Indexer stalled - Indexer::MutationQueue Waiting for Node Alloc

1. Install CB Servers on 4 boxes
2. Create a bucket with following document
key1 = 'demo_key'
value1 =

{ "name":"demo_value", "lastname":'lastname', "areapin":'', "preference":'veg', "type":'' }

While doing a set using SDK change type to odd or even. Add another field ID which add the number of the document.
3. Create 3 indexes:
Create primary index on voltest01
create index index5 on voltest01(type) using gsi
create index index6 on voltest01(id) using gsi
4. Do following mutations for over 4 hours:
First Add - 30608061 items
Delete - 15304031 itesm
Update - 15304030 items, update type = ‘update’
Create - 15304030 items
Basically do a 75 M mutations.

Expected result that all docs are indexed.

But one of the indexer is stuck forever -
2015-06-25T04:26:09.328Z+00:00 [Warn] Indexer::MutationQueue Waiting for Node Alloc for 43696350 Milliseconds Vbucket 512
2015-06-25T04:26:09.358Z+00:00 [Warn] Indexer::MutationQueue Waiting for Node Alloc for 43696380 Milliseconds Vbucket 512
2015-06-25T04:26:09.388Z+00:00 [Warn] Indexer::MutationQueue Waiting for Node Alloc for 43696410 Milliseconds Vbucket 512

There are quite a number of bugs around this area:
MB-15254
MB-15427

And there has been few changes to the compaction area, so recommendation is :

a) Increase memory for indexer to 6 GB
b) retest with new build

Keeping the priority and assigning the defect to myself, will update after run against new build.

Boxes used - 8 core CPU and 32G RAM