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Simplifications to the VDBE bytecode that handles LIMIT and OFFSET.

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FossilOrigin-Name: 041df7c2f14b95868a08090354ebb3308050790e
This commit is contained in:
drh 2015-10-06 21:07:06 +00:00
parent a2507137f3
commit 8b0cf38a12
5 changed files with 47 additions and 52 deletions
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18
manifest
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@ -1,5 +1,5 @@
C Optimizations\sfor\sfts5\sexpressions\sthat\sfilter\son\scolumn.\sMore\sstill\sto\scome.
D 2015-10-06T20:53:26.753
C Simplifications\sto\sthe\sVDBE\sbytecode\sthat\shandles\sLIMIT\sand\sOFFSET.
D 2015-10-06T21:07:06.319
F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
F Makefile.in 2143eeef6d0cc26006ae5fc4bb242a4a8b973412
F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@ -335,14 +335,14 @@ F src/parse.y f599aa5e871a493330d567ced93de696f61f48f7
F src/pcache.c 24be750c79272e0ca7b6e007bc94999700f3e5ef
F src/pcache.h 9968603796240cdf83da7e7bef76edf90619cea9
F src/pcache1.c e822007159d53a7ea7aa040d6e28964ddb6de083
F src/pragma.c 234814978bcd35bce6e2874dfb2f5b5e28e7fb38
F src/pragma.c dcfe3a35d2de935feeaba1455528b4a5c4f1208c
F src/pragma.h 631a91c8b0e6ca8f051a1d8a4a0da4150e04620a
F src/prepare.c 82e5db1013846a819f198336fed72c44c974e7b1
F src/printf.c 0c4bcdd1c2e2521024f0a69cb5eb334f86b3652a
F src/random.c ba2679f80ec82c4190062d756f22d0c358180696
F src/resolve.c 1954a0f01bf65d78d7d559aea3d5c67f33376d91
F src/rowset.c eccf6af6d620aaa4579bd3b72c1b6395d9e9fa1e
F src/select.c 8fb8cb0230aed9b12b3582ddc366ffbc549041d7
F src/select.c 2c4bfdf7c797df9b43121ed7850bf939b6f27405
F src/shell.c dfd18e56fcb88dd79378774e9bc3246a9bd52243
F src/sqlite.h.in 4b76d74d69af48c534c58fb723137dc6944bdedc
F src/sqlite3.rc 992c9f5fb8285ae285d6be28240a7e8d3a7f2bad
@ -405,7 +405,7 @@ F src/update.c a134027f59c7eb6e63ed18e2d5dd8ef0ce7f8ff8
F src/utf.c fc6b889ba0779b7722634cdeaa25f1930d93820c
F src/util.c fc612367108b74573c5fd13a85d0a23027f438bd
F src/vacuum.c 2ddd5cad2a7b9cef7f9e431b8c7771634c6b1701
F src/vdbe.c 5048103aa6bc9c01bf1a4620729256d1e873bb6c
F src/vdbe.c d263ec6b29d8e8e8178235b8403a00ccb48748d0
F src/vdbe.h 4bc88bd0e06f8046ee6ab7487c0015e85ad949ad
F src/vdbeInt.h 8b867eac234e28627ffcace3cd4b4b79bbec664b
F src/vdbeapi.c 020681b943e77766b32ae1cddf86d7831b7374ca
@ -1392,7 +1392,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
P 4b631364354068af95a01630469cb6fbfe8b52fd
R 8d25a208807a117d422df371476abd9e
U dan
Z f7ba9c7b6fd75653c93e200489a4e473
P bf1607ac155018573ca40fb58aca62c5fea7e60b
R f75f4370adf88bb173a9ed2d414ba858
U drh
Z 3f5b7bfbaf5afcf9be7e111589aea155

2
manifest.uuid
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@ -1 +1 @@
bf1607ac155018573ca40fb58aca62c5fea7e60b
041df7c2f14b95868a08090354ebb3308050790e

