fix

Author: achaikou

.github/workflows/benchmarks.yaml

@@ -84,10 +84,11 @@ jobs:
 
       - name: Set base datasource for comparison
         run: |
-          if [ "${{ github.event.inputs.compare_to_self }}" = "true" ]; then
-            echo "BASE_DATASOURCE=${{ matrix.datasource }}" >> $GITHUB_ENV
-          else
+          if [ "${{ github.event.inputs.compare_to_self }}" = "false" ]; then
             echo "BASE_DATASOURCE=default" >> $GITHUB_ENV
+          else
+            # also the case when compare_to_self="" because run is trigger by PR.
+            echo "BASE_DATASOURCE=${{ matrix.datasource }}" >> $GITHUB_ENV
           fi
 
       - name: Benchmark old commit