Socket connection with custom pattern causes massive (30sec+) UI lags

[chanibal]

Hi, just happened to get this strange issue. I successfully used serialized log4cxx SocketAppender output before, but had to switch to log4net's third party SocketAppender, that supports only PatternLayout.

OLV does receive logs from it, but does it extremely slow. After closing the sending app, the OLV UI is unusably slow, but does respond after a long time.

Used pattern:

type=log4j
pattern=TIMESTAMP LEVEL [THREAD]  MESSAGE
dateFormat=yyyy-MM-dd HH:mm:ss,SSS
name="Log4j-pattern: %d{ISO8601} %-5p [%t] %m%n [UTF-8]"
charset=UTF-8

Port: 4560

Data that causes the issue:

2020-02-03 17:38:35,706 INFO  [3] Logger attached/custom
2020-02-03 17:38:36,136 INFO  [3] Logger attached/gettype
2020-02-03 17:38:36,175 INFO  [7] Info #0
2020-02-03 17:38:37,182 INFO  [7] Info #1
2020-02-03 17:38:38,735 INFO  [7] Info #2
2020-02-03 17:38:39,742 INFO  [7] Info #3
2020-02-03 17:38:40,747 INFO  [7] Info #4
2020-02-03 17:38:41,754 INFO  [7] Info #5
2020-02-03 17:38:42,760 INFO  [14] Info #6
2020-02-03 17:38:43,775 INFO  [8] Info #7
2020-02-03 17:38:44,781 INFO  [7] Info #8
2020-02-03 17:38:45,787 INFO  [7] Info #9
2020-02-03 17:38:46,792 INFO  [14] Info #10
2020-02-03 17:38:47,797 INFO  [14] Info #11
2020-02-03 17:38:48,810 INFO  [14] Info #12
2020-02-03 17:38:49,831 INFO  [14] Info #13
2020-02-03 17:38:50,836 INFO  [8] Info #14
2020-02-03 17:38:51,839 INFO  [8] Info #15
2020-02-03 17:38:52,844 INFO  [14] Info #16

The above is attached as a file exactly as it went through the socket.

To replicate the issue, netcat the attachment to OLV:

nc localhost 4560 <debug.txt

Windows 10 Pro 64 bit (1903/18362.295), openjdk 13.0.1 2019-10-15.