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From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 0/3] fix reindex on multiple + overlapping Message-IDs
Date: Mon, 21 Oct 2019 11:02:18 +0000	[thread overview]
Message-ID: <20191021110221.23753-1-e@80x24.org> (raw)
In-Reply-To: <20191016211415.GA6084@dcvr>

This fixes my initial problems around --reindex not picking up
previously-skipped messages, and without having to add extra
command-line options.

It took several iterations and I considered relying on
"git log --reverse" since v2 epochs are limited in size
compared to v1.  But I'm glad we won't have to rely on the
expensive --reverse option and only internally reverse a
few rare messages which have multiple Message-IDs.

I'm actually satisfied with this because it doesn't involve
adding new switches to workaround buggy behavior, since
I considered (and rejected) a "--renumber" option.

original RFC: https://public-inbox.org/meta/20191017112215.GA13175@dcvr/

I'm still testing this with various repos, but the
linux-renesas-soc mirror from lore seems good when doing initial
indexing with an old version of this and using --reindex with
this patch, as all previously-missed messages are now indexed.

Eric Wong (3):
  v2writable: set unindexed article number
  v2writable: improve "num_for" API and disambiguate
  v2writable: reindex handles 3-headered monsters

 TODO                          |   3 +
 lib/PublicInbox/OverIdx.pm    |  14 ++
 lib/PublicInbox/V2Writable.pm | 257 +++++++++++++++++++++++-----------
 t/v2reindex.t                 |  66 +++++++++
 4 files changed, 256 insertions(+), 84 deletions(-)

Interdiff:
diff --git a/lib/PublicInbox/OverIdx.pm b/lib/PublicInbox/OverIdx.pm
index 1ff435d7..64277342 100644
--- a/lib/PublicInbox/OverIdx.pm
+++ b/lib/PublicInbox/OverIdx.pm
@@ -343,18 +343,18 @@ sub remove_oid {
 	$nr;
 }
 
-sub num_for_oid {
+sub num_mid0_for_oid {
 	my ($self, $oid, $mid) = @_;
-	my $num;
+	my ($num, $mid0);
 	$self->begin_lazy;
 	each_by_mid($self, $mid, ['ddd'], sub {
 		my ($smsg) = @_;
 		my $blob = $smsg->{blob};
 		return 1 if (!defined($blob) || $blob ne $oid); # continue;
-		$num = $smsg->{num};
+		($num, $mid0) = ($smsg->{num}, $smsg->{mid});
 		0; # done
 	});
-	$num;
+	($num, $mid0);
 }
 
 sub create_tables {
diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 6e1ac5e3..7ece6b01 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -155,8 +155,7 @@ sub _add {
 	# leaking FDs to it...
 	$self->idx_init;
 
-	my $mid0;
-	my $num = num_for($self, $mime, \$mid0);
+	my ($num, $mid0) = v2_num_for($self, $mime);
 	defined $num or return; # duplicate
 	defined $mid0 or die "BUG: $mid0 undefined\n";
 	my $im = $self->importer;
@@ -172,16 +171,15 @@ sub _add {
 	$cmt;
 }
 
-sub num_for {
-	my ($self, $mime, $mid0) = @_;
+sub v2_num_for {
+	my ($self, $mime) = @_;
 	my $mids = mids($mime->header_obj);
 	if (@$mids) {
 		my $mid = $mids->[0];
 		my $num = $self->{mm}->mid_insert($mid);
 		if (defined $num) { # common case
-			$$mid0 = $mid;
-			return $num;
-		};
+			return ($num, $mid);
+		}
 
 		# crap, Message-ID is already known, hope somebody just resent:
 		foreach my $m (@$mids) {
@@ -190,7 +188,7 @@ sub num_for {
 			# easy, don't store duplicates
 			# note: do not add more diagnostic info here since
 			# it gets noisy on public-inbox-watch restarts
-			return if $existing;
+			return () if $existing;
 		}
 
 		# AltId may pre-populate article numbers (e.g. X-Mail-Count
@@ -201,8 +199,7 @@ sub num_for {
 			my $num = $self->{mm}->num_for($mid);
 
 			if (defined $num && !$self->{over}->get_art($num)) {
-				$$mid0 = $mid;
-				return $num;
+				return ($num, $mid);
 			}
 		}
 
@@ -215,39 +212,38 @@ sub num_for {
 			$num = $self->{mm}->mid_insert($m);
 			if (defined $num) {
 				warn "alternative <$m> for <$mid> found\n";
-				$$mid0 = $m;
-				return $num;
+				return ($num, $m);
 			}
 		}
 	}
 	# none of the existing Message-IDs are good, generate a new one:
-	num_for_harder($self, $mime, $mid0);
+	v2_num_for_harder($self, $mime);
 }
 
