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Date: Fri, 24 Jan 2020 19:07:12 +0000
From: Eric Wong <e@yhbt.net>
To: meta@public-inbox.org
Subject: Re: [PATCH 3/4] ds: tmpio: store offsets per-buffer
Message-ID: <20200124190712.GA10143@dcvr>
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 <20200124094352.19437-4-e@yhbt.net>
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Eric Wong <e@yhbt.net> wrote:
> diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
> index 970061fd..a9ac7fcd 100644
> --- a/lib/PublicInbox/DS.pm
> +++ b/lib/PublicInbox/DS.pm
> @@ -490,12 +491,13 @@ sub drop {
>  # PerlIO::mmap or PerlIO::scalar if needed
>  sub tmpio ($$$) {
>      my ($self, $bref, $off) = @_;
> -    my $fh = tmpfile('wbuf', $self->{sock}, 1) or
> +    my $fh = tmpfile('wbuf', $self->{sock}, O_APPEND) or
>          return drop($self, "tmpfile $!");
>      $fh->autoflush(1);
> +    binmode $fh, ':unix'; # reduce syscalls for read() >8192 bytes

That binmode :unix call triggers a leak in Perl[1], going to
have to squash the patch below to workaround it:

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index a9ac7fcd..c76a5038 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -494,7 +494,6 @@ sub tmpio ($$$) {
     my $fh = tmpfile('wbuf', $self->{sock}, O_APPEND) or
         return drop($self, "tmpfile $!");
     $fh->autoflush(1);
-    binmode $fh, ':unix'; # reduce syscalls for read() >8192 bytes
     my $len = bytes::length($$bref) - $off;
     $fh->write($$bref, $len, $off) or return drop($self, "write ($len): $!");
     [ $fh, 0 ] # [1] = offset, [2] = length, not set by us


... And perhaps just use sysread() instead of read(), since
I'm not seeing a good reason to keep compatibility with
PerlIO::scalar for buffering, after all.

[1] http://nntp.perl.org/group/perl.perl5.porters/256918