HASHELEMENT::link, HASHHDR::max_bucket, MOD, HTAB::sshift, HASHHDR::ssize, and HTAB::ssize.

Referenced by AtAbort_Portals(), AtCleanup_Portals(), AtEOSubXact_RelationCache(), AtEOXact_RelationCache(), AtPrepare_Locks(), AtSubAbort_Portals(), AtSubCleanup_Portals(), AtSubCommit_Portals(), CheckForBufferLeaks(), CheckTableForSerializableConflictIn(), compute_array_stats(), compute_tsvector_stats(), dblink_get_connections(), DropAllPredicateLocksFromTable(), DropAllPreparedStatements(), end_heap_rewrite(), entry_dealloc(), entry_reset(), forget_invalid_pages(), forget_invalid_pages_db(), gc_qtexts(), GetLockmodeName(), GetLockStatusData(), GetPredicateLockStatusData(), GetRunningTransactionLocks(), InvalidateAttoptCacheCallback(), InvalidateOprCacheCallBack(), InvalidateOprProofCacheCallBack(), InvalidateShippableCacheCallback(), InvalidateTableSpaceCacheCallback(), InvalidateTSCacheCallBack(), LockReassignCurrentOwner(), LockReleaseAll(), LockReleaseCurrentOwner(), LockReleaseSession(), logical_end_heap_rewrite(), logical_heap_rewrite_flush_mappings(), logicalrep_relmap_invalidate_cb(), logicalrep_typmap_invalidate_cb(), mdsync(), packArcInfoCmp(), packGraph(), pg_cursor(), pg_prepared_statement(), pg_stat_statements_internal(), pgfdw_inval_callback(), pgfdw_subxact_callback(), pgfdw_xact_callback(), pgss_shmem_shutdown(), pgstat_send_funcstats(), pgstat_vacuum_stat(), pgstat_write_db_statsfile(), pgstat_write_statsfiles(), plperl_fini(), PortalHashTableDeleteAll(), PostPrepare_Locks(), PreCommit_Portals(), prune_element_hashtable(), prune_lexemes_hashtable(), rebuild_database_list(), rel_sync_cache_publication_cb(), RelationCacheInitializePhase3(), RelationCacheInvalidate(), RelfilenodeMapInvalidateCallback(), RememberFsyncRequest(), ReorderBufferToastReset(), selectColorTrigrams(), smgrcloseall(), ThereAreNoReadyPortals(), TypeCacheOpcCallback(), TypeCacheRelCallback(), write_relcache_init_file(), and XLogCheckInvalidPages().

