X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FSearchIdx.pm;h=8810fe76450dde64728d715e4e63f14b3c6bb741;hb=d73d783ab2cf14ba28ca63723223d8c85a68cdd5;hp=25452daec4280eae41a3d8f311c49bd2d5c0cbde;hpb=6ca633a1360a0974a8ebb117554a856022d797c6;p=public-inbox.git

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index 25452dae..eb620f44 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -1,620 +1,860 @@
-# Copyright (C) 2015 all contributors <meta@public-inbox.org>
-# License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt)
+# Copyright (C) 2015-2020 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 # based on notmuch, but with no concept of folders, files or flags
 #
 # Indexes mail with Xapian and our (SQLite-based) ::Msgmap for use
 # with the web and NNTP interfaces.  This index maintains thread
-# relationships for use by Mail::Thread.  This writes to the search
-# index.
+# relationships for use by PublicInbox::SearchThread.
+# This writes to the search index.
 package PublicInbox::SearchIdx;
 use strict;
-use warnings;
-use Fcntl qw(:flock :DEFAULT);
-use Email::MIME;
-use Email::MIME::ContentType;
-$Email::MIME::ContentType::STRICT_PARAMS = 0;
-use base qw(PublicInbox::Search);
-use PublicInbox::MID qw/mid_clean id_compress mid_mime/;
+use v5.10.1;
+use parent qw(PublicInbox::Search PublicInbox::Lock Exporter);
+use PublicInbox::Eml;
+use PublicInbox::InboxWritable;
+use PublicInbox::MID qw(mids_for_index mids);
 use PublicInbox::MsgIter;
+use PublicInbox::IdxStack;
 use Carp qw(croak);
 use POSIX qw(strftime);
-require PublicInbox::Git;
-*xpfx = *PublicInbox::Search::xpfx;
-
-use constant MAX_MID_SIZE => 244; # max term size - 1 in Xapian
-use constant {
-	PERM_UMASK => 0,
-	OLD_PERM_GROUP => 1,
-	OLD_PERM_EVERYBODY => 2,
-	PERM_GROUP => 0660,
-	PERM_EVERYBODY => 0664,
-};
+use PublicInbox::OverIdx;
+use PublicInbox::Spawn qw(spawn nodatacow_dir);
+use PublicInbox::Git qw(git_unquote);
+use PublicInbox::MsgTime qw(msg_timestamp msg_datestamp);
+our @EXPORT_OK = qw(crlf_adjust log2stack is_ancestor check_size);
+my $X = \%PublicInbox::Search::X;
+my ($DB_CREATE_OR_OPEN, $DB_OPEN);
+our $DB_NO_SYNC = 0;
+our $BATCH_BYTES = $ENV{XAPIAN_FLUSH_THRESHOLD} ? 0x7fffffff : 1_000_000;
+use constant DEBUG => !!$ENV{DEBUG};
+
+my $xapianlevels = qr/\A(?:full|medium)\z/;
+my $hex = '[a-f0-9]';
+my $OID = $hex .'{40,}';
 
 sub new {
-	my ($class, $inbox, $creat) = @_;
-	my $git_dir = $inbox;
-	my $altid;
-	if (ref $inbox) {
-		$git_dir = $inbox->{mainrepo};
-		$altid = $inbox->{altid};
-		if ($altid) {
-			require PublicInbox::AltId;
-			$altid = [ map {
-				PublicInbox::AltId->new($inbox, $_);
-			} @$altid ];
+	my ($class, $ibx, $creat, $shard) = @_;
+	ref $ibx or die "BUG: expected PublicInbox::Inbox object: $ibx";
+	my $levels = qr/\A(?:full|medium|basic)\z/;
+	my $inboxdir = $ibx->{inboxdir};
+	my $version = $ibx->version;
+	my $indexlevel = 'full';
+	my $altid = $ibx->{altid};
+	if ($altid) {
+		require PublicInbox::AltId;
+		$altid = [ map { PublicInbox::AltId->new($ibx, $_); } @$altid ];
+	}
+	if ($ibx->{indexlevel}) {
+		if ($ibx->{indexlevel} =~ $levels) {
+			$indexlevel = $ibx->{indexlevel};
+		} else {
+			die("Invalid indexlevel $ibx->{indexlevel}\n");
 		}
 	}
-	require Search::Xapian::WritableDatabase;
-	my $self = bless { git_dir => $git_dir, -altid => $altid }, $class;
-	my $perm = $self->_git_config_perm;
-	my $umask = _umask_for($perm);
-	$self->{umask} = $umask;
-	$self->{lock_path} = "$git_dir/ssoma.lock";
-	$self->{git} = PublicInbox::Git->new($git_dir);
+	$ibx = PublicInbox::InboxWritable->new($ibx);
+	my $self = bless {
+		ibx => $ibx,
+		xpfx => $inboxdir, # for xpfx_init
+		-altid => $altid,
+		ibx_ver => $version,
+		indexlevel => $indexlevel,
+	}, $class;
+	$self->xpfx_init;
+	$self->{-set_indexlevel_once} = 1 if $indexlevel eq 'medium';
+	if ($ibx->{-skip_docdata}) {
+		$self->{-set_skip_docdata_once} = 1;
+		$self->{-skip_docdata} = 1;
+	}
+	$ibx->umask_prepare;
+	if ($version == 1) {
+		$self->{lock_path} = "$inboxdir/ssoma.lock";
+		my $dir = $self->xdir;
+		$self->{oidx} = PublicInbox::OverIdx->new("$dir/over.sqlite3");
+		$self->{oidx}->{-no_fsync} = 1 if $ibx->{-no_fsync};
+	} elsif ($version == 2) {
+		defined $shard or die "shard is required for v2\n";
+		# shard is a number
+		$self->{shard} = $shard;
+		$self->{lock_path} = undef;
+	} else {
+		die "unsupported inbox version=$version\n";
+	}
 	$self->{creat} = ($creat || 0) == 1;
 	$self;
 }
 
-sub _xdb_release {
-	my ($self) = @_;
-	my $xdb = delete $self->{xdb} or croak 'not acquired';
-	$xdb->close;
-	_lock_release($self) if $self->{creat};
-	undef;
-}
+sub need_xapian ($) { $_[0]->{indexlevel} =~ $xapianlevels }
 
-sub _xdb_acquire {
-	my ($self) = @_;
-	croak 'already acquired' if $self->{xdb};
-	my $dir = PublicInbox::Search->xdir($self->{git_dir});
-	my $flag = Search::Xapian::DB_OPEN;
-	if ($self->{creat}) {
-		require File::Path;
-		_lock_acquire($self);
-		File::Path::mkpath($dir);
-		$self->{batch_size} = 100;
-		$flag = Search::Xapian::DB_CREATE_OR_OPEN;
+sub idx_release {
+	my ($self, $wake) = @_;
+	if (need_xapian($self)) {
+		my $xdb = delete $self->{xdb} or croak 'not acquired';
+		$xdb->close;
 	}
-	$self->{xdb} = Search::Xapian::WritableDatabase->new($dir, $flag);
+	$self->lock_release($wake) if $self->{creat};
+	undef;
 }
 
