/ Check-in [b5b18f66]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Allow an entire partition to be cached in a temp table for all types of window frames. This is required by nth_value() and others.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | exp-window-functions
Files: files | file ages | folders
SHA3-256: b5b18f661341d8d450147e62d321791c706f16c0550bcd98eec3e0220c039189
User & Date: dan 2018-06-01 21:00:08
Context
2018-06-02
21:04
Add support for window functions row_number(), rank(), dense_rank() and percent_rank(). check-in: 91c1cb7a user: dan tags: exp-window-functions
2018-06-01
21:00
Allow an entire partition to be cached in a temp table for all types of window frames. This is required by nth_value() and others. check-in: b5b18f66 user: dan tags: exp-window-functions
2018-05-30
20:44
Allow min() and max() to be used as window functions. check-in: c16125a8 user: dan tags: exp-window-functions
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/window.c.

189
190
191
192
193
194
195





















































196
197
198
199
200
201
202
...
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
...
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
...
439
440
441
442
443
444
445

446
447

448


449
450
451
452
453
454
455
...
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
...
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
...
549
550
551
552
553
554
555












































































































































556
557
558
559
560
561
562
...
565
566
567
568
569
570
571














572
573
574
575
576
577
578
...
738
739
740
741
742
743
744

745
746
747
748
749
750
751
752
753











754
755
756
757
758
      }else{
        sqlite3VdbeChangeP3(v, -1, pWin->regResult);
      }
    }
  }
}























































/*
** ROWS BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING
** ----------------------------------------------------
**
** Pseudo-code for the implementation of this window frame type is as
** follows. sqlite3WhereBegin() has already been called to generate the
................................................................................
  int regGosub, 
  int addrGosub
){
  Window *pMWin = p->pWin;
  Vdbe *v = sqlite3GetVdbe(pParse);
  Window *pWin;
  int k;
  int iSubCsr = p->pSrc->a[0].iCursor;
  int nSub = p->pSrc->a[0].pTab->nCol;
  int regFlushPart;               /* Register for "Gosub flush_partition" */
  int lblFlushPart;               /* Label for "Gosub flush_partition" */
  int lblFlushDone;               /* Label for "Gosub flush_partition_done" */

  int reg = pParse->nMem+1;
  int regRecord = reg+nSub;
  int regRowid = regRecord+1;
  int addr;
  int csrStart = pParse->nTab++;
  int csrEnd = pParse->nTab++;
  int regStart;                    /* Value of <expr> PRECEDING */
  int regEnd;                      /* Value of <expr> FOLLOWING */
  int addrNext;
  int addrGoto;
................................................................................
  if( pMWin->eType==TK_RANGE 
   && pMWin->eStart==TK_CURRENT 
   && pMWin->eEnd==TK_UNBOUNDED
  ){
    bRange = 1;
  }

  pParse->nMem += nSub + 2;

  /* Allocate register and label for the "flush_partition" sub-routine. */
  regFlushPart = ++pParse->nMem;
  lblFlushPart = sqlite3VdbeMakeLabel(v);
  lblFlushDone = sqlite3VdbeMakeLabel(v);

  regStart = ++pParse->nMem;
  regEnd = ++pParse->nMem;

  /* Martial the row returned by the sub-select into an array of 
  ** registers. */
  for(k=0; k<nSub; k++){
    sqlite3VdbeAddOp3(v, OP_Column, iSubCsr, k, reg+k);
  }
  sqlite3VdbeAddOp3(v, OP_MakeRecord, reg, nSub, regRecord);

  /* Check if this is the start of a new partition. If so, call the
  ** flush_partition sub-routine.  */
  if( pMWin->pPartition ){
    ExprList *pPart = pMWin->pPartition;
    int nPart = (pPart ? pPart->nExpr : 0);
    int regNewPart = reg + pMWin->nBufferCol;
    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);

    addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart,nPart);
    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
    sqlite3VdbeAddOp3(v, OP_Jump, addr+2, addr+4, addr+2);
    sqlite3VdbeAddOp2(v, OP_Gosub, regFlushPart, lblFlushPart);
    sqlite3VdbeAddOp3(v, OP_Copy, regNewPart, pMWin->regPart, nPart);
  }