1386 {
1387  HTAB *hashp;
1388  HASHHDR *hctl;
1389  uint32 max_bucket;
1390  long ssize;
1391  long segment_num;
1392  long segment_ndx;
1393  HASHSEGMENT segp;
1394  uint32 curBucket;
1395  HASHELEMENT *curElem;
1396 
1397  if ((curElem = status->curEntry) != NULL)
1398  {
1399  /* Continuing scan of curBucket... */
1400  status->curEntry = curElem->link;
1401  if (status->curEntry == NULL) /* end of this bucket */
1402  ++status->curBucket;
1403  return (void *) ELEMENTKEY(curElem);
1404  }
1405 
1406  /*
1407  * Search for next nonempty bucket starting at curBucket.
1408  */
1409  curBucket = status->curBucket;
1410  hashp = status->hashp;
1411  hctl = hashp->hctl;
1412  ssize = hashp->ssize;
1413  max_bucket = hctl->max_bucket;
1414 
1415  if (curBucket > max_bucket)
1416  {
1417  hash_seq_term(status);
1418  return NULL; /* search is done */
1419  }
1420 
1421  /*
1422  * first find the right segment in the table directory.
1423  */
1424  segment_num = curBucket >> hashp->sshift;
1425  segment_ndx = MOD(curBucket, ssize);
1426 
1427  segp = hashp->dir[segment_num];
1428 
1429  /*
1430  * Pick up the first item in this bucket's chain. If chain is not empty
1431  * we can begin searching it. Otherwise we have to advance to find the
1432  * next nonempty bucket. We try to optimize that case since searching a
1433  * near-empty hashtable has to iterate this loop a lot.
1434  */
1435  while ((curElem = segp[segment_ndx]) == NULL)
1436  {
1437  /* empty bucket, advance to next */
1438  if (++curBucket > max_bucket)
1439  {
1440  status->curBucket = curBucket;
1441  hash_seq_term(status);
1442  return NULL; /* search is done */
1443  }
1444  if (++segment_ndx >= ssize)
1445  {
1446  segment_num++;
1447  segment_ndx = 0;
1448  segp = hashp->dir[segment_num];
1449  }
1450  }
1451 
1452  /* Begin scan of curBucket... */
1453  status->curEntry = curElem->link;
1454  if (status->curEntry == NULL) /* end of this bucket */
1455  ++curBucket;
1456  status->curBucket = curBucket;
1457  return (void *) ELEMENTKEY(curElem);
1458 }
uint32 curBucket
Definition: hsearch.h:115
uint32 max_bucket
Definition: dynahash.c:174
#define ELEMENTKEY(helem)
Definition: dynahash.c:233
HASHELEMENT * curEntry
Definition: hsearch.h:116
Definition: dynahash.c:208
long ssize
Definition: dynahash.c:226
int sshift
Definition: dynahash.c:227
#define MOD(x, y)
Definition: dynahash.c:244
HASHHDR * hctl
Definition: dynahash.c:210
unsigned int uint32
Definition: c.h:296
HTAB * hashp
Definition: hsearch.h:114
struct HASHELEMENT * link
Definition: hsearch.h:53
HASHSEGMENT * dir
Definition: dynahash.c:211
void hash_seq_term(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1461

◆ hash_seq_term()

void hash_seq_term ( HASH_SEQ_STATUS status)

Definition at line 1461 of file dynahash.c.

References deregister_seq_scan(), HTAB::frozen, and HASH_SEQ_STATUS::hashp.

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

1462 {
1463  if (!status->hashp->frozen)
1464  deregister_seq_scan(status->hashp);
1465 }
HTAB * hashp
Definition: hsearch.h:114
bool frozen
Definition: dynahash.c:222
static void deregister_seq_scan(HTAB *hashp)
Definition: dynahash.c:1795

◆ hash_stats()

void hash_stats ( const char *  where,
HTAB hashp 
)

Definition at line 829 of file dynahash.c.

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

Referenced by hash_destroy().

830 {
831 #if HASH_STATISTICS
832  fprintf(stderr, "%s: this HTAB -- accesses %ld collisions %ld\n",
833  where, hashp->hctl->accesses, hashp->hctl->collisions);
834 
835  fprintf(stderr, "hash_stats: entries %ld keysize %ld maxp %u segmentcount %ld\n",
836  hash_get_num_entries(hashp), (long) hashp->hctl->keysize,
837  hashp->hctl->max_bucket, hashp->hctl->nsegs);
838  fprintf(stderr, "%s: total accesses %ld total collisions %ld\n",
839  where, hash_accesses, hash_collisions);
840  fprintf(stderr, "hash_stats: total expansions %ld\n",
841  hash_expansions);
842 #endif
843 }
Size keysize
Definition: dynahash.c:179
uint32 max_bucket
Definition: dynahash.c:174
long hash_get_num_entries(HTAB *hashp)
Definition: dynahash.c:1331
HASHHDR * hctl
Definition: dynahash.c:210
long nsegs
Definition: dynahash.c:173

◆ hash_update_hash_key()

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

Definition at line 1111 of file dynahash.c.

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

Referenced by PostPrepare_Locks().

1114 {
1115  HASHELEMENT *existingElement = ELEMENT_FROM_KEY(existingEntry);
1116  HASHHDR *hctl = hashp->hctl;
1117  uint32 newhashvalue;
1118  Size keysize;
1119  uint32 bucket;
1120  uint32 newbucket;
1121  long segment_num;
1122  long segment_ndx;
1123  HASHSEGMENT segp;
1124  HASHBUCKET currBucket;
1125  HASHBUCKET *prevBucketPtr;
1126  HASHBUCKET *oldPrevPtr;
1127  HashCompareFunc match;
1128 
1129 #if HASH_STATISTICS
1130  hash_accesses++;
1131  hctl->accesses++;
1132 #endif
1133 
1134  /* disallow updates if frozen */
1135  if (hashp->frozen)
1136  elog(ERROR, "cannot update in frozen hashtable \"%s\"",
1137  hashp->tabname);
1138 
1139  /*
1140  * Lookup the existing element using its saved hash value. We need to do
1141  * this to be able to unlink it from its hash chain, but as a side benefit
1142  * we can verify the validity of the passed existingEntry pointer.
1143  */
1144  bucket = calc_bucket(hctl, existingElement->hashvalue);
1145 
1146  segment_num = bucket >> hashp->sshift;
1147  segment_ndx = MOD(bucket, hashp->ssize);
1148 
1149  segp = hashp->dir[segment_num];
1150 
1151  if (segp == NULL)
1152  hash_corrupted(hashp);
1153 
1154  prevBucketPtr = &segp[segment_ndx];
1155  currBucket = *prevBucketPtr;
1156 
1157  while (currBucket != NULL)
1158  {
1159  if (currBucket == existingElement)
1160  break;
1161  prevBucketPtr = &(currBucket->link);
1162  currBucket = *prevBucketPtr;
1163  }
1164 
1165  if (currBucket == NULL)
1166  elog(ERROR, "hash_update_hash_key argument is not in hashtable \"%s\"",
1167  hashp->tabname);
1168 
1169  oldPrevPtr = prevBucketPtr;
1170 
1171  /*
1172  * Now perform the equivalent of a HASH_ENTER operation to locate the hash
1173  * chain we want to put the entry into.
1174  */
1175  newhashvalue = hashp->hash(newKeyPtr, hashp->keysize);
1176 
1177  newbucket = calc_bucket(hctl, newhashvalue);
1178 
1179  segment_num = newbucket >> hashp->sshift;
1180  segment_ndx = MOD(newbucket, hashp->ssize);
1181 
1182  segp = hashp->dir[segment_num];
1183 
1184  if (segp == NULL)
1185  hash_corrupted(hashp);
1186 
1187  prevBucketPtr = &segp[segment_ndx];
1188  currBucket = *prevBucketPtr;
1189 
1190  /*
1191  * Follow collision chain looking for matching key
1192  */
1193  match = hashp->match; /* save one fetch in inner loop */
1194  keysize = hashp->keysize; /* ditto */
1195 
1196  while (currBucket != NULL)
1197  {
1198  if (currBucket->hashvalue == newhashvalue &&
1199  match(ELEMENTKEY(currBucket), newKeyPtr, keysize) == 0)
1200  break;
1201  prevBucketPtr = &(currBucket->link);
1202  currBucket = *prevBucketPtr;
1203 #if HASH_STATISTICS
1204  hash_collisions++;
1205  hctl->collisions++;
1206 #endif
1207  }
1208 
1209  if (currBucket != NULL)
1210  return false; /* collision with an existing entry */
1211 
1212  currBucket = existingElement;
1213 
1214  /*
1215  * If old and new hash values belong to the same bucket, we need not
1216  * change any chain links, and indeed should not since this simplistic
1217  * update will corrupt the list if currBucket is the last element. (We
1218  * cannot fall out earlier, however, since we need to scan the bucket to
1219  * check for duplicate keys.)
1220  */
1221  if (bucket != newbucket)
1222  {
1223  /* OK to remove record from old hash bucket's chain. */
1224  *oldPrevPtr = currBucket->link;
1225 
1226  /* link into new hashbucket chain */
1227  *prevBucketPtr = currBucket;
1228  currBucket->link = NULL;
1229  }
1230 
1231  /* copy new key into record */
1232  currBucket->hashvalue = newhashvalue;
1233  hashp->keycopy(ELEMENTKEY(currBucket), newKeyPtr, keysize);
1234 
1235  /* rest of record is untouched */
1236 
1237  return true;
1238 }
int(* HashCompareFunc)(const void *key1, const void *key2, Size keysize)
Definition: hsearch.h:29
Size keysize
Definition: dynahash.c:225
static uint32 calc_bucket(HASHHDR *hctl, uint32 hash_val)
Definition: dynahash.c:863
#define ELEMENTKEY(helem)
Definition: dynahash.c:233
#define ELEMENT_FROM_KEY(key)
Definition: dynahash.c:238
HashValueFunc hash
Definition: dynahash.c:212
long ssize
Definition: dynahash.c:226
#define ERROR
Definition: elog.h:43
int sshift
Definition: dynahash.c:227
#define MOD(x, y)
Definition: dynahash.c:244
HASHHDR * hctl
Definition: dynahash.c:210
static void hash_corrupted(HTAB *hashp)
Definition: dynahash.c:1700
unsigned int uint32
Definition: c.h:296
HashCompareFunc match
Definition: dynahash.c:213
bool frozen
Definition: dynahash.c:222
HashCopyFunc keycopy
Definition: dynahash.c:214
size_t Size
Definition: c.h:404
char * tabname
Definition: dynahash.c:217
struct HASHELEMENT * link
Definition: hsearch.h:53
HASHSEGMENT * dir
Definition: dynahash.c:211
#define elog
Definition: elog.h:219
uint32 hashvalue
Definition: hsearch.h:54

