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Fix a bug in RANGE window functions that use "ORDER BY <expr> DESC NULLS FIRST" as the window-frame ORDER BY clause.

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FossilOrigin-Name: 39b4cad4a51bb5116d62ffb16ac36d96a9280321b049eb2d008605392f52a459
This commit is contained in:
dan
2019-08-30 16:14:58 +00:00
parent ae144a1c9f
commit 8b47f52082
5 changed files with 119 additions and 35 deletions
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106
src/window.c
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@@ -1854,31 +1854,42 @@ static void windowIfNewPeer(
/*
** This function is called as part of generating VM programs for RANGE
** offset PRECEDING/FOLLOWING frame boundaries. Assuming "ASC" order for
** the ORDER BY term in the window, it generates code equivalent to:
** the ORDER BY term in the window, and that argument op is OP_Ge, it generates
** code equivalent to:
**
** if( csr1.peerVal + regVal >= csr2.peerVal ) goto lbl;
**
** A special type of arithmetic is used such that if csr.peerVal is not
** a numeric type (real or integer), then the result of the addition is
** a copy of csr1.peerVal.
** The value of parameter op may also be OP_Gt or OP_Le. In these cases the
** operator in the above pseudo-code is replaced with ">" or "<=", respectively.
**
** If the sort-order for the ORDER BY term in the window is DESC, then the
** comparison is reversed. Instead of adding regVal to csr1.peerVal, it is
** subtracted. And the comparison operator is inverted to - ">=" becomes "<=",
** ">" becomes "<", and so on. So, with DESC sort order, if the argument op
** is OP_Ge, the generated code is equivalent to:
**
** if( csr1.peerVal - regVal <= csr2.peerVal ) goto lbl;
**
** A special type of arithmetic is used such that if csr1.peerVal is not
** a numeric type (real or integer), then the result of the addition addition
** or subtraction is a a copy of csr1.peerVal.
*/
static void windowCodeRangeTest(
WindowCodeArg *p,
int op, /* OP_Ge, OP_Gt, or OP_Le */
int csr1,
int regVal,
int csr2,
int lbl
int csr1, /* Cursor number for cursor 1 */
int regVal, /* Register containing non-negative number */
int csr2, /* Cursor number for cursor 2 */
int lbl /* Jump destination if the condition is true */
){
Parse *pParse = p->pParse;
Vdbe *v = sqlite3GetVdbe(pParse);
int reg1 = sqlite3GetTempReg(pParse);
int reg2 = sqlite3GetTempReg(pParse);
int arith = OP_Add;
int addrGe;
ExprList *pOrderBy = p->pMWin->pOrderBy;
int regString = ++pParse->nMem;
ExprList *pOrderBy = p->pMWin->pOrderBy; /* ORDER BY clause for this window */
int reg1 = sqlite3GetTempReg(pParse); /* Register for csr1.peerVal+regVal */
int reg2 = sqlite3GetTempReg(pParse); /* Regiser for csr2.peerVal */
int regString = ++pParse->nMem; /* Register for constant value '' */
int arith = OP_Add; /* OP_Add or OP_Subtract */
int addrGe; /* Jump destination */
assert( op==OP_Ge || op==OP_Gt || op==OP_Le );
assert( pOrderBy && pOrderBy->nExpr==1 );
@@ -1891,47 +1902,92 @@ static void windowCodeRangeTest(
arith = OP_Subtract;
}
/* Read the peer-value from each cursor into a register */
windowReadPeerValues(p, csr1, reg1);
windowReadPeerValues(p, csr2, reg2);
/* Check if the peer value for csr1 value is a text or blob by comparing
** it to the smallest possible string - ''. If it is, jump over the
** OP_Add or OP_Subtract operation and proceed directly to the comparison. */
VdbeModuleComment((v, "CodeRangeTest: if( R%d %s R%d %s R%d ) goto lbl",
reg1, (arith==OP_Add ? "+" : "-"), regVal,
((op==OP_Ge) ? ">=" : (op==OP_Le) ? "<=" : (op==OP_Gt) ? ">" : "<"), reg2
));
/* Register reg1 currently contains csr1.peerVal (the peer-value from csr1).
