我有3个节点的ejabberd集群（ejabberd 15.10，后端会话数据库-Redis 2.8.17）。在其中一个节点上大约有128000个用户联机后（ejabberdctl stats onlineusersnode-20190），定期在error.log中出现错误：
2019-07-04 12:57:54.386 [error] <0.12231.633> gen_fsm <0.12231.633> in state session_established terminated with reason: {timeout,{gen_server,call,[ejabberd_redis_client,{pipeline,[[[<<"*">>,"4",<<"\r\n">>],[[<<"$">>,"4",<<"\r\n">>,<<"HSET">>,<<"\r\n">>],[<<"$">>,"61",<<"\r\n">>,<<"ejabberd:sm:560dfb9f-80bd-11e6-80e3-0025904f970d@buhphone.com">>,<<"\r\n">>],[<<"$">>,"51",<<"\r\n">>,<<131,104,2,104,3,98,0,0,6,26,98,0,3,78,53,98,0,11,233,28,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,51,120,109,112,112,50,0,0,47,199,0,0,2,121,1>>,<<"\r\n">>],[<<"$">>,"283",<<"\r\n">>,<<131,104,6,100,0,7,115,101,115,115,105,111,110,...>>,...]]],...]},...]}}
2019-07-04 12:57:54.387 [error] <0.12231.633> CRASH REPORT Process <0.12231.633> with 0 neighbours exited with reason: {timeout,{gen_server,call,[ejabberd_redis_client,{pipeline,[[[<<"*">>,"4",<<"\r\n">>],[[<<"$">>,"4",<<"\r\n">>,<<"HSET">>,<<"\r\n">>],[<<"$">>,"61",<<"\r\n">>,<<"ejabberd:sm:560dfb9f-80bd-11e6-80e3-0025904f970d@buhphone.com">>,<<"\r\n">>],[<<"$">>,"51",<<"\r\n">>,<<131,104,2,104,3,98,0,0,6,26,98,0,3,78,53,98,0,11,233,28,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,51,120,109,112,112,50,0,0,47,199,0,0,2,121,1>>,<<"\r\n">>],[<<"$">>,"283",<<"\r\n">>,<<131,104,6,100,0,7,115,101,115,115,105,111,110,...>>,...]]],...]},...]}} in p1_fsm:terminate/8 line 760
2019-07-04 12:57:54.387 [error] <0.420.0> Supervisor ejabberd_c2s_sup had child undefined started with {ejabberd_c2s,start_link,undefined} at <0.12231.633> exit with reason {timeout,{gen_server,call,[ejabberd_redis_client,{pipeline,[[[<<"*">>,"4",<<"\r\n">>],[[<<"$">>,"4",<<"\r\n">>,<<"HSET">>,<<"\r\n">>],[<<"$">>,"61",<<"\r\n">>,<<"ejabberd:sm:560dfb9f-80bd-11e6-80e3-0025904f970d@buhphone.com">>,<<"\r\n">>],[<<"$">>,"51",<<"\r\n">>,<<131,104,2,104,3,98,0,0,6,26,98,0,3,78,53,98,0,11,233,28,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,51,120,109,112,112,50,0,0,47,199,0,0,2,121,1>>,<<"\r\n">>],[<<"$">>,"283",<<"\r\n">>,<<131,104,6,100,0,7,115,101,115,115,105,111,110,...>>,...]]],...]},...]}} in context child_terminated
2019-07-04 12:57:54.406 [error] <0.5558.678> gen_fsm <0.5558.678> in state session_established terminated with reason: {timeout,{gen_server,call,[ejabberd_redis_client,{pipeline,[[[<<"*">>,"4",<<"\r\n">>],[[<<"$">>,"4",<<"\r\n">>,<<"HSET">>,<<"\r\n">>],[<<"$">>,"61",<<"\r\n">>,<<"ejabberd:sm:c1efbd7f-b093-49fe-857e-4055a1d7cb6d@buhphone.com">>,<<"\r\n">>],[<<"$">>,"51",<<"\r\n">>,<<131,104,2,104,3,98,0,0,6,26,98,0,3,84,14,98,0,5,45,215,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,51,120,109,112,112,50,0,0,21,182,0,0,2,166,1>>,<<"\r\n">>],[<<"$">>,"283",<<"\r\n">>,<<131,104,6,100,0,7,115,101,115,115,105,111,110,...>>,...]]],...]},...]}}
2019-07-04 12:57:54.407 [error] <0.5558.678> CRASH REPORT Process <0.5558.678> with 0 neighbours exited with reason: {timeout,{gen_server,call,[ejabberd_redis_client,{pipeline,[[[<<"*">>,"4",<<"\r\n">>],[[<<"$">>,"4",<<"\r\n">>,<<"HSET">>,<<"\r\n">>],[<<"$">>,"61",<<"\r\n">>,<<"ejabberd:sm:c1efbd7f-b093-49fe-857e-4055a1d7cb6d@buhphone.com">>,<<"\r\n">>],[<<"$">>,"51",<<"\r\n">>,<<131,104,2,104,3,98,0,0,6,26,98,0,3,84,14,98,0,5,45,215,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,51,120,109,112,112,50,0,0,21,182,0,0,2,166,1>>,<<"\r\n">>],[<<"$">>,"283",<<"\r\n">>,<<131,104,6,100,0,7,115,101,115,115,105,111,110,...>>,...]]],...]},...]}} in p1_fsm:terminate/8 line 760
