X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FSearchIdx.pm;h=fd0d320e8685fe34c37b5f07162d3e81da2f0c06;hb=1c9be46742295e943f7d919ee01ecbf134cbf493;hp=05bf3465af16b2f4e9b02a3a9fdd2af330d7e768;hpb=a4f7622064f71c02102cb17fce0b4e67782059fc;p=public-inbox.git

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index 05bf3465..fd0d320e 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -1,13 +1,27 @@
-# Copyright (C) 2015, all contributors <meta@public-inbox.org>
+# Copyright (C) 2015 all contributors <meta@public-inbox.org>
 # License: AGPLv3 or later (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 PublicInbox::SearchThread.
+# This writes to the search index.
 package PublicInbox::SearchIdx;
 use strict;
 use warnings;
+use Fcntl qw(:flock :DEFAULT);
+use PublicInbox::MIME;
+use Email::MIME::ContentType;
+$Email::MIME::ContentType::STRICT_PARAMS = 0;
 use base qw(PublicInbox::Search);
-use PublicInbox::MID qw/mid_clean mid_compressed/;
+use PublicInbox::MID qw/mid_clean id_compress mid_mime/;
+use PublicInbox::MsgIter;
+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,
@@ -17,131 +31,212 @@ use constant {
 };
 
 sub new {
-	my ($class, $git_dir, $writable) = @_;
-	my $dir = $class->xdir($git_dir);
+	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 ];
+		}
+	}
 	require Search::Xapian::WritableDatabase;
-	my $flag = Search::Xapian::DB_OPEN;
-	my $self = bless { git_dir => $git_dir }, $class;
+	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->{xdb} = $self->with_umask(sub {
-		if ($writable == 1) {
-			require File::Path;
-			File::Path::mkpath($dir);
-			$flag = Search::Xapian::DB_CREATE_OR_OPEN;
-		}
-		Search::Xapian::WritableDatabase->new($dir, $flag);
-	});
+	$self->{lock_path} = "$git_dir/ssoma.lock";
+	$self->{git} = PublicInbox::Git->new($git_dir);
+	$self->{creat} = ($creat || 0) == 1;
 	$self;
 }
 
+sub _xdb_release {
+	my ($self) = @_;
+	my $xdb = delete $self->{xdb} or croak 'not acquired';
+	$xdb->close;
+	_lock_release($self) if $self->{creat};
+	undef;
+}
+
+sub _xdb_acquire {
+	my ($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;
+	}
+	$self->{xdb} = Search::Xapian::WritableDatabase->new($dir, $flag);
+}
+
+# we only acquire the flock if creating or reindexing;
+# PublicInbox::Import already has the lock on its own.
+sub _lock_acquire {
+	my ($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} = $lockfh;
+}
+
+sub _lock_release {
+	my ($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";
+}
+
+sub add_val ($$$) {
+	my ($doc, $col, $num) = @_;
+	$num = Search::Xapian::sortable_serialise($num);
+	$doc->add_value($col, $num);
+}
+
+sub add_values ($$$) {
+	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!);
+
+	my $yyyymmdd = strftime('%Y%m%d', gmtime($ts));
+	add_val($doc, PublicInbox::Search::YYYYMMDD, $yyyymmdd);
+}
+
+sub index_users ($$) {
+	my ($tg, $smsg) = @_;
+
+	my $from = $smsg->from;
+	my $to = $smsg->to;
+	my $cc = $smsg->cc;
+
+	$tg->index_text($from, 1, 'A'); # A - author
+	$tg->increase_termpos;
+	$tg->index_text($to, 1, 'XTO') if $to ne '';
+	$tg->increase_termpos;
+	$tg->index_text($cc, 1, 'XCC') if $cc ne '';
+	$tg->increase_termpos;
+}
+
+sub index_body ($$$) {
+	my ($tg, $lines, $inc) = @_;
+	$tg->index_text(join("\n", @$lines), $inc, $inc ? 'XNQ' : 'XQUOT');
+	@$lines = ();
+	$tg->increase_termpos;
+}
+
 sub add_message {
-	my ($self, $mime) = @_; # mime = Email::MIME object
+	my ($self, $mime, $bytes, $num, $blob) = @_; # mime = Email::MIME object
 	my $db = $self->{xdb};
 
