PostgreSQL Source Code  git master
hashsort.c File Reference
#include "postgres.h"
#include "access/hash.h"
#include "miscadmin.h"
#include "utils/tuplesort.h"
Include dependency graph for hashsort.c:

Go to the source code of this file.

Data Structures

struct  HSpool
 

Functions

HSpool_h_spoolinit (Relation heap, Relation index, uint32 num_buckets)
 
void _h_spooldestroy (HSpool *hspool)
 
void _h_spool (HSpool *hspool, ItemPointer self, Datum *values, bool *isnull)
 
void _h_indexbuild (HSpool *hspool, Relation heapRel)
 

Function Documentation

◆ _h_indexbuild()

void _h_indexbuild ( HSpool hspool,
Relation  heapRel 
)

Definition at line 116 of file hashsort.c.

References _hash_doinsert(), _hash_get_indextuple_hashkey(), _hash_hashkey2bucket(), Assert, HSpool::high_mask, HSpool::index, HSpool::low_mask, HSpool::max_buckets, HSpool::sortstate, tuplesort_getindextuple(), and tuplesort_performsort().

Referenced by hashbuild().

117 {
118  IndexTuple itup;
119 #ifdef USE_ASSERT_CHECKING
120  uint32 hashkey = 0;
121 #endif
122 
124 
125  while ((itup = tuplesort_getindextuple(hspool->sortstate, true)) != NULL)
126  {
127  /*
128  * Technically, it isn't critical that hash keys be found in sorted
129  * order, since this sorting is only used to increase locality of
130  * access as a performance optimization. It still seems like a good
131  * idea to test tuplesort.c's handling of hash index tuple sorts
132  * through an assertion, though.
133  */
134 #ifdef USE_ASSERT_CHECKING
135  uint32 lasthashkey = hashkey;
136 
138  hspool->max_buckets, hspool->high_mask,
139  hspool->low_mask);
140  Assert(hashkey >= lasthashkey);
141 #endif
142 
143  _hash_doinsert(hspool->index, itup, heapRel);
144  }
145 }
IndexTuple tuplesort_getindextuple(Tuplesortstate *state, bool forward)
Definition: tuplesort.c:2215
void _hash_doinsert(Relation rel, IndexTuple itup, Relation heapRel)
Definition: hashinsert.c:37
void tuplesort_performsort(Tuplesortstate *state)
Definition: tuplesort.c:1790
Bucket _hash_hashkey2bucket(uint32 hashkey, uint32 maxbucket, uint32 highmask, uint32 lowmask)
Definition: hashutil.c:125
Tuplesortstate * sortstate
Definition: hashsort.c:38
uint32 low_mask
Definition: hashsort.c:47
uint32 high_mask
Definition: hashsort.c:46
uint32 _hash_get_indextuple_hashkey(IndexTuple itup)
Definition: hashutil.c:299
unsigned int uint32
Definition: c.h:325
uint32 max_buckets
Definition: hashsort.c:48
Relation index
Definition: hashsort.c:39
#define Assert(condition)
Definition: c.h:699

◆ _h_spool()

void _h_spool ( HSpool hspool,
ItemPointer  self,
Datum values,
bool isnull 
)

Definition at line 105 of file hashsort.c.

References HSpool::index, HSpool::sortstate, and tuplesort_putindextuplevalues().

Referenced by hashbuildCallback().

106 {
108  self, values, isnull);
109 }
Tuplesortstate * sortstate
Definition: hashsort.c:38
Relation index
Definition: hashsort.c:39
void tuplesort_putindextuplevalues(Tuplesortstate *state, Relation rel, ItemPointer self, Datum *values, bool *isnull)
Definition: tuplesort.c:1477
static Datum values[MAXATTR]
Definition: bootstrap.c:164

◆ _h_spooldestroy()

void _h_spooldestroy ( HSpool hspool)

Definition at line 95 of file hashsort.c.

References pfree(), HSpool::sortstate, and tuplesort_end().

Referenced by hashbuild().

96 {
97  tuplesort_end(hspool->sortstate);
98  pfree(hspool);
99 }
Tuplesortstate * sortstate
Definition: hashsort.c:38
void pfree(void *pointer)
Definition: mcxt.c:1031
void tuplesort_end(Tuplesortstate *state)
Definition: tuplesort.c:1235

◆ _h_spoolinit()

HSpool* _h_spoolinit ( Relation  heap,
Relation  index,
uint32  num_buckets 
)

Definition at line 56 of file hashsort.c.

References _hash_log2(), HSpool::high_mask, HSpool::index, HSpool::low_mask, maintenance_work_mem, HSpool::max_buckets, palloc0(), HSpool::sortstate, and tuplesort_begin_index_hash().

Referenced by hashbuild().

57 {
58  HSpool *hspool = (HSpool *) palloc0(sizeof(HSpool));
59 
60  hspool->index = index;
61 
62  /*
63  * Determine the bitmask for hash code values. Since there are currently
64  * num_buckets buckets in the index, the appropriate mask can be computed
65  * as follows.
66  *
67  * NOTE : This hash mask calculation should be in sync with similar
68  * calculation in _hash_init_metabuffer.
69  */
70  hspool->high_mask = (((uint32) 1) << _hash_log2(num_buckets + 1)) - 1;
71  hspool->low_mask = (hspool->high_mask >> 1);
72  hspool->max_buckets = num_buckets - 1;
73 
74  /*
75  * We size the sort area as maintenance_work_mem rather than work_mem to
76  * speed index creation. This should be OK since a single backend can't
77  * run multiple index creations in parallel.
78  */
80  index,
81  hspool->high_mask,
82  hspool->low_mask,
83  hspool->max_buckets,
85  NULL,
86  false);
87 
88  return hspool;
89 }
Tuplesortstate * tuplesort_begin_index_hash(Relation heapRel, Relation indexRel, uint32 high_mask, uint32 low_mask, uint32 max_buckets, int workMem, SortCoordinate coordinate, bool randomAccess)
Definition: tuplesort.c:1053
Tuplesortstate * sortstate
Definition: hashsort.c:38
uint32 low_mask
Definition: hashsort.c:47
uint32 high_mask
Definition: hashsort.c:46
unsigned int uint32
Definition: c.h:325
void * palloc0(Size size)
Definition: mcxt.c:955
uint32 max_buckets
Definition: hashsort.c:48
Relation index
Definition: hashsort.c:39
int maintenance_work_mem
Definition: globals.c:123
uint32 _hash_log2(uint32 num)
Definition: hashutil.c:141