为提高效率，请提供以下信息，问题描述清晰能够更快得到解决：
【TiDB 版本】4.0.10
MySQL 版本 5.6.22
备份目标库比较大
报错信息 [writer_util.go:202] [“fail to scan from sql.Row”]
一开始是32线程，后来调整到8线程，还是报错 信息内容相同
看
if err = fileRowIter.Decode(row); err != nil {
log.Error(“fail to scan from sql.Row”, zap.Error(err))
return errors.Trace(err)
}
解码失败导致的？
具体日志信息如下
[root@YZ-222-90-222 bin]# ./dumpling -u xx -p xx -P 3306 -h 127.0.0.1 -B xx --filetype sql --threads 32 -o /export/tidb-data/backup/dazhihui -F 512MiB
Release version: v4.0.10
Git commit hash: 5e6981efa173ff525abb31c6e62a50ecd6da6a09
Git branch: heads/refs/tags/v4.0.10
Build timestamp: 2021-01-14 12:39:07Z
Go version: go version go1.13 linux/amd64
[2021/02/19 15:55:55.814 +08:00] [INFO] [config.go:596] [“detect server type”] [type=MySQL]
[2021/02/19 15:55:55.814 +08:00] [INFO] [config.go:615] [“detect server version”] [version=5.6.16-log]
[2021/02/19 15:57:18.655 +08:00] [INFO] [dump.go:173] [“All the dumping transactions have started. Start to unlock tables”]
[2021/02/19 15:59:18.655 +08:00] [INFO] [status.go:37] [progress] [tables=“273/1015 (26.9%)”] [“finished rows”=63246806] [“finished size”=12.85GB] [“average speed(MiB/s)”=102.13631200167188]
[2021/02/19 16:01:18.655 +08:00] [INFO] [status.go:37] [progress] [tables=“299/1015 (29.5%)”] [“finished rows”=134388953] [“finished size”=28.42GB] [“average speed(MiB/s)”=123.7023331049533]
[2021/02/19 16:03:18.655 +08:00] [INFO] [status.go:37] [progress] [tables=“327/1015 (32.2%)”] [“finished rows”=194548953] [“finished size”=43.82GB] [“average speed(MiB/s)”=122.4302868485057]
[2021/02/19 16:05:18.655 +08:00] [INFO] [status.go:37] [progress] [tables=“421/1015 (41.5%)”] [“finished rows”=248285580] [“finished size”=59.09GB] [“average speed(MiB/s)”=121.36668877604895]
[2021/02/19 16:07:18.655 +08:00] [INFO] [status.go:37] [progress] [tables=“512/1015 (50.4%)”] [“finished rows”=311942934] [“finished size”=75.08GB] [“average speed(MiB/s)”=127.06049677014298]
[2021/02/19 16:09:18.655 +08:00] [INFO] [status.go:37] [progress] [tables=“525/1015 (51.7%)”] [“finished rows”=384954932] [“finished size”=90.9GB] [“average speed(MiB/s)”=125.73231293889278]
[2021/02/19 16:11:18.655 +08:00] [INFO] [status.go:37] [progress] [tables=“560/1015 (55.2%)”] [“finished rows”=451870542] [“finished size”=106.9GB] [“average speed(MiB/s)”=127.10284187433716]
[mysql] 2021/02/19 16:12:18 packets.go:36: read tcp 10.222.90.222:58916->172.25.29.26:3306: i/o timeout
[2021/02/19 16:12:18.678 +08:00] [ERROR] [writer_util.go:202] [“fail to scan from sql.Row”] [error=“context canceled”] [errorVerbose=“context canceled\ngithub.com/pingcap/errors.AddStack\
\tgithub.com/pingcap/errors@v0.11.5-0.20200917111840-a15ef68f753d/errors.go:174\
github.com/pingcap/errors.Trace\
\tgithub.com/pingcap/errors@v0.11.5-0.20200917111840-a15ef68f753d/juju_adaptor.go:15\
github.com/pingcap/dumpling/v4/export.decodeFromRows\
\tgithub.com/pingcap/dumpling@/v4/export/ir.go:67\
github.com/pingcap/dumpling/v4/export.(*rowIter).Decode\
\tgithub.com/pingcap/dumpling@/v4/export/ir_impl.go:37\
github.com/pingcap/dumpling/v4/export.WriteInsert\
\tgithub.com/pingcap/dumpling@/v4/export/writer_util.go:201\
github.com/pingcap/dumpling/v4/export.FileFormat.WriteInsert\
\tgithub.com/pingcap/dumpling@/v4/export/writer_util.go:593\
github.com/pingcap/dumpling/v4/export.(*Writer).tryToWriteTableData\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:204\
github.com/pingcap/dumpling/v4/export.(*Writer).WriteTableData.func1\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:190\
github.com/pingcap/br/pkg/utils.WithRetry\
\tgithub.com/pingcap/br@v0.0.0-20201119111016-600102357a27/pkg/utils/retry.go:34\
