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Simplify the window function code generator some more.

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FossilOrigin-Name: 45cbd3b4498cea8856f189e9d0a192556d4f15212055b8328a1beca6083fc47a
This commit is contained in:
dan
2019-03-06 21:04:11 +00:00
parent b33487b0b6
commit 00267b8a7b
3 changed files with 184 additions and 91 deletions
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261
src/window.c
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@@ -1844,8 +1844,8 @@ static void windowCodeRowExprStep(
}
/*
** Return true if the entire partition should be cached in the temp
** table before processing.
** Return true if the entire partition should be cached in the ephemeral
** table before processing any rows.
*/
static int windowCachePartition(Window *pMWin){
Window *pWin;
@@ -1863,6 +1863,135 @@ static int windowCachePartition(Window *pMWin){
return 0;
}
typedef struct WindowCodeArg WindowCodeArg;
struct WindowCodeArg {
Parse *pParse;
Window *pMWin;
Vdbe *pVdbe;
int regGosub;
int addrGosub;
int regArg;
};
#define WINDOW_RETURN_ROW 1
#define WINDOW_AGGINVERSE 2
#define WINDOW_AGGSTEP 3
static int windowCodeOp(
WindowCodeArg *p,
int op,
int csr,
int regCountdown,
int jumpOnEof
){
int ret = 0;
Vdbe *v = p->pVdbe;
int addrIf = 0;
if( regCountdown>0 ){
addrIf = sqlite3VdbeAddOp3(v, OP_IfPos, regCountdown, 0, 1);
}
if( jumpOnEof ){
sqlite3VdbeAddOp2(v, OP_Next, csr, sqlite3VdbeCurrentAddr(v)+2);
ret = sqlite3VdbeAddOp0(v, OP_Goto);
}else{
sqlite3VdbeAddOp2(v, OP_Next, csr, sqlite3VdbeCurrentAddr(v)+1);
}
switch( op ){
case WINDOW_RETURN_ROW:
windowAggFinal(p->pParse, p->pMWin, 0);
windowReturnOneRow(p->pParse, p->pMWin, p->regGosub, p->addrGosub);
break;
case WINDOW_AGGINVERSE:
windowAggStep(p->pParse, p->pMWin, csr, 1, p->regArg, p->pMWin->regSize);
break;
case WINDOW_AGGSTEP:
windowAggStep(p->pParse, p->pMWin, csr, 0, p->regArg, p->pMWin->regSize);
break;
}
if( ret ){
sqlite3VdbeJumpHere(v, ret);
}
if( regCountdown>0 ){
sqlite3VdbeJumpHere(v, addrIf);
}
return ret;
