X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FSearchIdx.pm;h=eb620f44fe990e4c38514d9375fa6328ae30e80d;hb=d73d783ab2cf14ba28ca63723223d8c85a68cdd5;hp=1b86f7278e785ecd88dbb5d83eafd33adb0d656b;hpb=1b7e935ab1690e28d790d8db5af2714f13c258cc;p=public-inbox.git

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index 1b86f727..eb620f44 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -1,4 +1,4 @@
-# Copyright (C) 2015-2018 all contributors <meta@public-inbox.org>
+# 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
 #
@@ -8,74 +8,73 @@
 # This writes to the search index.
 package PublicInbox::SearchIdx;
 use strict;
-use warnings;
-use base qw(PublicInbox::Search PublicInbox::Lock);
-use PublicInbox::MIME;
+use v5.10.1;
+use parent qw(PublicInbox::Search PublicInbox::Lock Exporter);
+use PublicInbox::Eml;
 use PublicInbox::InboxWritable;
-use PublicInbox::MID qw/mid_clean id_compress mid_mime mids/;
+use PublicInbox::MID qw(mids_for_index mids);
 use PublicInbox::MsgIter;
+use PublicInbox::IdxStack;
 use Carp qw(croak);
 use POSIX qw(strftime);
 use PublicInbox::OverIdx;
-use PublicInbox::Spawn qw(spawn);
+use PublicInbox::Spawn qw(spawn nodatacow_dir);
 use PublicInbox::Git qw(git_unquote);
-use Compress::Zlib qw(compress);
-
-use constant {
-	BATCH_BYTES => defined($ENV{XAPIAN_FLUSH_THRESHOLD}) ?
-			0x7fffffff : 1_000_000,
-	DEBUG => !!$ENV{DEBUG},
-};
+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, $ibx, $creat, $part) = @_;
+	my ($class, $ibx, $creat, $shard) = @_;
+	ref $ibx or die "BUG: expected PublicInbox::Inbox object: $ibx";
 	my $levels = qr/\A(?:full|medium|basic)\z/;
-	my $mainrepo = $ibx; # for "public-inbox-index" w/o entry in config
-	my $git_dir = $mainrepo;
-	my ($altid, $git);
-	my $version = 1;
+	my $inboxdir = $ibx->{inboxdir};
+	my $version = $ibx->version;
 	my $indexlevel = 'full';
-	if (ref $ibx) {
-		$mainrepo = $ibx->{mainrepo};
-		$altid = $ibx->{altid};
-		$version = $ibx->{version} || 1;
-		if ($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");
-			}
+	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");
 		}
-	} else { # v1
-		$ibx = { mainrepo => $git_dir, version => 1 };
 	}
 	$ibx = PublicInbox::InboxWritable->new($ibx);
-	require Search::Xapian::WritableDatabase;
 	my $self = bless {
-		mainrepo => $mainrepo,
-		-inbox => $ibx,
-		git => $ibx->git,
+		ibx => $ibx,
+		xpfx => $inboxdir, # for xpfx_init
 		-altid => $altid,
-		version => $version,
+		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) {
-		$self->{lock_path} = "$mainrepo/ssoma.lock";
+		$self->{lock_path} = "$inboxdir/ssoma.lock";
 		my $dir = $self->xdir;
-		$self->{over} = PublicInbox::OverIdx->new("$dir/over.sqlite3");
+		$self->{oidx} = PublicInbox::OverIdx->new("$dir/over.sqlite3");
+		$self->{oidx}->{-no_fsync} = 1 if $ibx->{-no_fsync};
 	} elsif ($version == 2) {
-		defined $part or die "partition is required for v2\n";
-		# partition is a number
-		$self->{partition} = $part;
+		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";
@@ -84,66 +83,109 @@ sub new {
 	$self;
 }
 
-sub _xdb_release {
-	my ($self) = @_;
-	my $xdb = delete $self->{xdb} or croak 'not acquired';
-	$xdb->close;
-	$self->lock_release if $self->{creat};
+sub need_xapian ($) { $_[0]->{indexlevel} =~ $xapianlevels }
+
+sub idx_release {
+	my ($self, $wake) = @_;
+	if (need_xapian($self)) {
+		my $xdb = delete $self->{xdb} or croak 'not acquired';
+		$xdb->close;
+	}
+	$self->lock_release($wake) if $self->{creat};
 	undef;
 }
 
