-
Notifications
You must be signed in to change notification settings - Fork 1.6k
/
sql_window.cc
3349 lines (2869 loc) · 90.8 KB
/
sql_window.cc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
Copyright (c) 2016, 2022 MariaDB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#include "mariadb.h"
#include "sql_parse.h"
#include "sql_select.h"
#include "sql_list.h"
#include "item_windowfunc.h"
#include "filesort.h"
#include "sql_base.h"
#include "sql_window.h"
bool
Window_spec::check_window_names(List_iterator_fast<Window_spec> &it)
{
if (window_names_are_checked)
return false;
const char *name= this->name();
const char *ref_name= window_reference();
it.rewind();
Window_spec *win_spec;
while((win_spec= it++) && win_spec != this)
{
const char *win_spec_name= win_spec->name();
if (!win_spec_name)
break;
if (name && my_strcasecmp(system_charset_info, name, win_spec_name) == 0)
{
my_error(ER_DUP_WINDOW_NAME, MYF(0), name);
return true;
}
if (ref_name &&
my_strcasecmp(system_charset_info, ref_name, win_spec_name) == 0)
{
if (partition_list->elements)
{
my_error(ER_PARTITION_LIST_IN_REFERENCING_WINDOW_SPEC, MYF(0),
ref_name);
return true;
}
if (win_spec->order_list->elements && order_list->elements)
{
my_error(ER_ORDER_LIST_IN_REFERENCING_WINDOW_SPEC, MYF(0), ref_name);
return true;
}
if (win_spec->window_frame)
{
my_error(ER_WINDOW_FRAME_IN_REFERENCED_WINDOW_SPEC, MYF(0), ref_name);
return true;
}
referenced_win_spec= win_spec;
if (partition_list->elements == 0)
partition_list= win_spec->partition_list;
if (order_list->elements == 0)
order_list= win_spec->order_list;
}
}
if (ref_name && !referenced_win_spec)
{
my_error(ER_WRONG_WINDOW_SPEC_NAME, MYF(0), ref_name);
return true;
}
window_names_are_checked= true;
return false;
}
void
Window_spec::print(String *str, enum_query_type query_type)
{
str->append('(');
print_partition(str, query_type);
print_order(str, query_type);
if (window_frame)
window_frame->print(str, query_type);
str->append(')');
}
void
Window_spec::print_partition(String *str, enum_query_type query_type)
{
if (partition_list->first)
{
str->append(STRING_WITH_LEN(" partition by "));
st_select_lex::print_order(str, partition_list->first, query_type);
}
}
void
Window_spec::print_order(String *str, enum_query_type query_type)
{
if (order_list->first)
{
str->append(STRING_WITH_LEN(" order by "));
st_select_lex::print_order(str, order_list->first, query_type);
}
}
bool
Window_frame::check_frame_bounds()
{
if ((top_bound->is_unbounded() &&
top_bound->precedence_type == Window_frame_bound::FOLLOWING) ||
(bottom_bound->is_unbounded() &&
bottom_bound->precedence_type == Window_frame_bound::PRECEDING) ||
(top_bound->precedence_type == Window_frame_bound::CURRENT &&
bottom_bound->precedence_type == Window_frame_bound::PRECEDING) ||
(bottom_bound->precedence_type == Window_frame_bound::CURRENT &&
top_bound->precedence_type == Window_frame_bound::FOLLOWING))
{
my_error(ER_BAD_COMBINATION_OF_WINDOW_FRAME_BOUND_SPECS, MYF(0));
return true;
}
return false;
}
void
Window_frame::print(String *str, enum_query_type query_type)
{
switch (units) {
case UNITS_ROWS:
str->append(STRING_WITH_LEN(" rows "));
break;
case UNITS_RANGE:
str->append(STRING_WITH_LEN(" range "));
break;
default:
DBUG_ASSERT(0);
}
str->append(STRING_WITH_LEN("between "));
top_bound->print(str, query_type);
str->append(STRING_WITH_LEN(" and "));
bottom_bound->print(str, query_type);
if (exclusion != EXCL_NONE)
{
str->append(STRING_WITH_LEN(" exclude "));
switch (exclusion) {
case EXCL_CURRENT_ROW:
str->append(STRING_WITH_LEN(" current row "));
break;
case EXCL_GROUP:
str->append(STRING_WITH_LEN(" group "));
break;
case EXCL_TIES:
str->append(STRING_WITH_LEN(" ties "));
break;
default:
DBUG_ASSERT(0);
;
}
}
}
void
Window_frame_bound::print(String *str, enum_query_type query_type)
{
if (precedence_type == CURRENT)
{
str->append(STRING_WITH_LEN(" current row "));
return;
}
if (is_unbounded())
str->append(STRING_WITH_LEN(" unbounded "));
else
offset->print(str ,query_type);
switch (precedence_type) {
case PRECEDING:
str->append(STRING_WITH_LEN(" preceding "));
break;
case FOLLOWING:
str->append(STRING_WITH_LEN(" following "));
break;
default:
DBUG_ASSERT(0);
}
}
/*
Setup window functions in a select
*/
int
setup_windows(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables,
List<Item> &fields, List<Item> &all_fields,
List<Window_spec> &win_specs, List<Item_window_func> &win_funcs)
{
Window_spec *win_spec;
DBUG_ENTER("setup_windows");
List_iterator<Window_spec> it(win_specs);
/*
Move all unnamed specifications after the named ones.
