mysql innodb cluster 3 nodes, 2 lagging almost 24 hours I have a 3 node setup and the 2 read only nodes are way behind (like 24 hours) from the rw node.. 

I saw here:  https://bugs.mysql.com/bug.php?id=86797 to restart the lagging node and will pick up by itself.. 
since I was not very convinced I did this in just one node.. 
restarted ok and came to the cluster in "RECOVERING" mode
such good... 
But now I am checking and the Q is super big getting bigger
and when I compare the data in one table to the one in RW is updating.. just very slow like one a sec .. so is not picking up any slack.. it should go faster to pick up with the RW node right?


 CHANNEL_NAME: group_replication_applier
                           VIEW_ID: 15255041(deleted)
                         MEMBER_ID: 47dbb651-XXXXX (deleted)
       COUNT_TRANSACTIONS_IN_QUEUE: 218417
        COUNT_TRANSACTIONS_CHECKED: 0
          COUNT_CONFLICTS_DETECTED: 0
COUNT_TRANSACTIONS_ROWS_VALIDATING: 0
TRANSACTIONS_COMMITTED_ALL_MEMBERS: 1667fe4c-5033-11e8-b942-(Deleted)-3140512,
617916a6-5032-11e8-ad5b-(Deleted):1-14
    LAST_CONFLICT_FREE_TRANSACTION:


note: I added the deleted for privacy.
on my other node is also behind around 24 hours says Q is 0 


select * from replication_group_member_stats\G
*************************** 1. row ***************************
                      CHANNEL_NAME: group_replication_applier
                           VIEW_ID: 1525504100(Deleted):13
                         MEMBER_ID: 617916a6-5032-11e8-(deleted)
       COUNT_TRANSACTIONS_IN_QUEUE: 0
        COUNT_TRANSACTIONS_CHECKED: 6846224
          COUNT_CONFLICTS_DETECTED: 0
COUNT_TRANSACTIONS_ROWS_VALIDATING: 5921012
TRANSACTIONS_COMMITTED_ALL_MEMBERS: 1667fe4c-5033-11e8-b942-0cc(deleted):1-3173566,
617916a6-5032-11e8-ad5b-(deleted):1-14
    LAST_CONFLICT_FREE_TRANSACTION: 1667fe4c-5033-11e8-b942-0(deleted)
1 row in set (0.0004 sec)

I am researching but is confusing some is for mysql 8.x like this solution:
http://lefred.be/content/mysql-innodb-cluster-how-to-handle-fc/

and other info I found is for master/slave so is not related..

Also looking into the parallel slave options but not sure if this will make any difference.

NOTE: the hardware is exactly the same on all 3 nodes.

thanks
Hello for those out there with similar issues I fixed it thanks to this amazing blog post.
https://thoughts.t37.net/fixing-a-very-lagging-mysql-replication-db6eb5a6e15d
basically my changes: 


STOP SLAVE;
SET GLOBAL slave_parallel_workers=40;
START SLAVE;
set GLOBAL sync_binlog=0;
SET GLOBAL innodb_flush_log_at_trx_commit=2;
SET GLOBAL innodb_flush_log_at_timeout=1800;`


I already had the MT setup so just needed to add this and 40 workers.
Hope this will help other people..