-# we only acquire the flock if creating or reindexing;
-# PublicInbox::Import already has the lock on its own.
-sub _lock_acquire {
-	my ($self) = @_;
-	croak 'already locked' if $self->{lockfh};
-	sysopen(my $lockfh, $self->{lock_path}, O_WRONLY|O_CREAT) or
-		die "failed to open lock $self->{lock_path}: $!\n";
-	flock($lockfh, LOCK_EX) or die "lock failed: $!\n";
-	$self->{lockfh} = $lockfh;
+sub load_xapian_writable () {
+	return 1 if $X->{WritableDatabase};
+	PublicInbox::Search::load_xapian() or return;
+	my $xap = $PublicInbox::Search::Xap;
+	for (qw(Document TermGenerator WritableDatabase)) {
+		$X->{$_} = $xap.'::'.$_;
+	}
+	eval 'require '.$X->{WritableDatabase} or die;
+	*sortable_serialise = $xap.'::sortable_serialise';
+	$DB_CREATE_OR_OPEN = eval($xap.'::DB_CREATE_OR_OPEN()');
+	$DB_OPEN = eval($xap.'::DB_OPEN()');
+	my $ver = (eval($xap.'::major_version()') << 16) |
+		(eval($xap.'::minor_version()') << 8);
+	$DB_NO_SYNC = 0x4 if $ver >= 0x10400;
+	1;
 }
 
-sub _lock_release {
+sub idx_acquire {
 	my ($self) = @_;
-	my $lockfh = delete $self->{lockfh} or croak 'not locked';
-	flock($lockfh, LOCK_UN) or die "unlock failed: $!\n";
-	close $lockfh or die "close failed: $!\n";
+	my $flag;
+	my $dir = $self->xdir;
+	if (need_xapian($self)) {
+		croak 'already acquired' if $self->{xdb};
+		load_xapian_writable();
+		$flag = $self->{creat} ? $DB_CREATE_OR_OPEN : $DB_OPEN;
+	}
+	if ($self->{creat}) {
+		require File::Path;
+		$self->lock_acquire;
+
+		# don't create empty Xapian directories if we don't need Xapian
+		my $is_shard = defined($self->{shard});
+		if (!-d $dir && (!$is_shard ||
+				($is_shard && need_xapian($self)))) {
+			File::Path::mkpath($dir);
+			nodatacow_dir($dir);
+			$self->{-set_has_threadid_once} = 1;
+		}
+	}
+	return unless defined $flag;
+	$flag |= $DB_NO_SYNC if $self->{ibx}->{-no_fsync};
+	my $xdb = eval { ($X->{WritableDatabase})->new($dir, $flag) };
+	croak "Failed opening $dir: $@" if $@;
+	$self->{xdb} = $xdb;
 }
 
 sub add_val ($$$) {
 	my ($doc, $col, $num) = @_;
-	$num = Search::Xapian::sortable_serialise($num);
+	$num = sortable_serialise($num);
 	$doc->add_value($col, $num);
 }
 
-sub add_values ($$$) {
-	my ($smsg, $bytes, $num) = @_;
-
-	my $ts = $smsg->ts;
-	my $doc = $smsg->{doc};
-	add_val($doc, &PublicInbox::Search::TS, $ts);
-
-	defined($num) and add_val($doc, &PublicInbox::Search::NUM, $num);
-
-	defined($bytes) and add_val($doc, &PublicInbox::Search::BYTES, $bytes);
-
-	add_val($doc, &PublicInbox::Search::LINES,
-			$smsg->{mime}->body_raw =~ tr!\n!\n!);
+sub term_generator ($) { # write-only
+	my ($self) = @_;
 
-	my $yyyymmdd = strftime('%Y%m%d', gmtime($ts));
-	$doc->add_value(&PublicInbox::Search::YYYYMMDD, $yyyymmdd);
+	$self->{term_generator} //= do {
+		my $tg = $X->{TermGenerator}->new;
+		$tg->set_stemmer($self->stemmer);
+		$tg;
+	}
 }
 
-sub index_users ($$) {
-	my ($tg, $smsg) = @_;
-
-	my $from = $smsg->from;
-	my $to = $smsg->to;
-	my $cc = $smsg->cc;
+sub index_text ($$$$) {
+	my ($self, $text, $wdf_inc, $prefix) = @_;
+	my $tg = term_generator($self); # man Search::Xapian::TermGenerator
 
-	$tg->index_text($from, 1, 'A'); # A - author
-	$tg->increase_termpos;
-	$tg->index_text($to, 1, 'XTO') if $to ne '';
-	$tg->increase_termpos;
-	$tg->index_text($cc, 1, 'XCC') if $cc ne '';
-	$tg->increase_termpos;
+	if ($self->{indexlevel} eq 'full') {
+		$tg->index_text($text, $wdf_inc, $prefix);
+		$tg->increase_termpos;
+	} else {
+		$tg->index_text_without_positions($text, $wdf_inc, $prefix);
+	}
 }
 
-sub add_message {
-	my ($self, $mime, $bytes, $num, $blob) = @_; # mime = Email::MIME object
-	my $db = $self->{xdb};
-
-	my ($doc_id, $old_tid);
-	my $mid = mid_clean(mid_mime($mime));
-	my $ct_msg = $mime->header('Content-Type') || 'text/plain';
+sub index_headers ($$) {
+	my ($self, $smsg) = @_;
+	my @x = (from => 'A', # Author
+		subject => 'S', to => 'XTO', cc => 'XCC');
+	while (my ($field, $pfx) = splice(@x, 0, 2)) {
+		my $val = $smsg->{$field};
+		index_text($self, $val, 1, $pfx) if $val ne '';
+	}
+}
 