We could have avoided it if we had built two separate lists for
named and unnamed specifications.
*/
Query_arena *arena, backup;
arena= thd->activate_stmt_arena_if_needed(&backup);
uint i = 0;
uint elems= win_specs.elements;
while ((win_spec= it++) && i++ < elems)
{
if (win_spec->name() == NULL)
{
it.remove();
win_specs.push_back(win_spec);
}
}
if (arena)
thd->restore_active_arena(arena, &backup);
it.rewind();
List_iterator_fast<Window_spec> itp(win_specs);
while ((win_spec= it++))
{
bool hidden_group_fields;
if (win_spec->check_window_names(itp) ||
setup_group(thd, ref_pointer_array, tables, fields, all_fields,
win_spec->partition_list->first, &hidden_group_fields,
true) ||
setup_order(thd, ref_pointer_array, tables, fields, all_fields,
win_spec->order_list->first, true) ||
(win_spec->window_frame &&
win_spec->window_frame->check_frame_bounds()))
{
DBUG_RETURN(1);
}
if (win_spec->window_frame &&
win_spec->window_frame->exclusion != Window_frame::EXCL_NONE)
{
my_error(ER_FRAME_EXCLUSION_NOT_SUPPORTED, MYF(0));
DBUG_RETURN(1);
}
/*
For "win_func() OVER (ORDER BY order_list RANGE BETWEEN ...)",
- ORDER BY order_list must not be ommitted
- the list must have a single element.
*/
if (win_spec->window_frame &&
win_spec->window_frame->units == Window_frame::UNITS_RANGE)
{
if (win_spec->order_list->elements != 1)
{
my_error(ER_RANGE_FRAME_NEEDS_SIMPLE_ORDERBY, MYF(0));
DBUG_RETURN(1);
}
/*
"The declared type of SK shall be numeric, datetime, or interval"
we don't support datetime or interval, yet.
*/
Item_result rtype= win_spec->order_list->first->item[0]->result_type();
if (rtype != REAL_RESULT && rtype != INT_RESULT &&
rtype != DECIMAL_RESULT)
{
my_error(ER_WRONG_TYPE_FOR_RANGE_FRAME, MYF(0));
DBUG_RETURN(1);
}
/*
"The declared type of UVS shall be numeric if the declared type of SK
is numeric; otherwise, it shall be an interval type that may be added
to or subtracted from the declared type of SK"
*/
Window_frame_bound *bounds[]= {win_spec->window_frame->top_bound,
win_spec->window_frame->bottom_bound,
NULL};
for (Window_frame_bound **pbound= &bounds[0]; *pbound; pbound++)
{
if (!(*pbound)->is_unbounded() &&
((*pbound)->precedence_type == Window_frame_bound::FOLLOWING ||
(*pbound)->precedence_type == Window_frame_bound::PRECEDING))
{
Item_result rtype= (*pbound)->offset->result_type();
if (rtype != REAL_RESULT && rtype != INT_RESULT &&
rtype != DECIMAL_RESULT)
{
my_error(ER_WRONG_TYPE_FOR_RANGE_FRAME, MYF(0));
DBUG_RETURN(1);
}
}
}
}
/* "ROWS PRECEDING|FOLLOWING $n" must have a numeric $n */
if (win_spec->window_frame &&
win_spec->window_frame->units == Window_frame::UNITS_ROWS)
{
Window_frame_bound *bounds[]= {win_spec->window_frame->top_bound,
win_spec->window_frame->bottom_bound,
NULL};
for (Window_frame_bound **pbound= &bounds[0]; *pbound; pbound++)
{
if (!(*pbound)->is_unbounded() &&
((*pbound)->precedence_type == Window_frame_bound::FOLLOWING ||
(*pbound)->precedence_type == Window_frame_bound::PRECEDING))
{
Item *offset= (*pbound)->offset;
if (offset->result_type() != INT_RESULT)
{
my_error(ER_WRONG_TYPE_FOR_ROWS_FRAME, MYF(0));
DBUG_RETURN(1);
}
}
}
}
}
List_iterator_fast<Item_window_func> li(win_funcs);
while (Item_window_func * win_func_item= li++)
{
if (win_func_item->check_result_type_of_order_item())
DBUG_RETURN(1);
}
DBUG_RETURN(0);
}
/**
@brief
Find fields common for all partition lists used in window functions
@param thd The thread handle
@details
This function looks for the field references in the partition lists
of all window functions used in this select that are common for
all the partition lists. The function returns an ORDER list contained
all such references.The list either is specially built by the function
or is taken directly from the first window specification.