-sub _xdb_acquire {
+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 $ver >= 0x10400;
+	1;
+}
+
+sub idx_acquire {
 	my ($self) = @_;
-	croak 'already acquired' if $self->{xdb};
+	my $flag;
 	my $dir = $self->xdir;
-	my $flag = Search::Xapian::DB_OPEN;
+	if (need_xapian($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;
 		$self->lock_acquire;
-		File::Path::mkpath($dir);
-		$flag = Search::Xapian::DB_CREATE_OR_OPEN;
+
+		# 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;
+		}
 	}
-	$self->{xdb} = Search::Xapian::WritableDatabase->new($dir, $flag);
+	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 index_text ($$$$)
-{
-	my ($self, $field, $n, $text) = @_;
-	my $tg = $self->term_generator;
+sub term_generator ($) { # write-only
+	my ($self) = @_;
+
+	$self->{term_generator} //= do {
+		my $tg = $X->{TermGenerator}->new;
+		$tg->set_stemmer($self->stemmer);
+		$tg;
+	}
+}
+
+sub index_text ($$$$) {
+	my ($self, $text, $wdf_inc, $prefix) = @_;
+	my $tg = term_generator($self); # man Search::Xapian::TermGenerator
 
 	if ($self->{indexlevel} eq 'full') {
-		$tg->index_text($field, $n, $text);
+		$tg->index_text($text, $wdf_inc, $prefix);
 		$tg->increase_termpos;
 	} else {
-		$tg->index_text_without_positions($field, $n, $text);
+		$tg->index_text_without_positions($text, $wdf_inc, $prefix);
 	}
 }
 
-sub index_users ($$) {
+sub index_headers ($$) {
 	my ($self, $smsg) = @_;
-
-	my $from = $smsg->from;
-	my $to = $smsg->to;
-	my $cc = $smsg->cc;
-
-	$self->index_text($from, 1, 'A'); # A - author
-	$self->index_text($to, 1, 'XTO') if $to ne '';
-	$self->index_text($cc, 1, 'XCC') if $cc ne '';
+	my @x = (from => 'A', # Author
+		subject => 'S', to => 'XTO', cc => 'XCC');
+	while (my ($field, $pfx) = splice(@x, 0, 2)) {
+		my $val = $smsg->{$field};
+		index_text($self, $val, 1, $pfx) if $val ne '';
+	}
 }
 
 sub index_diff_inc ($$$$) {
 	my ($self, $text, $pfx, $xnq) = @_;
 	if (@$xnq) {
-		$self->index_text(join("\n", @$xnq), 1, 'XNQ');
+		index_text($self, join("\n", @$xnq), 1, 'XNQ');
 		@$xnq = ();
 	}
-	$self->index_text($text, 1, $pfx);
+	index_text($self, $text, 1, $pfx);
 }
 
 sub index_old_diff_fn {
@@ -158,7 +200,7 @@ sub index_old_diff_fn {
 		$fb = join('/', @fb);
 		if ($fa eq $fb) {
 			unless ($seen->{$fa}++) {
-				$self->index_diff_inc($fa, 'XDFN', $xnq);
+				index_diff_inc($self, $fa, 'XDFN', $xnq);
 			}
 			return 1;
 		}
@@ -169,22 +211,18 @@ sub index_old_diff_fn {
 }
 