2019-07-04 12:57:54.407 [error] <0.420.0> Supervisor ejabberd_c2s_sup had child undefined started with {ejabberd_c2s,start_link,undefined} at <0.5558.678> exit with reason {timeout,{gen_server,call,[ejabberd_redis_client,{pipeline,[[[<<"*">>,"4",<<"\r\n">>],[[<<"$">>,"4",<<"\r\n">>,<<"HSET">>,<<"\r\n">>],[<<"$">>,"61",<<"\r\n">>,<<"ejabberd:sm:c1efbd7f-b093-49fe-857e-4055a1d7cb6d@buhphone.com">>,<<"\r\n">>],[<<"$">>,"51",<<"\r\n">>,<<131,104,2,104,3,98,0,0,6,26,98,0,3,84,14,98,0,5,45,215,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,51,120,109,112,112,50,0,0,21,182,0,0,2,166,1>>,<<"\r\n">>],[<<"$">>,"283",<<"\r\n">>,<<131,104,6,100,0,7,115,101,115,115,105,111,110,...>>,...]]],...]},...]}} in context child_terminated
2019-07-04 12:57:54.426 [error] <0.14888.624>@ejabberd_c2s:handle_info:1759 Unexpected info: {#Ref<0.0.297795585.190373>,{ok,[<<131,104,2,104,3,98,0,0,6,26,98,0,3,49,230,98,0,1,114,42,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,51,120,109,112,112,50,0,0,58,40,0,0,2,112,1>>,<<131,104,6,100,0,7,115,101,115,115,105,111,110,104,2,104,3,98,0,0,6,26,98,0,3,49,230,98,0,1,114,42,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,51,120,109,112,112,50,0,0,58,40,0,0,2,112,1,104,3,109,0,0,0,36,97,51,49,50,54,56,49,98,45,49,51,53,97,45,52,55,49,99,45,98,101,102,55,45,51,99,102,55,102,100,55,54,51,51,101,97,109,0,0,0,12,98,117,104,112,104,111,110,101,46,99,111,109,109,0,0,0,11,100,101,115,107,45,56,51,56,49,55,51,104,2,109,0,0,0,36,97,51,49,50,54,56,49,98,45,49,51,53,97,45,52,55,49,99,45,98,101,102,55,45,51,99,102,55,102,100,55,54,51,51,101,97,109,0,0,0,12,98,117,104,112,104,111,110,101,46,99,111,109,97,0,108,0,0,0,3,104,2,100,0,2,105,112,104,2,104,4,97,192,97,168,97,15,97,10,98,0,0,214,200,104,2,100,0,4,99,111,110,110,100,0,3,99,50,115,104,2,100,0,11,97,117,116,104,95,109,111,100,117,108,101,100,0,18,101,106,97,98,98,101,114,100,95,97,117,116,104,95,111,100,98,99,106>>]}}
2019-07-04 12:57:54.448 [error] <0.23600.657>@ejabberd_c2s:handle_info:1759 Unexpected info: {#Ref<0.0.90701829.122096>,{ok,[<<131,104,2,104,3,98,0,0,6,26,98,0,3,89,215,98,0,7,158,200,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,50,120,109,112,112,50,0,0,63,182,0,0,3,131,3>>,<<131,104,6,100,0,7,115,101,115,115,105,111,110,104,2,104,3,98,0,0,6,26,98,0,3,89,215,98,0,7,158,200,103,100,0,18,101,106,97,98,98,101,114,100,64,115,114,118,50,120,109,112,112,50,0,0,63,182,0,0,3,131,3,104,3,109,0,0,0,36,98,97,100,48,51,50,52,102,45,99,100,52,54,45,52,57,52,98,45,56,48,100,56,45,101,53,53,48,52,98,48,53,49,97,50,98,109,0,0,0,12,98,117,104,112,104,111,110,101,46,99,111,109,109,0,0,0,11,100,101,115,107,45,56,50,53,50,48,52,104,2,109,0,0,0,36,98,97,100,48,51,50,52,102,45,99,100,52,54,45,52,57,52,98,45,56,48,100,56,45,101,53,53,48,52,98,48,53,49,97,50,98,109,0,0,0,12,98,117,104,112,104,111,110,101,46,99,111,109,97,0,108,0,0,0,3,104,2,100,0,2,105,112,104,2,104,4,97,192,97,168,97,15,97,222,98,0,0,176,171,104,2,100,0,4,99,111,110,110,100,0,3,99,50,115,104,2,100,0,11,97,117,116,104,95,109,111,100,117,108,101,100,0,18,101,106,97,98,98,101,114,100,95,97,117,116,104,95,111,100,98,99,106>>]}}