Slightly more light weight health check (#100)

.circleci/pgcat.toml

@@ -14,7 +14,7 @@ port = 6432
 # How long to wait before aborting a server connection (ms).
 connect_timeout = 100
 
-# How much time to give `SELECT 1` health check query to return with a result (ms).
+# How much time to give the health check query to return with a result (ms).
 healthcheck_timeout = 100
 
 # For how long to ban a server if it fails a health check (seconds).

src/pool.rs

@@ -328,7 +328,7 @@ impl ConnectionPool {
 
             match tokio::time::timeout(
                 tokio::time::Duration::from_millis(healthcheck_timeout),
-                server.query("SELECT 1"),
+                server.query(";"),
             )
             .await
             {