  /* Buffer the current row in the ephemeral table. */
  sqlite3VdbeAddOp2(v, OP_NewRowid, pMWin->iEphCsr, regRowid);
  sqlite3VdbeAddOp3(v, OP_Insert, pMWin->iEphCsr, regRecord, regRowid);

  /* End of the input loop */
  sqlite3WhereEnd(pWInfo);

  /* Invoke "flush_partition" to deal with the final (or only) partition */
  sqlite3VdbeAddOp2(v, OP_Gosub, regFlushPart, lblFlushPart);
  addrGoto = sqlite3VdbeAddOp0(v, OP_Goto);

  /* Start of "flush_partition" */
  sqlite3VdbeResolveLabel(v, lblFlushPart);
  sqlite3VdbeAddOp2(v, OP_Once, 0, sqlite3VdbeCurrentAddr(v)+3);
  sqlite3VdbeAddOp2(v, OP_OpenDup, csrStart, pMWin->iEphCsr);
  sqlite3VdbeAddOp2(v, OP_OpenDup, csrEnd, pMWin->iEphCsr);
................................................................................
  */
  if( pMWin->pEnd && pMWin->pStart && pMWin->eStart==TK_FOLLOWING ){
    assert( pMWin->eEnd==TK_FOLLOWING );
    sqlite3VdbeAddOp3(v, OP_Subtract, regStart, regEnd, regEnd);
  }

  /* Initialize the accumulator register for each window function to NULL */

  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);

  }



  sqlite3VdbeAddOp2(v, OP_Rewind, pMWin->iEphCsr, lblFlushDone);
  sqlite3VdbeAddOp2(v, OP_Rewind, csrStart, lblFlushDone);
  sqlite3VdbeChangeP5(v, 1);
  sqlite3VdbeAddOp2(v, OP_Rewind, csrEnd, lblFlushDone);
  sqlite3VdbeChangeP5(v, 1);

................................................................................
  ** do nothing.  */
  addrTop = sqlite3VdbeCurrentAddr(v);
  if( pMWin->eEnd==TK_PRECEDING ){
    addrIfPos1 = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0 , 1);
  }
  sqlite3VdbeAddOp2(v, OP_Next, csrEnd, sqlite3VdbeCurrentAddr(v)+2);
  addr = sqlite3VdbeAddOp0(v, OP_Goto);
  windowAggStep(pParse, pMWin, csrEnd, 0, reg);
  if( pMWin->eEnd==TK_UNBOUNDED ){
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
    sqlite3VdbeJumpHere(v, addr);
    addrTop = sqlite3VdbeCurrentAddr(v);
  }else{
    sqlite3VdbeJumpHere(v, addr);
    if( pMWin->eEnd==TK_PRECEDING ){
................................................................................
      addrJumpHere = sqlite3VdbeAddOp3(v, OP_IfPos, regStart, 0 , 1);
    }
    if( bRange ){
      sqlite3VdbeAddOp3(v, OP_IfPos, regPeer, sqlite3VdbeCurrentAddr(v)+2, 1);
      addrJumpHere = sqlite3VdbeAddOp0(v, OP_Goto);
    }
    sqlite3VdbeAddOp2(v, OP_Next, csrStart, sqlite3VdbeCurrentAddr(v)+1);
    windowAggStep(pParse, pMWin, csrStart, 1, reg);
    if( bRange ){
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrJumpHere-1);
    }
    if( addrJumpHere ){
      sqlite3VdbeJumpHere(v, addrJumpHere);
    }
  }
................................................................................
  /* Jump to here to skip over flush_partition */
  sqlite3VdbeJumpHere(v, addrGoto);
}

/*
** RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
**












































































































































**   ...
**     if( new partition ){
**       AggFinal (xFinalize)
**       Gosub addrGosub
**       ResetSorter eph-table
**     }
**     else if( new peer ){
................................................................................
**       ResetSorter eph-table
**     }
**     AggStep
**     Insert (record into eph-table)
**   sqlite3WhereEnd()
**   AggFinal (xFinalize)
**   Gosub addrGosub