@retval
pointer to the first element of the ORDER list contained field
references common for all partition lists
0 if no such reference is found.
*/
ORDER *st_select_lex::find_common_window_func_partition_fields(THD *thd)
{
ORDER *ord;
Item *item;
DBUG_ASSERT(window_funcs.elements);
List_iterator_fast<Item_window_func> it(window_funcs);
Item_window_func *first_wf= it++;
if (!first_wf->window_spec->partition_list)
return 0;
List<Item> common_fields;
uint first_partition_elements= 0;
for (ord= first_wf->window_spec->partition_list->first; ord; ord= ord->next)
{
if ((*ord->item)->real_item()->type() == Item::FIELD_ITEM)
common_fields.push_back(*ord->item, thd->mem_root);
first_partition_elements++;
}
if (window_specs.elements == 1 &&
common_fields.elements == first_partition_elements)
return first_wf->window_spec->partition_list->first;
List_iterator<Item> li(common_fields);
Item_window_func *wf;
while (common_fields.elements && (wf= it++))
{
if (!wf->window_spec->partition_list)
return 0;
while ((item= li++))
{
for (ord= wf->window_spec->partition_list->first; ord; ord= ord->next)
{
if (item->eq(*ord->item, false))
break;
}
if (!ord)
li.remove();
}
li.rewind();
}
if (!common_fields.elements)
return 0;
if (common_fields.elements == first_partition_elements)
return first_wf->window_spec->partition_list->first;
SQL_I_List<ORDER> res_list;
for (ord= first_wf->window_spec->partition_list->first, item= li++;
ord; ord= ord->next)
{
if (item != *ord->item)
continue;
if (add_to_list(thd, res_list, item, ord->direction))
return 0;
item= li++;
}
return res_list.first;
}
/////////////////////////////////////////////////////////////////////////////
// Sorting window functions to minimize the number of table scans
// performed during the computation of these functions
/////////////////////////////////////////////////////////////////////////////
#define CMP_LT -2 // Less than
#define CMP_LT_C -1 // Less than and compatible
#define CMP_EQ 0 // Equal to
#define CMP_GT_C 1 // Greater than and compatible
#define CMP_GT 2 // Greater then
static
int compare_order_elements(ORDER *ord1, int weight1,
ORDER *ord2, int weight2)
{
if (*ord1->item == *ord2->item && ord1->direction == ord2->direction)
return CMP_EQ;
Item *item1= (*ord1->item)->real_item();
Item *item2= (*ord2->item)->real_item();
bool item1_field= (item1->type() == Item::FIELD_ITEM);
bool item2_field= (item2->type() == Item::FIELD_ITEM);
ptrdiff_t cmp;
if (item1_field && item2_field)
{
DBUG_ASSERT(((Item_field *) item1)->field->table ==
((Item_field *) item2)->field->table);
cmp= ((Item_field *) item1)->field->field_index -
((Item_field *) item2)->field->field_index;
}
else if (item1_field && !item2_field)
return CMP_LT;
else if (!item1_field && item2_field)
return CMP_LT;
else
{
/*
Ok, item1_field==NULL and item2_field==NULL.
We're not able to compare Item expressions. Order them according to
their passed "weight" (which comes from Window_spec::win_spec_number):
*/
if (weight1 != weight2)
cmp= weight1 - weight2;
else
{
/*
The weight is the same. That is, the elements come from the same
window specification... This shouldn't happen.
