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Overview
| Comment: | Inline the relevent parts of sqlite3ExprAlloc() into spanExpr(), for a performance improvement. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
fe89225eab777c2c9cb1cbc31092b9e3 |
| User & Date: | drh 2016-09-26 12:38:22 |
Context
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2016-09-26
| ||
| 14:39 | When flattening a query of the form "SELECT * FROM (SELECT * FROM tbl WHERE x=?) WHERE y=?", ensure that the final WHERE clause is "x=? AND y=?" instead of "y=? AND x=?". Although it is still not guaranteed, this makes the order in which WHERE clause terms are processed comport more closely to users expectations. (check-in: cf7f9e6d user: dan tags: trunk) | |
| 12:38 | Inline the relevent parts of sqlite3ExprAlloc() into spanExpr(), for a performance improvement. (check-in: fe89225e user: drh tags: trunk) | |
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2016-09-24
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| 17:42 | Omit the LikeOp object from the parser. Change more sqlite3PExpr() calls into sqlite3ExprAlloc() calls. (check-in: 795454a3 user: drh tags: trunk) | |
Changes
Changes to src/parse.y.
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if( Y.n>0 ) sqlite3ExprListSetName(pParse, A, &Y, 1);
sqlite3ExprListSetSpan(pParse,A,&X);
}
selcollist(A) ::= sclp(A) STAR. {
Expr *p = sqlite3Expr(pParse->db, TK_ASTERISK, 0);
A = sqlite3ExprListAppend(pParse, A, p);
}
selcollist(A) ::= sclp(A) nm(X) DOT STAR(Y). {
Expr *pRight = sqlite3PExpr(pParse, TK_ASTERISK, 0, 0, &Y);
Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, &X);
Expr *pDot = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
A = sqlite3ExprListAppend(pParse,A, pDot);
}
// An option "AS <id>" phrase that can follow one of the expressions that
// define the result set, or one of the tables in the FROM clause.
................................................................................
}
/* Construct a new Expr object from a single identifier. Use the
** new Expr to populate pOut. Set the span of pOut to be the identifier
** that created the expression.
*/
static void spanExpr(ExprSpan *pOut, Parse *pParse, int op, Token t){
pOut->pExpr = sqlite3ExprAlloc(pParse->db, op, &t, 1);
pOut->zStart = t.z;
pOut->zEnd = &t.z[t.n];
if( pOut->pExpr ) pOut->pExpr->flags |= EP_Leaf;
}
}
expr(A) ::= term(A).
expr(A) ::= LP(B) expr(X) RP(E).
{spanSet(&A,&B,&E); /*A-overwrites-B*/ A.pExpr = X.pExpr;}
term(A) ::= NULL(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/}
................................................................................
Expr *temp1 = sqlite3ExprAlloc(pParse->db, TK_ID, &X, 1);
Expr *temp2 = sqlite3ExprAlloc(pParse->db, TK_ID, &Y, 1);
Expr *temp3 = sqlite3ExprAlloc(pParse->db, TK_ID, &Z, 1);
Expr *temp4 = sqlite3PExpr(pParse, TK_DOT, temp2, temp3, 0);
spanSet(&A,&X,&Z); /*A-overwrites-X*/
A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp4, 0);
}
term(A) ::= INTEGER|FLOAT|BLOB(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/}
term(A) ::= STRING(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/}
expr(A) ::= VARIABLE(X). {
if( !(X.z[0]=='#' && sqlite3Isdigit(X.z[1])) ){
spanExpr(&A, pParse, TK_VARIABLE, X);
sqlite3ExprAssignVarNumber(pParse, A.pExpr);
}else{
/* When doing a nested parse, one can include terms in an expression
** that look like this: #1 #2 ... These terms refer to registers
................................................................................
