FW: Legacy replication slave node full sync

-----Original Message-----
From: Erick Erickson [mailto:erickerickson@gmail.com]
Sent: 23 March 2018 03:48
To: solr-user <solr-user@lucene.apache.org>
Subject: Re: Legacy replication slave node full sync

1a> Replication pulls down changed segments, which includes _changed_
segments. Say I have 10 segments in my index and they all get merged into a
single segment that now contains the entire index. Then the changed segment
is replicated.

1b> If you're polling interval is such that all the segments get
replaced between synchronizations, then the entire index will be fetch at
the next poll.

2> You can turn on infoStream logging, see the reference guide.
WARNING: this will produce a _lot_ of output.

Why is this important? It's expected that occasionally a replication may
pull down the entire index, doing a forceMerge on the master for instance.
If you're saying that occasionally replication _replaces existing segments_
with fresh ones of the same name from the master, then that's a mystery. If
you're saying that occasionally all the segments are pulled from the master
and all the old segments are deleted from the slave, then that's expected,
in this case there will be no segments in common.

Best,
Erick

On Thu, Mar 22, 2018 at 11:10 AM, Yunee Lee <yunee.lee@infor.com> wrote:
> Hi,
> I have two questions regarding legacy master /slave node replication
architecture.
> We noticed that slave node does full sync time to time.
>
> 1. What type of event or configuration does trigger the full sync in
slave node?
> I can not locate exact time and frequency from the logs. Please let me
know.
> 2. If master nodes' index merges is related to trigger the full sync
replication, then how can I find the index merge logging in solr log from
master node?
> Please share the documentation if I can reference.
> Thanks.
>