*/
DBUG_ASSERT(0);
cmp= item1 - item2;
}
}
if (cmp == 0)
{
if (ord1->direction == ord2->direction)
return CMP_EQ;
return ord1->direction > ord2->direction ? CMP_GT : CMP_LT;
}
else
return cmp > 0 ? CMP_GT : CMP_LT;
}
static
int compare_order_lists(SQL_I_List<ORDER> *part_list1,
int spec_number1,
SQL_I_List<ORDER> *part_list2,
int spec_number2)
{
if (part_list1 == part_list2)
return CMP_EQ;
ORDER *elem1= part_list1->first;
ORDER *elem2= part_list2->first;
for ( ; elem1 && elem2; elem1= elem1->next, elem2= elem2->next)
{
int cmp;
// remove all constants as we don't need them for comparision
while(elem1 && ((*elem1->item)->real_item())->const_item())
{
elem1= elem1->next;
continue;
}
while(elem2 && ((*elem2->item)->real_item())->const_item())
{
elem2= elem2->next;
continue;
}
if (!elem1 || !elem2)
break;
if ((cmp= compare_order_elements(elem1, spec_number1,
elem2, spec_number2)))
return cmp;
}
if (elem1)
return CMP_GT_C;
if (elem2)
return CMP_LT_C;
return CMP_EQ;
}
static
int compare_window_frame_bounds(Window_frame_bound *win_frame_bound1,
Window_frame_bound *win_frame_bound2,
bool is_bottom_bound)
{
int res;
if (win_frame_bound1->precedence_type != win_frame_bound2->precedence_type)
{
res= win_frame_bound1->precedence_type > win_frame_bound2->precedence_type ?
CMP_GT : CMP_LT;
if (is_bottom_bound)
res= -res;
return res;
}
if (win_frame_bound1->is_unbounded() && win_frame_bound2->is_unbounded())
return CMP_EQ;
if (!win_frame_bound1->is_unbounded() && !win_frame_bound2->is_unbounded())
{
if (win_frame_bound1->offset->eq(win_frame_bound2->offset, true))
return CMP_EQ;
else
{
res= strcmp(win_frame_bound1->offset->name.str,
win_frame_bound2->offset->name.str);
res= res > 0 ? CMP_GT : CMP_LT;
if (is_bottom_bound)
res= -res;
return res;
}
}
/*
Here we have:
win_frame_bound1->is_unbounded() != win_frame_bound1->is_unbounded()
*/
return is_bottom_bound != win_frame_bound1->is_unbounded() ? CMP_LT : CMP_GT;
}
static
int compare_window_frames(Window_frame *win_frame1,
Window_frame *win_frame2)
{
int cmp;
if (win_frame1 == win_frame2)
return CMP_EQ;
if (!win_frame1)
return CMP_LT;
if (!win_frame2)
return CMP_GT;
if (win_frame1->units != win_frame2->units)
return win_frame1->units > win_frame2->units ? CMP_GT : CMP_LT;
cmp= compare_window_frame_bounds(win_frame1->top_bound,
win_frame2->top_bound,
false);
if (cmp)
return cmp;
cmp= compare_window_frame_bounds(win_frame1->bottom_bound,
win_frame2->bottom_bound,
true);
if (cmp)
return cmp;
if (win_frame1->exclusion != win_frame2->exclusion)
return win_frame1->exclusion > win_frame2->exclusion ? CMP_GT_C : CMP_LT_C;
return CMP_EQ;
}
static
int compare_window_spec_joined_lists(Window_spec *win_spec1,
Window_spec *win_spec2)
{
win_spec1->join_partition_and_order_lists();
win_spec2->join_partition_and_order_lists();
int cmp= compare_order_lists(win_spec1->partition_list,
win_spec1->win_spec_number,
win_spec2->partition_list,
win_spec2->win_spec_number);
win_spec1->disjoin_partition_and_order_lists();
win_spec2->disjoin_partition_and_order_lists();
return cmp;
}
static
int compare_window_funcs_by_window_specs(Item_window_func *win_func1,
Item_window_func *win_func2,
void *arg)
{
int cmp;
Window_spec *win_spec1= win_func1->window_spec;
Window_spec *win_spec2= win_func2->window_spec;
if (win_spec1 == win_spec2)
return CMP_EQ;
cmp= compare_order_lists(win_spec1->partition_list,
win_spec1->win_spec_number,
win_spec2->partition_list,
win_spec2->win_spec_number);
if (cmp == CMP_EQ)
{
/*
Partition lists contain the same elements.
