Simplifications to the row-value IN operator logic. Do not let the query

planner accept a WhereLoop for a row-value IN operator that uses the same
index column more than once.

FossilOrigin-Name: d2adf61f21a3ce901a2b08199ad0de191e88ef16e097c5f7a75c95ad958eff12

2 files changed, 23 insertions, 18 deletions

diff --git a/src/where.c b/src/where.c
index 6a195dd2d..5d80dd3d6 100644
--- a/src/where.c
+++ b/src/where.c
@@ -3239,6 +3239,7 @@ static int whereLoopAddBtreeIndex(
       if( ExprUseXSelect(pExpr) ){
         /* "x IN (SELECT ...)":  TUNING: the SELECT returns 25 rows */
         int i;
+        int bRedundant = 0;
         nIn = 46;  assert( 46==sqlite3LogEst(25) );
 
         /* The expression may actually be of the form (x, y) IN (SELECT...).
@@ -3247,7 +3248,20 @@ static int whereLoopAddBtreeIndex(
         ** for each such term. The following loop checks that pTerm is the
         ** first such term in use, and sets nIn back to 0 if it is not. */
         for(i=0; i<pNew->nLTerm-1; i++){
-          if( pNew->aLTerm[i] && pNew->aLTerm[i]->pExpr==pExpr ) nIn = 0;
+          if( pNew->aLTerm[i] && pNew->aLTerm[i]->pExpr==pExpr ){
+            nIn = 0;
+            if( pNew->aLTerm[i]->u.x.iField == pTerm->u.x.iField ){
+              /* Detect when two or more columns of an index match the same 
+              ** column of a vector IN operater, and avoid adding the column
+              ** to the WhereLoop more than once.  See tag-20250707-01
+              ** in test/rowvalue.test */
+              bRedundant = 1;
+            }
+          }
+        }
+        if( bRedundant ){
+          pNew->nLTerm--;
+          continue;
         }
       }else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
         /* "x IN (value, value, ...)" */
diff --git a/src/wherecode.c b/src/wherecode.c
index cc672aa83..eb508d938 100644
--- a/src/wherecode.c
+++ b/src/wherecode.c
@@ -695,7 +695,7 @@ static SQLITE_NOINLINE void codeINTerm(
       return;
     }
   }
-  for(i=iEq;i<pLoop->nLTerm; i++){
+  for(i=iEq; i<pLoop->nLTerm; i++){
     assert( pLoop->aLTerm[i]!=0 );
     if( pLoop->aLTerm[i]->pExpr==pX ) nEq++;
   }
@@ -704,22 +704,13 @@ static SQLITE_NOINLINE void codeINTerm(
   if( !ExprUseXSelect(pX) || pX->x.pSelect->pEList->nExpr==1 ){
     eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, 0, &iTab);
   }else{
-    Expr *pExpr = pTerm->pExpr;
-    if( pExpr->iTable==0 || !ExprHasProperty(pExpr, EP_Subrtn) ){
-      sqlite3 *db = pParse->db;
-      pX = removeUnindexableInClauseTerms(pParse, iEq, pLoop, pX);
-      if( !db->mallocFailed ){
-        aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*nEq);
-        eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap,&iTab);
-        pExpr->iTable = iTab;
-      }
-      sqlite3ExprDelete(db, pX);
-    }else{
-      int n = sqlite3ExprVectorSize(pX->pLeft);
-      aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*MAX(nEq,n));
-      eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap, &iTab);
+    sqlite3 *db = pParse->db;
+    Expr *pXMod = removeUnindexableInClauseTerms(pParse, iEq, pLoop, pX);
+    if( !db->mallocFailed ){
+      aiMap = (int*)sqlite3DbMallocZero(db, sizeof(int)*nEq);
+      eType = sqlite3FindInIndex(pParse, pXMod, IN_INDEX_LOOP, 0, aiMap, &iTab);
     }
-    pX = pExpr;
+    sqlite3ExprDelete(db, pXMod);
   }
 
   if( eType==IN_INDEX_INDEX_DESC ){
@@ -749,7 +740,7 @@ static SQLITE_NOINLINE void codeINTerm(
   if( pIn ){
     int iMap = 0;               /* Index in aiMap[] */
     pIn += i;
-    for(i=iEq;i<pLoop->nLTerm; i++){
+    for(i=iEq; i<pLoop->nLTerm; i++){
       if( pLoop->aLTerm[i]->pExpr==pX ){
         int iOut = iTarget + i - iEq;
         if( eType==IN_INDEX_ROWID ){