Comment 12 for bug 1589014

Reviewed: https://review.opencontrail.org/21274
Committed: http://github.org/Juniper/contrail-controller/commit/825f26b3f6ab67683030dfcbfb7107185da6d1e9
Submitter: Zuul
Branch: R3.0

commit 825f26b3f6ab67683030dfcbfb7107185da6d1e9
Author: Ranjeet R <email address hidden>
Date: Fri Jun 17 10:58:02 2016 -0700

Fixes: API Server Performance Optimization Placeholder bug

Test setup
20000 VMs 20000 VMIs 20000 Instance IPs
API server startup takes 6 minutes 7 seconds to start

This commit has two improvements -
1. In Dbe_resync, we yield the greenlet to make sure that
Zookeeper heartbeats are working. But during startup, ZK
heartbeats are not relevant. Improves perf from 6:07 to 4:35.

2. In IFMAP publish call, the cache organization was not
efficient. We use the following schema now.

id_to_metas = { 'id': //id1
{'meta_name':
{'': prop_value} or // If the meta is a prop
{id2:ref_value} //If the meta is a ref
changes in object_delete/update to take care of this organization.
Improves perf from 4:35 to 3:35
Updating UTs to reflect this/

3. Eduoard's change of using ujson instead of simplejson in
https://review.opencontrail.org/21049 brings down the time to
another 20 seconds, 3:35 to 315

4. Not sending the VM's UVE trace during startup
is saving another 25 seconds
3:15 to 2:50

Change-Id: I23a6f1c039683624aee23b7fe16539f0aa1f7537
Partial-Bug: 1589014