◆ hdefault()

static void hdefault ( HTAB hashp)
static

Definition at line 566 of file dynahash.c.

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

Referenced by hash_create().

567 {
568  HASHHDR *hctl = hashp->hctl;
569 
570  MemSet(hctl, 0, sizeof(HASHHDR));
571 
572  hctl->dsize = DEF_DIRSIZE;
573  hctl->nsegs = 0;
574 
575  /* rather pointless defaults for key & entry size */
576  hctl->keysize = sizeof(char *);
577  hctl->entrysize = 2 * sizeof(char *);
578 
579  hctl->num_partitions = 0; /* not partitioned */
580 
581  hctl->ffactor = DEF_FFACTOR;
582 
583  /* table has no fixed maximum size */
584  hctl->max_dsize = NO_MAX_DSIZE;
585 
586  hctl->ssize = DEF_SEGSIZE;
587  hctl->sshift = DEF_SEGSIZE_SHIFT;
588 
589 #ifdef HASH_STATISTICS
590  hctl->accesses = hctl->collisions = 0;
591 #endif
592 }
Size keysize
Definition: dynahash.c:179
long dsize
Definition: dynahash.c:172
Size entrysize
Definition: dynahash.c:180
#define NO_MAX_DSIZE
Definition: hsearch.h:100
long num_partitions
Definition: dynahash.c:181
#define MemSet(start, val, len)
Definition: c.h:853
long ffactor
Definition: dynahash.c:182
#define DEF_SEGSIZE_SHIFT
Definition: dynahash.c:111
long max_dsize
Definition: dynahash.c:183
HASHHDR * hctl
Definition: dynahash.c:210
long ssize
Definition: dynahash.c:184
int sshift
Definition: dynahash.c:185
#define DEF_FFACTOR
Definition: dynahash.c:113
#define DEF_SEGSIZE
Definition: dynahash.c:110
#define DEF_DIRSIZE
Definition: dynahash.c:112
long nsegs
Definition: dynahash.c:173

◆ init_htab()

static bool init_htab ( HTAB hashp,
long  nelem 
)
static

Definition at line 632 of file dynahash.c.

References HTAB::alloc, choose_nelem_alloc(), HTAB::dir, HASHHDR::dsize, HASHHDR::entrysize, HASHHDR::ffactor, 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, HASHHDR::num_partitions, seg_alloc(), SpinLockInit, HASHHDR::sshift, and HASHHDR::ssize.

Referenced by hash_create().