 sub index_diff ($$$) {
-	my ($self, $lines, $doc) = @_;
+	my ($self, $txt, $doc) = @_;
 	my %seen;
 	my $in_diff;
 	my @xnq;
 	my $xnq = \@xnq;
-	foreach (@$lines) {
+	foreach (split(/\n/, $txt)) {
 		if ($in_diff && s/^ //) { # diff context
-			$self->index_diff_inc($_, 'XDFCTX', $xnq);
+			index_diff_inc($self, $_, 'XDFCTX', $xnq);
 		} elsif (/^-- $/) { # email signature begins
 			$in_diff = undef;
-		} elsif (m!^diff --git ("?a/.+) ("?b/.+)\z!) {
-			my ($fa, $fb) = ($1, $2);
-			my $fn = (split('/', git_unquote($fa), 2))[1];
-			$seen{$fn}++ or $self->index_diff_inc($fn, 'XDFN', $xnq);
-			$fn = (split('/', git_unquote($fb), 2))[1];
-			$seen{$fn}++ or $self->index_diff_inc($fn, 'XDFN', $xnq);
+		} elsif (m!^diff --git "?[^/]+/.+ "?[^/]+/.+\z!) {
+			# wait until "---" and "+++" to capture filenames
 			$in_diff = 1;
 		# traditional diff:
 		} elsif (m/^diff -(.+) (\S+) (\S+)$/) {
@@ -192,26 +230,28 @@ sub index_diff ($$$) {
 			push @xnq, $_;
 			# only support unified:
 			next unless $opt =~ /[uU]/;
-			$in_diff = $self->index_old_diff_fn(\%seen, $fa, $fb,
+			$in_diff = index_old_diff_fn($self, \%seen, $fa, $fb,
 							$xnq);
-		} elsif (m!^--- ("?a/.+)!) {
-			my $fn = (split('/', git_unquote($1), 2))[1];
-			$seen{$fn}++ or $self->index_diff_inc($fn, 'XDFN', $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!^\+\+\+ ("?b/.+)!)  {
-			my $fn = (split('/', git_unquote($1), 2))[1];
-			$seen{$fn}++ or $self->index_diff_inc($fn, 'XDFN', $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 (/^--- (\S+)/) {
 			$in_diff = $1;
 			push @xnq, $_;
 		} elsif (defined $in_diff && /^\+\+\+ (\S+)/) {
-			$in_diff = $self->index_old_diff_fn(\%seen, $in_diff, $1,
-							$xnq);
+			$in_diff = index_old_diff_fn($self, \%seen, $in_diff,
+							$1, $xnq);
 		} elsif ($in_diff && s/^\+//) { # diff added
-			$self->index_diff_inc($_, 'XDFB', $xnq);
+			index_diff_inc($self, $_, 'XDFB', $xnq);
 		} elsif ($in_diff && s/^-//) { # diff removed
-			$self->index_diff_inc($_, 'XDFA', $xnq);
+			index_diff_inc($self, $_, 'XDFA', $xnq);
 		} elsif (m!^index ([a-f0-9]+)\.\.([a-f0-9]+)!) {
 			my ($ba, $bb) = ($1, $2);
 			index_git_blob_id($doc, 'XDFPRE', $ba);
@@ -221,7 +261,7 @@ sub index_diff ($$$) {
 			# traditional diff w/o -p
 		} elsif (/^@@ (?:\S+) (?:\S+) @@\s*(\S+.*)$/) {
 			# hunk header context
-			$self->index_diff_inc($1, 'XDFHH', $xnq);
+			index_diff_inc($self, $1, 'XDFHH', $xnq);
 		# ignore the following lines:
 		} elsif (/^(?:dis)similarity index/ ||
 				/^(?:old|new) mode/ ||
@@ -232,7 +272,9 @@ sub index_diff ($$$) {
 				/^Binary files .* differ/) {
 			push @xnq, $_;
 		} elsif ($_ eq '') {
-			$in_diff = undef;
+			# 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 '';
@@ -240,84 +282,99 @@ sub index_diff ($$$) {
 		}
 	}
 
-	$self->index_text(join("\n", @xnq), 1, 'XNQ');
+	index_text($self, join("\n", @xnq), 1, 'XNQ');
 }
 
-sub index_body ($$$) {
-	my ($self, $lines, $doc) = @_;
-	my $txt = join("\n", @$lines);
-	if ($doc) {
-		# does it look like a diff?
-		if ($txt =~ /^(?:diff|---|\+\+\+) /ms) {
-			$txt = undef;
-			$self->index_diff($lines, $doc);
-		} else {
-			$self->index_text($txt, 1, 'XNQ');
-		}
-	} else {
-		$self->index_text($txt, 0, 'XQUOT');
+sub index_xapian { # msg_iter callback
+	my $part = $_[0]->[0]; # ignore $depth and $idx
+	my ($self, $doc) = @{$_[1]};
+	my $ct = $part->content_type || 'text/plain';
+	my $fn = $part->filename;
+	if (defined $fn && $fn ne '') {
+		index_text($self, $fn, 1, 'XFN');
+	}
+	if ($part->{is_submsg}) {
+		my $mids = mids_for_index($part);
+		index_ids($self, $doc, $part, $mids);
+		my $smsg = bless {}, 'PublicInbox::Smsg';
+		$smsg->populate($part);
+		index_headers($self, $smsg);
 	}
-	@$lines = ();
-}
-
-sub add_xapian ($$$$$) {
-	my ($self, $mime, $num, $oid, $mids, $mid0) = @_;
-	my $smsg = PublicInbox::SearchMsg->new($mime);
-	my $doc = Search::Xapian::Document->new;
-	my $subj = $smsg->subject;
-	add_val($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);
-
-	my $tg = $self->term_generator;
-
-	$tg->set_document($doc);
-	$self->index_text($subj, 1, 'S') if $subj;
-	$self->index_users($smsg);
-
-	msg_iter($mime, sub {
-		my ($part, $depth, @idx) = @{$_[0]};
-		my $ct = $part->content_type || 'text/plain';
-		my $fn = $part->filename;
-		if (defined $fn && $fn ne '') {
-			$self->index_text($fn, 1, 'XFN');
-		}
 