-	eval {
-		die 'Message-ID too long' if length($mid) > MAX_MID_SIZE;
-		my $smsg = $self->lookup_message($mid);
-		if ($smsg) {
-			# convert a ghost to a regular message
-			# it will also clobber any existing regular message
-			$doc_id = $smsg->doc_id;
-			$old_tid = $smsg->thread_id;
+sub index_diff_inc ($$$$) {
+	my ($self, $text, $pfx, $xnq) = @_;
+	if (@$xnq) {
+		index_text($self, join("\n", @$xnq), 1, 'XNQ');
+		@$xnq = ();
+	}
+	index_text($self, $text, 1, $pfx);
+}
+
+sub index_old_diff_fn {
+	my ($self, $seen, $fa, $fb, $xnq) = @_;
+
+	# no renames or space support for traditional diffs,
+	# find the number of leading common paths to strip:
+	my @fa = split('/', $fa);
+	my @fb = split('/', $fb);
+	while (scalar(@fa) && scalar(@fb)) {
+		$fa = join('/', @fa);
+		$fb = join('/', @fb);
+		if ($fa eq $fb) {
+			unless ($seen->{$fa}++) {
+				index_diff_inc($self, $fa, 'XDFN', $xnq);
+			}
+			return 1;
 		}
-		$smsg = PublicInbox::SearchMsg->new($mime);
-		my $doc = $smsg->{doc};
-		$doc->add_term(xpfx('mid') . $mid);
-
-		my $subj = $smsg->subject;
-		if ($subj ne '') {
-			my $path = $self->subject_path($subj);
-			$doc->add_term(xpfx('path') . id_compress($path));
+		shift @fa;
+		shift @fb;
+	}
+	0;
+}
+
+sub index_diff ($$$) {
+	my ($self, $txt, $doc) = @_;
+	my %seen;
+	my $in_diff;
+	my @xnq;
+	my $xnq = \@xnq;
+	foreach (split(/\n/, $txt)) {
+		if ($in_diff && s/^ //) { # diff context
+			index_diff_inc($self, $_, 'XDFCTX', $xnq);
+		} elsif (/^-- $/) { # email signature begins
+			$in_diff = undef;
+		} elsif (m!^diff --git "?[^/]+/.+ "?[^/]+/.+\z!) {
+			# wait until "---" and "+++" to capture filenames
+			$in_diff = 1;
+		# traditional diff:
+		} elsif (m/^diff -(.+) (\S+) (\S+)$/) {
+			my ($opt, $fa, $fb) = ($1, $2, $3);
+			push @xnq, $_;
+			# only support unified:
+			next unless $opt =~ /[uU]/;
+			$in_diff = index_old_diff_fn($self, \%seen, $fa, $fb,
+							$xnq);
+		} elsif (m!^--- ("?[^/]+/.+)!) {
+			my $fn = $1;
+			$fn = (split('/', git_unquote($fn), 2))[1];
+			$seen{$fn}++ or index_diff_inc($self, $fn, 'XDFN', $xnq);
+			$in_diff = 1;
+		} elsif (m!^\+\+\+ ("?[^/]+/.+)!)  {
+			my $fn = $1;
+			$fn = (split('/', git_unquote($fn), 2))[1];
+			$seen{$fn}++ or index_diff_inc($self, $fn, 'XDFN', $xnq);
+			$in_diff = 1;
+		} elsif (/^--- (\S+)/) {
+			$in_diff = $1;
+			push @xnq, $_;
+		} elsif (defined $in_diff && /^\+\+\+ (\S+)/) {
+			$in_diff = index_old_diff_fn($self, \%seen, $in_diff,
+							$1, $xnq);
+		} elsif ($in_diff && s/^\+//) { # diff added
+			index_diff_inc($self, $_, 'XDFB', $xnq);
+		} elsif ($in_diff && s/^-//) { # diff removed
+			index_diff_inc($self, $_, 'XDFA', $xnq);
+		} elsif (m!^index ([a-f0-9]+)\.\.([a-f0-9]+)!) {
+			my ($ba, $bb) = ($1, $2);
+			index_git_blob_id($doc, 'XDFPRE', $ba);
+			index_git_blob_id($doc, 'XDFPOST', $bb);
+			$in_diff = 1;
+		} elsif (/^@@ (?:\S+) (?:\S+) @@\s*$/) {
+			# traditional diff w/o -p
+		} elsif (/^@@ (?:\S+) (?:\S+) @@\s*(\S+.*)$/) {
+			# hunk header context
+			index_diff_inc($self, $1, 'XDFHH', $xnq);
+		# ignore the following lines:
+		} elsif (/^(?:dis)similarity index/ ||
+				/^(?:old|new) mode/ ||
+				/^(?:deleted|new) file mode/ ||
+				/^(?:copy|rename) (?:from|to) / ||
+				/^(?:dis)?similarity index / ||
+				/^\\ No newline at end of file/ ||
+				/^Binary files .* differ/) {
+			push @xnq, $_;
+		} elsif ($_ eq '') {
+			# possible to be in diff context, some mail may be
+			# stripped by MUA or even GNU diff(1).  "git apply"
+			# treats a bare "\n" as diff context, too
+		} else {
+			push @xnq, $_;
+			warn "non-diff line: $_\n" if DEBUG && $_ ne '';
+			$in_diff = undef;
 		}
+	}
 
-		add_values($smsg, $bytes, $num);
+	index_text($self, join("\n", @xnq), 1, 'XNQ');
+}
 
-		my $tg = $self->term_generator;
+sub index_xapian { # msg_iter callback
+	my $part = $_[0]->[0]; # ignore $depth and $idx
+	my ($self, $doc) = @{$_[1]};
+	my $ct = $part->content_type || 'text/plain';
+	my $fn = $part->filename;
+	if (defined $fn && $fn ne '') {
+		index_text($self, $fn, 1, 'XFN');
+	}
+	if ($part->{is_submsg}) {
+		my $mids = mids_for_index($part);
+		index_ids($self, $doc, $part, $mids);
+		my $smsg = bless {}, 'PublicInbox::Smsg';
+		$smsg->populate($part);
+		index_headers($self, $smsg);
+	}
 
-		$tg->set_document($doc);
-		$tg->index_text($subj, 1, 'S') if $subj;
-		$tg->increase_termpos;
+	my ($s, undef) = msg_part_text($part, $ct);
+	defined $s or return;
+	$_[0]->[0] = $part = undef; # free memory
 
-		index_users($tg, $smsg);
-
-		msg_iter($mime, sub {
-			my ($part, $depth, @idx) = @{$_[0]};
-			my $ct = $part->content_type || $ct_msg;
-
-			# account for filter bugs...
-			$ct =~ m!\btext/plain\b!i or return;
-
-			my (@orig, @quot);
-			my $body = $part->body;
-			$part->body_set('');
-			my @lines = split(/\n/, $body);
-			while (defined(my $l = shift @lines)) {
-				if ($l =~ /^>/) {
-					push @quot, $l;
-				} else {
-					push @orig, $l;
-				}
-			}
-			if (@quot) {
-				my $s = join("\n", @quot);
-				@quot = ();
-				$tg->index_text($s, 0, 'XQUOT');
-				$tg->increase_termpos;
-			}
-			if (@orig) {
-				my $s = join("\n", @orig);
-				@orig = ();
-				$tg->index_text($s, 1, 'XNQ');
-				$tg->increase_termpos;
+	# split off quoted and unquoted blocks:
+	my @sections = PublicInbox::MsgIter::split_quotes($s);
+	undef $s; # free memory
+	for my $txt (@sections) {
+		if ($txt =~ /\A>/) {
+			index_text($self, $txt, 0, 'XQUOT');
+		} else {
+			# does it look like a diff?
+			if ($txt =~ /^(?:diff|---|\+\+\+) /ms) {
+				index_diff($self, $txt, $doc);
+			} else {
+				index_text($self, $txt, 1, 'XNQ');
 			}
-		});
+		}
+		undef $txt; # free memory
+	}
+}
 
