[BUG]In csv mode, **.dat** files occasionally start with 'INSERT INTO tabName VALUES' in the last line of records

[huangzhiyong]

Describe the bug
With csv enabled, the exported file should be in plain text format. But there is a chance that the last line in the .dat file starts with 'INSERT INTO tabName VALUES'. as follows:

...(omit)
2020004998,...(omit)
INSERT INTO reconciledItem VALUES2020004999,...(omit)

To Reproduce
Command executed:
mydumper -T $tabName -h test.host -u xxxx -p xxxxx -B $DB -k -m -o $outputDir -L $logFile -t 12 --order-by-primary --csv --where "$pkName >= $minNum and $pkName < $curMax"

What mydumper and myloader version has been used?
mydumper 0.12.3-[1,2], built against MySQL 5.7.37-40

Expected behavior
In csv mode, it should be in plain text format, and no SQL should appear

Log
no error log

Environment (please complete the following information):

• OS version: [e.g. CentOS 7.9, Ubuntu 20.04] 4.14.181-140.257.amzn2.x86_64
• MyDumper version: [ mydumper --version ]: mydumper 0.12.3-[1,2], built against MySQL 5.7.37-40