fix: prevent reuse of broken connections in postgres pool (#7792)

this updates the error handler we have on the postgres connection
object to release back with an error in the case of an error so
the underlying `pg-pool` knows to remove the connection from the
rotation

src/driver/aurora-data-api-pg/AuroraDataApiPostgresQueryRunner.ts

@@ -41,11 +41,6 @@ export class AuroraDataApiPostgresQueryRunner extends PostgresQueryRunnerWrapper
      */
     protected databaseConnectionPromise: Promise<any>;
 
-    /**
-     * Special callback provided by a driver used to release a created connection.
-     */
-    protected releaseCallback: Function;
-
     // -------------------------------------------------------------------------
     // Constructor
     // -------------------------------------------------------------------------

src/driver/postgres/PostgresQueryRunner.ts

@@ -50,7 +50,7 @@ export class PostgresQueryRunner extends BaseQueryRunner implements QueryRunner
     /**
      * Special callback provided by a driver used to release a created connection.
      */
-    protected releaseCallback: Function;
+    protected releaseCallback?: (err: any) => void;
 
     // -------------------------------------------------------------------------
     // Constructor
@@ -84,7 +84,7 @@ export class PostgresQueryRunner extends BaseQueryRunner implements QueryRunner
                 this.driver.connectedQueryRunners.push(this);
                 this.databaseConnection = connection;
 
-                const onErrorCallback = () => this.release();
+                const onErrorCallback = (err: Error) => this.releasePostgresConnection(err);
                 this.releaseCallback = () => {
                     this.databaseConnection.removeListener("error", onErrorCallback);
                     release();
@@ -99,7 +99,7 @@ export class PostgresQueryRunner extends BaseQueryRunner implements QueryRunner
                 this.driver.connectedQueryRunners.push(this);
                 this.databaseConnection = connection;
 
-                const onErrorCallback = () => this.release();
+                const onErrorCallback = (err: Error) => this.releasePostgresConnection(err);
                 this.releaseCallback = () => {
                     this.databaseConnection.removeListener("error", onErrorCallback);
                     release();
@@ -114,22 +114,33 @@ export class PostgresQueryRunner extends BaseQueryRunner implements QueryRunner
     }
 
     /**
-     * Releases used database connection.
-     * You cannot use query runner methods once its released.
+     * Release a connection back to the pool, optionally specifying an Error to release with.
+     * Per pg-pool documentation this will prevent the pool from re-using the broken connection.
      */
-    release(): Promise<void> {
+    private async releasePostgresConnection(err?: Error) {
         if (this.isReleased) {
-            return Promise.resolve();
+            return
         }
 
         this.isReleased = true;
-        if (this.releaseCallback)
-            this.releaseCallback();
+        if (this.releaseCallback) {
+            this.releaseCallback(err);
+            this.releaseCallback = undefined
+        }
 
         const index = this.driver.connectedQueryRunners.indexOf(this);
-        if (index !== -1) this.driver.connectedQueryRunners.splice(index, 1);
 
-        return Promise.resolve();
+        if (index !== -1) {
+            this.driver.connectedQueryRunners.splice(index, 1);
+        }
+    }
+
+    /**
+     * Releases used database connection.
+     * You cannot use query runner methods once its released.
+     */
+    release(): Promise<void> {
+        return this.releasePostgresConnection();
     }
 
     /**