-		link_message($self, $smsg, $old_tid);
-		$tg->index_text($mid, 1, 'XMID');
-		$doc->set_data($smsg->to_doc_data($blob));
+sub index_ids ($$$$) {
+	my ($self, $doc, $hdr, $mids) = @_;
+	for my $mid (@$mids) {
+		index_text($self, $mid, 1, 'XM');
 
-		if (my $altid = $self->{-altid}) {
-			foreach my $alt (@$altid) {
+		# because too many Message-IDs are prefixed with
+		# "Pine.LNX."...
+		if ($mid =~ /\w{12,}/) {
+			my @long = ($mid =~ /(\w{3,}+)/g);
+			index_text($self, join(' ', @long), 1, 'XM');
+		}
+	}
+	$doc->add_boolean_term('Q' . $_) for @$mids;
+	for my $l ($hdr->header_raw('List-Id')) {
+		$l =~ /<([^>]+)>/ or next;
+		my $lid = $1;
+		$doc->add_boolean_term('G' . $lid);
+		index_text($self, $lid, 1, 'XL'); # probabilistic
+	}
+}
+
+sub add_xapian ($$$$) {
+	my ($self, $eml, $smsg, $mids) = @_;
+	my $doc = $X->{Document}->new;
+	add_val($doc, PublicInbox::Search::TS(), $smsg->{ts});
+	my @ds = gmtime($smsg->{ds});
+	my $yyyymmdd = strftime('%Y%m%d', @ds);
+	add_val($doc, PublicInbox::Search::YYYYMMDD(), $yyyymmdd);
+	my $dt = strftime('%Y%m%d%H%M%S', @ds);
+	add_val($doc, PublicInbox::Search::DT(), $dt);
+	add_val($doc, PublicInbox::Search::BYTES(), $smsg->{bytes});
+	add_val($doc, PublicInbox::Search::UID(), $smsg->{num});
+	add_val($doc, PublicInbox::Search::THREADID, $smsg->{tid});
+
+	my $tg = term_generator($self);
+	$tg->set_document($doc);
+	index_headers($self, $smsg);
+
+	msg_iter($eml, \&index_xapian, [ $self, $doc ]);
+	index_ids($self, $doc, $eml, $mids);
+
+	# by default, we maintain compatibility with v1.5.0 and earlier
+	# by writing to docdata.glass, users who never exect to downgrade can
+	# use --skip-docdata
+	if (!$self->{-skip_docdata}) {
+		# WWW doesn't need {to} or {cc}, only NNTP
+		$smsg->{to} = $smsg->{cc} = '';
+		PublicInbox::OverIdx::parse_references($smsg, $eml, $mids);
+		my $data = $smsg->to_doc_data;
+		$doc->set_data($data);
+	}
+
+	if (my $altid = $self->{-altid}) {
+		foreach my $alt (@$altid) {
+			my $pfx = $alt->{xprefix};
+			foreach my $mid (@$mids) {
 				my $id = $alt->mid2alt($mid);
 				next unless defined $id;
-				$doc->add_term($alt->{xprefix} . $id);
+				$doc->add_boolean_term($pfx . $id);
 			}
 		}
-		if (defined $doc_id) {
-			$db->replace_document($doc_id, $doc);
-		} else {
-			$doc_id = $db->add_document($doc);
-		}
-	};
-
-	if ($@) {
-		warn "failed to index message <$mid>: $@\n";
-		return undef;
 	}
-	$doc_id;
+	$self->{xdb}->replace_document($smsg->{num}, $doc);
 }
 
-# returns deleted doc_id on success, undef on missing
-sub remove_message {
-	my ($self, $mid) = @_;
-	my $db = $self->{xdb};
-	my $doc_id;
-	$mid = mid_clean($mid);
+sub _msgmap_init ($) {
+	my ($self) = @_;
+	die "BUG: _msgmap_init is only for v1\n" if $self->{ibx_ver} != 1;
+	$self->{mm} //= eval {
+		require PublicInbox::Msgmap;
+		my $rw = $self->{ibx}->{-no_fsync} ? 2 : 1;
+		PublicInbox::Msgmap->new($self->{ibx}->{inboxdir}, $rw);
+	};
+}
+
+sub add_message {
+	# mime = PublicInbox::Eml or Email::MIME object
+	my ($self, $mime, $smsg, $sync) = @_;
+	my $mids = mids_for_index($mime);
+	$smsg //= bless { blob => '' }, 'PublicInbox::Smsg'; # test-only compat
+	$smsg->{mid} //= $mids->[0]; # v1 compatibility
+	$smsg->{num} //= do { # v1
+		_msgmap_init($self);
+		index_mm($self, $mime, $smsg->{blob}, $sync);
+	};
+
+	# v1 and tests only:
+	$smsg->populate($mime, $sync);
+	$smsg->{bytes} //= length($mime->as_string);
 
 	eval {
-		$doc_id = $self->find_unique_doc_id('mid', $mid);
-		$db->delete_document($doc_id) if defined $doc_id;
+		# order matters, overview stores every possible piece of
+		# data in doc_data (deflated).  Xapian only stores a subset
+		# of the fields which exist in over.sqlite3.  We may stop
+		# storing doc_data in Xapian sometime after we get multi-inbox
+		# search working.
+		if (my $oidx = $self->{oidx}) { # v1 only
+			$oidx->add_overview($mime, $smsg);
+		}
+		if (need_xapian($self)) {
+			add_xapian($self, $mime, $smsg, $mids);
+		}
 	};
 
 	if ($@) {
-		warn "failed to remove message <$mid>: $@\n";
+		warn "failed to index message <".join('> <',@$mids).">: $@\n";
 		return undef;
 	}
-	$doc_id;
+	$smsg->{num};
+}
+
+sub xdb_remove {
+	my ($self, $oid, @removed) = @_;
+	my $xdb = $self->{xdb} or return;
+	for my $num (@removed) {
+		my $doc = eval { $xdb->get_document($num) };
+		unless ($doc) {
+			warn "E: $@\n" if $@;
+			warn "E: #$num $oid missing in Xapian\n";
+			next;
+		}
+		my $smsg = bless {}, 'PublicInbox::Smsg';
+		$smsg->load_expand($doc);
+		my $blob = $smsg->{blob} // '(unset)';
+		if ($blob eq $oid) {
+			$xdb->delete_document($num);
+		} else {
+			warn "E: #$num $oid != $blob in Xapian\n";
+		}
+	}
 }
 
-sub term_generator { # write-only
-	my ($self) = @_;
-
-	my $tg = $self->{term_generator};
-	return $tg if $tg;
+sub remove_by_oid {
+	my ($self, $oid, $num) = @_;
+	die "BUG: remove_by_oid is v2-only\n" if $self->{oidx};
+	$self->begin_txn_lazy;
+	xdb_remove($self, $oid, $num) if need_xapian($self);
+}
 
-	$tg = Search::Xapian::TermGenerator->new;
-	$tg->set_stemmer($self->stemmer);
+sub index_git_blob_id {
+	my ($doc, $pfx, $objid) = @_;
 
-	$self->{term_generator} = $tg;
+	my $len = length($objid);
+	for (my $len = length($objid); $len >= 7; ) {
+		$doc->add_term($pfx.$objid);
+		$objid = substr($objid, 0, --$len);
+	}
 }
 
-# increments last_thread_id counter
-# returns a 64-bit integer represented as a hex string
-sub next_thread_id {
-	my ($self) = @_;
-	my $db = $self->{xdb};
-	my $last_thread_id = int($db->get_metadata('last_thread_id') || 0);
-
-	$db->set_metadata('last_thread_id', ++$last_thread_id);
-
-	$last_thread_id;
-}
-
-sub link_message {
-	my ($self, $smsg, $old_tid) = @_;
-	my $doc = $smsg->{doc};
-	my $mid = $smsg->mid;
-	my $mime = $smsg->mime;
-	my $hdr = $mime->header_obj;
-	my $refs = $hdr->header_raw('References');
-	my @refs = $refs ? ($refs =~ /<([^>]+)>/g) : ();
-	if (my $irt = $hdr->header_raw('In-Reply-To')) {
-		# last References should be $irt
-		# we will de-dupe later
-		push @refs, mid_clean($irt);
-	}
-
-	my $tid;
-	if (@refs) {
-		my %uniq = ($mid => 1);
-		my @orig_refs = @refs;
-		@refs = ();
-
-		# prevent circular references via References: here:
-		foreach my $ref (@orig_refs) {
-			if (length($ref) > MAX_MID_SIZE) {
-				warn "References: <$ref> too long, ignoring\n";
-			}
-			next if $uniq{$ref};
-			$uniq{$ref} = 1;
-			push @refs, $ref;
-		}
+# v1 only
+sub unindex_eml {
+	my ($self, $oid, $eml) = @_;
+	my $mids = mids($eml);
+	my $nr = 0;
+	my %tmp;
+	for my $mid (@$mids) {
+		my @removed = $self->{oidx}->remove_oid($oid, $mid);
+		$nr += scalar @removed;
+		$tmp{$_}++ for @removed;
 	}
-	if (@refs) {
-		$smsg->{references} = '<'.join('> <', @refs).'>';
-
-		# first ref *should* be the thread root,
-		# but we can never trust clients to do the right thing
-		my $ref = shift @refs;
-		$tid = $self->_resolve_mid_to_tid($ref);
-		$self->merge_threads($tid, $old_tid) if defined $old_tid;
+	if (!$nr) {
+		$mids = join('> <', @$mids);
+		warn "W: <$mids> missing for removal from overview\n";
+	}
+	while (my ($num, $nr) = each %tmp) {
+		warn "BUG: $num appears >1 times ($nr) for $oid\n" if $nr != 1;
+	}
+	if ($nr) {
+		$self->{mm}->num_delete($_) for (keys %tmp);
+	} else { # just in case msgmap and over.sqlite3 become desynched:
+		$self->{mm}->mid_delete($mids->[0]);
+	}
+	xdb_remove($self, $oid, keys %tmp) if need_xapian($self);
+}
 
-		# the rest of the refs should point to this tid:
-		foreach $ref (@refs) {
-			my $ptid = $self->_resolve_mid_to_tid($ref);
-			merge_threads($self, $tid, $ptid);
+sub index_mm {
+	my ($self, $mime, $oid, $sync) = @_;
+	my $mids = mids($mime);
+	my $mm = $self->{mm};
+	if ($sync->{reindex}) {
+		my $oidx = $self->{oidx};
+		for my $mid (@$mids) {
+			my ($num, undef) = $oidx->num_mid0_for_oid($oid, $mid);
+			return $num if defined $num;
 		}
+		$mm->num_for($mids->[0]) // $mm->mid_insert($mids->[0]);
 	} else {
-		$tid = $self->next_thread_id;
+		# fallback to num_for since filters like RubyLang set the number
+		$mm->mid_insert($mids->[0]) // $mm->num_for($mids->[0]);
 	}
-	$doc->add_term(xpfx('thread') . $tid);
 }
 
-sub index_blob {
-	my ($self, $mime, $bytes, $num, $blob) = @_;
-	$self->add_message($mime, $bytes, $num, $blob);
+# returns the number of bytes to add if given a non-CRLF arg
+sub crlf_adjust ($) {
+	if (index($_[0], "\r\n") < 0) {
+		# common case is LF-only, every \n needs an \r;
+		# so favor a cheap tr// over an expensive m//g
+		$_[0] =~ tr/\n/\n/;
+	} else { # count number of '\n' w/o '\r', expensive:
+		scalar(my @n = ($_[0] =~ m/(?<!\r)\n/g));
+	}
 }
 
-sub unindex_blob {
-	my ($self, $mime) = @_;
-	my $mid = eval { mid_clean(mid_mime($mime)) };
-	$self->remove_message($mid) if defined $mid;
+sub index_both { # git->cat_async callback
+	my ($bref, $oid, $type, $size, $sync) = @_;
+	my ($nr, $max) = @$sync{qw(nr max)};
+	++$$nr;
+	$$max -= $size;
+	$size += crlf_adjust($$bref);
+	my $smsg = bless { bytes => $size, blob => $oid }, 'PublicInbox::Smsg';
+	my $self = $sync->{sidx};
+	my $eml = PublicInbox::Eml->new($bref);
+	$smsg->{num} = index_mm($self, $eml, $oid, $sync) or
+		die "E: could not generate NNTP article number for $oid";
+	add_message($self, $eml, $smsg, $sync);
 }
 
-sub index_mm {
-	my ($self, $mime) = @_;
-	$self->{mm}->mid_insert(mid_clean(mid_mime($mime)));
+sub unindex_both { # git->cat_async callback
+	my ($bref, $oid, $type, $size, $self) = @_;
+	unindex_eml($self, $oid, PublicInbox::Eml->new($bref));
 }
 
-sub unindex_mm {
-	my ($self, $mime) = @_;
-	$self->{mm}->mid_delete(mid_clean(mid_mime($mime)));
+# called by public-inbox-index
+sub index_sync {
+	my ($self, $opt) = @_;
+	delete $self->{lock_path} if $opt->{-skip_lock};
+	$self->{ibx}->with_umask(\&_index_sync, $self, $opt);
+	if ($opt->{reindex}) {
+		my %again = %$opt;
+		delete @again{qw(rethread reindex)};
+		index_sync($self, \%again);
+	}
 }
 
-sub index_mm2 {
-	my ($self, $mime, $bytes, $blob) = @_;
-	my $num = $self->{mm}->num_for(mid_clean(mid_mime($mime)));
-	index_blob($self, $mime, $bytes, $num, $blob);
+sub check_size { # check_async cb for -index --max-size=...
+	my ($oid, $type, $size, $arg, $git) = @_;
+	(($type // '') eq 'blob') or die "E: bad $oid in $git->{git_dir}";
+	if ($size <= $arg->{max_size}) {
+		$git->cat_async($oid, $arg->{index_oid}, $arg);
+	} else {
+		warn "W: skipping $oid ($size > $arg->{max_size})\n";
+	}
 }
 
