Optimize the IS NULL and IS NOT NULL operators so that they avoid loading

large strings or blobs off of disk if all it needs to know is whether or
not the string or blob is NULL.

FossilOrigin-Name: cb94350185f555c333b628ee846c47bcc9df5f76bb82de569b8322f30dbbe1bc

1 files changed, 2 insertions, 0 deletions

diff --git a/src/expr.c b/src/expr.c
index baa0fe647..bceb5efb0 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -5241,6 +5241,7 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
       assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
       assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );
       r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      sqlite3VdbeTypeofColumn(v, r1);
       sqlite3VdbeAddOp2(v, op, r1, dest);
       VdbeCoverageIf(v, op==TK_ISNULL);
       VdbeCoverageIf(v, op==TK_NOTNULL);
@@ -5415,6 +5416,7 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
     case TK_ISNULL:
     case TK_NOTNULL: {
       r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      sqlite3VdbeTypeofColumn(v, r1);
       sqlite3VdbeAddOp2(v, op, r1, dest);
       testcase( op==TK_ISNULL );   VdbeCoverageIf(v, op==TK_ISNULL);
       testcase( op==TK_NOTNULL );  VdbeCoverageIf(v, op==TK_NOTNULL);