-		my ($s, undef) = msg_part_text($part, $ct);
-		defined $s or return;
+	my ($s, undef) = msg_part_text($part, $ct);
+	defined $s or return;
+	$_[0]->[0] = $part = undef; # free memory
 
-		my (@orig, @quot);
-		my @lines = split(/\n/, $s);
-		while (defined(my $l = shift @lines)) {
-			if ($l =~ /^>/) {
-				$self->index_body(\@orig, $doc) if @orig;
-				push @quot, $l;
+	# split off quoted and unquoted blocks:
+	my @sections = PublicInbox::MsgIter::split_quotes($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 {
-				$self->index_body(\@quot, 0) if @quot;
-				push @orig, $l;
+				index_text($self, $txt, 1, 'XNQ');
 			}
 		}
-		$self->index_body(\@quot, 0) if @quot;
-		$self->index_body(\@orig, $doc) if @orig;
-	});
+		undef $txt; # free memory
+	}
+}
 
-	foreach my $mid (@$mids) {
-		$self->index_text($mid, 1, 'XM');
+sub index_ids ($$$$) {
+	my ($self, $doc, $hdr, $mids) = @_;
+	for my $mid (@$mids) {
+		index_text($self, $mid, 1, 'XM');
 
 		# because too many Message-IDs are prefixed with
 		# "Pine.LNX."...
 		if ($mid =~ /\w{12,}/) {
 			my @long = ($mid =~ /(\w{3,}+)/g);
-			$self->index_text(join(' ', @long), 1, 'XM');
+			index_text($self, join(' ', @long), 1, 'XM');
 		}
 	}
-	$smsg->{to} = $smsg->{cc} = '';
-	PublicInbox::OverIdx::parse_references($smsg, $mid0, $mids);
-	my $data = $smsg->to_doc_data($oid, $mid0);
-	$doc->set_data($data);
+	$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 ($$$$) {
+	my ($self, $eml, $smsg, $mids) = @_;
+	my $doc = $X->{Document}->new;
+	add_val($doc, PublicInbox::Search::TS(), $smsg->{ts});
+	my @ds = gmtime($smsg->{ds});
+	my $yyyymmdd = strftime('%Y%m%d', @ds);
+	add_val($doc, PublicInbox::Search::YYYYMMDD(), $yyyymmdd);
+	my $dt = strftime('%Y%m%d%H%M%S', @ds);
+	add_val($doc, PublicInbox::Search::DT(), $dt);
+	add_val($doc, PublicInbox::Search::BYTES(), $smsg->{bytes});
+	add_val($doc, PublicInbox::Search::UID(), $smsg->{num});
+	add_val($doc, PublicInbox::Search::THREADID, $smsg->{tid});
+
+	my $tg = term_generator($self);
+	$tg->set_document($doc);
+	index_headers($self, $smsg);
+
+	msg_iter($eml, \&index_xapian, [ $self, $doc ]);
+	index_ids($self, $doc, $eml, $mids);
+
+	# by default, we maintain compatibility with v1.5.0 and earlier
+	# by writing to docdata.glass, users who never exect to downgrade can
+	# use --skip-docdata
+	if (!$self->{-skip_docdata}) {
+		# WWW doesn't need {to} or {cc}, only NNTP
+		$smsg->{to} = $smsg->{cc} = '';
+		PublicInbox::OverIdx::parse_references($smsg, $eml, $mids);
+		my $data = $smsg->to_doc_data;
+		$doc->set_data($data);
+	}
+
 	if (my $altid = $self->{-altid}) {
 		foreach my $alt (@$altid) {
 			my $pfx = $alt->{xprefix};
@@ -328,25 +385,45 @@ sub add_xapian ($$$$$) {
 			}
 		}
 	}
-	$doc->add_boolean_term('Q' . $_) foreach @$mids;
-	$self->{xdb}->replace_document($num, $doc);
+	$self->{xdb}->replace_document($smsg->{num}, $doc);
+}
+
+sub _msgmap_init ($) {
+	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 = Email::MIME object
-	my ($self, $mime, $bytes, $num, $oid, $mid0) = @_;
-	my $mids = mids($mime->header_obj);
-	$mid0 = $mids->[0] unless defined $mid0; # v1 compatibility
-	unless (defined $num) { # v1
-		$self->_msgmap_init;
-		$num = index_mm($self, $mime);
-	}
+	# mime = PublicInbox::Eml or Email::MIME object
+	my ($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 {
-		if ($self->{indexlevel} =~ $xapianlevels) {
-			$self->add_xapian($mime, $num, $oid, $mids, $mid0)
+		# 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 (my $over = $self->{over}) {
-			$over->add_overview($mime, $bytes, $num, $oid, $mid0);
+		if (need_xapian($self)) {
+			add_xapian($self, $mime, $smsg, $mids);
 		}
 	};
 