*/
static void windowCodeDefaultStep(
  Parse *pParse, 
  Select *p,
  WhereInfo *pWInfo,
  int regGosub, 
  int addrGosub
................................................................................
  WhereInfo *pWInfo,
  int regGosub, 
  int addrGosub,
  int *pbLoop
){
  Window *pMWin = p->pWin;


  if( (pMWin->eType==TK_ROWS 
   && (pMWin->eStart!=TK_UNBOUNDED||pMWin->eEnd!=TK_CURRENT||!pMWin->pOrderBy))
   || (pMWin->eStart==TK_CURRENT&&pMWin->eEnd==TK_UNBOUNDED&&pMWin->pOrderBy)
  ){
    *pbLoop = 0;
    windowCodeRowExprStep(pParse, p, pWInfo, regGosub, addrGosub);
    return;
  }












  *pbLoop = 1;
  windowCodeDefaultStep(pParse, p, pWInfo, regGosub, addrGosub);
}









>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







<





|
|
<







 







<
<








<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
|
<
|
<
<
<
<
<
<
<
<
<
<







 







>


>

>
>







 







|







 







|







 







>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







>




<




>
>
>
>
>
>
>
>
>
>
>





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
...
378
379
380
381
382
383
384

385
386
387
388
389
390
391

392
393
394
395
396
397
398
...
420
421
422
423
424
425
426


427
428
429
430
431
432
433
434


















435

436










437
438
439
440
441
442
443
...
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
...
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
...
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
...
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
...
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
...
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
      }else{
        sqlite3VdbeChangeP3(v, -1, pWin->regResult);
      }
    }
  }
}

static void windowPartitionCache(
  Parse *pParse,
  Select *p,
  WhereInfo *pWInfo,
  int regFlushPart,
  int lblFlushPart
){
  Window *pMWin = p->pWin;
  Vdbe *v = sqlite3GetVdbe(pParse);
  Window *pWin;
  int iSubCsr = p->pSrc->a[0].iCursor;
  int nSub = p->pSrc->a[0].pTab->nCol;
  int k;

  int reg = pParse->nMem+1;
  int regRecord = reg+nSub;
  int regRowid = regRecord+1;

  pParse->nMem += nSub + 2;

  /* Martial the row returned by the sub-select into an array of 
  ** registers. */
  for(k=0; k<nSub; k++){
    sqlite3VdbeAddOp3(v, OP_Column, iSubCsr, k, reg+k);
  }
  sqlite3VdbeAddOp3(v, OP_MakeRecord, reg, nSub, regRecord);

  /* Check if this is the start of a new partition. If so, call the
  ** flush_partition sub-routine.  */
  if( pMWin->pPartition ){
    int addr;
    ExprList *pPart = pMWin->pPartition;
    int nPart = (pPart ? pPart->nExpr : 0);
    int regNewPart = reg + pMWin->nBufferCol;
    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);

    addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart,nPart);
    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
    sqlite3VdbeAddOp3(v, OP_Jump, addr+2, addr+4, addr+2);
    sqlite3VdbeAddOp3(v, OP_Copy, regNewPart, pMWin->regPart, nPart-1);
    sqlite3VdbeAddOp2(v, OP_Gosub, regFlushPart, lblFlushPart);
  }

  /* Buffer the current row in the ephemeral table. */
  sqlite3VdbeAddOp2(v, OP_NewRowid, pMWin->iEphCsr, regRowid);
  sqlite3VdbeAddOp3(v, OP_Insert, pMWin->iEphCsr, regRecord, regRowid);

  /* End of the input loop */
  sqlite3WhereEnd(pWInfo);

  /* Invoke "flush_partition" to deal with the final (or only) partition */
  sqlite3VdbeAddOp2(v, OP_Gosub, regFlushPart, lblFlushPart);
}

