Rajani Karuturi fb4e6ed6ba Merge pull request #894 from sudhansu7/CLOUDSTACK-8917
CLOUDSTACK-8917 : Instance tab takes long time to load with 12K Vmsmodified sql that is used for retrieving vm count .

In load test environment listVirtualmachine takes 8-11 sec to load. This environment has around 12k active VMs. Total number of rows is 190K.

Performance bottleneck in listVirtualmachine command is fetching the count and distinct vms.
{noformat}
        // search vm details by ids
        Pair<List<UserVmJoinVO>, Integer> uniqueVmPair = _userVmJoinDao.searchAndCount(sc, searchFilter);
        Integer count = uniqueVmPair.second();
{noformat}

 This takes 95% of the total time.

To fetch the count and distinct vms we are using below sqls.

 Query 1:
{noformat}
SELECT DISTINCT(user_vm_view.id) FROM user_vm_view WHERE user_vm_view.account_type != 5  AND user_vm_view.display_vm = 1  AND user_vm_view.removed IS NULL  ORDER BY user_vm_view.id ASC  LIMIT 0, 20
 {noformat}

 Query 2:

select count(distinct id) from user_vm_view WHERE user_vm_view.account_type != 5  AND user_vm_view.display_vm = 1  AND user_vm_view.removed IS NULL

Query 2 is a problematic query.

If we rewrite the query as mentioned below then it will be ~2x faster.

select count(*) from (select distinct id from user_vm_view WHERE user_vm_view.account_type != 5  AND user_vm_view.display_vm = 1  AND user_vm_view.removed IS NULL) as temp;

Mysql Test result:

With 134 active Vms (total rows 349)
mysql> select count(*) from vm_instance;
+----------+
| count(*) |
+----------+
|      349 |
+----------+
1 row in set (0.00 sec)
mysql> select count(*) from user_vm_view;
+----------+
| count(*) |
+----------+
|      135 |
+----------+
1 row in set (0.02 sec)
mysql> select count(distinct id) from user_vm_view WHERE user_vm_view.account_type != 5  AND user_vm_view.display_vm = 1  AND user_vm_view.removed IS NULL;
+--------------------+
| count(distinct id) |
+--------------------+
|                134 |
+--------------------+
1 row in set (0.02 sec)

mysql> select count(*) from (select distinct id from user_vm_view WHERE user_vm_view.account_type != 5  AND user_vm_view.display_vm = 1  AND user_vm_view.removed IS NULL) as temp;
+----------+
| count(*) |
+----------+
|      134 |
+----------+
1 row in set (0.01 sec)

With 14326 active Vms (total rows 195660)

mysql> select count(*) from vm_instance;
+----------+
| count(*) |
+----------+
|   195660 |
+----------+
1 row in set (0.04 sec)
mysql> select count(*) from user_vm_view;
+----------+
| count(*) |
+----------+
|    41313 |
+----------+
1 row in set (4.55 sec)
mysql> select count(distinct id) from user_vm_view WHERE user_vm_view.account_type != 5  AND user_vm_view.display_vm = 1  AND user_vm_view.removed IS NULL;
+--------------------+
| count(distinct id) |
+--------------------+
|              14326 |
+--------------------+
1 row in set (7.39 sec)

mysql> select count(*) from (select distinct id from user_vm_view WHERE user_vm_view.account_type != 5  AND user_vm_view.display_vm = 1  AND user_vm_view.removed IS NULL) as temp;
+----------+
| count(*) |
+----------+
|    14326 |
+----------+
1 row in set (2.08 sec)

UI test Results:
Before:
![screen shot 2015-09-28 at 2 19 55 pm](https://cloud.githubusercontent.com/assets/1062642/10133848/66af7c40-65fe-11e5-9ef5-ec6489c0fc06.png)

After
![screen shot 2015-09-28 at 2 33 38 pm](https://cloud.githubusercontent.com/assets/1062642/10133852/6f512c9a-65fe-11e5-9ea1-890cf84d02b4.png)

* pr/894:
  CLOUDSTACK-8917 : Instance tab takes long time to load with 12K active VM (total vms: 190K)

Signed-off-by: Rajani Karuturi <rajani.karuturi@citrix.com>
2015-10-27 12:17:55 +05:30
..