Compactor errors, should I be concerned?

Recently upgraded a development cluster from 4.0 -> 4.6, using provided docker images. Everything seems to be working fine, but one thing that was quite noticeable was that compaction was triggered by this upgrade. In the server logs, I see errors coming from that. I haven’t noticed any ill effects of this, but it doesn’t look OK. Should this be a cause for concern?

Apologies for atrocious formatting, this is coming straight from the server logs page.

Compactor for view `models/_design/otto` (pid [{type,view},
                                               {name,
                                                <<"models/_design/otto">>},
                                               {important,false},
                                               {fa,
                                                {#Fun<compaction_new_daemon.25.102846360>,
                                                 [<<"models">>,
                                                  <<"_design/otto">>,
                                                  {config,
                                                   {30,undefined},
                                                   {30,undefined},
                                                   undefined,false,false,
                                                   {daemon_config,30,131072,
                                                    20971520}},
                                                  false,
                                                  {[{type,bucket}]}]}}]) terminated unexpectedly (ignoring this): {badmatch,
                                                                                                                   {badmatch,
                                                                                                                    {error,
                                                                                                                     {error,
                                                                                                                      {{case_clause,
                                                                                                                        {{error,
                                                                                                                          vbucket_stream_not_found},
                                                                                                                         {bufsocket,
                                                                                                                          #Port<11633.10254>,
                                                                                                                          <<>>}}},
                                                                                                                       [{couch_dcp_client,
                                                                                                                         init,
                                                                                                                         1,
                                                                                                                         [{file,
                                                                                                                           "/home/couchbase/jenkins/workspace/watson-unix/couchdb/src/couch_dcp/src/couch_dcp_client.erl"},
                                                                                                                          {line,
                                                                                                                           299}]},
                                                                                                                        {gen_server,
                                                                                                                         init_it,
                                                                                                                         6,
                                                                                                                         [{file,
                                                                                                                           "gen_server.erl"},
                                                                                                                          {line,
                                                                                                                           304}]},
                                                                                                                        {proc_lib,
                                                                                                                         init_p_do_apply,
                                                                                                                         3,
                                                                                                                         [{file,
                                                                                                                           "proc_lib.erl"},
                                                                                                                          {line,
                                                                                                                           239}]}]}}}}}


Compactor for view `mapreduce_view/models/_design/otto/main` (pid [{type,view},
                                                                   {important,
                                                                    true},
                                                                   {name,
                                                                    <<"mapreduce_view/models/_design/otto/main">>},
                                                                   {fa,
                                                                    {#Fun<compaction_new_daemon.23.102846360>,
                                                                     [<<"models">>,
                                                                      <<"_design/otto">>,
                                                                      mapreduce_view,
                                                                      main,
                                                                      {config,
                                                                       {30,
                                                                        undefined},
                                                                       {30,
                                                                        undefined},
                                                                       undefined,
                                                                       false,
                                                                       false,
                                                                       {daemon_config,
                                                                        30,
                                                                        131072,
                                                                        20971520}},
                                                                      false,
                                                                      {[{type,
                                                                         bucket}]}]}}]) terminated unexpectedly: {badmatch,
                                                                                                                  {badmatch,
                                                                                                                   {error,
                                                                                                                    {error,
                                                                                                                     {{case_clause,
                                                                                                                       {{error,
                                                                                                                         vbucket_stream_not_found},
                                                                                                                        {bufsocket,
                                                                                                                         #Port<11633.10254>,
                                                                                                                         <<>>}}},
                                                                                                                      [{couch_dcp_client,
                                                                                                                        init,
                                                                                                                        1,
                                                                                                                        [{file,
                                                                                                                          "/home/couchbase/jenkins/workspace/watson-unix/couchdb/src/couch_dcp/src/couch_dcp_client.erl"},
                                                                                                                         {line,
                                                                                                                          299}]},
                                                                                                                       {gen_server,
                                                                                                                        init_it,
                                                                                                                        6,
                                                                                                                        [{file,
                                                                                                                          "gen_server.erl"},
                                                                                                                         {line,
                                                                                                                          304}]},
                                                                                                                       {proc_lib,
                                                                                                                        init_p_do_apply,
                                                                                                                        3,
                                                                                                                        [{file,
                                                                                                                          "proc_lib.erl"},
                                                                                                                         {line,
                                                                                                                          239}]}]}}}}}

If it doesn’t come up persistently, then I’d say it’s safe to ignore. You have a situation there where it’s rebuilding the index and the DCP stream of data goes missing. It should restart it and will probably complete the next time is my guess.

This compaction/rematerialization of indexes may have an impact on any stale = false view queries (basically preventing them), but would otherwise just be background work.