GitHub user sudhansu7 opened a pull request:
https://github.com/apache/cloudstack/pull/894
CLOUDSTACK-8917 : Instance tab takes long time to load with 12K Vms
modified 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:

After

You can merge this pull request into a Git repository by running:
$ git pull https://github.com/sudhansu7/cloudstack CLOUDSTACK-8917
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/cloudstack/pull/894.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #894
----
commit c28a58a8ff4ddde7b86e151ffee35ad26645e584
Author: Sudhansu <[email protected]>
Date: 2015-09-28T10:54:26Z
CLOUDSTACK-8917 : Instance tab takes long time to load with 12K active VM
(total vms: 190K)
modified sql that is used for retrieving vm count .
----
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