-sub unindex_mm2 {
-	my ($self, $mime) = @_;
-	$self->{mm}->mid_delete(mid_clean(mid_mime($mime)));
-	unindex_blob($self, $mime);
-}
+sub v1_checkpoint ($$;$) {
+	my ($self, $sync, $stk) = @_;
+	$self->{ibx}->git->check_async_wait;
+	$self->{ibx}->git->cat_async_wait;
 
-sub index_both {
-	my ($self, $mime, $bytes, $blob) = @_;
-	my $num = index_mm($self, $mime);
-	index_blob($self, $mime, $bytes, $num, $blob);
-}
+	# latest_cmt may be undef
+	my $newest = $stk ? $stk->{latest_cmt} : undef;
+	if ($newest) {
+		my $cur = $self->{mm}->last_commit || '';
+		if (need_update($self, $cur, $newest)) {
+			$self->{mm}->last_commit($newest);
+		}
+	} else {
+		${$sync->{max}} = $self->{batch_bytes};
+	}
 
-sub unindex_both {
-	my ($self, $mime) = @_;
-	unindex_blob($self, $mime);
-	unindex_mm($self, $mime);
-}
+	$self->{mm}->{dbh}->commit;
+	if ($newest && need_xapian($self)) {
+		my $xdb = $self->{xdb};
+		my $cur = $xdb->get_metadata('last_commit');
+		if (need_update($self, $cur, $newest)) {
+			$xdb->set_metadata('last_commit', $newest);
+		}
 
-sub do_cat_mail {
-	my ($git, $blob, $sizeref) = @_;
-	my $mime = eval {
-		my $str = $git->cat_file($blob, $sizeref);
-		# fixup bugs from import:
-		$$str =~ s/\A[\r\n]*From [^\r\n]*\r?\n//s;
-		Email::MIME->new($str);
-	};
-	$@ ? undef : $mime;
+		# let SearchView know a full --reindex was done so it can
+		# generate ->has_threadid-dependent links
+		if ($sync->{reindex} && !ref($sync->{reindex})) {
+			my $n = $xdb->get_metadata('has_threadid');
+			$xdb->set_metadata('has_threadid', '1') if $n ne '1';
+		}
+	}
+
+	$self->{oidx}->rethread_done($sync->{-opt}) if $newest; # all done
+	commit_txn_lazy($self);
+	$self->{ibx}->git->cleanup;
+	my $nr = ${$sync->{nr}};
+	idx_release($self, $nr);
+	# let another process do some work...
+	if (my $pr = $sync->{-opt}->{-progress}) {
+		$pr->("indexed $nr/$sync->{ntodo}\n") if $nr;
+	}
+	if (!$stk) { # more to come
+		begin_txn_lazy($self);
+		$self->{mm}->{dbh}->begin_work;
+	}
 }
 
-sub index_sync {
-	my ($self, $opts) = @_;
-	with_umask($self, sub { $self->_index_sync($opts) });
-}
-
-sub rlog {
-	my ($self, $log, $add_cb, $del_cb, $batch_cb) = @_;
-	my $hex = '[a-f0-9]';
-	my $h40 = $hex .'{40}';
-	my $addmsg = qr!^:000000 100644 \S+ ($h40) A\t${hex}{2}/${hex}{38}$!;
-	my $delmsg = qr!^:100644 000000 ($h40) \S+ D\t${hex}{2}/${hex}{38}$!;
-	my $git = $self->{git};
-	my $latest;
-	my $bytes;
-	my $max = $self->{batch_size}; # may be undef
-	local $/ = "\n";
-	my $line;
-	while (defined($line = <$log>)) {
-		if ($line =~ /$addmsg/o) {
-			my $blob = $1;
-			my $mime = do_cat_mail($git, $blob, \$bytes) or next;
-			$add_cb->($self, $mime, $bytes, $blob);
-		} elsif ($line =~ /$delmsg/o) {
-			my $blob = $1;
-			my $mime = do_cat_mail($git, $blob) or next;
-			$del_cb->($self, $mime);
-		} elsif ($line =~ /^commit ($h40)/o) {
-			if (defined $max && --$max <= 0) {
-				$max = $self->{batch_size};
-				$batch_cb->($latest, 1);
+# only for v1
+sub process_stack {
+	my ($self, $sync, $stk) = @_;
+	my $git = $self->{ibx}->git;
+	my $max = $self->{batch_bytes};
+	my $nr = 0;
+	$sync->{nr} = \$nr;
+	$sync->{max} = \$max;
+	$sync->{sidx} = $self;
+
+	$self->{mm}->{dbh}->begin_work;
+	if (my @leftovers = keys %{delete($sync->{D}) // {}}) {
+		warn('W: unindexing '.scalar(@leftovers)." leftovers\n");
+		for my $oid (@leftovers) {
+			$oid = unpack('H*', $oid);
+			$git->cat_async($oid, \&unindex_both, $self);
+		}
+	}
+	if ($sync->{max_size} = $sync->{-opt}->{max_size}) {
+		$sync->{index_oid} = \&index_both;
+	}
+	while (my ($f, $at, $ct, $oid) = $stk->pop_rec) {
+		if ($f eq 'm') {
+			my $arg = { %$sync, autime => $at, cotime => $ct };
+			if ($sync->{max_size}) {
+				$git->check_async($oid, \&check_size, $arg);
+			} else {
+				$git->cat_async($oid, \&index_both, $arg);
 			}
-			$latest = $1;
+			v1_checkpoint($self, $sync) if $max <= 0;
+		} elsif ($f eq 'd') {
+			$git->cat_async($oid, \&unindex_both, $self);
 		}
 	}
-	$batch_cb->($latest, 0);
+	v1_checkpoint($self, $sync, $stk);
 }
 
-sub _msgmap_init {
-	my ($self) = @_;
-	$self->{mm} = eval {
-		require PublicInbox::Msgmap;
-		PublicInbox::Msgmap->new($self->{git_dir}, 1);
-	};
-}
+sub log2stack ($$$$) {
+	my ($sync, $git, $range, $ibx) = @_;
+	my $D = $sync->{D}; # OID_BIN => NR (if reindexing, undef otherwise)
+	my ($add, $del);
+	if ($ibx->version == 1) {
+		my $path = $hex.'{2}/'.$hex.'{38}';
+		$add = qr!\A:000000 100644 \S+ ($OID) A\t$path$!;
+		$del = qr!\A:100644 000000 ($OID) \S+ D\t$path$!;
+	} else {
+		$del = qr!\A:\d{6} 100644 $OID ($OID) [AM]\td$!;
+		$add = qr!\A:\d{6} 100644 $OID ($OID) [AM]\tm$!;
+	}
 
