it happens time out per 1minute when use etcd v3 watch method

problem

when I use etcd v3 watch method(default params),The following questions occurs:

1. it happens time out per 1minute .
2. There is a lot of connection building with etcd server in per worker progress

log info:

2020/04/15 15:05:34 [info] 9020#9020: *20628390 [lua] v3.lua:502: request_chunk(): http request method: POST path: /v3beta/watch body: {"create_request":{"range_end":"*********","start_revision":6647555,"key":"L2V0Y2QvY2ZnL2dsb2JhbA=="}} query: nil, context: ngx.timer
2020/04/15 15:06:34 [info] 9020#9020: *20628390 [lua] v3.lua:502: request_chunk(): http request method: POST path: /v3beta/watch body: {"create_request":{"range_end":"*********","start_revision":6647555,"key":"L2V0Y2QvY2ZnL2dsb2JhbA=="}} query: nil, context: ngx.timer
2020/04/15 15:07:34 [info] 9020#9020: *20628390 [lua] v3.lua:502: request_chunk(): http request method: POST path: /v3beta/watch body: {"create_request":{"range_end":"*********","start_revision":6647555,"key":"L2V0Y2QvY2ZnL2dsb2JhbA=="}} query: nil, context: ngx.timer
2020/04/15 15:08:34 [info] 9020#9020: *20628390 [lua] v3.lua:502: request_chunk(): http request method: POST path: /v3beta/watch body: {"create_request":{"range_end":"*********","start_revision":6647555,"key":"L2V0Y2QvY2ZnL2dsb2JhbA=="}} query: nil, context: ngx.timer
.......

other info:

etcd endpoints has three ip list such as (1.1.1.1:2379;1.1.1.2:2379;1.1.1.3:2379;)

connection info:
such as worker id: 9020 exits 58 establish connection

root@****:~# netstat -apn|grep 2379 |grep 'ESTABLISHED 9020' |wc -l
58

@YuanSheng Wang Have you met this problem? How to solve

Start with the watch implementation in v3.lua, especially request_chunk() around line 502, and reproduce the report using the default watch parameters and the three listed etcd endpoints. Trace the one-minute timeout and repeated connections from the log, then verify that the resolved behavior no longer produces the reported timeout or connection buildup.