tidb 日志有warn 报警unexpected `Flen` value(-1) in CONCAT's args

Hacker_tn1kaAuv · 2020 年10 月 13 日 06:49

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【TiDB 版本】：V3.0.15
【问题描述】：
tidb 日志一直有下面的warn 告警：
[WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]

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yilong · 2020 年10 月 13 日 07:34

能否发一段包含告警的完整日志，发生前的日志也发送一下，多谢。

Hacker_tn1kaAuv · 2020 年10 月 13 日 07:56

[2020/10/13 15:50:24.065 +08:00] [INFO] [set.go:192] [“set session var”] [conn=1217654] [name=character_set_results] [val=NULL]
[2020/10/13 15:50:24.736 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:50:36.041 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:50:48.101 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:50:50.354 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:50:51.674 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:50:52.066 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:50:52.360 +08:00] [INFO] [server.go:374] [“new connection”] [conn=1217656] [remoteAddr=]
[2020/10/13 15:50:52.398 +08:00] [INFO] [set.go:192] [“set session var”] [conn=1217656] [name=character_set_results] [val=NULL]
[2020/10/13 15:51:08.669 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:51:15.672 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:51:30.195 +08:00] [INFO] [client_batch.go:611] [“recycle idle connection”] [target=]
[2020/10/13 15:51:38.382 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:52:02.195 +08:00] [INFO] [client_batch.go:611] [“recycle idle connection”] [target=]
[2020/10/13 15:52:02.196 +08:00] [INFO] [client_batch.go:611] [“recycle idle connection”] [target=]
[2020/10/13 15:52:08.699 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:52:43.770 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:52:48.337 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:52:52.466 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:53:00.195 +08:00] [INFO] [client_batch.go:611] [“recycle idle connection”] [target=]
[2020/10/13 15:53:14.151 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:53:15.258 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:53:17.195 +08:00] [INFO] [client_batch.go:611] [“recycle idle connection”] [target=]
[2020/10/13 15:53:21.696 +08:00] [INFO] [client_batch.go:611] [“recycle idle connection”] [target=]
[2020/10/13 15:53:25.084 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:53:28.554 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:53:55.308 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:54:16.230 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:54:25.267 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:54:35.603 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:54:42.097 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:54:42.596 +08:00] [INFO] [server.go:374] [“new connection”] [conn=1217665] [remoteAddr=]
[2020/10/13 15:54:42.610 +08:00] [INFO] [set.go:192] [“set session var”] [conn=1217665] [name=character_set_results] [val=NULL]
[2020/10/13 15:54:49.639 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:54:51.888 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:54:53.224 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:54:53.674 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:54:57.870 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:55:12.173 +08:00] [INFO] [server.go:374] [“new connection”] [conn=1217667] [remoteAddr=]
[2020/10/13 15:55:12.187 +08:00] [INFO] [set.go:192] [“set session var”] [conn=1217667] [name=character_set_results] [val=NULL]
[2020/10/13 15:55:18.101 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]
[2020/10/13 15:55:18.874 +08:00] [WARN] [builtin_string.go:269] [“unexpected Flen value(-1) in CONCAT’s args”] [“arg’s index”=0]

yilong · 2020 年10 月 13 日 08:18

您好，请问您这边知道是哪个 sql 导致的报错吗？
如果不清楚，需要开启 general log 来找到报错 sql ，多谢。注意在业务低峰期执行，开启general log 会打印较多日志
https://docs.pingcap.com/zh/tidb/stable/system-variables#tidb_general_log

set tidb_general_log = on; – 找一个 tidb 开启 general log
找到 sql 后，
set tidb_general_log = 0; – 关闭 general log

Hacker_tn1kaAuv · 2020 年10 月 13 日 08:47

开启了，没有报错的SQL

yilong · 2020 年10 月 13 日 09:20

麻烦把开启的日志上传下吧，多谢。
是否有多个 tidb-server，其他tidb-server 有报错吗？换个开启试试，多谢。

Hacker_tn1kaAuv · 2020 年10 月 13 日 09:24

找到了，SELECT
CONCAT(
CAST(OPERDATE AS CHAR),
‘|’,
LPAD(OPERTIME, 8, ‘0’)
) AS POSTSTR 这个concat 为什么会引起报警？

yilong · 2020 年10 月 13 日 09:43

麻烦上传完整的 sql 和使用到的表结构，多谢。

Hacker_tn1kaAuv · 2020 年10 月 13 日 09:50

OPERDATE bigint(20) DEFAULT NULL,
OPERTIME bigint(20) DEFAULT NULL

SELECT
  		CONCAT(
			CAST(OPERDATE AS CHAR),
			'|',
			LPAD(OPERTIME, 8, '0')
		) AS POSTSTR		FROM
		tables

Hacker_tn1kaAuv · 2020 年10 月 13 日 10:07

知道问题原因了，是因为第一个参数在做类型转化的时候，需要定义类型的长度，不然concat 会有warn提示长度为空 unexpected Flen value(-1) ，改成这样就可以了
CONCAT(CAST(OPERDATE AS CHAR(8)),’|’,LPAD(OPERTIME,8,‘0’)) AS POSTSTR,

yilong · 2020 年10 月 13 日 11:04

system · 2022 年10 月 31 日 19:08

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