-sub _git_log {
-	my ($self, $range) = @_;
-	$self->{git}->popen(qw/log --reverse --no-notes --no-color
-				--raw -r --no-abbrev/, $range);
+	# Count the new files so they can be added newest to oldest
+	# and still have numbers increasing from oldest to newest
+	my $fh = $git->popen(qw(log --raw -r --pretty=tformat:%at-%ct-%H
+				--no-notes --no-color --no-renames --no-abbrev),
+				$range);
+	my ($at, $ct, $stk);
+	while (<$fh>) {
+		if (/\A([0-9]+)-([0-9]+)-($OID)$/o) {
+			($at, $ct) = ($1 + 0, $2 + 0);
+			$stk //= PublicInbox::IdxStack->new($3);
+		} elsif (/$del/) {
+			my $oid = $1;
+			if ($D) { # reindex case
+				$D->{pack('H*', $oid)}++;
+			} else { # non-reindex case:
+				$stk->push_rec('d', $at, $ct, $oid);
+			}
+		} elsif (/$add/) {
+			my $oid = $1;
+			if ($D) {
+				my $oid_bin = pack('H*', $oid);
+				my $nr = --$D->{$oid_bin};
+				delete($D->{$oid_bin}) if $nr <= 0;
+
+				# nr < 0 (-1) means it never existed
+				$stk->push_rec('m', $at, $ct, $oid) if $nr < 0;
+			} else {
+				$stk->push_rec('m', $at, $ct, $oid);
+			}
+		}
+	}
+	close $fh or die "git log failed: \$?=$?";
+	$stk //= PublicInbox::IdxStack->new;
+	$stk->read_prepare;
 }
 
-# indexes all unindexed messages
-sub _index_sync {
-	my ($self, $opts) = @_;
-	my $tip = $opts->{ref} || 'HEAD';
-	my $reindex = $opts->{reindex};
-	my ($mkey, $last_commit, $lx, $xlog);
-	$self->{git}->batch_prepare;
-	my $xdb = _xdb_acquire($self);
-	$xdb->begin_transaction;
-	do {
-		$xlog = undef;
-		$mkey = 'last_commit';
-		$last_commit = $xdb->get_metadata('last_commit');
-		$lx = $last_commit;
-		if ($reindex) {
-			$lx = '';
-			$mkey = undef if $last_commit ne '';
-		}
-		$xdb->cancel_transaction;
-		$xdb = _xdb_release($self);
+sub prepare_stack ($$$) {
+	my ($self, $sync, $range) = @_;
+	my $git = $self->{ibx}->git;
 
-		# ensure we leak no FDs to "git log"
-		my $range = $lx eq '' ? $tip : "$lx..$tip";
-		$xlog = _git_log($self, $range);
+	if (index($range, '..') < 0) {
+		# don't show annoying git errors to users who run -index
+		# on empty inboxes
+		$git->qx(qw(rev-parse -q --verify), "$range^0");
+		return PublicInbox::IdxStack->new->read_prepare if $?;
+	}
+	$sync->{D} = $sync->{reindex} ? {} : undef; # OID_BIN => NR
+	log2stack($sync, $git, $range, $self->{ibx});
+}
+
+# --is-ancestor requires git 1.8.0+
+sub is_ancestor ($$$) {
+	my ($git, $cur, $tip) = @_;
+	return 0 unless $git->check($cur);
+	my $cmd = [ 'git', "--git-dir=$git->{git_dir}",
+		qw(merge-base --is-ancestor), $cur, $tip ];
+	my $pid = spawn($cmd);
+	waitpid($pid, 0) == $pid or die join(' ', @$cmd) .' did not finish';
+	$? == 0;
+}
+
+sub need_update ($$$) {
+	my ($self, $cur, $new) = @_;
+	my $git = $self->{ibx}->git;
+	return 1 if $cur && !is_ancestor($git, $cur, $new);
+	my $range = $cur eq '' ? $new : "$cur..$new";
+	chomp(my $n = $git->qx(qw(rev-list --count), $range));
+	($n eq '' || $n > 0);
+}
+
+# The last git commit we indexed with Xapian or SQLite (msgmap)
+# This needs to account for cases where Xapian or SQLite is
+# out-of-date with respect to the other.
+sub _last_x_commit {
+	my ($self, $mm) = @_;
+	my $lm = $mm->last_commit || '';
+	my $lx = '';
+	if (need_xapian($self)) {
+		$lx = $self->{xdb}->get_metadata('last_commit') || '';
+	} else {
+		$lx = $lm;
+	}
+	# Use last_commit from msgmap if it is older or unset
+	if (!$lm || ($lx && $lm && is_ancestor($self->{ibx}->git, $lm, $lx))) {
+		$lx = $lm;
+	}
+	$lx;
+}
 
-		$xdb = _xdb_acquire($self);
-		$xdb->begin_transaction;
-	} while ($xdb->get_metadata('last_commit') ne $last_commit);
+sub reindex_from ($$) {
+	my ($reindex, $last_commit) = @_;
+	return $last_commit unless $reindex;
+	ref($reindex) eq 'HASH' ? $reindex->{from} : '';
+}
 
+# indexes all unindexed messages (v1 only)
+sub _index_sync {
+	my ($self, $opt) = @_;
+	my $tip = $opt->{ref} || 'HEAD';
+	my $git = $self->{ibx}->git;
+	$self->{batch_bytes} = $opt->{batch_size} // $BATCH_BYTES;
+	$git->batch_prepare;
+	my $pr = $opt->{-progress};
+	my $sync = { reindex => $opt->{reindex}, -opt => $opt };
+	my $xdb = $self->begin_txn_lazy;
+	$self->{oidx}->rethread_prepare($opt);
 	my $mm = _msgmap_init($self);
-	my $dbh = $mm->{dbh} if $mm;
-	my $mm_only;
-	my $cb = sub {
-		my ($commit, $more) = @_;
-		if ($dbh) {
-			$mm->last_commit($commit) if $commit;
-			$dbh->commit;
-		}
-		if (!$mm_only) {
-			$xdb->set_metadata($mkey, $commit) if $mkey && $commit;
-			$xdb->commit_transaction;
-			$xdb = _xdb_release($self);
-		}
-		# let another process do some work... <
-		if ($more) {
-			if (!$mm_only) {
-				$xdb = _xdb_acquire($self);
-				$xdb->begin_transaction;
-			}
-			$dbh->begin_work if $dbh;
-		}
-	};
-
-	if ($mm) {
-		$dbh->begin_work;
-		my $lm = $mm->last_commit || '';
-		if ($lm eq $lx) {
-			# Common case is the indexes are synced,
-			# we only need to run git-log once:
-			rlog($self, $xlog, *index_both, *unindex_both, $cb);
+	if ($sync->{reindex}) {
+		my $last = $mm->last_commit;
+		if ($last) {
+			$tip = $last;
 		} else {
-			# Uncommon case, msgmap and xapian are out-of-sync
-			# do not care for performance (but git is fast :>)
-			# This happens if we have to reindex Xapian since
-			# msgmap is a frozen format and our Xapian format
-			# is evolving.
-			my $r = $lm eq '' ? $tip : "$lm..$tip";
-
-			# first, ensure msgmap is up-to-date:
-			my $mkey_prev = $mkey;
-			$mkey = undef; # ignore xapian, for now
-			my $mlog = _git_log($self, $r);
-			$mm_only = 1;
-			rlog($self, $mlog, *index_mm, *unindex_mm, $cb);
-			$mm_only = $mlog = undef;
-
-			# now deal with Xapian
-			$mkey = $mkey_prev;
-			$dbh = undef;
-			rlog($self, $xlog, *index_mm2, *unindex_mm2, $cb);
+			# somebody just blindly added --reindex when indexing
+			# for the first time, allow it:
+			undef $sync->{reindex};
 		}
-	} else {
-		# user didn't install DBD::SQLite and DBI
-		rlog($self, $xlog, *index_blob, *unindex_blob, $cb);
 	}
+	my $last_commit = _last_x_commit($self, $mm);
+	my $lx = reindex_from($sync->{reindex}, $last_commit);
+	my $range = $lx eq '' ? $tip : "$lx..$tip";
+	$pr->("counting changes\n\t$range ... ") if $pr;
+	my $stk = prepare_stack($self, $sync, $range);
+	$sync->{ntodo} = $stk ? $stk->num_records : 0;
+	$pr->("$sync->{ntodo}\n") if $pr; # continue previous line
+	process_stack($self, $sync, $stk);
 }
 
