diff --git a/ci/scripts/run-unit-test.sh b/ci/scripts/run-unit-test.sh
index c1b7a1b71782..0199308ee189 100755
--- a/ci/scripts/run-unit-test.sh
+++ b/ci/scripts/run-unit-test.sh
@@ -3,6 +3,24 @@
 # Exits as soon as any line fails.
 set -euo pipefail
 
+RUN_ALL=0
+
+while getopts 'a:' opt; do
+    case ${opt} in
+        a )
+            RUN_ALL=1
+            ;;
+        \? )
+            echo "Invalid Option: -$OPTARG" 1>&2
+            exit 1
+            ;;
+        : )
+            echo "Invalid option: $OPTARG requires an argument" 1>&2
+            ;;
+    esac
+done
+shift $((OPTIND -1))
+
 REPO_ROOT=${PWD}
 
 echo "+++ Run python UDF SDK unit tests"
@@ -10,9 +28,39 @@ cd ${REPO_ROOT}/src/udf/python
 python3 -m pytest
 cd ${REPO_ROOT}
 
-echo "+++ Run unit tests with coverage"
-# use tee to disable progress bar
-NEXTEST_PROFILE=ci cargo llvm-cov nextest --lcov --output-path lcov.info --features failpoints,sync_point --workspace --exclude risingwave_simulation
+# NOTE(kwannoel): The slow test section is updated manually, via feedback from CI's slow test output.
+SLOW_TEST_PATTERN="\
+test(executor::join::chunked_data::tests::test_try_from_zero_chunk_size_should_fail) or \
+test(executor::join::chunked_data::tests::test_zero_chunk_size_should_fail) or \
+test(error::tests::test_display_internal_error) or \
+test(util::panic::tests::test_sync_not_work) or \
+test(delete_range_runner::tests::test_small_data) or \
+test(parser::debezium::simd_json_parser::tests::test2_mysql::test2_debezium_json_parser_overflow_f64) or \
+test(backup_restore::restore::tests::test_sanity_check_monotonicity_requirement) or \
+test(backup_restore::restore::tests::test_sanity_check_superset_requirement) or \
+test(stream::stream_manager::tests::test_failpoints_drop_mv_recovery) or \
+test(dml_manager::tests::test_bad_schema) or \
+test(hummock::conflict_detector::test::test_write_below_epoch_watermark) or \
+test(hummock::conflict_detector::test::test_write_conflict_in_multi_batch) or \
+test(hummock::conflict_detector::test::test_write_conflict_in_one_batch) or \
+test(hummock::conflict_detector::test::test_write_to_archived_epoch) or \
+test(hummock::shared_buffer::shared_buffer_batch::tests::test_invalid_table_id) or \
+test(row_serde::value_serde::tests::test_row_hard3)"
+# NOTE(kwannoel): Limitation of https://nexte.st/book/filter-expressions.html.
+# not($SLOW_TEST_PATTERN) is not supported, so we have to use all() - ($SLOW_TEST_PATTERN).
+FAST_TEST_PATTERN="all() - (${SLOW_TEST_PATTERN})"
+
+echo "+++ Run fast unit tests"
+NEXTEST_PROFILE=ci cargo llvm-cov nextest --lcov --output-path lcov.info --features failpoints,sync_point --workspace --exclude risingwave_simulation \
+-E "$FAST_TEST_PATTERN"
+
+if [[ $RUN_ALL -eq "1" ]]; then
+  echo "+++ Run slow unit tests"
+  NEXTEST_PROFILE=ci cargo llvm-cov nextest --lcov --output-path lcov.info --features failpoints,sync_point --workspace --exclude risingwave_simulation \
+  -E "$SLOW_TEST_PATTERN"
+else
+  echo "--- Skip slow unit tests"
+fi
 
 echo "--- Codecov upload coverage reports"
 curl -Os https://uploader.codecov.io/latest/linux/codecov && chmod +x codecov
diff --git a/ci/workflows/main-cron.yml b/ci/workflows/main-cron.yml
index ca4da72794b1..1b46d45a1846 100644
--- a/ci/workflows/main-cron.yml
+++ b/ci/workflows/main-cron.yml
@@ -148,7 +148,7 @@ steps:
   # The timeout should be strictly more than timeout in `pull-request.yml`.
   # This ensures our `main-cron` workflow will be stable.
   - label: "unit test"
-    command: "ci/scripts/unit-test.sh"
+    command: "ci/scripts/unit-test.sh -a"
     plugins:
       - ./ci/plugins/swapfile
       - seek-oss/aws-sm#v2.3.1: