CS-12510: Deleting the host_details and inserting them back causes deadlocks.

Changes:
- 3.0.4 release has a patch where a unique key is added on host_details.
- But this key is not present in 3.0.4 GA
- So 3.0.5 upgrade has to consider both cases and add the key only if it does not exist in the 3.0.4 version.

server/src/com/cloud/upgrade/dao/Upgrade304to305.java

@@ -53,6 +53,7 @@ public class Upgrade304to305 extends Upgrade30xBase implements DbUpgrade {
 
     @Override
     public void performDataMigration(Connection conn) {
+        addHostDetailsUniqueKey(conn);
         addVpcProvider(conn);
         updateRouterNetworkRef(conn);
     }
@@ -171,4 +172,36 @@ public class Upgrade304to305 extends Upgrade30xBase implements DbUpgrade {
         }
         s_logger.debug("Done updating router/network references");        
     }
+    
+    private void addHostDetailsUniqueKey(Connection conn) {
+        s_logger.debug("Checking if host_details unique key exists, if not we will add it");
+        PreparedStatement pstmt = null;
+        ResultSet rs = null;
+        try {
+            pstmt = conn.prepareStatement("SHOW INDEX FROM `cloud`.`host_details` WHERE KEY_NAME = 'uk_host_id_name'");
+            rs = pstmt.executeQuery();
+            if (rs.next()) {
+                s_logger.debug("Unique key already exists on host_details - not adding new one");
+            }else{
+                //add the key
+                PreparedStatement pstmtUpdate = conn.prepareStatement("ALTER TABLE `cloud`.`host_details` ADD CONSTRAINT UNIQUE KEY `uk_host_id_name` (`host_id`, `name`)");
+                pstmtUpdate.executeUpdate();
+                s_logger.debug("Unique key did not exist on host_details -  added new one");
+                pstmtUpdate.close();
+            }
+        } catch (SQLException e) {
+            throw new CloudRuntimeException("Failed to check/update the host_details unique key ", e);
+        } finally {
+            try {
+                if (rs != null) {
+                    rs.close();
+                }
+
+                if (pstmt != null) {
+                    pstmt.close();
+                }
+            } catch (SQLException e) {
+            }
+        }
+    }
 }

setup/db/create-schema.sql

@@ -833,7 +833,7 @@ CREATE TABLE `cloud`.`host_details` (
   `value` varchar(255) NOT NULL,
   PRIMARY KEY (`id`),
   CONSTRAINT `fk_host_details__host_id` FOREIGN KEY (`host_id`) REFERENCES `host`(`id`) ON DELETE CASCADE,
-  CONSTRAINT UNIQUE KEY (`host_id`, `name`)
+  CONSTRAINT UNIQUE KEY `uk_host_id_name` (`host_id`, `name`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 CREATE TABLE  `cloud`.`mshost` (

setup/db/db/schema-304to305.sql

@@ -350,7 +350,5 @@ UPDATE `cloud`.`hypervisor_capabilities` SET `max_data_volumes_limit`=13 WHERE `
 SET SQL_SAFE_UPDATES=1;
 UPDATE `cloud`.`configuration` SET description='In second, timeout for creating volume from snapshot' WHERE name='create.volume.from.snapshot.wait';
 
-ALTER TABLE `cloud`.`host_details` ADD CONSTRAINT UNIQUE KEY (`host_id`, `name`);
-
 INSERT IGNORE INTO `cloud`.`configuration` VALUES ('Account Defaults', 'DEFAULT', 'management-server', 'max.account.vpcs', '20', 'The default maximum number of vpcs that can be created for an account');
 INSERT IGNORE INTO `cloud`.`configuration` VALUES ('Project Defaults', 'DEFAULT', 'management-server', 'max.project.vpcs', '20', 'The default maximum number of vpcs that can be created for a project');