enhancement: when fetch == 0, pushdown limit 0 instead skip+fetch.

apache · Nov 23, 2022 · 5ee8559 · 5ee8559
1 parent d355f69
commit 5ee8559
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/datafusion/optimizer/src/limit_push_down.rs b/datafusion/optimizer/src/limit_push_down.rs
@@ -122,7 +122,7 @@ impl OptimizerRule for LimitPushDown {
 
         let plan = match &*limit.input {
             LogicalPlan::TableScan(scan) => {
-                let limit = fetch + skip;
+                let limit = if fetch != 0 { fetch + skip } else { 0 };
                 let new_input = LogicalPlan::TableScan(TableScan {
                     table_name: scan.table_name.clone(),
                     source: scan.source.clone(),
@@ -756,7 +756,7 @@ mod test {
             .build()?;
 
         let expected = "Limit: skip=1000, fetch=0\
-        \n  TableScan: test, fetch=1000";
+        \n  TableScan: test, fetch=0";
 
         assert_optimized_plan_eq(&plan, expected)
     }
@@ -771,7 +771,7 @@ mod test {
             .build()?;
 
         let expected = "Limit: skip=1000, fetch=0\
-        \n  TableScan: test, fetch=1000";
+        \n  TableScan: test, fetch=0";
 
         assert_optimized_plan_eq(&plan, expected)
     }