@@ -354,101 +431,35 @@ sub add_message {
 		warn "failed to index message <".join('> <',@$mids).">: $@\n";
 		return undef;
 	}
-	$num;
-}
-
-# returns begin and end PostingIterator
-sub find_doc_ids {
-	my ($self, $termval) = @_;
-	my $db = $self->{xdb};
-
-	($db->postlist_begin($termval), $db->postlist_end($termval));
-}
-
-# v1 only
-sub batch_do {
-	my ($self, $termval, $cb) = @_;
-	my $batch_size = 1000; # don't let @ids grow too large to avoid OOM
-	while (1) {
-		my ($head, $tail) = $self->find_doc_ids($termval);
-		return if $head == $tail;
-		my @ids;
-		for (; $head != $tail && @ids < $batch_size; $head->inc) {
-			push @ids, $head->get_docid;
-		}
-		$cb->(\@ids);
-	}
-}
-
-# v1 only, where $mid is unique
-sub remove_message {
-	my ($self, $mid) = @_;
-	my $db = $self->{xdb};
-	$mid = mid_clean($mid);
-
-	if (my $over = $self->{over}) {
-		my $nr = eval { $over->remove_oid(undef, $mid) };
-		if ($@) {
-			warn "failed to remove <$mid> from overview: $@\n";
-		} elsif ($nr == 0) {
-			warn "<$mid> missing for removal from overview\n";
+	$smsg->{num};
+}
+
+sub xdb_remove {
+	my ($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;
 		}
-	}
-	return if $self->{indexlevel} !~ $xapianlevels;
-	my $nr = 0;
-	eval {
-		batch_do($self, 'Q' . $mid, sub {
-			my ($ids) = @_;
-			$db->delete_document($_) for @$ids;
-			$nr = scalar @$ids;
-		});
-	};
-	if ($@) {
-		warn "failed to remove <$mid> from Xapian: $@\n";
-	} elsif ($nr == 0) {
-		warn "<$mid> missing for removal from Xapian\n";
-	}
-}
-
-# MID is a hint in V2
-sub remove_by_oid {
-	my ($self, $oid, $mid) = @_;
-	my $db = $self->{xdb};
-
-	$self->{over}->remove_oid($oid, $mid) if $self->{over};
-
-	# XXX careful, we cannot use batch_do here since we conditionally
-	# delete documents based on other factors, so we cannot call
-	# find_doc_ids twice.
-	my ($head, $tail) = $self->find_doc_ids('Q' . $mid);
-	return if $head == $tail;
-
-	# there is only ONE element in @delete unless we
-	# have bugs in our v2writable deduplication check
-	my @delete;
-	for (; $head != $tail; $head->inc) {
-		my $docid = $head->get_docid;
-		my $doc = $db->get_document($docid);
-		my $smsg = PublicInbox::SearchMsg->wrap($mid);
+		my $smsg = bless {}, 'PublicInbox::Smsg';
 		$smsg->load_expand($doc);
-		if ($smsg->{blob} eq $oid) {
-			push(@delete, $docid);
+		my $blob = $smsg->{blob} // '(unset)';
+		if ($blob eq $oid) {
+			$xdb->delete_document($num);
+		} else {
+			warn "E: #$num $oid != $blob in Xapian\n";
 		}
 	}
-	$db->delete_document($_) foreach @delete;
-	scalar(@delete);
 }
 
-sub term_generator { # write-only
-	my ($self) = @_;
-
-	my $tg = $self->{term_generator};
-	return $tg if $tg;
-
-	$tg = Search::Xapian::TermGenerator->new;
-	$tg->set_stemmer($self->stemmer);
-
-	$self->{term_generator} = $tg;
+sub remove_by_oid {
+	my ($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);
 }
 
 sub index_git_blob_id {
@@ -461,179 +472,246 @@ sub index_git_blob_id {
 	}
 }
 
-sub unindex_blob {
-	my ($self, $mime) = @_;
-	my $mid = eval { mid_clean(mid_mime($mime)) };
-	$self->remove_message($mid) if defined $mid;
+# v1 only
+sub unindex_eml {
+	my ($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 (!$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);
 }
 
