Use the SQLITE_CONSTRAINT return value from xBestIndex to prohibit bad

query plans in the pragma virtual table.

FossilOrigin-Name: b1259d4448f744861e416f42328c1450854370e5c77102d2a5abe5cf6c7f12bd

1 files changed, 7 insertions, 10 deletions

diff --git a/src/pragma.c b/src/pragma.c
index d14428f75..8af18cbf2 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -2870,9 +2870,9 @@ static int pragmaVtabBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
   seen[0] = 0;
   seen[1] = 0;
   for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
-    if( pConstraint->usable==0 ) continue;
-    if( pConstraint->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
     if( pConstraint->iColumn < pTab->iHidden ) continue;
+    if( pConstraint->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
+    if( pConstraint->usable==0 ) return SQLITE_CONSTRAINT;
     j = pConstraint->iColumn - pTab->iHidden;
     assert( j < 2 );
     seen[j] = i+1;
@@ -2885,16 +2885,13 @@ static int pragmaVtabBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
   j = seen[0]-1;
   pIdxInfo->aConstraintUsage[j].argvIndex = 1;
   pIdxInfo->aConstraintUsage[j].omit = 1;
-  if( seen[1]==0 ){
-    pIdxInfo->estimatedCost = (double)1000;
-    pIdxInfo->estimatedRows = 1000;
-    return SQLITE_OK;
-  }
   pIdxInfo->estimatedCost = (double)20;
   pIdxInfo->estimatedRows = 20;
-  j = seen[1]-1;
-  pIdxInfo->aConstraintUsage[j].argvIndex = 2;
-  pIdxInfo->aConstraintUsage[j].omit = 1;
+  if( seen[1] ){
+    j = seen[1]-1;
+    pIdxInfo->aConstraintUsage[j].argvIndex = 2;
+    pIdxInfo->aConstraintUsage[j].omit = 1;
+  }
   return SQLITE_OK;
 }