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Improved technique for parsing the ON and USING clauses of a join is faster

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and uses less memory.

FossilOrigin-Name: 158156a3e3d50042cafc75dea3aaaa68b1f2efb9c3d178518ea6e68e32e0d21c
This commit is contained in:
drh
2022-04-07 01:11:13 +00:00
parent 200adc9e75
commit d44f8b2385
16 changed files with 150 additions and 113 deletions
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31
src/build.c
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@@ -4710,7 +4710,7 @@ void sqlite3IdListDelete(sqlite3 *db, IdList *pList){
*/
int sqlite3IdListIndex(IdList *pList, const char *zName){
int i;
if( pList==0 ) return -1;
assert( pList!=0 );
for(i=0; i<pList->nId; i++){
if( sqlite3StrICmp(pList->a[i].zName, zName)==0 ) return i;
}
@@ -4913,8 +4913,11 @@ void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
if( pItem->fg.isTabFunc ) sqlite3ExprListDelete(db, pItem->u1.pFuncArg);
sqlite3DeleteTable(db, pItem->pTab);
if( pItem->pSelect ) sqlite3SelectDelete(db, pItem->pSelect);
if( pItem->pOn ) sqlite3ExprDelete(db, pItem->pOn);
if( pItem->pUsing ) sqlite3IdListDelete(db, pItem->pUsing);
if( pItem->fg.isUsing ){
sqlite3IdListDelete(db, pItem->u3.pUsing);
}else if( pItem->u3.pOn ){
sqlite3ExprDelete(db, pItem->u3.pOn);
}
}
sqlite3DbFreeNN(db, pList);
}
@@ -4942,14 +4945,13 @@ SrcList *sqlite3SrcListAppendFromTerm(
Token *pDatabase, /* Name of the database containing pTable */
Token *pAlias, /* The right-hand side of the AS subexpression */
Select *pSubquery, /* A subquery used in place of a table name */
Expr *pOn, /* The ON clause of a join */
IdList *pUsing /* The USING clause of a join */
OnOrUsing *pOnUsing /* Either the ON clause or the USING clause */
){
SrcItem *pItem;
sqlite3 *db = pParse->db;
if( !p && (pOn || pUsing) ){
if( !p && pOnUsing!=0 && (pOnUsing->pOn || pOnUsing->pUsing) ){
sqlite3ErrorMsg(pParse, "a JOIN clause is required before %s",
(pOn ? "ON" : "USING")
(pOnUsing->pOn ? "ON" : "USING")
);
goto append_from_error;
}
@@ -4970,14 +4972,21 @@ SrcList *sqlite3SrcListAppendFromTerm(
pItem->zAlias = sqlite3NameFromToken(db, pAlias);
}
pItem->pSelect = pSubquery;
pItem->pOn = pOn;
pItem->pUsing = pUsing;
assert( pOnUsing==0 || pOnUsing->pOn==0 || pOnUsing->pUsing==0 );
assert( pItem->fg.isUsing==0 );
if( pOnUsing==0 ){
pItem->u3.pOn = 0;
}else if( pOnUsing->pUsing ){
pItem->fg.isUsing = 1;
pItem->u3.pUsing = pOnUsing->pUsing;
}else{
pItem->u3.pOn = pOnUsing->pOn;
}
return p;
append_from_error:
assert( p==0 );
sqlite3ExprDelete(db, pOn);
sqlite3IdListDelete(db, pUsing);
sqlite3ClearOnOrUsing(db, pOnUsing);
sqlite3SelectDelete(db, pSubquery);
return 0;
}