 sub index_mm {
-	my ($self, $mime) = @_;
-	my $mid = mid_clean(mid_mime($mime));
+	my ($self, $mime, $oid, $sync) = @_;
+	my $mids = mids($mime);
 	my $mm = $self->{mm};
-	my $num;
-
-	if (defined $self->{regen_down}) {
-		$num = $mm->num_for($mid) and return $num;
-
-		while (($num = $self->{regen_down}--) > 0) {
-			if ($mm->mid_set($num, $mid) != 0) {
-				return $num;
-			}
-		}
-	} elsif (defined $self->{regen_up}) {
-		$num = $mm->num_for($mid) and return $num;
-
-		# this is to fixup old bugs due to add-remove-add
-		while (($num = ++$self->{regen_up})) {
-			if ($mm->mid_set($num, $mid) != 0) {
-				return $num;
-			}
+	if ($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 {
+		# fallback to num_for since filters like RubyLang set the number
+		$mm->mid_insert($mids->[0]) // $mm->num_for($mids->[0]);
 	}
-
-	$num = $mm->mid_insert($mid) and return $num;
-
-	# fallback to num_for since filters like RubyLang set the number
-	$mm->num_for($mid);
-}
-
-sub unindex_mm {
-	my ($self, $mime) = @_;
-	$self->{mm}->mid_delete(mid_clean(mid_mime($mime)));
 }
 
-sub index_both {
-	my ($self, $mime, $bytes, $blob) = @_;
-	my $num = index_mm($self, $mime);
-	add_message($self, $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_both {
-	my ($self, $mime) = @_;
-	unindex_blob($self, $mime);
-	unindex_mm($self, $mime);
+sub index_both { # git->cat_async callback
+	my ($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 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;
-		PublicInbox::MIME->new($str);
-	};
-	$@ ? undef : $mime;
+sub unindex_both { # git->cat_async callback
+	my ($bref, $oid, $type, $size, $self) = @_;
+	unindex_eml($self, $oid, PublicInbox::Eml->new($bref));
 }
 
+# called by public-inbox-index
 sub index_sync {
-	my ($self, $opts) = @_;
-	$self->{-inbox}->with_umask(sub { $self->_index_sync($opts) })
+	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 batch_adjust ($$$$) {
-	my ($max, $bytes, $batch_cb, $latest) = @_;
-	$$max -= $bytes;
-	if ($$max <= 0) {
-		$$max = BATCH_BYTES;
-		$batch_cb->($latest);
+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";
 	}
 }
 
-# only for v1
-sub read_log {
-	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 = BATCH_BYTES;
-	local $/ = "\n";
-	my %D;
-	my $line;
-	my $newest;
-	while (defined($line = <$log>)) {
-		if ($line =~ /$addmsg/o) {
-			my $blob = $1;
-			if (delete $D{$blob}) {
-				if (defined $self->{regen_down}) {
-					my $num = $self->{regen_down}--;
-					$self->{mm}->num_highwater($num);
-				}
-				next;
-			}
-			my $mime = do_cat_mail($git, $blob, \$bytes) or next;
-			batch_adjust(\$max, $bytes, $batch_cb, $latest);
-			$add_cb->($self, $mime, $bytes, $blob);
-		} elsif ($line =~ /$delmsg/o) {
-			my $blob = $1;
-			$D{$blob} = 1;
-		} elsif ($line =~ /^commit ($h40)/o) {
-			$latest = $1;
-			$newest ||= $latest;
+sub v1_checkpoint ($$;$) {
+	my ($self, $sync, $stk) = @_;
+	$self->{ibx}->git->check_async_wait;
+	$self->{ibx}->git->cat_async_wait;
+
+	# 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};
 	}
-	# get the leftovers
-	foreach my $blob (keys %D) {
-		my $mime = do_cat_mail($git, $blob, \$bytes) or next;
-		$del_cb->($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', $newest);
+		}
+
+		# let SearchView know a full --reindex was done so it can
+		# generate ->has_threadid-dependent links
+		if ($sync->{reindex} && !ref($sync->{reindex})) {
+			my $n = $xdb->get_metadata('has_threadid');
+			$xdb->set_metadata('has_threadid', '1') if $n ne '1';
+		}
 	}
-	$batch_cb->($latest, $newest);
-}
 