633 {
634  HASHHDR *hctl = hashp->hctl;
635  HASHSEGMENT *segp;
636  int nbuckets;
637  int nsegs;
638  int i;
639 
640  /*
641  * initialize mutexes if it's a partitioned table
642  */
643  if (IS_PARTITIONED(hctl))
644  for (i = 0; i < NUM_FREELISTS; i++)
645  SpinLockInit(&(hctl->freeList[i].mutex));
646 
647  /*
648  * Divide number of elements by the fill factor to determine a desired
649  * number of buckets. Allocate space for the next greater power of two
650  * number of buckets
651  */
652  nbuckets = next_pow2_int((nelem - 1) / hctl->ffactor + 1);
653 
654  /*
655  * In a partitioned table, nbuckets must be at least equal to
656  * num_partitions; were it less, keys with apparently different partition
657  * numbers would map to the same bucket, breaking partition independence.
658  * (Normally nbuckets will be much bigger; this is just a safety check.)
659  */
660  while (nbuckets < hctl->num_partitions)
661  nbuckets <<= 1;
662 
663  hctl->max_bucket = hctl->low_mask = nbuckets - 1;
664  hctl->high_mask = (nbuckets << 1) - 1;
665 
666  /*
667  * Figure number of directory segments needed, round up to a power of 2
668  */
669  nsegs = (nbuckets - 1) / hctl->ssize + 1;
670  nsegs = next_pow2_int(nsegs);
671 
672  /*
673  * Make sure directory is big enough. If pre-allocated directory is too
674  * small, choke (caller screwed up).
675  */
676  if (nsegs > hctl->dsize)
677  {
678  if (!(hashp->dir))
679  hctl->dsize = nsegs;
680  else
681  return false;
682  }
683 
684  /* Allocate a directory */
685  if (!(hashp->dir))
686  {
687  CurrentDynaHashCxt = hashp->hcxt;
688  hashp->dir = (HASHSEGMENT *)
689  hashp->alloc(hctl->dsize * sizeof(HASHSEGMENT));
690  if (!hashp->dir)
691  return false;
692  }
693 
694  /* Allocate initial segments */
695  for (segp = hashp->dir; hctl->nsegs < nsegs; hctl->nsegs++, segp++)
696  {
697  *segp = seg_alloc(hashp);
698  if (*segp == NULL)
699  return false;
700  }
701 
702  /* Choose number of entries to allocate at a time */
704 
705 #if HASH_DEBUG
706  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",
707  "TABLE POINTER ", hashp,
708  "DIRECTORY SIZE ", hctl->dsize,
709  "SEGMENT SIZE ", hctl->ssize,
710  "SEGMENT SHIFT ", hctl->sshift,
711  "FILL FACTOR ", hctl->ffactor,
712  "MAX BUCKET ", hctl->max_bucket,
713  "HIGH MASK ", hctl->high_mask,
714  "LOW MASK ", hctl->low_mask,
715  "NSEGS ", hctl->nsegs);
716 #endif
717  return true;
718 }
long dsize
Definition: dynahash.c:172
uint32 max_bucket
Definition: dynahash.c:174
Size entrysize
Definition: dynahash.c:180
#define IS_PARTITIONED(hctl)
Definition: dynahash.c:199
#define SpinLockInit(lock)
Definition: spin.h:60
#define NUM_FREELISTS
Definition: dynahash.c:116
HashAllocFunc alloc
Definition: dynahash.c:215
slock_t mutex
Definition: dynahash.c:143
uint32 low_mask
Definition: dynahash.c:176
long ffactor
Definition: dynahash.c:182
HASHHDR * hctl
Definition: dynahash.c:210
uint32 high_mask
Definition: dynahash.c:175
static int next_pow2_int(long num)
Definition: dynahash.c:1738
long ssize
Definition: dynahash.c:184
FreeListData freeList[NUM_FREELISTS]
Definition: dynahash.c:168
MemoryContext hcxt
Definition: dynahash.c:216
int nelem_alloc
Definition: dynahash.c:186
static HASHSEGMENT seg_alloc(HTAB *hashp)
Definition: dynahash.c:1634
static int choose_nelem_alloc(Size entrysize)
Definition: dynahash.c:599
static MemoryContext CurrentDynaHashCxt
Definition: dynahash.c:275
int i
HASHSEGMENT * dir
Definition: dynahash.c:211
int sshift
Definition: dynahash.c:185
long nsegs
Definition: dynahash.c:173

◆ my_log2()

int my_log2 ( long  num)

Definition at line 1714 of file dynahash.c.

