How to truncate the redirect log output file in Linux?

I have a program running all the time and redirect the stderr output to a log file.

spark-submit --master local[*] --class my.spark.streaming.program 2>file.log &

Now that the file.log size has exceeded 2GB.

I want to empty it(clear only previous data, retain future data), but the program can't be interrupted.

I used the following command and found that the front of the file was filled with 0x00, but the file size has not changed.

echo "" > file.log

Is there any way to make the running program reset the offset of the file file.log write?

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