我可以在Perl中打开的文件句柄数量是否有限制？ [英] Is there a limit to the number of file handles I can open in Perl?
问题描述
我正在设置包含文件句柄的哈希引用。
I am setting up a hash reference containing file handles.
我输入文件的第四列包含一个标识符字段，用于命名文件句柄的目的地：
The fourth column of my input file contains an identifier field that I am using to name the file handle's destination:
col1 col2 col3 id-0008 col5
col1 col2 col3 id-0002 col5
col1 col2 col3 id-0001 col5
col1 col2 col3 id-0001 col5
col1 col2 col3 id-0007 col5
...
col1 col2 col3 id-0003 col5
我使用GNU核心实用程序来获取标识符列表：
I use GNU core utilities to get a list of the identifiers:
$ cut -f4 myFile | sort | uniq
id-0001
id-0002
...
此列中可以有超过1024个唯一标识符，我需要为每个标识符打开一个文件句柄，并将该句柄放入哈希引用中。
There can be more than 1024 unique identifiers in this column, and I need to open a file handle for each identifier and put that handle into a hash reference.
my $fhsRef;
my $fileOfInterest = "/foo/bar/fileOfInterest.txt";
openFileHandles($fileOfInterest);
closeFileHandles();
sub openFileHandles {
my ($fn) = @_;
print STDERR "getting set names... (this may take a few moments)\n";
my $resultStr = `cut -f4 $fn | sort | uniq`;
chomp($resultStr);
my @setNames = split("\n", $resultStr);
foreach my $setName (@setNames) {
my $destDir = "$rootDir/$subDir/$setName"; if (! -d $destDir) { mkpath $destDir; }
my $destFn = "$destDir/coordinates.bed";
local *FILE;
print STDERR "opening handle to: $destFn\n";
open (FILE, "> $destFn") or die "could not open handle to $destFn\n$!\n";
$fhsRef->{$setName}->{fh} = *FILE;
$fhsRef->{$setName}->{fn} = $destFn;
}
}
sub closeFileHandles {
foreach my $setName (keys %{$fhsRef}) {
print STDERR "closing handle to: ".$fhsRef->{$setName}->{fn}."\n";
close $fhsRef->{$setName}->{fh};
}
}
问题是我的代码死了等价 id-1022 ：
The problem is that my code is dying at the equivalent of id-1022:
opening handle to: /foo/bar/baz/id-0001/coordinates.bed
opening handle to: /foo/bar/baz/id-0002/coordinates.bed
...
opening handle to: /foo/bar/baz/id-1022/coordinates.bed
could not open handle to /foo/bar/baz/id-1022/coordinates.bed
0
6144 at ./process.pl line 66.
Perl的上限是否可以打开或存储的文件句柄数量在哈希引用？或者我在其他地方犯了另一个错误？
Is there an upper limit in Perl to the number of file handles I can open or store in a hash reference? Or have I made another mistake elsewhere?
推荐答案
所有编程语言中每个进程的打开文件数量都有限制。
There is a limit to the number of open files per process in all programming languages.
这实际上是操作系统强加的限制，以防止恶意（或虚假）程序消耗系统的所有资源，这可能导致操作系统冻结。
This is actually a limit imposed by the operating system to prevent malicious (or bogus) programs to consume all the resources of the system, which could cause a freeze of the OS.
如果您使用的是基于Linux（非Mac）的操作系统，请查看 ulimit 和 /etc/security/limits.conf文件。
If you are using a Linux-based (non-Mac) OS, check out ulimit and /etc/security/limits.conf.
ulimit -n 2048
这适用于大多数Linux发行版。
This should work on most Linux distros.
我不知道Mac的配置（它在这个特定点上与Unix不同）和/或Windows。
I don't know the configuration for Mac (it differs from Unix on this specific point) and/or Windows.
编辑：
限制操作系统OS X使用 launchctl 工具定义：
The limit os OS X is defined using the launchctl tool:
launchctl limit maxfiles 2048 unlimited
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