diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php
index 641dd7d..f472e82 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php
@@ -241,6 +241,40 @@ function initializeDatabase() {
         LANGUAGE \'sql\'
       ');
 
+      // Handle concats with three arguments as well.
+      db_query('CREATE OR REPLACE FUNCTION "concat"(anynonarray, anynonarray, anynonarray) RETURNS TEXT AS
+        \'SELECT CAST($1 AS text) || CAST($2 AS text) || CAST($3 AS text);\'
+        LANGUAGE \'SQL\'
+      ');
+      db_query('CREATE OR REPLACE FUNCTION "concat"(anynonarray, anynonarray, text) RETURNS TEXT AS
+        \'SELECT CAST($1 AS text) || CAST($2 AS text) || $3;\'
+        LANGUAGE \'SQL\'
+      ');
+      db_query('CREATE OR REPLACE FUNCTION "concat"(anynonarray, text, anynonarray) RETURNS TEXT AS
+        \'SELECT CAST($1 AS text) || $2 || CAST($3 AS text);\'
+        LANGUAGE \'SQL\'
+      ');
+      db_query('CREATE OR REPLACE FUNCTION "concat"(anynonarray, text, text) RETURNS TEXT AS
+        \'SELECT CAST($1 AS text) || $2 || $3;\'
+        LANGUAGE \'SQL\'
+      ');
+      db_query('CREATE OR REPLACE FUNCTION "concat"(text, anynonarray, anynonarray) RETURNS TEXT AS
+        \'SELECT $1 || CAST($2 AS text) || CAST($3 AS text);\'
+        LANGUAGE \'SQL\'
+      ');
+      db_query('CREATE OR REPLACE FUNCTION "concat"(text, anynonarray, text) RETURNS TEXT AS
+        \'SELECT $1 || CAST($2 AS text) || $3;\'
+        LANGUAGE \'SQL\'
+      ');
+      db_query('CREATE OR REPLACE FUNCTION "concat"(text, text, anynonarray) RETURNS TEXT AS
+        \'SELECT $1 || $2 || CAST($3 AS text);\'
+        LANGUAGE \'SQL\'
+      ');
+      db_query('CREATE OR REPLACE FUNCTION "concat"(text, text, text) RETURNS TEXT AS
+        \'SELECT $1 || $2 || $3;\'
+        LANGUAGE \'SQL\'
+      ');
+
       $this->pass(t('PostgreSQL has initialized itself.'));
     }
     catch (\Exception $e) {