-	my $doc_id;
-	my $mid_orig = mid_clean($mime->header('Message-ID'));
-	my $mid = mid_compressed($mid_orig);
-	my $was_ghost = 0;
-	my $ct_msg = $mime->header('Content-Type') || 'text/plain';
+	my ($doc_id, $old_tid);
+	my $mid = mid_clean(mid_mime($mime));
 
 	eval {
+		die 'Message-ID too long' if length($mid) > MAX_MID_SIZE;
 		my $smsg = $self->lookup_message($mid);
-		my $doc;
-
 		if ($smsg) {
-			$smsg->ensure_metadata;
 			# convert a ghost to a regular message
 			# it will also clobber any existing regular message
-			$smsg->mime($mime);
-			$doc = $smsg->{doc};
-
-			my $type = xpfx('type');
-			eval {
-				$doc->remove_term($type . 'ghost');
-				$was_ghost = 1;
-			};
-
-			# probably does not exist:
-			eval { $doc->remove_term($type . 'mail') };
-			$doc->add_term($type . 'mail');
-		}  else {
-			$smsg = PublicInbox::SearchMsg->new($mime);
-			$doc = $smsg->{doc};
-			$doc->add_term(xpfx('mid') . $mid);
+			$doc_id = $smsg->{doc_id};
+			$old_tid = $smsg->thread_id;
 		}
+		$smsg = PublicInbox::SearchMsg->new($mime);
+		my $doc = $smsg->{doc};
+		$doc->add_term(xpfx('mid') . $mid);
 
 		my $subj = $smsg->subject;
-
-		if (length $subj) {
-			$doc->add_term(xpfx('subject') . $subj);
-
+		if ($subj ne '') {
 			my $path = $self->subject_path($subj);
-			$doc->add_term(xpfx('path') . mid_compressed($path));
+			$doc->add_term(xpfx('path') . id_compress($path));
 		}
 
-		my $from = $smsg->from_name;
-		my $date = $smsg->date;
-		my $ts = Search::Xapian::sortable_serialise($smsg->ts);
-		$doc->add_value(PublicInbox::Search::TS, $ts);
+		add_values($smsg, $bytes, $num);
 
 		my $tg = $self->term_generator;
 
 		$tg->set_document($doc);
 		$tg->index_text($subj, 1, 'S') if $subj;
 		$tg->increase_termpos;
-		$tg->index_text($subj) if $subj;
-		$tg->increase_termpos;
 
-		$tg->index_text($smsg->from->format);
-		$tg->increase_termpos;
+		index_users($tg, $smsg);
 
-		$mime->walk_parts(sub {
-			my ($part) = @_;
-			return if $part->subparts; # walk_parts already recurses
-			my $ct = $part->content_type || $ct_msg;
+		msg_iter($mime, sub {
+			my ($part, $depth, @idx) = @{$_[0]};
+			my $ct = $part->content_type || 'text/plain';
+			my $fn = $part->filename;
+			if (defined $fn && $fn ne '') {
+				$tg->index_text($fn, 1, 'XFN');
+			}
 
-			# account for filter bugs...
-			$ct =~ m!\btext/plain\b!i or return;
+			return if $ct =~ m!\btext/x?html\b!i;
+
+			my $s = eval { $part->body_str };
+			if ($@) {
+				if ($ct =~ m!\btext/plain\b!i) {
+					# Try to assume UTF-8 because Alpine
+					# seems to do wacky things and set
+					# charset=X-UNKNOWN
+					$part->charset_set('UTF-8');
+					$s = eval { $part->body_str };
+					$s = $part->body if $@;
+				}
+			}
+			defined $s 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 =~ /^\s*>/) {
+				if ($l =~ /^>/) {
+					index_body($tg, \@orig, 1) if @orig;
 					push @quot, $l;
 				} else {
+					index_body($tg, \@quot, 0) if @quot;
 					push @orig, $l;
 				}
 			}
-			if (@quot) {
-				$tg->index_text(join("\n", @quot), 0);
-				@quot = ();
-				$tg->increase_termpos;
-			}
-			if (@orig) {
-				$tg->index_text(join("\n", @orig));
-				@orig = ();
-				$tg->increase_termpos;
-			}
+			index_body($tg, \@quot, 0) if @quot;
+			index_body($tg, \@orig, 1) if @orig;
 		});
 