-sub _msgmap_init {
-	my ($self) = @_;
-	die "BUG: _msgmap_init is only for v1\n" if $self->{version} != 1;
-	$self->{mm} ||= eval {
-		require PublicInbox::Msgmap;
-		PublicInbox::Msgmap->new($self->{mainrepo}, 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 _git_log {
-	my ($self, $range) = @_;
-	my $git = $self->{git};
-
-	if (index($range, '..') < 0) {
-		# don't show annoying git errrors to users who run -index
-		# on empty inboxes
-		$git->qx(qw(rev-parse -q --verify), "$range^0");
-		if ($?) {
-			open my $fh, '<', '/dev/null' or
-				die "failed to open /dev/null: $!\n";
-			return $fh;
+# only for v1
+sub process_stack {
+	my ($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, $arg);
+			}
+			v1_checkpoint($self, $sync) if $max <= 0;
+		} elsif ($f eq 'd') {
+			$git->cat_async($oid, \&unindex_both, $self);
 		}
 	}
+	v1_checkpoint($self, $sync, $stk);
+}
+
+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$!;
+	}
 
 	# Count the new files so they can be added newest to oldest
 	# and still have numbers increasing from oldest to newest
-	my $fcount = 0;
-	# can't use 'rev-list --count' if we use --diff-filter
-	my $fh = $git->popen(qw(log --pretty=tformat:%h
-			     --no-notes --no-color --no-renames
-			     --diff-filter=AM), $range);
-	++$fcount while <$fh>;
-	my $high = $self->{mm}->num_highwater;
-
-	if (index($range, '..') < 0) {
-		if ($high && $high == $fcount) {
-			# fix up old bugs in full indexes which caused messages to
-			# not appear in Msgmap
-			$self->{regen_up} = $high;
-		} else {
-			# normal regen is for for fresh data
-			$self->{regen_down} = $fcount;
+	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);
+			}
 		}
-	} else {
-		# Give oldest messages the smallest numbers
-		$self->{regen_down} = $high + $fcount;
 	}
+	close $fh or die "git log failed: \$?=$?";
+	$stk //= PublicInbox::IdxStack->new;
+	$stk->read_prepare;
+}
+
+sub prepare_stack ($$$) {
+	my ($self, $sync, $range) = @_;
+	my $git = $self->{ibx}->git;
 
-	$git->popen(qw/log --no-notes --no-color --no-renames
-				--raw -r --no-abbrev/, $range);
+	if (index($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+
@@ -643,14 +721,13 @@ sub is_ancestor ($$$) {
 	my $cmd = [ 'git', "--git-dir=$git->{git_dir}",
 		qw(merge-base --is-ancestor), $cur, $tip ];
 	my $pid = spawn($cmd);
-	defined $pid or die "spawning ".join(' ', @$cmd)." failed: $!";
 	waitpid($pid, 0) == $pid or die join(' ', @$cmd) .' did not finish';
 	$? == 0;
 }
 
 sub need_update ($$$) {
 	my ($self, $cur, $new) = @_;
-	my $git = $self->{git};
+	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), $range));
@@ -664,77 +741,54 @@ sub _last_x_commit {
 	my ($self, $mm) = @_;
 	my $lm = $mm->last_commit || '';
 	my $lx = '';
-	if ($self->{indexlevel} =~ $xapianlevels) {
+	if (need_xapian($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 && $lx && is_ancestor($self->{git}, $lm, $lx))) {
+	if (!$lm || ($lx && $lm && is_ancestor($self->{ibx}->git, $lm, $lx))) {
 		$lx = $lm;
 	}
 	$lx;
 }
 
+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, $opts) = @_;
-	my $tip = $opts->{ref} || 'HEAD';
-	my ($last_commit, $lx, $xlog);
-	my $git = $self->{git};
+	my ($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);
-	do {
-		$xlog = undef;
-		$last_commit = _last_x_commit($self, $mm);
-		$lx = $opts->{reindex} ? '' : $last_commit;
-
-		$self->{over}->rollback_lazy;
-		$self->{over}->disconnect;
-		$git->cleanup;
-		delete $self->{txn};
-		$xdb->cancel_transaction;
-		$xdb = _xdb_release($self);
-
-		# ensure we leak no FDs to "git log" with Xapian <= 1.2
-		my $range = $lx eq '' ? $tip : "$lx..$tip";
-		$xlog = _git_log($self, $range);
-
-		$xdb = $self->begin_txn_lazy;
-	} while (_last_x_commit($self, $mm) ne $last_commit);
-
-	my $dbh = $mm->{dbh} if $mm;
-	my $cb = sub {
-		my ($commit, $newest) = @_;
-		if ($dbh) {
-			if ($newest) {
-				my $cur = $mm->last_commit || '';
-				if (need_update($self, $cur, $newest)) {
-					$mm->last_commit($newest);
-				}
-			}
-			$dbh->commit;
-		}
-		if ($newest && $self->{indexlevel} =~ $xapianlevels) {
-			my $cur = $xdb->get_metadata('last_commit');
-			if (need_update($self, $cur, $newest)) {
-				$xdb->set_metadata('last_commit', $newest);
-			}
-		}
-		$self->commit_txn_lazy;
-		$git->cleanup;
-		$xdb = _xdb_release($self);
-		# let another process do some work... <
-		if (!$newest) {
-			$xdb = $self->begin_txn_lazy;
-			$dbh->begin_work if $dbh;
+	if ($sync->{reindex}) {
+		my $last = $mm->last_commit;
+		if ($last) {
+			$tip = $last;
+		} else {
+			# somebody just blindly added --reindex when indexing
+			# for the first time, allow it:
+			undef $sync->{reindex};
 		}
-	};
-
-	$dbh->begin_work;
-	read_log($self, $xlog, *index_both, *unindex_both, $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);
 }
 