11
src/pragma.c
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@ -1361,8 +1361,9 @@ void sqlite3Pragma(
*/
static const int iLn = VDBE_OFFSET_LINENO(2);
static const VdbeOpList endCode[] = {
{ OP_IfNeg, 1, 0, 0}, /* 0 */
{ OP_String8, 0, 3, 0}, /* 1 */
{ OP_AddImm, 1, 0, 0}, /* 0 */
{ OP_If, 1, 0, 0}, /* 1 */
{ OP_String8, 0, 3, 0}, /* 2 */
{ OP_ResultRow, 3, 1, 0},
};
@ -1563,9 +1564,9 @@ void sqlite3Pragma(
}
}
addr = sqlite3VdbeAddOpList(v, ArraySize(endCode), endCode, iLn);
sqlite3VdbeChangeP3(v, addr, -mxErr);
sqlite3VdbeJumpHere(v, addr);
sqlite3VdbeChangeP4(v, addr+1, "ok", P4_STATIC);
sqlite3VdbeChangeP2(v, addr, -mxErr);
sqlite3VdbeJumpHere(v, addr+1);
sqlite3VdbeChangeP4(v, addr+2, "ok", P4_STATIC);
}
break;
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */

28
src/select.c
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@ -579,7 +579,7 @@ static void pushOntoSorter(
}else{
iLimit = pSelect->iLimit;
}
addr = sqlite3VdbeAddOp3(v, OP_IfNotZero, iLimit, 0, -1); VdbeCoverage(v);
addr = sqlite3VdbeAddOp3(v, OP_IfNotZero, iLimit, 0, 1); VdbeCoverage(v);
sqlite3VdbeAddOp1(v, OP_Last, pSort->iECursor);
sqlite3VdbeAddOp1(v, OP_Delete, pSort->iECursor);
sqlite3VdbeJumpHere(v, addr);
@ -595,11 +595,8 @@ static void codeOffset(
int iContinue /* Jump here to skip the current record */
){
if( iOffset>0 ){
int addr;
addr = sqlite3VdbeAddOp3(v, OP_IfNeg, iOffset, 0, -1); VdbeCoverage(v);
sqlite3VdbeGoto(v, iContinue);
VdbeComment((v, "skip OFFSET records"));
sqlite3VdbeJumpHere(v, addr);
sqlite3VdbeAddOp3(v, OP_IfPos, iOffset, iContinue, 1); VdbeCoverage(v);
VdbeComment((v, "OFFSET"));
}
}
@ -1815,7 +1812,7 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
Vdbe *v = 0;
int iLimit = 0;
int iOffset;
int addr1, n;
int n;
if( p->iLimit ) return;
/*
@ -1850,14 +1847,10 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
sqlite3ExprCode(pParse, p->pOffset, iOffset);
sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset); VdbeCoverage(v);
VdbeComment((v, "OFFSET counter"));
addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iOffset); VdbeCoverage(v);
sqlite3VdbeAddOp2(v, OP_Integer, 0, iOffset);
sqlite3VdbeJumpHere(v, addr1);
sqlite3VdbeAddOp3(v, OP_SetIfNotPos, iOffset, iOffset, 0);
sqlite3VdbeAddOp3(v, OP_Add, iLimit, iOffset, iOffset+1);
VdbeComment((v, "LIMIT+OFFSET"));
addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit); VdbeCoverage(v);
sqlite3VdbeAddOp2(v, OP_Integer, -1, iOffset+1);
sqlite3VdbeJumpHere(v, addr1);
sqlite3VdbeAddOp3(v, OP_SetIfNotPos, iLimit, iOffset+1, -1);
}
}
}
@ -2274,14 +2267,9 @@ static int multiSelect(
addr = sqlite3VdbeAddOp1(v, OP_IfNot, p->iLimit); VdbeCoverage(v);
VdbeComment((v, "Jump ahead if LIMIT reached"));
if( p->iOffset ){
int addr2;
sqlite3VdbeAddOp3(v, OP_SetIfNotPos, p->iOffset, p->iOffset, 0);
sqlite3VdbeAddOp3(v, OP_Add, p->iLimit, p->iOffset, p->iOffset+1);
addr2 = sqlite3VdbeAddOp1(v, OP_IfPos, p->iOffset); VdbeCoverage(v);
sqlite3VdbeAddOp2(v, OP_SCopy, p->iLimit, p->iOffset+1);
sqlite3VdbeJumpHere(v, addr2);
addr2 = sqlite3VdbeAddOp1(v, OP_IfPos, p->iLimit); VdbeCoverage(v);
sqlite3VdbeAddOp2(v, OP_Integer, -1, p->iOffset+1);
sqlite3VdbeJumpHere(v, addr2);
sqlite3VdbeAddOp3(v, OP_SetIfNotPos, p->iLimit, p->iOffset+1, -1);
}
}
explainSetInteger(iSub2, pParse->iNextSelectId);