-		if ($was_ghost) {
-			$doc_id = $smsg->doc_id;
-			$self->link_message($smsg, 0);
-			$doc->set_data($smsg->to_doc_data);
+		link_message($self, $smsg, $old_tid);
+		$tg->index_text($mid, 1, 'XMID');
+		$doc->set_data($smsg->to_doc_data($blob));
+
+		if (my $altid = $self->{-altid}) {
+			foreach my $alt (@$altid) {
+				my $id = $alt->mid2alt($mid);
+				next unless defined $id;
+				$doc->add_term($alt->{xprefix} . $id);
+			}
+		}
+		if (defined $doc_id) {
 			$db->replace_document($doc_id, $doc);
 		} else {
-			$self->link_message($smsg, 0);
-			$doc->set_data($smsg->to_doc_data);
 			$doc_id = $db->add_document($doc);
 		}
 	};
 
 	if ($@) {
-		warn "failed to index message <$mid_orig>: $@\n";
+		warn "failed to index message <$mid>: $@\n";
 		return undef;
 	}
 	$doc_id;
@@ -149,11 +244,10 @@ sub add_message {
 
 # returns deleted doc_id on success, undef on missing
 sub remove_message {
-	my ($self, $mid_orig) = @_;
+	my ($self, $mid) = @_;
 	my $db = $self->{xdb};
 	my $doc_id;
-	$mid_orig = mid_clean($mid_orig);
-	my $mid = mid_compressed($mid_orig);
+	$mid = mid_clean($mid);
 
 	eval {
 		$doc_id = $self->find_unique_doc_id('mid', $mid);
@@ -161,7 +255,7 @@ sub remove_message {
 	};
 
 	if ($@) {
-		warn "failed to remove message <$mid_orig>: $@\n";
+		warn "failed to remove message <$mid>: $@\n";
 		return undef;
 	}
 	$doc_id;
@@ -179,8 +273,6 @@ sub term_generator { # write-only
 	$self->{term_generator} = $tg;
 }
 
-sub next_doc_id { $_[0]->{xdb}->get_lastdocid + 1 }
-
 # increments last_thread_id counter
 # returns a 64-bit integer represented as a hex string
 sub next_thread_id {
@@ -194,147 +286,246 @@ sub next_thread_id {
 }
 
 sub link_message {
-	my ($self, $smsg, $is_ghost) = @_;
-
-	if ($is_ghost) {
-		$smsg->ensure_metadata;
-	} else {
-		$self->link_message_to_parents($smsg);
-	}
-}
-
-sub link_message_to_parents {
-	my ($self, $smsg) = @_;
+	my ($self, $smsg, $old_tid) = @_;
 	my $doc = $smsg->{doc};
-	my $mid = mid_compressed($smsg->mid);
-	my $mime = $smsg->mime;
-	my $refs = $mime->header('References');
-	my @refs = $refs ? ($refs =~ /<([^>]+)>/g) : ();
-	my $irt = $mime->header('In-Reply-To');
-	if ($irt) {
-		$irt = mid_compressed(mid_clean($irt));
-
-		# maybe some crazies will try to make a circular reference:
-		if ($irt eq $mid) {
-			$irt = undef;
-		} else {
-			# last References should be $irt
-			# we will de-dupe later
-			push @refs, $irt;
-		}
-	}
+	my $mid = $smsg->mid;
+	my $mime = $smsg->{mime};
+	my $hdr = $mime->header_obj;
+
+	# last References should be IRT, but some mail clients do things
+	# out of order, so trust IRT over References iff IRT exists
+	my @refs = ($hdr->header_raw('References'),
+			$hdr->header_raw('In-Reply-To'));
+	@refs = ((join(' ', @refs)) =~ /<([^>]+)>/g);
 
 	my $tid;
 	if (@refs) {
-		my @crefs = map { mid_compressed($_) } @refs;
 		my %uniq = ($mid => 1);
+		my @orig_refs = @refs;
+		@refs = ();
 
