The ST uses huge amounts of memory and that may be pushing your script into swap usage.

Anyway, it seems to me that in your particular case, just sorting the lines unprocessed will produce the same result: 

for my $key(sort keys %hash) {
    print FH1_sorting "$key -> $hash{$key}";
}

[download]

You could also use the external sort program and consolidate duplicates afterwards. Or use some sorting module as Sort::External or Sort::Key.

In reply to Re: perl ST sort performance issue for large file? by salva
in thread perl ST sort performance issue for large file? by rkshyam

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