bzcat/zcat does eat huge amounts of memory.
Markus Gothe
nietzsche at lysator.liu.se
Sat Apr 20 13:52:57 UTC 2019
Maybe this has been fixed since 1.20.2 or maybe is due to the pipe.
For me it is most notable with bzcat. Will have to investigate this further on Tuesday.
//M
Sent from my BlackBerry — the most secure mobile device
Original Message
From: vda.linux at googlemail.com
Sent: 20 April 2019 14:37
To: nietzsche at lysator.liu.se
Cc: busybox at busybox.net
Subject: Re: bzcat/zcat does eat huge amounts of memory.
On Fri, Apr 19, 2019 at 4:23 PM Markus Gothe <nietzsche at lysator.liu.se> wrote:
>
> Seems to me that the implementation is seriously flawed, it decompress the whole file into the heap and then print it out.
Can't reproduce:
$ ./busybox zcat 392mbyte_gzipped_file.gz >/dev/null & pid=$!; pmap
$pid; while pmap $pid; do sleep 1; done
30164: ./busybox zcat 392mbyte_gzipped_file.gz
0000000008048000 960K r-x-- busybox
0000000008138000 4K rw--- busybox
0000000008139000 4K rw--- [ anon ]
00000000083f6000 4K rw--- [ anon ]
00000000f7741000 64K rw--- [ anon ]
00000000f7751000 12K r---- [ anon ]
00000000f7754000 8K r-x-- [ anon ]
00000000ffa06000 132K rw--- [ stack ]
total 1188K
30164: ./busybox zcat 392mbyte_gzipped_file.gz
0000000008048000 960K r-x-- busybox
0000000008138000 4K rw--- busybox
0000000008139000 4K rw--- [ anon ]
00000000083f6000 4K rw--- [ anon ]
00000000f7741000 64K rw--- [ anon ]
00000000f7751000 12K r---- [ anon ]
00000000f7754000 8K r-x-- [ anon ]
00000000ffa06000 132K rw--- [ stack ]
total 1188K
30164: ./busybox zcat 392mbyte_gzipped_file.gz
0000000008048000 960K r-x-- busybox
0000000008138000 4K rw--- busybox
0000000008139000 4K rw--- [ anon ]
00000000083f6000 4K rw--- [ anon ]
00000000f7741000 64K rw--- [ anon ]
00000000f7751000 12K r---- [ anon ]
00000000f7754000 8K r-x-- [ anon ]
00000000ffa06000 132K rw--- [ stack ]
total 1188K
30164: ./busybox zcat 392mbyte_gzipped_file.gz
0000000008048000 960K r-x-- busybox
0000000008138000 4K rw--- busybox
0000000008139000 4K rw--- [ anon ]
00000000083f6000 4K rw--- [ anon ]
00000000f7741000 64K rw--- [ anon ]
00000000f7751000 12K r---- [ anon ]
00000000f7754000 8K r-x-- [ anon ]
00000000ffa06000 132K rw--- [ stack ]
total 1188K
...
...
30164: ./busybox zcat 392mbyte_gzipped_file.gz
0000000008048000 960K r-x-- busybox
0000000008138000 4K rw--- busybox
0000000008139000 4K rw--- [ anon ]
00000000083f6000 4K rw--- [ anon ]
00000000f7741000 64K rw--- [ anon ]
00000000f7751000 12K r---- [ anon ]
00000000f7754000 8K r-x-- [ anon ]
00000000ffa06000 132K rw--- [ stack ]
total 1188K
I see no memory usage growth. At all.
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