 		# prevent circular references via References: here:
-		@refs = ();
-		foreach my $ref (@crefs) {
+		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;
 		}
 	}
-	if (@refs) {
-		$doc->add_term(xpfx('inreplyto') . $irt) if defined $irt;
-		$smsg->{references_sorted} = '<'.join('><', @refs).'>';
 
-		my $ref_pfx = xpfx('references');
+	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;
-		$doc->add_term($ref_pfx . $ref);
 		$tid = $self->_resolve_mid_to_tid($ref);
+		$self->merge_threads($tid, $old_tid) if defined $old_tid;
 
 		# the rest of the refs should point to this tid:
 		foreach $ref (@refs) {
-			$doc->add_term($ref_pfx . $ref);
 			my $ptid = $self->_resolve_mid_to_tid($ref);
-			if ($tid ne $ptid) {
-				$self->merge_threads($tid, $ptid);
-			}
+			merge_threads($self, $tid, $ptid);
 		}
 	} else {
-		$tid = $self->next_thread_id;
+		$tid = defined $old_tid ? $old_tid : $self->next_thread_id;
 	}
 	$doc->add_term(xpfx('thread') . $tid);
 }
 
 sub index_blob {
-	my ($self, $git, $blob) = @_;
-	my $mime = do_cat_mail($git, $blob) or return;
-	eval { $self->add_message($mime) };
-	warn "W: index_blob $blob: $@\n" if $@;
+	my ($self, $mime, $bytes, $num, $blob) = @_;
+	$self->add_message($mime, $bytes, $num, $blob);
 }
 
 sub unindex_blob {
-	my ($self, $git, $blob) = @_;
-	my $mime = do_cat_mail($git, $blob) or return;
-	my $mid = $mime->header('Message-ID');
-	eval { $self->remove_message($mid) } if defined $mid;
-	warn "W: unindex_blob $blob: $@\n" if $@;
+	my ($self, $mime) = @_;
+	my $mid = eval { mid_clean(mid_mime($mime)) };
+	$self->remove_message($mid) if defined $mid;
+}
+
+sub index_mm {
+	my ($self, $mime) = @_;
+	$self->{mm}->mid_insert(mid_clean(mid_mime($mime)));
+}
+
+sub unindex_mm {
+	my ($self, $mime) = @_;
+	$self->{mm}->mid_delete(mid_clean(mid_mime($mime)));
+}
+
+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, $blob);
+}
+
+sub unindex_mm2 {
+	my ($self, $mime) = @_;
+	$self->{mm}->mid_delete(mid_clean(mid_mime($mime)));
+	unindex_blob($self, $mime);
+}
+
+sub index_both {
+	my ($self, $mime, $bytes, $blob) = @_;
+	my $num = index_mm($self, $mime);
+	index_blob($self, $mime, $bytes, $num, $blob);
+}
+
+sub unindex_both {
+	my ($self, $mime) = @_;
+	unindex_blob($self, $mime);
+	unindex_mm($self, $mime);
 }
 
 sub do_cat_mail {
-	my ($git, $blob) = @_;
+	my ($git, $blob, $sizeref) = @_;
 	my $mime = eval {
-		my $str = $git->cat_file($blob);
-		Email::MIME->new($str);
+		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 index_sync {
-	my ($self, $head) = @_;
-	$self->with_umask(sub { $self->_index_sync($head) });
+	my ($self, $opts) = @_;
+	with_umask($self, sub { $self->_index_sync($opts) });
 }
 
-# indexes all unindexed messages
-sub _index_sync {
-	my ($self, $head) = @_;
-	require PublicInbox::GitCatFile;
-	my $db = $self->{xdb};
+sub rlog {
+	my ($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}$!;
-	$head ||= 'HEAD';
+	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);
+			}
+			$latest = $1;
+		}
+	}
+	$batch_cb->($latest, 0);
+}
 