 sub DESTROY {
@@ -743,66 +797,63 @@ sub DESTROY {
 	$_[0]->{lockfh} = undef;
 }
 
-# remote_* subs are only used by SearchIdxPart
-sub remote_commit {
+sub _begin_txn {
 	my ($self) = @_;
-	if (my $w = $self->{w}) {
-		print $w "commit\n" or die "failed to write commit: $!";
-	} else {
-		$self->commit_txn_lazy;
-	}
+	my $xdb = $self->{xdb} || idx_acquire($self);
+	$self->{oidx}->begin_lazy if $self->{oidx};
+	$xdb->begin_transaction if $xdb;
+	$self->{txn} = 1;
+	$xdb;
 }
 
-sub remote_close {
+sub begin_txn_lazy {
 	my ($self) = @_;
-	if (my $w = delete $self->{w}) {
-		my $pid = delete $self->{pid} or die "no process to wait on\n";
-		print $w "close\n" or die "failed to write to pid:$pid: $!\n";
-		close $w or die "failed to close pipe for pid:$pid: $!\n";
-		waitpid($pid, 0) == $pid or die "remote process did not finish";
-		$? == 0 or die ref($self)." pid:$pid exited with: $?";
-	} else {
-		die "transaction in progress $self\n" if $self->{txn};
-		$self->_xdb_release if $self->{xdb};
-	}
+	$self->{ibx}->with_umask(\&_begin_txn, $self) if !$self->{txn};
 }
 
-sub remote_remove {
-	my ($self, $oid, $mid) = @_;
-	if (my $w = $self->{w}) {
-		# triggers remove_by_oid in a partition
-		print $w "D $oid $mid\n" or die "failed to write remove $!";
-	} else {
-		$self->begin_txn_lazy;
-		$self->remove_by_oid($oid, $mid);
+# store 'indexlevel=medium' in v2 shard=0 and v1 (only one shard)
+# This metadata is read by Admin::detect_indexlevel:
+sub set_metadata_once {
+	my ($self) = @_;
+
+	return if $self->{shard}; # only continue if undef or 0, not >0
+	my $xdb = $self->{xdb};
+
+	if (delete($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');
 	}
 }
 
-sub begin_txn_lazy {
+sub _commit_txn {
 	my ($self) = @_;
-	return if $self->{txn};
-
-	$self->{-inbox}->with_umask(sub {
-		my $xdb = $self->{xdb} || $self->_xdb_acquire;
-		$self->{over}->begin_lazy if $self->{over};
-		$xdb->begin_transaction;
-		$self->{txn} = 1;
-		$xdb;
-	});
+	if (my $xdb = $self->{xdb}) {
+		set_metadata_once($self);
+		$xdb->commit_transaction;
+	}
+	$self->{oidx}->commit_lazy if $self->{oidx};
 }
 
 sub commit_txn_lazy {
 	my ($self) = @_;
-	delete $self->{txn} or return;
-	$self->{-inbox}->with_umask(sub {
-		$self->{xdb}->commit_transaction;
-		$self->{over}->commit_lazy if $self->{over};
-	});
+	delete($self->{txn}) and
+		$self->{ibx}->with_umask(\&_commit_txn, $self);
 }
 
 sub worker_done {
 	my ($self) = @_;
-	die "$$ $0 xdb not released\n" if $self->{xdb};
+	if (need_xapian($self)) {
+		die "$$ $0 xdb not released\n" if $self->{xdb};
+	}
 	die "$$ $0 still in transaction\n" if $self->{txn};
 }