Token t = X; /*A-overwrites-X*/
assert( t.n>=2 );
spanSet(&A, &t, &t);
if( pParse->nested==0 ){
sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", &t);
A.pExpr = 0;
}else{
A.pExpr = sqlite3PExpr(pParse, TK_REGISTER, 0, 0, &t);
if( A.pExpr ) sqlite3GetInt32(&t.z[1], &A.pExpr->iTable);
}
}
}
expr(A) ::= expr(A) COLLATE ids(C). {
A.pExpr = sqlite3ExprAddCollateToken(pParse, A.pExpr, &C, 1);
A.zEnd = &C.z[C.n];
|
| | > > > > > > > > > > > > > > > > > | < | | > > > > > > | |
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if( Y.n>0 ) sqlite3ExprListSetName(pParse, A, &Y, 1);
sqlite3ExprListSetSpan(pParse,A,&X);
}
selcollist(A) ::= sclp(A) STAR. {
Expr *p = sqlite3Expr(pParse->db, TK_ASTERISK, 0);
A = sqlite3ExprListAppend(pParse, A, p);
}
selcollist(A) ::= sclp(A) nm(X) DOT STAR. {
Expr *pRight = sqlite3PExpr(pParse, TK_ASTERISK, 0, 0, 0);
Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, &X);
Expr *pDot = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
A = sqlite3ExprListAppend(pParse,A, pDot);
}
// An option "AS <id>" phrase that can follow one of the expressions that
// define the result set, or one of the tables in the FROM clause.
................................................................................
}
/* Construct a new Expr object from a single identifier. Use the
** new Expr to populate pOut. Set the span of pOut to be the identifier
** that created the expression.
*/
static void spanExpr(ExprSpan *pOut, Parse *pParse, int op, Token t){
Expr *p = sqlite3DbMallocRawNN(pParse->db, sizeof(Expr)+t.n+1);
if( p ){
memset(p, 0, sizeof(Expr));
p->op = (u8)op;
p->flags = EP_Leaf;
p->iAgg = -1;
p->u.zToken = (char*)&p[1];
memcpy(p->u.zToken, t.z, t.n);
p->u.zToken[t.n] = 0;
if( sqlite3Isquote(p->u.zToken[0]) ){
if( p->u.zToken[0]=='"' ) p->flags |= EP_DblQuoted;
sqlite3Dequote(p->u.zToken);
}
#if SQLITE_MAX_EXPR_DEPTH>0
p->nHeight = 1;
#endif
}
pOut->pExpr = p;
pOut->zStart = t.z;
pOut->zEnd = &t.z[t.n];
}
}
expr(A) ::= term(A).
expr(A) ::= LP(B) expr(X) RP(E).
{spanSet(&A,&B,&E); /*A-overwrites-B*/ A.pExpr = X.pExpr;}
term(A) ::= NULL(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/}
................................................................................
Expr *temp1 = sqlite3ExprAlloc(pParse->db, TK_ID, &X, 1);
Expr *temp2 = sqlite3ExprAlloc(pParse->db, TK_ID, &Y, 1);
Expr *temp3 = sqlite3ExprAlloc(pParse->db, TK_ID, &Z, 1);
Expr *temp4 = sqlite3PExpr(pParse, TK_DOT, temp2, temp3, 0);
spanSet(&A,&X,&Z); /*A-overwrites-X*/
A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp4, 0);
}
term(A) ::= FLOAT|BLOB(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/}
term(A) ::= STRING(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/}
term(A) ::= INTEGER(X). {
A.pExpr = sqlite3ExprAlloc(pParse->db, TK_INTEGER, &X, 1);
A.zStart = X.z;
A.zEnd = X.z + X.n;
if( A.pExpr ) A.pExpr->flags |= EP_Leaf;
}
expr(A) ::= VARIABLE(X). {
if( !(X.z[0]=='#' && sqlite3Isdigit(X.z[1])) ){
spanExpr(&A, pParse, TK_VARIABLE, X);
sqlite3ExprAssignVarNumber(pParse, A.pExpr);
}else{
/* When doing a nested parse, one can include terms in an expression
** that look like this: #1 #2 ... These terms refer to registers
................................................................................
Token t = X; /*A-overwrites-X*/
assert( t.n>=2 );
spanSet(&A, &t, &t);
if( pParse->nested==0 ){
sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", &t);
A.pExpr = 0;
}else{
A.pExpr = sqlite3PExpr(pParse, TK_REGISTER, 0, 0, 0);
if( A.pExpr ) sqlite3GetInt32(&t.z[1], &A.pExpr->iTable);
}
}
}
expr(A) ::= expr(A) COLLATE ids(C). {
A.pExpr = sqlite3ExprAddCollateToken(pParse, A.pExpr, &C, 1);
A.zEnd = &C.z[C.n];
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