diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7964f6541f..5942199d43 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -366,11 +366,11 @@ jobs:
     timeout-minutes: 60
     strategy:
       matrix:
-        instance: [0, 1, 2, 3]
+        instance: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
     env:
       MIGRATIONS_TEST_MIGRATE: 1
       # XXX: `MATRIX_INSTANCE_TOTAL` must be hardcoded to the length of `strategy.matrix.instance`.
-      MATRIX_INSTANCE_TOTAL: 4
+      MATRIX_INSTANCE_TOTAL: 16
       TEST_GROUP_STRATEGY: ROUND_ROBIN
 
     steps: