diff --git a/src/Command/SetCustomerGeneratedIdCommand.php b/src/Command/SetCustomerGeneratedIdCommand.php
index f031ca08..b2518a14 100644
--- a/src/Command/SetCustomerGeneratedIdCommand.php
+++ b/src/Command/SetCustomerGeneratedIdCommand.php
@@ -14,8 +14,6 @@ use Doctrine\DBAL\DBALException;
 
 use App\Entity\Customer;
 
-use App\Service\UniqueIdGenerator;
-
 use PDO;
 
 class SetCustomerGeneratedIdCommand extends Command
@@ -23,12 +21,13 @@ class SetCustomerGeneratedIdCommand extends Command
     const GENERATED_ID_LENGTH = 40;
 
     private $em;
-    private $id_gen;
+    protected $cust_generated_ids;
 
-    public function __construct(EntityManagerInterface $em, UniqueIdGenerator $id_gen)
+    public function __construct(EntityManagerInterface $em)
     {
         $this->em = $em;
-        $this->id_gen = $id_gen;
+
+        $this->loadGeneratedIds();
 
         parent::__construct();
     }
@@ -43,9 +42,7 @@ class SetCustomerGeneratedIdCommand extends Command
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $em  = $this->em;
-
-        $batch_size = 20;
-        $i = 1;
+        $db = $em->getConnection();
 
         $em->getConnection()->getConfiguration()->setSQLLogger(null);
 
@@ -58,47 +55,29 @@ class SetCustomerGeneratedIdCommand extends Command
             $cust = $row[0];
             $output->writeln('Processing customer ' . $cust->getID());
 
-            // retry until we get a unique generated id
             while (true)
             {
-                try
+                $generated_id = $this->generateUniqueId(self::GENERATED_ID_LENGTH);
+
+                if (!isset($this->cust_generated_ids[$generated_id]))
                 {
-                    $generated_id = $this->generateUniqueId(self::GENERATED_ID_LENGTH);
+                    $update_sql = 'UPDATE customer SET generated_id = :generated_id WHERE id = :cust_id';
+                    $update_stmt = $db->prepare($update_sql);
+                    $update_stmt->execute([
+                        'generated_id' => $generated_id,
+                        'cust_id' => $cust->getID(),
+                    ]);
 
-                    // set generated id
-                    $cust->setGeneratedId($generated_id);
+                    // add generated id to hash
+                    $this->cust_generated_ids[$generated_id] = $cust;
 
-                    // reopen in case we get an exception
-                    if (!$em->isOpen())
-                    {
-                        $em = $em->create(
-                            $em->getConnection(),
-                            $em->getConfiguration()
-                        );
-                    }
-
-                    //++$i;
-                    //if (($i % $batch_size) === 0)
-                    //{
-                    $em->flush();
-                    $em->clear();
-                    //}
+                    break;
                 }
-                catch (DBALException $e)
-                {
-                    error_log($e->getMessage());
-                    // delay one second and try again
-                    sleep(1);
-                    continue;
-                }
-
-                break;
             }
+
             $em->detach($row[0]);
         }
 
-        //$em->flush();
-
         return 0;
     }
 
@@ -107,4 +86,29 @@ class SetCustomerGeneratedIdCommand extends Command
         return substr(md5(time()), 0, $str_length);
     }
 
+    protected function loadGeneratedIds()
+    {
+        error_log('loading generated ids ');
+        $cust_q = $this->em->createQuery('select c from App\Entity\Customer c where c.generated_id is not null');
+        $cust_iter = $cust_q->iterate();
+
+        $this->cust_generated_ids = [];
+        foreach ($cust_iter as $row)
+        {
+            $customer = $row[0];
+            $generated_id = $customer->getGeneratedID();
+            error_log('generated id = ' . $generated_id);
+            if ($generated_id != null)
+            {
+                error_log('generated id is not null ' . $generated_id);
+                if (!isset($this->cust_generated_ids[$generated_id]))
+                {
+                    error_log('setting to hash ' . $generated_id);
+                    $this->cust_generated_ids[$generated_id] = $customer;
+                }
+            }
+
+            $this->em->detach($row[0]);
+        }
+    }
 }
diff --git a/src/Entity/Customer.php b/src/Entity/Customer.php
index 60f9f716..a3dfa931 100644
--- a/src/Entity/Customer.php
+++ b/src/Entity/Customer.php
@@ -12,11 +12,15 @@ use App\Ramcar\CustomerClassification;
 
 /**
  * @ORM\Entity
- * @ORM\Table(name="customer", indexes={
- *     @ORM\Index(name="phone_mobile_idx", columns={"phone_mobile"}),
- *     @ORM\Index(columns={"first_name"}, flags={"fulltext"}),
- *     @ORM\Index(columns={"last_name"}, flags={"fulltext"}),
-       @ORM\Index(name="generated_id_idx", columns={"generated_id"})
+ * @ORM\Table(name="customer", 
+ *     uniqueConstraints={
+ *         @ORM\UniqueConstraint(columns={"generated_id"})
+ *     },
+ *     indexes={
+ *         @ORM\Index(name="phone_mobile_idx", columns={"phone_mobile"}),
+ *         @ORM\Index(columns={"first_name"}, flags={"fulltext"}),
+ *         @ORM\Index(columns={"last_name"}, flags={"fulltext"}),
+           @ORM\Index(name="generated_id_idx", columns={"generated_id"})
  * })
  */
 class Customer
diff --git a/src/Service/UniqueIdGenerator.php b/src/Service/UniqueIdGenerator.php
index 90af3369..972a7ef8 100644
--- a/src/Service/UniqueIdGenerator.php
+++ b/src/Service/UniqueIdGenerator.php
@@ -9,26 +9,27 @@ use App\Entity\Customer;
 class UniqueIdGenerator
 {
     protected $em;
+    protected $cust_generated_ids;
 
     public function __construct(EntityManagerInterface $em)
     {
         $this->em = $em;
+
+        $this->loadGeneratedIds();
     }
 
     public function generateCustomerUniqueId($str_length)
     {
         $em = $this->em;
 
-        // retry until we find no customer with the generated id
+        // retry until we have no duplicate generated id 
         while (true)
         {
             // generate the id
             $generated_id = $this->generateUniqueId($str_length);
 
             // check if generated id already exists
-            $cust = $em->getRepository(Customer::class)->findOneBy(['generated_id' => $generated_id]);
-
-            if ($cust == null)
+            if (!isset($this->cust_generated_ids[$generated_id]))
                 return $generated_id;
 
             sleep(1);
@@ -40,4 +41,30 @@ class UniqueIdGenerator
     {
         return substr(md5(time()), 0, $str_length);
     }
+
+    protected function loadGeneratedIds()
+    {
+        error_log('loading generated ids ');
+        $cust_q = $this->em->createQuery('select c from App\Entity\Customer c where c.generated_id is not null');
+        $cust_iter = $cust_q->iterate();
+
+        $this->cust_generated_ids = [];
+        foreach ($cust_iter as $row)
+        {
+            $customer = $row[0];
+            $generated_id = $customer->getGeneratedID();
+            error_log('generated id = ' . $generated_id);
+            if ($generated_id != null)
+            {
+                error_log('generated id is not null ' . $generated_id);
+                if (!isset($this->cust_generated_ids[$generated_id]))
+                {
+                    error_log('setting to hash ' . $generated_id);
+                    $this->cust_generated_ids[$generated_id] = $customer;
+                }
+            }
+
+            $this->em->detach($row[0]);
+        }
+    }
 }