-sub num_for_harder {
-	my ($self, $mime, $mid0) = @_;
+sub v2_num_for_harder {
+	my ($self, $mime) = @_;
 
 	my $hdr = $mime->header_obj;
 	my $dig = content_digest($mime);
-	$$mid0 = PublicInbox::Import::digest2mid($dig, $hdr);
-	my $num = $self->{mm}->mid_insert($$mid0);
+	my $mid0 = PublicInbox::Import::digest2mid($dig, $hdr);
+	my $num = $self->{mm}->mid_insert($mid0);
 	unless (defined $num) {
 		# it's hard to spoof the last Received: header
 		my @recvd = $hdr->header_raw('Received');
 		$dig->add("Received: $_") foreach (@recvd);
-		$$mid0 = PublicInbox::Import::digest2mid($dig, $hdr);
-		$num = $self->{mm}->mid_insert($$mid0);
+		$mid0 = PublicInbox::Import::digest2mid($dig, $hdr);
+		$num = $self->{mm}->mid_insert($mid0);
 
 		# fall back to a random Message-ID and give up determinism:
 		until (defined($num)) {
 			$dig->add(rand);
-			$$mid0 = PublicInbox::Import::digest2mid($dig, $hdr);
-			warn "using random Message-ID <$$mid0> as fallback\n";
-			$num = $self->{mm}->mid_insert($$mid0);
+			$mid0 = PublicInbox::Import::digest2mid($dig, $hdr);
+			warn "using random Message-ID <$mid0> as fallback\n";
+			$num = $self->{mm}->mid_insert($mid0);
 		}
 	}
-	PublicInbox::Import::append_mid($hdr, $$mid0);
-	$num;
+	PublicInbox::Import::append_mid($hdr, $mid0);
+	($num, $mid0);
 }
 
 sub idx_shard {
@@ -845,142 +841,157 @@ sub mark_deleted ($$$$) {
 	}
 }
 
-sub regen_art_num ($$$$$) {
-	my ($self, $sync, $git, $oid, $mids) = @_;
-	my $num = $sync->{regen}--;
-	my $mm = $self->{mm};
-	if ($num > 0) {
-		foreach my $mid (reverse @$mids) {
-			if ($mm->mid_set($num, $mid) == 1) {
-				return ($num, $mid);
-			}
-		}
+sub reindex_checkpoint ($$$) {
+	my ($self, $sync, $git) = @_;
 
-		# nope, not using the regen number because either we
-		# have or overlap Message-IDs with another message.
-		$sync->{regen}++;
-		$num = undef;
-	}
-
-	# --reindex was broken when Message-IDs were reused with a
-	# message that already had multiple Message-IDs.  This causes
-	# failures when using --reindex again.  The least bad option is
-	# to show messages twice to NNTP clients, rather than lose/drop
-	# messages entirely.
-	#
-	# create a new article number?
-	for my $mid (@$mids) {
-		$num = $self->{mm}->mid_insert($mid);
-		return ($num, $mid) if defined $num;
-	}
-
-	# swap article numbers with a previously regenerated (newer message)
-	# which has an overlapping Message-ID.  The current $oid is older
-	# than $smsg->{blob} in git history since we regen walks backwards.
-	my $reindex_q = $sync->{reindex_q} //= [];
-	for my $mid (@$mids) {
-		my $n = $self->{mm}->num_for($mid);
-		next unless defined $n;
-		if (my $smsg = $self->{over}->get_art($n)) {
-			push @$reindex_q, $smsg->{blob};
-			return ($n, $mid);
-		}
+	$git->cleanup;
+	$sync->{mm_tmp}->atfork_prepare;
+	$self->done; # release lock
+
+	if (my $pr = $sync->{-opt}->{-progress}) {
+		my ($bn) = (split('/', $git->{git_dir}))[-1];
+		$pr->("$bn ".sprintf($sync->{-regen_fmt}, $sync->{nr}));
 	}
-	warn "W: ran out of article numbers on $oid\n";
-	(undef, undef);
+
+	# allow -watch or -mda to write...
+	$self->idx_init; # reacquire lock
+	$sync->{mm_tmp}->atfork_parent;
 }
 