github.com/pingcap/dumpling/v4/export.(*Writer).WriteTableData\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:161\
github.com/pingcap/dumpling/v4/export.(*Writer).handleTask\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:104\
github.com/pingcap/dumpling/v4/export.(*Writer).run\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:86\
github.com/pingcap/dumpling/v4/export.(*Dumper).startWriters.func4\
\tgithub.com/pingcap/dumpling@/v4/export/dump.go:253\
golang.org/x/sync/errgroup.(*Group).Go.func1\
\tgolang.org/x/sync@v0.0.0-20200625203802-6e8e738ad208/errgroup/errgroup.go:57\
runtime.goexit\
\truntime/asm_amd64.s:1357”] [stack=“github.com/pingcap/dumpling/v4/export.WriteInsert\
\tgithub.com/pingcap/dumpling@/v4/export/writer_util.go:202\
github.com/pingcap/dumpling/v4/export.FileFormat.WriteInsert\
\tgithub.com/pingcap/dumpling@/v4/export/writer_util.go:593\
github.com/pingcap/dumpling/v4/export.(*Writer).tryToWriteTableData\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:204\
github.com/pingcap/dumpling/v4/export.(*Writer).WriteTableData.func1\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:190\
github.com/pingcap/br/pkg/utils.WithRetry\
\tgithub.com/pingcap/br@v0.0.0-20201119111016-600102357a27/pkg/utils/retry.go:34\
github.com/pingcap/dumpling/v4/export.(*Writer).WriteTableData\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:161\
github.com/pingcap/dumpling/v4/export.(*Writer).handleTask\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:104\
github.com/pingcap/dumpling/v4/export.(*Writer).run\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:86\
github.com/pingcap/dumpling/v4/export.(*Dumper).startWriters.func4\
\tgithub.com/pingcap/dumpling@/v4/export/dump.go:253\
golang.org/x/sync/errgroup.(*Group).Go.func1\
\tgolang.org/x/sync@v0.0.0-20200625203802-6e8e738ad208/errgroup/errgroup.go:57”]
[2021/02/19 16:12:18.682 +08:00] [ERROR] [writer_util.go:202] [“fail to scan from sql.Row”] [error=“context canceled”] [errorVerbose=“context canceled\ngithub.com/pingcap/errors.AddStack\
\tgithub.com/pingcap/errors@v0.11.5-0.20200917111840-a15ef68f753d/errors.go:174\
github.com/pingcap/errors.Trace\
\tgithub.com/pingcap/errors@v0.11.5-0.20200917111840-a15ef68f753d/juju_adaptor.go:15\
github.com/pingcap/dumpling/v4/export.decodeFromRows\
\tgithub.com/pingcap/dumpling@/v4/export/ir.go:67\
github.com/pingcap/dumpling/v4/export.(*rowIter).Decode\
\tgithub.com/pingcap/dumpling@/v4/export/ir_impl.go:37\
github.com/pingcap/dumpling/v4/export.WriteInsert\
\tgithub.com/pingcap/dumpling@/v4/export/writer_util.go:201\
github.com/pingcap/dumpling/v4/export.FileFormat.WriteInsert\
\tgithub.com/pingcap/dumpling@/v4/export/writer_util.go:593\
github.com/pingcap/dumpling/v4/export.(*Writer).tryToWriteTableData\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:204\
github.com/pingcap/dumpling/v4/export.(*Writer).WriteTableData.func1\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:190\
github.com/pingcap/br/pkg/utils.WithRetry\
\tgithub.com/pingcap/br@v0.0.0-20201119111016-600102357a27/pkg/utils/retry.go:34\
github.com/pingcap/dumpling/v4/export.(*Writer).WriteTableData\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:161\
github.com/pingcap/dumpling/v4/export.(*Writer).handleTask\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:104\
github.com/pingcap/dumpling/v4/export.(*Writer).run\
\tgithub.com/pingcap/dumpling@/v4/export/writer.go:86\
github.com/pingcap/dumpling/v4/export.(*Dumper).startWriters.func4\
\tgithub.com/pingcap/dumpling@/v4/export/dump.go:253\
golang.org/x/sync/errgroup.(*Group).Go.func1\
\tgolang.org/x/sync@v0.0.0-20200625203802-6e8e738ad208/errgroup/errgroup.go:57\
runtime.goexit\
\truntime/asm_amd64.s:1357”]