References i.

Referenced by ExecChooseHashTableSize(), ExecHashTableCreate(), hash_create(), next_pow2_int(), and next_pow2_long().

1715 {
1716  int i;
1717  long limit;
1718 
1719  /* guard against too-large input, which would put us into infinite loop */
1720  if (num > LONG_MAX / 2)
1721  num = LONG_MAX / 2;
1722 
1723  for (i = 0, limit = 1; limit < num; i++, limit <<= 1)
1724  ;
1725  return i;
1726 }
int i

◆ next_pow2_int()

static int next_pow2_int ( long  num)
static

Definition at line 1738 of file dynahash.c.

References my_log2().

Referenced by hash_create(), and init_htab().

1739 {
1740  if (num > INT_MAX / 2)
1741  num = INT_MAX / 2;
1742  return 1 << my_log2(num);
1743 }
int my_log2(long num)
Definition: dynahash.c:1714

◆ next_pow2_long()

static long next_pow2_long ( long  num)
static

Definition at line 1730 of file dynahash.c.

References my_log2().

Referenced by hash_estimate_size(), and hash_select_dirsize().

1731 {
1732  /* my_log2's internal range check is sufficient */
1733  return 1L << my_log2(num);
1734 }
int my_log2(long num)
Definition: dynahash.c:1714

◆ register_seq_scan()

static void register_seq_scan ( HTAB hashp)
static

Definition at line 1783 of file dynahash.c.

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

Referenced by hash_seq_init().

1784 {
1786  elog(ERROR, "too many active hash_seq_search scans, cannot start one on \"%s\"",
1787  hashp->tabname);
1788  seq_scan_tables[num_seq_scans] = hashp;
1790  num_seq_scans++;
1791 }
static int seq_scan_level[MAX_SEQ_SCANS]
Definition: dynahash.c:1777
#define ERROR
Definition: elog.h:43
#define MAX_SEQ_SCANS
Definition: dynahash.c:1774
static int num_seq_scans
Definition: dynahash.c:1778
static HTAB * seq_scan_tables[MAX_SEQ_SCANS]
Definition: dynahash.c:1776
int GetCurrentTransactionNestLevel(void)
Definition: xact.c:754
char * tabname
Definition: dynahash.c:217
#define elog
Definition: elog.h:219

◆ seg_alloc()

static HASHSEGMENT seg_alloc ( HTAB hashp)
static

Definition at line 1634 of file dynahash.c.

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

Referenced by expand_table(), and init_htab().

1635 {
1636  HASHSEGMENT segp;
1637 
1638  CurrentDynaHashCxt = hashp->hcxt;
1639  segp = (HASHSEGMENT) hashp->alloc(sizeof(HASHBUCKET) * hashp->ssize);
1640 
1641  if (!segp)
1642  return NULL;
1643 
1644  MemSet(segp, 0, sizeof(HASHBUCKET) * hashp->ssize);
1645 
1646  return segp;
1647 }
HashAllocFunc alloc
Definition: dynahash.c:215
#define MemSet(start, val, len)
Definition: c.h:853
HASHBUCKET * HASHSEGMENT
Definition: dynahash.c:122
long ssize
Definition: dynahash.c:226
MemoryContext hcxt
Definition: dynahash.c:216
static MemoryContext CurrentDynaHashCxt
Definition: dynahash.c:275

◆ string_compare()

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

Definition at line 293 of file dynahash.c.

Referenced by hash_create().

294 {
295  return strncmp(key1, key2, keysize - 1);
296 }

Variable Documentation

◆ CurrentDynaHashCxt

MemoryContext CurrentDynaHashCxt = NULL
static

Definition at line 275 of file dynahash.c.

Referenced by hash_create().

◆ num_seq_scans

int num_seq_scans = 0
static

◆ seq_scan_level

int seq_scan_level[MAX_SEQ_SCANS]
static

Definition at line 1777 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 1776 of file dynahash.c.