-sub reindex_oid ($$$$) {
+# only for a few odd messages with multiple Message-IDs
+sub reindex_oid_m ($$$$) {
 	my ($self, $sync, $git, $oid) = @_;
-	my $len;
+	my ($num, $mid0, $len);
 	my $msgref = $git->cat_file($oid, \$len);
 	my $mime = PublicInbox::MIME->new($$msgref);
 	my $mids = mids($mime->header_obj);
 	my $cid = content_id($mime);
+	die "BUG: reindex_oid_m called for <=1 mids" if scalar(@$mids) <= 1;
 
-	# get the NNTP article number we used before, which gets deleted
-	# from sync->{mm_tmp};
-	my $mid0;
-	my $num = -1;
-	my $del = 0;
-	my $reindex = $sync->{reindex};
-	if ($reindex) {
-		# see if it's already in the overview DB, but keep in mind
-		# --reindex may be used blindly w/o overview DB.
-		foreach my $mid (@$mids) {
-			$del += delete($sync->{D}->{"$mid\0$cid"}) ? 1 : 0;
-			my $n = $self->{over}->num_for_oid($oid, $mid);
-			if (defined $n) {
-				($num, $mid0) = ($n, $mid);
-				$self->{mm}->mid_set($num, $mid0);
-				last; # yay! reused
-			}
+	for my $mid (reverse @$mids) {
+		delete($sync->{D}->{"$mid\0$cid"}) and
+			die "BUG: reindex_oid should handle <$mid> delete";
+	}
+	for my $mid (reverse @$mids) {
+		($num, $mid0) = $self->{over}->num_mid0_for_oid($oid, $mid);
+		last if defined $num;
+	}
+	unless (defined($num)) {
+		for my $mid (reverse @$mids) {
+			# is this a number we got before?
+			$num = $sync->{mm_tmp}->num_for($mid);
+			next unless defined $num;
+			$mid0 = $mid;
+			last;
 		}
 	}
-
-	# not reindexing, or reindexing with broken/incomplete overview DB:
-	if (!defined($mid0)) {
-		# highest number wins for unseen messages
-		foreach my $mid (@$mids) {
-			$del += delete($sync->{D}->{"$mid\0$cid"}) ? 1 : 0;
-			my $n = $sync->{mm_tmp}->num_for($mid);
-			if (defined $n && $n > $num) {
-				($num, $mid0) = ($n, $mid);
-				$self->{mm}->mid_set($num, $mid0);
+	if (defined($num)) {
+		$sync->{mm_tmp}->num_delete($num);
+	} else {
+		$num = $sync->{regen}--;
+		if ($num <= 0) {
+			# fixup bugs in old mirrors on reindex
+			for my $mid (reverse @$mids) {
+				$num = $self->{mm}->mid_insert($mid);
+				next unless defined $num;
+				$mid0 = $mid;
+				last;
+			}
+			if (defined $mid0) {
+				if ($sync->{reindex}) {
+					warn "reindex added #$num <$mid0>\n";
+				}
+			} else {
+				warn "E: cannot find article #\n";
+				return;
+			}
+		} else { # $num > 0, use the new article number
+			for my $mid (reverse @$mids) {
+				$self->{mm}->mid_set($num, $mid) == 1 or next;
+				$mid0 = $mid;
+				last;
+			}
+			unless (defined $mid0) {
+				warn "E: cannot regen #$num\n";
+				return;
 			}
 		}
 	}
+	$sync->{nr}++;
+	if (do_idx($self, $msgref, $mime, $len, $num, $oid, $mid0)) {
+		reindex_checkpoint($self, $sync, $git);
+	}
+}
 
-	if (!defined($mid0) && !$del) {
-		($num, $mid0) = regen_art_num($self, $sync, $git, $oid, $mids);
-		if (!defined($mid0)) {
-			my $mm = $self->{mm};
-			my $id = '<' . join('> <', @$mids) . '>';
-			warn "Message-ID $id unusable for $num\n";
-			foreach my $mid (@$mids) {
-				defined(my $n = $mm->num_for($mid)) or next;
-				warn "#$n previously mapped for <$mid>\n";
-			}
-		}
+sub check_unindexed ($$$) {
+	my ($self, $num, $mid0) = @_;
+	my $unindexed = $self->{unindexed} // {};
+	my $n = delete($unindexed->{$mid0});
+	defined $n or return;
+	if ($n != $num) {
+		die "BUG: unindexed $n != $num <$mid0>\n";
+	} else {
+		$self->{mm}->mid_set($num, $mid0);
 	}
+}
 
-	if (!defined($mid0) || $del) {
-		if (!defined($mid0) && $del) { # expected for deletes
-			$num = $sync->{regen}--;
-			if (!$reindex) {
-				($num <= 0) and
-					die "BUG: ran out of article numbers\n";
+sub reindex_oid ($$$$) {
+	my ($self, $sync, $git, $oid) = @_;
+	my ($num, $mid0, $len);
+	my $msgref = $git->cat_file($oid, \$len);
+	return if $len == 0; # purged
+	my $mime = PublicInbox::MIME->new($$msgref);
+	my $mids = mids($mime->header_obj);
+	my $cid = content_id($mime);
+
+	if (scalar(@$mids) == 0) {
+		warn "E: $oid has no Message-ID, skipping\n";
+		return;
+	} elsif (scalar(@$mids) == 1) {
+		my $mid = $mids->[0];
+
+		# was the file previously marked as deleted?, skip if so
+		if (delete($sync->{D}->{"$mid\0$cid"})) {
+			if (!$sync->{reindex}) {
+				$num = $sync->{regen}--;
 				$self->{mm}->num_highwater($num);
 			}
-			return
+			return;
 		}
 
-		my $id = '<' . join('> <', @$mids) . '>';
-		defined($mid0) or
-			warn "Skipping $id, no article number found\n";
-		if ($del && defined($mid0)) {
-			warn "$id was deleted $del " .
-				"time(s) but mapped to article #$num\n";
+		# is this a number we got before?
+		$num = $sync->{mm_tmp}->num_for($mid);
+		if (defined $num) {
+			$mid0 = $mid;
+			check_unindexed($self, $num, $mid0);
+		} else {
+			$num = $sync->{regen}--;
+			die "BUG: ran out of article numbers\n" if $num <= 0;
+			if ($self->{mm}->mid_set($num, $mid) != 1) {
+				warn "E: unable to assign $num => <$mid>\n";
+				return;
+			}
+			$mid0 = $mid;
+		}
+	} else { # multiple MIDs are a weird case:
+		my $del = 0;
+		for (@$mids) {
+			$del += delete($sync->{D}->{"$_\0$cid"}) // 0;
+		}
+		if ($del) {
+			unindex_oid_remote($self, $oid, $_) for @$mids;
+			# do not delete from {mm_tmp}, since another
+			# single-MID message may use it.
+		} else { # handle them at the end:
+			push @{$sync->{multi_mid} //= []}, $oid;
 		}
 		return;
-
 	}
 	$sync->{mm_tmp}->mid_delete($mid0) or
 		die "failed to delete <$mid0> for article #$num\n";
 	$sync->{nr}++;
 	if (do_idx($self, $msgref, $mime, $len, $num, $oid, $mid0)) {
-		$git->cleanup;
-		$sync->{mm_tmp}->atfork_prepare;
-		$self->done; # release lock
-
-		if (my $pr = $sync->{-opt}->{-progress}) {
-			my ($bn) = (split('/', $git->{git_dir}))[-1];
-			$pr->("$bn ".sprintf($sync->{-regen_fmt}, $sync->{nr}));
-		}
-
-		# allow -watch or -mda to write...
-		$self->idx_init; # reacquire lock
-		$sync->{mm_tmp}->atfork_parent;
+		reindex_checkpoint($self, $sync, $git);
 	}
 }
 
@@ -1112,8 +1123,9 @@ sub unindex_oid_remote ($$$) {
 	$self->{over}->remove_oid($oid, $mid);
 }
 
-sub unindex_oid ($$$) {
-	my ($self, $git, $oid) = @_;
+sub unindex_oid ($$$;$) {
+	my ($self, $git, $oid, $unindexed) = @_;
+	my $mm = $self->{mm};
 	my $msgref = $git->cat_file($oid);
 	my $mime = PublicInbox::MIME->new($msgref);
 	my $mids = mids($mime->header_obj);
@@ -1133,8 +1145,11 @@ sub unindex_oid ($$$) {
 				join(',',sort keys %gone), "\n";
 		}
 		foreach my $num (keys %gone) {
-			$self->{unindexed}->{$_}++;
-			$self->{mm}->num_delete($num);
+			if ($unindexed) {
+				my $mid0 = $mm->mid_for($num);
+				$unindexed->{$mid0} = $num;
+			}
+			$mm->num_delete($num);
 		}
 		unindex_oid_remote($self, $oid, $mid);
 	}
@@ -1143,20 +1158,21 @@ sub unindex_oid ($$$) {
 my $x40 = qr/[a-f0-9]{40}/;
 sub unindex ($$$$) {
 	my ($self, $sync, $git, $unindex_range) = @_;
-	my $un = $self->{unindexed} ||= {}; # num => removal count
-	my $before = scalar keys %$un;
+	my $unindexed = $self->{unindexed} ||= {}; # $mid0 => $num
+	my $before = scalar keys %$unindexed;
+	# order does not matter, here:
 	my @cmd = qw(log --raw -r
 			--no-notes --no-color --no-abbrev --no-renames);
 	my $fh = $self->{reindex_pipe} = $git->popen(@cmd, $unindex_range);
 	while (<$fh>) {
 		/\A:\d{6} 100644 $x40 ($x40) [AM]\tm$/o or next;
-		unindex_oid($self, $git, $1);
+		unindex_oid($self, $git, $1, $unindexed);
 	}
 	delete $self->{reindex_pipe};
 	$fh = undef;
 