Let's use only one of the lists.
*/
if (!win_spec1->name() && win_spec2->name())
{
win_spec1->save_partition_list= win_spec1->partition_list;
win_spec1->partition_list= win_spec2->partition_list;
}
else
{
win_spec2->save_partition_list= win_spec2->partition_list;
win_spec2->partition_list= win_spec1->partition_list;
}
cmp= compare_order_lists(win_spec1->order_list,
win_spec1->win_spec_number,
win_spec2->order_list,
win_spec2->win_spec_number);
if (cmp != CMP_EQ)
return cmp;
/*
Order lists contain the same elements.
Let's use only one of the lists.
*/
if (!win_spec1->name() && win_spec2->name())
{
win_spec1->save_order_list= win_spec2->order_list;
win_spec1->order_list= win_spec2->order_list;
}
else
{
win_spec1->save_order_list= win_spec2->order_list;
win_spec2->order_list= win_spec1->order_list;
}
cmp= compare_window_frames(win_spec1->window_frame,
win_spec2->window_frame);
if (cmp != CMP_EQ)
return cmp;
/* Window frames are equal. Let's use only one of them. */
if (!win_spec1->name() && win_spec2->name())
win_spec1->window_frame= win_spec2->window_frame;
else
win_spec2->window_frame= win_spec1->window_frame;
return CMP_EQ;
}
if (cmp == CMP_GT || cmp == CMP_LT)
return cmp;
/* one of the partitions lists is the proper beginning of the another */
cmp= compare_window_spec_joined_lists(win_spec1, win_spec2);
if (CMP_LT_C <= cmp && cmp <= CMP_GT_C)
cmp= win_spec1->partition_list->elements <
win_spec2->partition_list->elements ? CMP_GT_C : CMP_LT_C;
return cmp;
}
#define SORTORDER_CHANGE_FLAG 1
#define PARTITION_CHANGE_FLAG 2
#define FRAME_CHANGE_FLAG 4
typedef int (*Item_window_func_cmp)(Item_window_func *f1,
Item_window_func *f2,
void *arg);
/*
@brief
Sort window functions so that those that can be computed together are
adjacent.
@detail
Sort window functions by their
- required sorting order,
- partition list,
- window frame compatibility.
The changes between the groups are marked by setting item_window_func->marker.
*/
static
void order_window_funcs_by_window_specs(List<Item_window_func> *win_func_list)
{
if (win_func_list->elements == 0)
return;
bubble_sort<Item_window_func>(win_func_list,
compare_window_funcs_by_window_specs,
NULL);
List_iterator_fast<Item_window_func> it(*win_func_list);
Item_window_func *prev= it++;
prev->marker= SORTORDER_CHANGE_FLAG |
PARTITION_CHANGE_FLAG |
FRAME_CHANGE_FLAG;
Item_window_func *curr;
while ((curr= it++))
{
Window_spec *win_spec_prev= prev->window_spec;
Window_spec *win_spec_curr= curr->window_spec;
curr->marker= 0;
if (!(win_spec_prev->partition_list == win_spec_curr->partition_list &&
win_spec_prev->order_list == win_spec_curr->order_list))
{
int cmp;
if (win_spec_prev->partition_list == win_spec_curr->partition_list)
cmp= compare_order_lists(win_spec_prev->order_list,
win_spec_prev->win_spec_number,
win_spec_curr->order_list,
win_spec_curr->win_spec_number);
else
cmp= compare_window_spec_joined_lists(win_spec_prev, win_spec_curr);
if (!(CMP_LT_C <= cmp && cmp <= CMP_GT_C))
{
curr->marker= SORTORDER_CHANGE_FLAG |
PARTITION_CHANGE_FLAG |
FRAME_CHANGE_FLAG;
}
else if (win_spec_prev->partition_list != win_spec_curr->partition_list)
{
curr->marker|= PARTITION_CHANGE_FLAG | FRAME_CHANGE_FLAG;
}
}
else if (win_spec_prev->window_frame != win_spec_curr->window_frame)
curr->marker|= FRAME_CHANGE_FLAG;
prev= curr;
}
}
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// Window Frames support
/////////////////////////////////////////////////////////////////////////////
// note: make rr_from_pointers static again when not need it here anymore
int rr_from_pointers(READ_RECORD *info);
/////////////////////////////////////////////////////////////////////////////
/*
A cursor over a sequence of rowids. One can
- Move to next rowid
