use scale factor 0.5 in tpcds data generation

Author: jayshrivastava

.github/workflows/ci.yml

@@ -55,7 +55,8 @@ jobs:
           echo "$HOME/.local/bin" >> $GITHUB_PATH
       - name: Run TPC-DS randomized test
         id: test
-        run: cargo test --features tpcds --test tpc_ds_randomized
+        # 0.5 scale factor produces a data dir which is 124MB
+        run: SCALE_FACTOR 0.5 cargo test --features tpcds --test tpc_ds_randomized
         continue-on-error: true
       - name: Upload test artifacts on failure
         if: failure() || steps.test.outcome == 'failure'