 	return unless $sync->{-opt}->{prune};
-	my $after = scalar keys %$un;
+	my $after = scalar keys %$unindexed;
 	return if $before == $after;
 
 	# ensure any blob can not longer be accessed via dumb HTTP
@@ -1208,16 +1224,6 @@ sub index_epoch ($$$) {
 		} elsif (/\A:\d{6} 100644 $x40 ($x40) [AM]\td$/o) {
 			mark_deleted($self, $sync, $git, $1);
 		}
-
-		while (my $reindex_q = delete $sync->{reindex_q}) {
-			my $all = $self->{-inbox}->git;
-			for my $oid (@$reindex_q) {
-				$self->{current_info} = "$i.git $oid";
-				warn "reindexing to shuffle article numbers\n";
-				reindex_oid($self, $sync, $all, $oid);
-			}
-			$all->cleanup;
-		}
 	}
 	$fh = undef;
 	delete $self->{reindex_pipe};
@@ -1259,10 +1265,22 @@ sub index_sync {
 
 	# unindex is required for leftovers if "deletes" affect messages
 	# in a previous fetch+index window:
+	my $git;
 	if (my @leftovers = values %{delete $sync->{D}}) {
-		my $git = $self->{-inbox}->git;
-		unindex_oid($self, $git, $_) for @leftovers;
-		$git->cleanup;
+		$git = $self->{-inbox}->git;
+		for my $oid (@leftovers) {
+			$self->{current_info} = "leftover $oid";
+			unindex_oid($self, $git, $oid);
+		}
+	}
+	if (my $multi_mid = delete $sync->{multi_mid}) {
+		$git //= $self->{-inbox}->git;
+
+		while (defined(my $oid = pop(@$multi_mid))) {
+			$self->{current_info} = "multi_mid $oid";
+			reindex_oid_m($self, $sync, $git, $oid);
+		}
+		$git->cleanup if $git;
 	}
 	$self->done;
 
diff --git a/t/v2reindex.t b/t/v2reindex.t
index 5de067c6..52711f8f 100644
--- a/t/v2reindex.t
+++ b/t/v2reindex.t
@@ -491,9 +491,10 @@ EOF
 	remove_tree($xap);
 	eval { $im->index_sync() };
 	is($@, '', 'no error from initial indexing');
+	is_deeply(\@warn, [], 'no warnings from initial index');
 	eval { $im->index_sync({reindex=>1}) };
 	is($@, '', 'no error from reindexing after reused Message-ID (x3)');
-	is_deeply(\@warn, [], 'no warnings');
+	is_deeply(\@warn, [], 'no warnings on reindex');
 }
 
 done_testing();

  parent reply	other threads:[~2019-10-21 11:02 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-16 21:14 BUG: --reindex broken on multiple Message-IDs reuse Eric Wong
2019-10-17 11:22 ` [RFC] v2writable: reindex handles 3-headed monsters [was: BUG: --reindex broken on multiple Message-IDs reuse] Eric Wong
2019-10-22  8:09   ` [RFC/HELP] search: multiple From/To/Cc/Subject (what about Date?) Eric Wong
2019-10-21 11:02 ` Eric Wong [this message]
2019-10-21 11:02   ` [PATCH 1/3] v2writable: set unindexed article number Eric Wong
2019-10-21 11:02   ` [PATCH 2/3] v2writable: improve "num_for" API and disambiguate Eric Wong
2019-10-21 11:02   ` [PATCH 3/3] v2writable: reindex handles 3-headered monsters Eric Wong
2019-10-21 11:34     ` Eric Wong
2019-10-22  1:28     ` [PATCH 4/3] v2writable: move git->cleanup to the correct place Eric Wong
2019-10-22  1:29       ` [PATCH 5/3] v2writable: use msgmap as multi_mid queue Eric Wong
2019-10-23 18:19   ` [PUSHED] fix reindex on multiple + overlapping Message-IDs Eric Wong

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