-# this will create a ghost as necessary
-sub _resolve_mid_to_tid {
-	my ($self, $mid) = @_;
-
-	my $smsg = $self->lookup_message($mid) || $self->create_ghost($mid);
-	$smsg->thread_id;
-}
-
-sub create_ghost {
-	my ($self, $mid) = @_;
-
-	my $tid = $self->next_thread_id;
-	my $doc = Search::Xapian::Document->new;
-	$doc->add_term(xpfx('mid') . $mid);
-	$doc->add_term(xpfx('thread') . $tid);
-	$doc->add_term(xpfx('type') . 'ghost');
-
-	my $smsg = PublicInbox::SearchMsg->wrap($doc, $mid);
-	$self->{xdb}->add_document($doc);
-
-	$smsg;
+sub DESTROY {
+	# order matters for unlocking
+	$_[0]->{xdb} = undef;
+	$_[0]->{lockfh} = undef;
 }
 
-sub merge_threads {
-	my ($self, $winner_tid, $loser_tid) = @_;
-	return if $winner_tid == $loser_tid;
-	my ($head, $tail) = $self->find_doc_ids('thread', $loser_tid);
-	my $thread_pfx = xpfx('thread');
-	my $db = $self->{xdb};
-
-	for (; $head != $tail; $head->inc) {
-		my $docid = $head->get_docid;
-		my $doc = $db->get_document($docid);
-		$doc->remove_term($thread_pfx . $loser_tid);
-		$doc->add_term($thread_pfx . $winner_tid);
-		$db->replace_document($docid, $doc);
-	}
+sub _begin_txn {
+	my ($self) = @_;
+	my $xdb = $self->{xdb} || idx_acquire($self);
+	$self->{oidx}->begin_lazy if $self->{oidx};
+	$xdb->begin_transaction if $xdb;
+	$self->{txn} = 1;
+	$xdb;
 }
 
-sub _read_git_config_perm {
+sub begin_txn_lazy {
 	my ($self) = @_;
-	my @cmd = qw(config core.sharedRepository);
-	my $fh = PublicInbox::Git->new($self->{git_dir})->popen(@cmd);
-	local $/ = "\n";
-	my $perm = <$fh>;
-	chomp $perm if defined $perm;
-	$perm;
+	$self->{ibx}->with_umask(\&_begin_txn, $self) if !$self->{txn};
 }
 
-sub _git_config_perm {
-	my $self = shift;
-	my $perm = scalar @_ ? $_[0] : _read_git_config_perm($self);
-	return PERM_GROUP if (!defined($perm) || $perm eq '');
-	return PERM_UMASK if ($perm eq 'umask');
-	return PERM_GROUP if ($perm eq 'group');
-	if ($perm =~ /\A(?:all|world|everybody)\z/) {
-		return PERM_EVERYBODY;
-	}
-	return PERM_GROUP if ($perm =~ /\A(?:true|yes|on|1)\z/);
-	return PERM_UMASK if ($perm =~ /\A(?:false|no|off|0)\z/);
+# store 'indexlevel=medium' in v2 shard=0 and v1 (only one shard)
+# This metadata is read by Admin::detect_indexlevel:
+sub set_metadata_once {
+	my ($self) = @_;
 
-	my $i = oct($perm);
-	return PERM_UMASK if ($i == PERM_UMASK);
-	return PERM_GROUP if ($i == OLD_PERM_GROUP);
-	return PERM_EVERYBODY if ($i == OLD_PERM_EVERYBODY);
+	return if $self->{shard}; # only continue if undef or 0, not >0
+	my $xdb = $self->{xdb};
 
-	if (($i & 0600) != 0600) {
-		die "core.sharedRepository mode invalid: ".
-		    sprintf('%.3o', $i) . "\nOwner must have permissions\n";
+	if (delete($self->{-set_has_threadid_once})) {
+		$xdb->set_metadata('has_threadid', '1');
+	}
+	if (delete($self->{-set_indexlevel_once})) {
+		my $level = $xdb->get_metadata('indexlevel');
+		if (!$level || $level ne 'medium') {
+			$xdb->set_metadata('indexlevel', 'medium');
+		}
+	}
+	if (delete($self->{-set_skip_docdata_once})) {
+		$xdb->get_metadata('skip_docdata') or
+			$xdb->set_metadata('skip_docdata', '1');
 	}
-	($i & 0666);
 }
 
-sub _umask_for {
-	my ($perm) = @_; # _git_config_perm return value
-	my $rv = $perm;
-	return umask if $rv == 0;
-
-	# set +x bit if +r or +w were set
-	$rv |= 0100 if ($rv & 0600);
-	$rv |= 0010 if ($rv & 0060);
-	$rv |= 0001 if ($rv & 0006);
-	(~$rv & 0777);
+sub _commit_txn {
+	my ($self) = @_;
+	if (my $xdb = $self->{xdb}) {
+		set_metadata_once($self);
+		$xdb->commit_transaction;
+	}
+	$self->{oidx}->commit_lazy if $self->{oidx};
 }
 
-sub with_umask {
-	my ($self, $cb) = @_;
-	my $old = umask $self->{umask};
-	my $rv = eval { $cb->() };
-	my $err = $@;
-	umask $old;
-	die $err if $@;
-	$rv;
+sub commit_txn_lazy {
+	my ($self) = @_;
+	delete($self->{txn}) and
+		$self->{ibx}->with_umask(\&_commit_txn, $self);
 }
 
-sub DESTROY {
-	# order matters for unlocking
-	$_[0]->{xdb} = undef;
-	$_[0]->{lockfh} = undef;
+sub worker_done {
+	my ($self) = @_;
+	if (need_xapian($self)) {
+		die "$$ $0 xdb not released\n" if $self->{xdb};
+	}
+	die "$$ $0 still in transaction\n" if $self->{txn};
 }
 
 1;