/*
** ROWS BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING
** ----------------------------------------------------
**
** Pseudo-code for the implementation of this window frame type is as
** follows. sqlite3WhereBegin() has already been called to generate the
................................................................................
  int regGosub, 
  int addrGosub
){
  Window *pMWin = p->pWin;
  Vdbe *v = sqlite3GetVdbe(pParse);
  Window *pWin;
  int k;

  int nSub = p->pSrc->a[0].pTab->nCol;
  int regFlushPart;               /* Register for "Gosub flush_partition" */
  int lblFlushPart;               /* Label for "Gosub flush_partition" */
  int lblFlushDone;               /* Label for "Gosub flush_partition_done" */

  int regArg;
  int nArg;

  int addr;
  int csrStart = pParse->nTab++;
  int csrEnd = pParse->nTab++;
  int regStart;                    /* Value of <expr> PRECEDING */
  int regEnd;                      /* Value of <expr> FOLLOWING */
  int addrNext;
  int addrGoto;
................................................................................
  if( pMWin->eType==TK_RANGE 
   && pMWin->eStart==TK_CURRENT 
   && pMWin->eEnd==TK_UNBOUNDED
  ){
    bRange = 1;
  }



  /* Allocate register and label for the "flush_partition" sub-routine. */
  regFlushPart = ++pParse->nMem;
  lblFlushPart = sqlite3VdbeMakeLabel(v);
  lblFlushDone = sqlite3VdbeMakeLabel(v);

  regStart = ++pParse->nMem;
  regEnd = ++pParse->nMem;



















  windowPartitionCache(pParse, p, pWInfo, regFlushPart, lblFlushPart);












  addrGoto = sqlite3VdbeAddOp0(v, OP_Goto);

  /* Start of "flush_partition" */
  sqlite3VdbeResolveLabel(v, lblFlushPart);
  sqlite3VdbeAddOp2(v, OP_Once, 0, sqlite3VdbeCurrentAddr(v)+3);
  sqlite3VdbeAddOp2(v, OP_OpenDup, csrStart, pMWin->iEphCsr);
  sqlite3VdbeAddOp2(v, OP_OpenDup, csrEnd, pMWin->iEphCsr);
................................................................................
  */
  if( pMWin->pEnd && pMWin->pStart && pMWin->eStart==TK_FOLLOWING ){
    assert( pMWin->eEnd==TK_FOLLOWING );
    sqlite3VdbeAddOp3(v, OP_Subtract, regStart, regEnd, regEnd);
  }

  /* Initialize the accumulator register for each window function to NULL */
  nArg = 0;
  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
    nArg = MAX(nArg, pWin->nArg);
  }
  regArg = pParse->nMem+1;
  pParse->nMem += nArg;

  sqlite3VdbeAddOp2(v, OP_Rewind, pMWin->iEphCsr, lblFlushDone);
  sqlite3VdbeAddOp2(v, OP_Rewind, csrStart, lblFlushDone);
  sqlite3VdbeChangeP5(v, 1);
  sqlite3VdbeAddOp2(v, OP_Rewind, csrEnd, lblFlushDone);
  sqlite3VdbeChangeP5(v, 1);

................................................................................
  ** do nothing.  */
  addrTop = sqlite3VdbeCurrentAddr(v);
  if( pMWin->eEnd==TK_PRECEDING ){
    addrIfPos1 = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0 , 1);
  }
  sqlite3VdbeAddOp2(v, OP_Next, csrEnd, sqlite3VdbeCurrentAddr(v)+2);
  addr = sqlite3VdbeAddOp0(v, OP_Goto);
  windowAggStep(pParse, pMWin, csrEnd, 0, regArg);
  if( pMWin->eEnd==TK_UNBOUNDED ){
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
    sqlite3VdbeJumpHere(v, addr);
    addrTop = sqlite3VdbeCurrentAddr(v);
  }else{
    sqlite3VdbeJumpHere(v, addr);
    if( pMWin->eEnd==TK_PRECEDING ){
................................................................................
      addrJumpHere = sqlite3VdbeAddOp3(v, OP_IfPos, regStart, 0 , 1);
    }
    if( bRange ){
      sqlite3VdbeAddOp3(v, OP_IfPos, regPeer, sqlite3VdbeCurrentAddr(v)+2, 1);
      addrJumpHere = sqlite3VdbeAddOp0(v, OP_Goto);
    }
    sqlite3VdbeAddOp2(v, OP_Next, csrStart, sqlite3VdbeCurrentAddr(v)+1);
    windowAggStep(pParse, pMWin, csrStart, 1, regArg);
    if( bRange ){
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrJumpHere-1);
    }
    if( addrJumpHere ){
      sqlite3VdbeJumpHere(v, addrJumpHere);
    }
  }
................................................................................
  /* Jump to here to skip over flush_partition */
  sqlite3VdbeJumpHere(v, addrGoto);
}