40
src/vdbe.c
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@ -5671,12 +5671,12 @@ case OP_MemMax: { /* in2 */
}
#endif /* SQLITE_OMIT_AUTOINCREMENT */
/* Opcode: IfPos P1 P2 * * *
** Synopsis: if r[P1]>0 goto P2
/* Opcode: IfPos P1 P2 P3 * *
** Synopsis: if r[P1]>0 then r[P1]-=P3, goto P2
**
** Register P1 must contain an integer.
** If the value of register P1 is 1 or greater, jump to P2 and
** add the literal value P3 to register P1.
** If the value of register P1 is 1 or greater, subtrace P3 from the
** value in P1 and jump to P2.
**
** If the initial value of register P1 is less than 1, then the
** value is unchanged and control passes through to the next instruction.
@ -5685,38 +5685,44 @@ case OP_IfPos: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
VdbeBranchTaken( pIn1->u.i>0, 2);
if( pIn1->u.i>0 ) goto jump_to_p2;
if( pIn1->u.i>0 ){
pIn1->u.i -= pOp->p3;
goto jump_to_p2;
}
break;
}
/* Opcode: IfNeg P1 P2 P3 * *
** Synopsis: r[P1]+=P3, if r[P1]<0 goto P2
/* Opcode: SetIfNotPos P1 P2 P3 * *
** Synopsis: if r[P1]<=0 then r[P2]=P3
**
** Register P1 must contain an integer. Add literal P3 to the value in
** register P1 then if the value of register P1 is less than zero, jump to P2.
** Register P1 must contain an integer.
** If the value of register P1 is not positive (if it is less than 1) then
** set the value of register P2 to be the integer P3.
*/
case OP_IfNeg: { /* jump, in1 */
case OP_SetIfNotPos: { /* in1, in2 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
pIn1->u.i += pOp->p3;
VdbeBranchTaken(pIn1->u.i<0, 2);
if( pIn1->u.i<0 ) goto jump_to_p2;
if( pIn1->u.i<=0 ){
pOut = out2Prerelease(p, pOp);
pOut->u.i = pOp->p3;
}
break;
}
/* Opcode: IfNotZero P1 P2 P3 * *
** Synopsis: if r[P1]!=0 then r[P1]+=P3, goto P2
** Synopsis: if r[P1]!=0 then r[P1]-=P3, goto P2
**
** Register P1 must contain an integer. If the content of register P1 is
** initially nonzero, then add P3 to P1 and jump to P2. If register P1 is
** initially zero, leave it unchanged and fall through.
** initially nonzero, then subtrace P3 from the value in register P1 and
** jump to P2. If register P1 is initially zero, leave it unchanged
** and fall through.
*/
case OP_IfNotZero: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
VdbeBranchTaken(pIn1->u.i<0, 2);
if( pIn1->u.i ){
pIn1->u.i += pOp->p3;
pIn1->u.i -= pOp->p3;
goto jump_to_p2;
}
break;