+1 for simplifying and using the Leader/Follower Terminology. Our company operates both SolrCloud, Standalone Solr, and Master/Slave Configurations, outside of the Solr Developer community, it's painful and confusing to talk about Master/Slave and Leader/Replica. It would be easier if we had the following:
The internal differences between manual configuration or SolrCloud being smart about managing and assigning roles are just the evolution of the design and details of a particular mode/implementation and shouldn't matter to the end-user. Today, when someone not involved in the Solr development looks at the terminology, it looks new terminology is introduced without thinking about existing customers or thinking through the system as a whole and how to best evolve it (not saying that's what happened, but just a perception). Adding new terminology should be introduced carefully and +1 on reducing the cognitive load on an average guy like me. - There are leaders and there are followers - Solr Clusters can be configured in two modes/implementation (SolrCloud or Master/Slave). This one is hard because you don't want to introduce yet another name here as people are now already familiar with it. - These modes happen to have different designs and depending upon the mode, you can go into the design differences of these two modes. Cheers! -- *Sameer Maggon* *SearchStax* | www.searchstax.com On Wed, Jun 17, 2020 at 2:22 PM gnandre <arnoldbron...@gmail.com> wrote: > +1 for Leader-Follower. How about Publisher-Subscriber? > > On Wed, Jun 17, 2020 at 5:19 PM Rahul Goswami <rahul196...@gmail.com> > wrote: > > > +1 on avoiding SolrCloud terminology. In the interest of keeping it > obvious > > and simple, may I I please suggest primary/secondary? > > > > On Wed, Jun 17, 2020 at 5:14 PM Atita Arora <atitaar...@gmail.com> > wrote: > > > > > I agree avoiding using of solr cloud terminology too. > > > > > > I may suggest going for "prime" and "clone" > > > (Short and precise as Master and Slave). > > > > > > Best, > > > Atita > > > > > > > > > > > > > > > > > > On Wed, 17 Jun 2020, 22:50 Walter Underwood, <wun...@wunderwood.org> > > > wrote: > > > > > > > I strongly disagree with using the Solr Cloud leader/follower > > terminology > > > > for non-Cloud clusters. People in my company are confused enough > > without > > > > using polysemous terminology. > > > > > > > > “This node is the leader, but it means something different than the > > > leader > > > > in this other cluster.” I’m dreading that conversation. > > > > > > > > I like “principal”. How about “clone” for the slave role? That > suggests > > > > that > > > > it does not accept updates and that it is loosely-coupled, only > > depending > > > > on the state of the no-longer-called-master. > > > > > > > > Chegg has five production Solr Cloud clusters and one production > > > > master/slave > > > > cluster, so this is not a hypothetical for us. We have 100+ Solr > hosts > > in > > > > production. > > > > > > > > wunder > > > > Walter Underwood > > > > wun...@wunderwood.org > > > > http://observer.wunderwood.org/ (my blog) > > > > > > > > > On Jun 17, 2020, at 1:36 PM, Trey Grainger <solrt...@gmail.com> > > wrote: > > > > > > > > > > Proposal: > > > > > "A Solr COLLECTION is composed of one or more SHARDS, which each > have > > > one > > > > > or more REPLICAS. Each replica can have a ROLE of either: > > > > > 1) A LEADER, which can process external updates for the shard > > > > > 2) A FOLLOWER, which receives updates from another replica" > > > > > > > > > > (Note: I prefer "role" but if others think it's too overloaded due > to > > > the > > > > > overseer role, we could replace it with "mode" or something > similar) > > > > > ------------------------------------------- > > > > > > > > > > To be explicit with the above definitions: > > > > > 1) In SolrCloud, the roles of leaders and followers can dynamically > > > > change > > > > > based upon the status of the cluster. In standalone mode, they can > be > > > > > changed by manual intervention. > > > > > 2) A leader does not have to have any followers (i.e. only one > active > > > > > replica) > > > > > 3) Each shard always has one leader. > > > > > 4) A follower can also pull updates from another follower instead > of > > a > > > > > leader (traditionally known as a REPEATER). A repeater is still a > > > > follower, > > > > > but would not be considered a leader because it can't process > > external > > > > > updates. > > > > > 5) A replica cannot be both a leader and a follower. > > > > > > > > > > In addition to the above roles, each replica can have a TYPE of one > > of: > > > > > 1) NRT - which can serve in the role of leader or follower > > > > > 2) TLOG - which can only serve in the role of follower > > > > > 3) PULL - which can only serve in the role of follower > > > > > > > > > > A replica's type may be changed automatically in the event that its > > > role > > > > > changes. > > > > > > > > > > I think this terminology is consistent with the current > > Leader/Follower > > > > > usage while also being able to easily accomodate a rename of the > > > > historical > > > > > master/slave terminology without mental gymnastics or the > > introduction > > > or > > > > > more cognitive load through new terminology. I think adopting the > > > > > Primary/Replica terminology will be incredibly confusing given the > > > > already > > > > > specific and well established meaning of "replica" within Solr. > > > > > > > > > > All the Best, > > > > > > > > > > Trey Grainger > > > > > Founder, Searchkernel > > > > > https://searchkernel.com > > > > > > > > > > > > > > > > > > > > On Wed, Jun 17, 2020 at 3:38 PM Anshum Gupta < > ans...@anshumgupta.net > > > > > > > wrote: > > > > > > > > > >> Hi everyone, > > > > >> > > > > >> Moving a conversation that was happening on the PMC list to the > > public > > > > >> forum. Most of the following is just me recapping the conversation > > > that > > > > has > > > > >> happened so far. > > > > >> > > > > >> Some members of the community have been discussing getting rid of > > the > > > > >> master/slave nomenclature from Solr. > > > > >> > > > > >> While this may require a non-trivial effort, a general consensus > so > > > far > > > > >> seems to be to start this process and switch over incrementally, > if > > a > > > > >> single change ends up being too big. > > > > >> > > > > >> There have been a lot of suggestions around what the new > > nomenclature > > > > might > > > > >> look like, a few people don’t want to overlap the naming here with > > > what > > > > >> already exists in SolrCloud i.e. leader/follower. > > > > >> > > > > >> Primary/Replica was an option that was suggested based on what > other > > > > >> vendors are moving towards based on Wikipedia: > > > > >> https://en.wikipedia.org/wiki/Master/slave_(technology) > > > > >> , however there were concerns around the use of “replica” as that > > > > denotes a > > > > >> very specific concept in SolrCloud. Current terminology clearly > > > > >> differentiates the use of the traditional replication model from > > > > SolrCloud > > > > >> and reusing the names would make it difficult for that to happen. > > > > >> > > > > >> There were similar concerns around using Leader/follower. > > > > >> > > > > >> Let’s continue this conversation here while making sure that we > > > converge > > > > >> without much bike-shedding. > > > > >> > > > > >> -Anshum > > > > >> > > > > > > > > > > > > > >