/*
** RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
**
**   flush_partition:
**     Once {
**       OpenDup (iEphCsr -> csrLead)
**     }
**     Integer ctr 0
**     foreach row (csrLead){
**       if( new peer ){
**         AggFinal (xValue)
**         for(i=0; i<ctr; i++){
**           Gosub addrGosub
**           Next iEphCsr
**         }
**         Integer ctr 0
**       }
**       AggStep (csrLead)
**       Incr ctr
**     }
**
**     AggFinal (xFinalize)
**     for(i=0; i<ctr; i++){
**       Gosub addrGosub
**       Next iEphCsr
**     }
**
**     ResetSorter (csr)
**     Return
**
** ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
** RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
** RANGE BETWEEN CURRENT ROW AND CURRENT ROW 
**
**   TODO.
*/
static void windowCodeCacheStep(
  Parse *pParse, 
  Select *p,
  WhereInfo *pWInfo,
  int regGosub, 
  int addrGosub
){
  Window *pMWin = p->pWin;
  Vdbe *v = sqlite3GetVdbe(pParse);
  Window *pWin;
  int k;
  int addr;
  ExprList *pPart = pMWin->pPartition;
  ExprList *pOrderBy = pMWin->pOrderBy;
  int nPeer = pOrderBy->nExpr;
  int regNewPeer;

  int addrGoto;                   /* Address of Goto used to jump flush_par.. */
  int addrRewind;                 /* Address of Rewind that starts loop */
  int regFlushPart;
  int lblFlushPart;
  int csrLead;
  int regCtr;
  int regArg;                     /* Register array to martial function args */
  int nArg;

  assert( (pMWin->eStart==TK_UNBOUNDED && pMWin->eEnd==TK_CURRENT) 
  );

  regNewPeer = pParse->nMem+1;
  pParse->nMem += nPeer;

  /* Allocate register and label for the "flush_partition" sub-routine. */
  regFlushPart = ++pParse->nMem;
  lblFlushPart = sqlite3VdbeMakeLabel(v);

  csrLead = pParse->nTab++;
  regCtr = ++pParse->nMem;

  windowPartitionCache(pParse, p, pWInfo, regFlushPart, lblFlushPart);
  addrGoto = sqlite3VdbeAddOp0(v, OP_Goto);

  /* Start of "flush_partition" */
  sqlite3VdbeResolveLabel(v, lblFlushPart);
  sqlite3VdbeAddOp2(v, OP_Once, 0, sqlite3VdbeCurrentAddr(v)+2);
  sqlite3VdbeAddOp2(v, OP_OpenDup, csrLead, pMWin->iEphCsr);

  /* Initialize the accumulator register for each window function to NULL */
  nArg = 0;
  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
    nArg = MAX(nArg, pWin->nArg);
  }
  regArg = pParse->nMem+1;
  pParse->nMem += nArg;

  sqlite3VdbeAddOp2(v, OP_Integer, 0, regCtr);
  addrRewind = sqlite3VdbeAddOp1(v, OP_Rewind, csrLead);
  sqlite3VdbeAddOp1(v, OP_Rewind, pMWin->iEphCsr);

  if( pOrderBy ){
    int addrJump;                 /* Address of OP_Jump below */
    int iOff = pMWin->nBufferCol + (pPart ? pPart->nExpr : 0);
    int regPeer = pMWin->regPart + (pPart ? pPart->nExpr : 0);
    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pOrderBy, 0, 0);

    for(k=0; k<nPeer; k++){
      sqlite3VdbeAddOp3(v, OP_Column, csrLead, iOff+k, regNewPeer+k);
    }

    addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPeer, regPeer, nPeer);
    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
    addrJump = sqlite3VdbeAddOp3(v, OP_Jump, addr+2, 0, addr+2);
    sqlite3VdbeAddOp3(v, OP_Copy, regNewPeer, regPeer, nPeer-1);
    windowAggFinal(pParse, pMWin, 0);
    sqlite3VdbeAddOp3(v, OP_IfPos, regCtr, sqlite3VdbeCurrentAddr(v)+2 , 1);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+3);
    sqlite3VdbeAddOp2(v, OP_Gosub, regGosub, addrGosub);
    sqlite3VdbeAddOp2(v, OP_Next, pMWin->iEphCsr, sqlite3VdbeCurrentAddr(v)-3);
    sqlite3VdbeJumpHere(v, addrJump);
  }

  windowAggStep(pParse, pMWin, csrLead, 0, regArg);
  sqlite3VdbeAddOp2(v, OP_AddImm, regCtr, 1);

  sqlite3VdbeAddOp2(v, OP_Next, csrLead, addrRewind+2);

  windowAggFinal(pParse, pMWin, 1);

  sqlite3VdbeAddOp3(v, OP_IfPos, regCtr, sqlite3VdbeCurrentAddr(v)+2 , 1);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+3);
  sqlite3VdbeAddOp2(v, OP_Gosub, regGosub, addrGosub);
  sqlite3VdbeAddOp2(v, OP_Next, pMWin->iEphCsr, sqlite3VdbeCurrentAddr(v)-3);

  sqlite3VdbeJumpHere(v, addrRewind);
  sqlite3VdbeJumpHere(v, addrRewind+1);
  sqlite3VdbeAddOp1(v, OP_ResetSorter, pMWin->iEphCsr);
  sqlite3VdbeAddOp1(v, OP_Return, regFlushPart);

  /* Jump to here to skip over flush_partition */
  sqlite3VdbeJumpHere(v, addrGoto);
}


/*
** RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
**
**   ...
**     if( new partition ){
**       AggFinal (xFinalize)
**       Gosub addrGosub
**       ResetSorter eph-table
**     }
**     else if( new peer ){
................................................................................
**       ResetSorter eph-table
**     }
**     AggStep
**     Insert (record into eph-table)
**   sqlite3WhereEnd()
**   AggFinal (xFinalize)
**   Gosub addrGosub
**
** RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
**
**   As above, except take no action for a "new peer". Invoke
**   the sub-routine once only for each partition.
**
** RANGE BETWEEN CURRENT ROW AND CURRENT ROW
**
**   As above, except that the "new peer" condition is handled in the
**   same way as "new partition" (so there is no "else if" block).
**
** ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
** 
**   As above, except assume every row is a "new peer".
*/
static void windowCodeDefaultStep(
  Parse *pParse, 
  Select *p,
  WhereInfo *pWInfo,
  int regGosub, 
  int addrGosub
................................................................................
  WhereInfo *pWInfo,
  int regGosub, 
  int addrGosub,
  int *pbLoop
){
  Window *pMWin = p->pWin;

  *pbLoop = 0;
  if( (pMWin->eType==TK_ROWS 
   && (pMWin->eStart!=TK_UNBOUNDED||pMWin->eEnd!=TK_CURRENT||!pMWin->pOrderBy))
   || (pMWin->eStart==TK_CURRENT&&pMWin->eEnd==TK_UNBOUNDED&&pMWin->pOrderBy)
  ){

    windowCodeRowExprStep(pParse, p, pWInfo, regGosub, addrGosub);
    return;
  }

#if 0
  if( pMWin->eType==TK_RANGE
   && pMWin->eStart==TK_UNBOUNDED
   && pMWin->eEnd==TK_CURRENT
   && pMWin->pOrderBy
  ){
    windowCodeCacheStep(pParse, p, pWInfo, regGosub, addrGosub);
    return;
  }
#endif

  *pbLoop = 1;
  windowCodeDefaultStep(pParse, p, pWInfo, regGosub, addrGosub);
}