**Describe the bug** There is a bug in pool when connection cannot be established at pool start. This bug will bite when you wish close the connection **To Reproduce** Steps to reproduce the behavior: 1. Start your deno server 2. Start your pool 3. Try to connect 4. Exception happen (good) 5. **Start database** 6. Try to connect 7. Do insert (OK, commited) 8. **Release pool client**, then 8.5. **Exception happens.** 9. **_but query succeeds_** **Expected behavior** No exception **This bug is not observed when database connection is ready at start**