** This block adds (or subtracts for DESC) the numeric value in regVal
** from it. Or, if reg1 is not numeric (it is a NULL, a text value or a blob),
** then leave reg1 as it is. In pseudo-code, this is implemented as:
**
** if( reg1>='' ) goto addrGe;
** reg1 = reg1 +/- regVal
** addrGe:
**
** Since all strings and blobs are greater-than-or-equal-to an empty string,
** the add/subtract is skipped for these, as required. If reg1 is a NULL,
** then the arithmetic is performed, but since adding or subtracting from
** NULL is always NULL anyway, this case is handled as required too. */
sqlite3VdbeAddOp4(v, OP_String8, 0, regString, 0, "", P4_STATIC);
addrGe = sqlite3VdbeAddOp3(v, OP_Ge, regString, 0, reg1);
VdbeCoverage(v);
sqlite3VdbeAddOp3(v, arith, regVal, reg1, reg1);
sqlite3VdbeJumpHere(v, addrGe);
/* If the BIGNULL flag is set for the ORDER BY, then it is required to
** consider NULL values to be larger than all other values, instead of
** the usual smaller. The VDBE opcodes OP_Ge and so on do not handle this
** (and adding that capability causes a performance regression), so
** instead if the BIGNULL flag is set then cases where either reg1 or
** reg2 are NULL are handled separately in the following block. The code
** generated is equivalent to:
**
** if( reg1 IS NULL ){
** if( op==OP_Gt ) goto lbl;
** if( op==OP_Ge && reg2 IS NOT NULL ) goto lbl;
** if( op==OP_Le && reg2 IS NULL ) goto lbl;
** }else if( reg2 IS NULL ){
** if( op==OP_Le ) goto lbl;
** }
**
** Additionally, if either reg1 or reg2 are NULL but the jump to lbl is
** not taken, control jumps over the comparison operator coded below this
** block. */
if( pOrderBy->a[0].sortFlags & KEYINFO_ORDER_BIGNULL ){
int addr;
addr = sqlite3VdbeAddOp1(v, OP_NotNull, reg1); VdbeCoverage(v);
/* This block runs if reg1 contains a NULL. */
int addr = sqlite3VdbeAddOp1(v, OP_NotNull, reg1); VdbeCoverage(v);
switch( op ){
case OP_Ge: sqlite3VdbeAddOp2(v, OP_Goto, 0, lbl); break;
case OP_Ge:
sqlite3VdbeAddOp2(v, OP_Goto, 0, lbl);
break;
case OP_Gt:
sqlite3VdbeAddOp2(v, OP_NotNull, reg2, lbl); VdbeCoverage(v);
break;
default:
assert( op==OP_Le );
default: assert( op==OP_Le );
sqlite3VdbeAddOp2(v, OP_IsNull, reg2, lbl); VdbeCoverage(v);
break;
}
sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+2);
sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+3);
/* This block runs if reg1 is not NULL, but reg2 is. */
sqlite3VdbeJumpHere(v, addr);
sqlite3VdbeAddOp2(v, OP_IsNull, reg2, lbl); VdbeCoverage(v);
if( op==OP_Gt || op==OP_Ge ){
sqlite3VdbeChangeP2(v, -1, sqlite3VdbeCurrentAddr(v)+1);
}
}
/* Compare registers reg2 and reg1, taking the jump if required. Note that
** control skips over this test if the BIGNULL flag is set and either
** reg1 or reg2 contain a NULL value. */
sqlite3VdbeAddOp3(v, op, reg2, lbl, reg1); VdbeCoverage(v);
sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
assert( op==OP_Ge || op==OP_Gt || op==OP_Lt || op==OP_Le );
testcase(op==OP_Ge); VdbeCoverageIf(v, op==OP_Ge);
testcase(op==OP_Lt); VdbeCoverageIf(v, op==OP_Lt);
testcase(op==OP_Le); VdbeCoverageIf(v, op==OP_Le);
testcase(op==OP_Gt); VdbeCoverageIf(v, op==OP_Gt);
sqlite3ReleaseTempReg(pParse, reg1);
sqlite3ReleaseTempReg(pParse, reg2);
VdbeModuleComment((v, "CodeRangeTest: end"));
}
/*