- jump to given number in the sequence
- Know the number of the current rowid (i.e. how many rowids have been read)
*/
class Rowid_seq_cursor
{
public:
Rowid_seq_cursor() : io_cache(NULL), ref_buffer(0) {}
virtual ~Rowid_seq_cursor()
{
if (ref_buffer)
my_free(ref_buffer);
if (io_cache)
{
end_slave_io_cache(io_cache);
my_free(io_cache);
io_cache= NULL;
}
}
private:
/* Length of one rowid element */
size_t ref_length;
/* If io_cache=!NULL, use it */
IO_CACHE *io_cache;
uchar *ref_buffer; /* Buffer for the last returned rowid */
ha_rows rownum; /* Number of the rowid that is about to be returned */
ha_rows current_ref_buffer_rownum;
bool ref_buffer_valid;
/* The following are used when we are reading from an array of pointers */
uchar *cache_start;
uchar *cache_pos;
uchar *cache_end;
public:
void init(READ_RECORD *info)
{
ref_length= info->ref_length;
if (info->read_record_func == rr_from_pointers)
{
io_cache= NULL;
cache_start= info->cache_pos;
cache_pos= info->cache_pos;
cache_end= info->cache_end;
}
else
{
//DBUG_ASSERT(info->read_record == rr_from_tempfile);
rownum= 0;
io_cache= (IO_CACHE*)my_malloc(sizeof(IO_CACHE), MYF(0));
init_slave_io_cache(info->io_cache, io_cache);
ref_buffer= (uchar*)my_malloc(ref_length, MYF(0));
ref_buffer_valid= false;
}
}
virtual int next()
{
/* Allow multiple next() calls in EOF state. */
if (at_eof())
return -1;
if (io_cache)
{
rownum++;
}
else
{
cache_pos+= ref_length;
DBUG_ASSERT(cache_pos <= cache_end);
}
return 0;
}
virtual int prev()
{
if (io_cache)
{
if (rownum == 0)
return -1;
rownum--;
return 0;
}
else
{
/* Allow multiple prev() calls when positioned at the start. */
if (cache_pos == cache_start)
return -1;
cache_pos-= ref_length;
DBUG_ASSERT(cache_pos >= cache_start);
return 0;
}
}
ha_rows get_rownum() const
{
if (io_cache)
return rownum;
else
return (cache_pos - cache_start) / ref_length;
}
void move_to(ha_rows row_number)
{
if (io_cache)
{
rownum= row_number;
}
else
{
cache_pos= MY_MIN(cache_end, cache_start + row_number * ref_length);
DBUG_ASSERT(cache_pos <= cache_end);
}
}
protected:
bool at_eof()
{
if (io_cache)
{
return rownum * ref_length >= io_cache->end_of_file;
}
else
return (cache_pos == cache_end);
}
bool get_curr_rowid(uchar **row_id)
{
if (io_cache)
{
DBUG_ASSERT(!at_eof());
if (!ref_buffer_valid || current_ref_buffer_rownum != rownum)
{
seek_io_cache(io_cache, rownum * ref_length);
if (my_b_read(io_cache,ref_buffer,ref_length))
{
/* Error reading from file. */
return true;
}
ref_buffer_valid= true;
current_ref_buffer_rownum = rownum;
}
*row_id = ref_buffer;
return false;
}
else
{
*row_id= cache_pos;
return false;
}
}
};
/*
Cursor which reads from rowid sequence and also retrieves table rows.
*/
class Table_read_cursor : public Rowid_seq_cursor
{
public:
virtual ~Table_read_cursor() = default;
void init(READ_RECORD *info)
{
Rowid_seq_cursor::init(info);
table= info->table;
record= info->record();
}
virtual int fetch()
{
if (at_eof())
return -1;
uchar* curr_rowid;
if (get_curr_rowid(&curr_rowid))
return -1;
return table->file->ha_rnd_pos(record, curr_rowid);
}
private:
/* The table that is acccesed by this cursor. */
TABLE *table;
/* Buffer where to store the table's record data. */
uchar *record;
// TODO(spetrunia): should move_to() also read row here?
};
/*
A cursor which only moves within a partition. The scan stops at the partition
end, and it needs an explicit command to move to the next partition.
This cursor can not move backwards.
*/
class Partition_read_cursor : public Table_read_cursor
{
public:
Partition_read_cursor(THD *thd, SQL_I_List<ORDER> *partition_list) :
bound_tracker(thd, partition_list) {}
void init(READ_RECORD *info)
{
Table_read_cursor::init(info);
bound_tracker.init();
end_of_partition= false;
}