}
/*
** This function - windowCodeStep() - generates the VM code that reads data
** from the sub-select and returns rows to the consumer. For the simplest
** case:
**
** ROWS BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING
**
** The VM code generated is equivalent in spirit to the following:
**
** while( !eof ){
** if( new partition ){
** Gosub flush
** }
** Insert new row into eph table.
**
** if( first row of partition ){
** Rewind(csrEnd, skipNext=1)
** Rewind(csrStart, skipNext=1)
** Rewind(csrCurrent, skipNext=1)
**
** regEnd = <expr2> // FOLLOWING expression
** regStart = <expr1> // PRECEDING expression
** }else{
** if( (regEnd--)<=0 ){
** Next(csrCurrent)
** Return one row.
** if( (regStart--)<0 ){
** Next(csrStart)
** AggInverse(csrStart)
** }
** }
** }
**
** Next(csrEnd)
** AggStep(csrEnd)
** }
** flush:
** while( 1 ){
** Next(csrCurrent)
** if( eof ) break
** Return one row.
** if( (regStart--)<0 ){
** Next(csrStart)
** AggInverse(csrStart)
** }
** }
** Empty eph table.
**
** More generally, the pattern used for all window types is:
**
** while( !eof ){
** if( new partition ){
** Gosub flush
** }
** Insert new row into eph table.
** if( first row of partition ){
** FIRST_ROW_CODE
** }else{
** SECOND_ROW_CODE
** }
** ALL_ROW_CODE
** }
** flush:
** FLUSH_CODE
** Empty eph table.
**
*/
static void windowCodeStep(
Parse *pParse,
Select *p,
@@ -1883,14 +2012,12 @@ static void windowCodeStep(
int regStart; /* Value of <expr> PRECEDING */
int regEnd; /* Value of <expr> FOLLOWING */
int iSubCsr = p->pSrc->a[0].iCursor;
int nSub = p->pSrc->a[0].pTab->nCol;
int k;
int iSubCsr = p->pSrc->a[0].iCursor; /* Cursor of sub-select */
int nSub = p->pSrc->a[0].pTab->nCol; /* Number of cols returned by sub */
int iCol; /* To iterate through sub cols */
int addrGoto;
int addrIf;
int addrIfEnd;
int addrIfStart;
int addrGosubFlush;
int addrInteger;
int addrCacheRewind;
@@ -1903,8 +2030,14 @@ static void windowCodeStep(
int reg = pParse->nMem+1;
int regRecord = reg+nSub;
int regRowid = regRecord+1;
WindowCodeArg s;
bCache = 1;
memset(&s, 0, sizeof(WindowCodeArg));
s.pParse = pParse;
s.pMWin = pMWin;
s.pVdbe = v;
s.regGosub = regGosub;
s.addrGosub = addrGosub;
pParse->nMem += 1 + nSub + 1;
@@ -1923,11 +2056,12 @@ static void windowCodeStep(
|| pMWin->eEnd==TK_PRECEDING
);
/* Load the column values for the row returned by the sub-select
** into an array of registers starting at reg. Assemble them into
** a record in register regRecord. TODO: An optimization here? */
for(k=0; k<nSub; k++){
sqlite3VdbeAddOp3(v, OP_Column, iSubCsr, k, reg+k);
for(iCol=0; iCol<nSub; iCol++){
sqlite3VdbeAddOp3(v, OP_Column, iSubCsr, iCol, reg+iCol);
}
sqlite3VdbeAddOp3(v, OP_MakeRecord, reg, nSub, regRecord);
@@ -1973,14 +2107,16 @@ static void windowCodeStep(
}
/* This block is run for the first row of each partition */
regArg = windowInitAccum(pParse, pMWin);
s.regArg = regArg = windowInitAccum(pParse, pMWin);
sqlite3ExprCode(pParse, pMWin->pStart, regStart);
windowCheckIntValue(pParse, regStart, 0);
sqlite3ExprCode(pParse, pMWin->pEnd, regEnd);
windowCheckIntValue(pParse, regEnd, 1);
if( pMWin->eStart==TK_FOLLOWING || pMWin->eEnd==TK_PRECEDING ){
if( pMWin->eStart==pMWin->eEnd
&& pMWin->eStart!=TK_CURRENT && pMWin->eStart!=TK_UNBOUNDED
){
int op = ((pMWin->eStart==TK_FOLLOWING) ? OP_Ge : OP_Le);
int addrGe = sqlite3VdbeAddOp3(v, op, regStart, 0, regEnd);
windowAggFinal(pParse, pMWin, 0);
@@ -2008,56 +2144,35 @@ static void windowCodeStep(
sqlite3VdbeAddOp2(v, OP_Integer, 0, pMWin->regFirst);
addrGoto = sqlite3VdbeAddOp0(v, OP_Goto);
/* This block is run for the second and subsequent rows of each partition */
/* Begin generating SECOND_ROW_CODE */
VdbeModuleComment((pParse->pVdbe, "Begin windowCodeStep.SECOND_ROW_CODE"));
if( bCache ){
addrCacheNext = sqlite3VdbeCurrentAddr(v);
}else{
sqlite3VdbeJumpHere(v, addrIf);
}
if( pMWin->eStart==TK_FOLLOWING ){
addrIfEnd = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0, 1);
windowAggFinal(pParse, pMWin, 0);
sqlite3VdbeAddOp2(v, OP_Next, csrCurrent, sqlite3VdbeCurrentAddr(v)+1);
windowReturnOneRow(pParse, pMWin, regGosub, addrGosub);
sqlite3VdbeJumpHere(v, addrIfEnd);
addrIfStart = sqlite3VdbeAddOp3(v, OP_IfPos, regStart, 0, 1);
sqlite3VdbeAddOp2(v, OP_Next, csrStart, sqlite3VdbeCurrentAddr(v)+1);
windowAggStep(pParse, pMWin, csrStart, 1, regArg, pMWin->regSize);
sqlite3VdbeJumpHere(v, addrIfStart);
windowCodeOp(&s, WINDOW_RETURN_ROW, csrCurrent, regEnd, 0);
windowCodeOp(&s, WINDOW_AGGINVERSE, csrStart, regStart, 0);
}else
if( pMWin->eEnd==TK_PRECEDING ){
addrIfEnd = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0, 1);
sqlite3VdbeAddOp2(v, OP_Next, csrEnd, sqlite3VdbeCurrentAddr(v)+1);
windowAggStep(pParse, pMWin, csrEnd, 0, regArg, pMWin->regSize);
sqlite3VdbeJumpHere(v, addrIfEnd);
windowAggFinal(pParse, pMWin, 0);
sqlite3VdbeAddOp2(v, OP_Next, csrCurrent, sqlite3VdbeCurrentAddr(v)+1);
windowReturnOneRow(pParse, pMWin, regGosub, addrGosub);
addrIfStart = sqlite3VdbeAddOp3(v, OP_IfPos, regStart, 0, 1);
sqlite3VdbeAddOp2(v, OP_Next, csrStart, sqlite3VdbeCurrentAddr(v)+1);
windowAggStep(pParse, pMWin, csrStart, 1, regArg, pMWin->regSize);
sqlite3VdbeJumpHere(v, addrIfStart);
windowCodeOp(&s, WINDOW_AGGSTEP, csrEnd, regEnd, 0);
windowCodeOp(&s, WINDOW_RETURN_ROW, csrCurrent, 0, 0);
windowCodeOp(&s, WINDOW_AGGINVERSE, csrStart, regStart, 0);
}else{
addrIfEnd = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0, 1);
windowAggFinal(pParse, pMWin, 0);
sqlite3VdbeAddOp2(v, OP_Next, csrCurrent, sqlite3VdbeCurrentAddr(v)+1);
windowReturnOneRow(pParse, pMWin, regGosub, addrGosub);
addrIfStart = sqlite3VdbeAddOp3(v, OP_IfPos, regStart, 0, 1);
sqlite3VdbeAddOp2(v, OP_Next, csrStart, sqlite3VdbeCurrentAddr(v)+1);
windowAggStep(pParse, pMWin, csrStart, 1, regArg, pMWin->regSize);
sqlite3VdbeJumpHere(v, addrIfStart);
sqlite3VdbeJumpHere(v, addrIfEnd);
int addr = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0, 1);
windowCodeOp(&s, WINDOW_RETURN_ROW, csrCurrent, 0, 0);
windowCodeOp(&s, WINDOW_AGGINVERSE, csrStart, regStart, 0);
sqlite3VdbeJumpHere(v, addr);
}
VdbeModuleComment((pParse->pVdbe, "End windowCodeStep.SECOND_ROW_CODE"));
VdbeModuleComment((pParse->pVdbe, "Begin windowCodeStep.ALL_ROW_CODE"));
sqlite3VdbeJumpHere(v, addrGoto);
if( pMWin->eEnd!=TK_PRECEDING ){
sqlite3VdbeAddOp2(v, OP_Next, csrEnd, sqlite3VdbeCurrentAddr(v)+1);
windowAggStep(pParse, pMWin, csrEnd, 0, regArg, pMWin->regSize);
windowCodeOp(&s, WINDOW_AGGSTEP, csrEnd, 0, 0);
}
VdbeModuleComment((pParse->pVdbe, "End windowCodeStep.ALL_ROW_CODE"));
/* End of the main input loop */
if( bCache ){
@@ -2070,56 +2185,34 @@ static void windowCodeStep(
/* Fall through */
VdbeModuleComment((pParse->pVdbe, "Begin windowCodeStep.FLUSH_CODE"));
if( pMWin->pPartition && bCache==0 ){
addrInteger = sqlite3VdbeAddOp2(v, OP_Integer, 0, regFlushPart);
sqlite3VdbeJumpHere(v, addrGosubFlush);
}
if( pMWin->eStart==TK_FOLLOWING ){
int addrBreak;
addrIfEnd = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0, 1);
sqlite3VdbeAddOp2(v, OP_Next, csrCurrent, sqlite3VdbeCurrentAddr(v)+2);
addrBreak = sqlite3VdbeAddOp0(v, OP_Goto);
windowAggFinal(pParse, pMWin, 0);
windowReturnOneRow(pParse, pMWin, regGosub, addrGosub);
sqlite3VdbeJumpHere(v, addrIfEnd);
addrIfStart = sqlite3VdbeAddOp3(v, OP_IfPos, regStart, 0, 1);
sqlite3VdbeAddOp2(v, OP_Next, csrStart, sqlite3VdbeCurrentAddr(v)+2);
sqlite3VdbeAddOp0(v, OP_Goto);
windowAggStep(pParse, pMWin, csrStart, 1, regArg, pMWin->regSize);
sqlite3VdbeJumpHere(v, addrIfStart);
sqlite3VdbeJumpHere(v, addrIfStart+2);
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrIfEnd);
sqlite3VdbeJumpHere(v, addrBreak);
if( pMWin->eEnd==TK_PRECEDING ){
windowCodeOp(&s, WINDOW_AGGSTEP, csrEnd, regEnd, 1);
windowCodeOp(&s, WINDOW_RETURN_ROW, csrCurrent, 0, 1);
}else{
sqlite3VdbeAddOp2(v, OP_Next, csrCurrent, sqlite3VdbeCurrentAddr(v)+2);
addrGoto = sqlite3VdbeAddOp0(v, OP_Goto);
if( pMWin->eEnd==TK_PRECEDING ){
addrIfEnd = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0, 1);
sqlite3VdbeAddOp2(v, OP_Next, csrEnd, sqlite3VdbeCurrentAddr(v)+1);
windowAggStep(pParse, pMWin, csrEnd, 0, regArg, pMWin->regSize);
sqlite3VdbeJumpHere(v, addrIfEnd);
windowAggFinal(pParse, pMWin, 0);
windowReturnOneRow(pParse, pMWin, regGosub, addrGosub);
int addrBreak;
int addrStart = sqlite3VdbeCurrentAddr(v);
if( pMWin->eStart==TK_FOLLOWING ){
addrBreak = windowCodeOp(&s, WINDOW_RETURN_ROW, csrCurrent, regEnd, 1);
windowCodeOp(&s, WINDOW_AGGINVERSE, csrStart, regStart, 1);
}else{
windowAggFinal(pParse, pMWin, 0);
windowReturnOneRow(pParse, pMWin, regGosub, addrGosub);
addrIfStart = sqlite3VdbeAddOp3(v, OP_IfPos, regStart, 0, 1);
sqlite3VdbeAddOp2(v, OP_Next, csrStart, sqlite3VdbeCurrentAddr(v)+1);
windowAggStep(pParse, pMWin, csrStart, 1, regArg, pMWin->regSize);
sqlite3VdbeJumpHere(v, addrIfStart);
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrGoto-1);
addrBreak = windowCodeOp(&s, WINDOW_RETURN_ROW, csrCurrent, 0, 1);
windowCodeOp(&s, WINDOW_AGGINVERSE, csrStart, regStart, 0);
}
sqlite3VdbeJumpHere(v, addrGoto);
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart);
sqlite3VdbeJumpHere(v, addrBreak);
}
if( bCache && addrShortcut>0 ) sqlite3VdbeJumpHere(v, addrShortcut);
sqlite3VdbeAddOp1(v, OP_ResetSorter, csrCurrent);
sqlite3VdbeAddOp2(v, OP_Integer, 0, pMWin->regSize);
if( bCache==0 ) sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regFirst);
VdbeModuleComment((pParse->pVdbe, "End windowCodeStep.FLUSH_CODE"));
if( pMWin->pPartition ){
sqlite3VdbeChangeP1(v, addrInteger, sqlite3VdbeCurrentAddr(v));
sqlite3VdbeAddOp1(v, OP_Return, regFlushPart);