Default minIdle the same as maxPoolSize.

src/main/java/com/zaxxer/hikari/HikariConfig.java

@@ -92,7 +92,7 @@ public class HikariConfig implements HikariConfigMBean
         idleTimeout = IDLE_TIMEOUT;
         isAutoCommit = true;
         isJdbc4connectionTest = true;
-        minIdle = 0;
+        minIdle = -1;
         maxPoolSize = 32;
         maxLifetime = MAX_LIFETIME;
         poolName = "HikariPool-" + poolNumber++;
@@ -667,6 +667,11 @@ public class HikariConfig implements HikariConfigMBean
             connectionTimeout = CONNECTION_TIMEOUT;
         }
 
+        if (minIdle < 0)
+        {
+            minIdle = maxPoolSize;
+        }
+
         if (idleTimeout < 0)
         {
             logger.error("idleTimeout cannot be negative.");