-	$db->begin_transaction;
-	eval {
-		my $git = PublicInbox::GitCatFile->new($self->{git_dir});
-
-		my $latest = $db->get_metadata('last_commit');
-		my $range = length $latest ? "$latest..$head" : $head;
-		$latest = undef;
-
-		# get indexed messages
-		my @cmd = ('git', "--git-dir=$self->{git_dir}", "log",
-			    qw/--reverse --no-notes --no-color --raw -r
-			       --no-abbrev/, $range);
-		my $pid = open(my $log, '-|', @cmd) or
-			die('open` '.join(' ', @cmd) . " pipe failed: $!\n");
-
-		while (my $line = <$log>) {
-			if ($line =~ /$addmsg/o) {
-				$self->index_blob($git, $1);
-			} elsif ($line =~ /$delmsg/o) {
-				$self->unindex_blob($git, $1);
-			} elsif ($line =~ /^commit ($h40)/o) {
-				$latest = $1;
+sub _msgmap_init {
+	my ($self) = @_;
+	$self->{mm} = eval {
+		require PublicInbox::Msgmap;
+		PublicInbox::Msgmap->new($self->{git_dir}, 1);
+	};
+}
+
+sub _git_log {
+	my ($self, $range) = @_;
+	$self->{git}->popen(qw/log --reverse --no-notes --no-color
+				--raw -r --no-abbrev/, $range);
+}
+
+# indexes all unindexed messages
+sub _index_sync {
+	my ($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);
+
+		# ensure we leak no FDs to "git log"
+		my $range = $lx eq '' ? $tip : "$lx..$tip";
+		$xlog = _git_log($self, $range);
+
+		$xdb = _xdb_acquire($self);
+		$xdb->begin_transaction;
+	} while ($xdb->get_metadata('last_commit') ne $last_commit);
+
+	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;
 		}
-		close $log;
-		$db->set_metadata('last_commit', $latest) if defined $latest;
 	};
-	if ($@) {
-		warn "indexing failed: $@\n";
-		$db->cancel_transaction;
+
+	if ($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);
+		} 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);
+		}
 	} else {
-		$db->commit_transaction;
+		# user didn't install DBD::SQLite and DBI
+		rlog($self, $xlog, *index_blob, *unindex_blob, $cb);
 	}
 }
 
@@ -347,18 +538,15 @@ sub _resolve_mid_to_tid {
 }
 
 sub create_ghost {
-	my ($self, $mid, $tid) = @_;
-
-	$mid = mid_compressed($mid);
-	$tid = $self->next_thread_id unless defined $tid;
+	my ($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);
-	$self->link_message($smsg, 1);
 	$self->{xdb}->add_document($doc);
 
 	$smsg;
@@ -366,6 +554,7 @@ sub create_ghost {
 
 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};
@@ -381,12 +570,10 @@ sub merge_threads {
 
 sub _read_git_config_perm {
 	my ($self) = @_;
-	my @cmd = ('git', "--git-dir=$self->{git_dir}",
-		   qw(config core.sharedRepository));
-	my $pid = open(my $fh, '-|', @cmd) or
-		die('open `'.join(' ', @cmd) . " pipe failed: $!\n");
+	my @cmd = qw(config core.sharedRepository);
+	my $fh = PublicInbox::Git->new($self->{git_dir})->popen(@cmd);
+	local $/ = "\n";
 	my $perm = <$fh>;
-	close $fh;
 	chomp $perm if defined $perm;
 	$perm;
 }
@@ -394,7 +581,7 @@ sub _read_git_config_perm {
 sub _git_config_perm {
 	my $self = shift;
 	my $perm = scalar @_ ? $_[0] : _read_git_config_perm($self);
-	return PERM_GROUP if (!defined($perm) || !length($perm));
+	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/) {
@@ -433,8 +620,14 @@ sub with_umask {
 	my $rv = eval { $cb->() };
 	my $err = $@;
 	umask $old;
-	die $err if $@;
+	die $err if $err;
 	$rv;
 }
 
+sub DESTROY {
+	# order matters for unlocking
+	$_[0]->{xdb} = undef;
+	$_[0]->{lockfh} = undef;
+}
+
 1;