is it safe to clear oroginal xlog after archiving it?

hi,
i have archive_command which copies the wal segment someplace.

is it safe, if i would do:
dd if=/dev/zero of=$ORIGINAL_XLOG_SEGMENT bs=1M count=16
before returning from archive_command script?

the point of doing so is pretty simple: i have a system with rather low
traffic, so i use archive_timeout. and most of the xlog segments are
unused, but they contain previous data, since the files are reused.

if zero-ing the files was safe, i could compress them more effectively.

i am aware that there is pg_lesslog or clearxlogtail, but if this
zeroing would be ok, then i'd rather use it (one less program to worry
about, and it looks safer because i modify file that will be overwritten
anyway).

Best regards,

depesz

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