v2: parallelize Xapian indexing

The parallelization requires splitting Msgmap, text+term
indexing, and thread-linking out into separate processes.

git-fast-import is fast, so we don't bother parallelizing it.

Msgmap (SQLite) and thread-linking (Xapian) must be serialized
because they rely on monotonically increasing numbers (NNTP
article number and internal thread_id, respectively).

We handle msgmap in the main process which drives fast-import.
When the article number is retrieved/generated, we write the
entire message to per-partition subprocesses via pipes for
expensive text+term indexing.

When these per-partition subprocesses are done with the
expensive text+term indexing, they write SearchMsg (small data)
to a shared pipe (inherited from the main V2Writable process)
back to the threader, which runs its own subprocess.

The number of text+term Xapian partitions is chosen at import
and can be made equal to the number of cores in a machine.

V2Writable --> Import -> git-fast-import
           \-> SearchIdxThread -> Msgmap (synchronous)
           \-> SearchIdxPart[n] -> SearchIdx[*]
	   \-> SearchIdxThread -> SearchIdx ("threader", a subprocess)

[* ] each subprocess writes to threader

8 files changed, 314 insertions, 71 deletions

diff --git a/MANIFEST b/MANIFEST
index 4b51b543..2a6f6f07 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -84,6 +84,8 @@ lib/PublicInbox/Reply.pm
 lib/PublicInbox/SaPlugin/ListMirror.pm
 lib/PublicInbox/Search.pm
 lib/PublicInbox/SearchIdx.pm
+lib/PublicInbox/SearchIdxPart.pm
+lib/PublicInbox/SearchIdxThread.pm
 lib/PublicInbox/SearchMsg.pm
 lib/PublicInbox/SearchThread.pm
 lib/PublicInbox/SearchView.pm
diff --git a/lib/PublicInbox/Import.pm b/lib/PublicInbox/Import.pm
index 1a2698a7..b650e4ef 100644
--- a/lib/PublicInbox/Import.pm
+++ b/lib/PublicInbox/Import.pm
@@ -280,14 +280,12 @@ sub add {
         $self->{bytes_added} += $n;
         print $w "blob\nmark :$blob\ndata ", $n, "\n" or wfail;
         print $w $str, "\n" or wfail;
-        $str = undef;
 
         # v2: we need this for Xapian
         if ($self->{want_object_id}) {
                 chomp($self->{last_object_id} = $self->get_mark(":$blob"));
-                $self->{last_object_size} = $n;
+                $self->{last_object} = [ $n, \$str ];
         }
-
         my $ref = $self->{ref};
         my $commit = $self->{mark}++;
         my $parent = $tip =~ /\A:/ ? $tip : undef;
diff --git a/lib/PublicInbox/Search.pm b/lib/PublicInbox/Search.pm
index eac11bd4..3b280598 100644
--- a/lib/PublicInbox/Search.pm
+++ b/lib/PublicInbox/Search.pm
@@ -124,7 +124,10 @@ sub xdir {
         if ($self->{version} == 1) {
                 "$self->{mainrepo}/public-inbox/xapian" . SCHEMA_VERSION;
         } else {
-                "$self->{mainrepo}/xap" . SCHEMA_VERSION;
+                my $dir = "$self->{mainrepo}/xap" . SCHEMA_VERSION;
+                my $part = $self->{partition};
+                defined $part or die "partition not given";
+                $dir .= "/$part";
         }
 }
 
diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index c6c5bd25..cc7e7ec9 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -51,7 +51,7 @@ sub git_unquote ($) {
 }
 
 sub new {
-        my ($class, $ibx, $creat) = @_;
+        my ($class, $ibx, $creat, $part) = @_;
         my $mainrepo = $ibx; # for "public-inbox-index" w/o entry in config
         my $git_dir = $mainrepo;
         my ($altid, $git);
@@ -83,7 +83,10 @@ sub new {
         if ($version == 1) {
                 $self->{lock_path} = "$mainrepo/ssoma.lock";
         } elsif ($version == 2) {
-                $self->{lock_path} = "$mainrepo/inbox.lock";
+                defined $part or die "partition is required for v2\n";
+                # partition is a number or "all"
+                $self->{partition} = $part;
+                $self->{lock_path} = undef;
                 $self->{msgmap_path} = "$mainrepo/msgmap.sqlite3";
         } else {
                 die "unsupported inbox version=$version\n";
@@ -119,14 +122,16 @@ sub _xdb_acquire {
 sub _lock_acquire {
         my ($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";
+        my $lock_path = $self->{lock_path} or return;
+        sysopen(my $lockfh, $lock_path, O_WRONLY|O_CREAT) or
+                die "failed to open lock $lock_path: $!\n";
         flock($lockfh, LOCK_EX) or die "lock failed: $!\n";
         $self->{lockfh} = $lockfh;
 }
 
 sub _lock_release {
         my ($self) = @_;
+        return unless $self->{lock_path};
         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";
@@ -138,8 +143,8 @@ sub add_val ($$$) {
         $doc->add_value($col, $num);
 }
 
-sub add_values ($$$) {
-        my ($smsg, $bytes, $num) = @_;
+sub add_values ($$$$) {
+        my ($smsg, $bytes, $num, $lines) = @_;
 
         my $ts = $smsg->ts;
         my $doc = $smsg->{doc};
@@ -149,8 +154,7 @@ sub add_values ($$$) {
 
         defined($bytes) and add_val($doc, &PublicInbox::Search::BYTES, $bytes);
 
-        add_val($doc, &PublicInbox::Search::LINES,
-                        $smsg->{mime}->body_raw =~ tr!\n!\n!);
+        add_val($doc, &PublicInbox::Search::LINES, $lines);
 
         my $yyyymmdd = strftime('%Y%m%d', gmtime($ts));
         add_val($doc, PublicInbox::Search::YYYYMMDD, $yyyymmdd);
@@ -281,6 +285,7 @@ sub add_message {
 
         my ($doc_id, $old_tid);
         my $mid = mid_clean(mid_mime($mime));
+        my $threader = $self->{threader};
 
         eval {
                 die 'Message-ID too long' if length($mid) > MAX_MID_SIZE;
@@ -289,19 +294,22 @@ sub add_message {
                         # 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;
+                        $old_tid = $smsg->thread_id unless $threader;
                 }
                 $smsg = PublicInbox::SearchMsg->new($mime);
                 my $doc = $smsg->{doc};
                 $doc->add_term('XMID' . $mid);
 
                 my $subj = $smsg->subject;
+                my $xpath;
                 if ($subj ne '') {
-                        my $path = $self->subject_path($subj);
-                        $doc->add_term('XPATH' . id_compress($path));
+                        $xpath = $self->subject_path($subj);
+                        $xpath = id_compress($xpath);
+                        $doc->add_term('XPATH' . $xpath);
                 }
 
-                add_values($smsg, $bytes, $num);
+                my $lines = $mime->body_raw =~ tr!\n!\n!;
+                add_values($smsg, $bytes, $num, $lines);
 
                 my $tg = $self->term_generator;
 
@@ -350,9 +358,16 @@ sub add_message {
                         index_body($tg, \@orig, $doc) if @orig;
                 });
 
-                link_message($self, $smsg, $old_tid);
+                # populates smsg->references for smsg->to_doc_data
+                my $refs = parse_references($smsg);
+                my $data = $smsg->to_doc_data($blob);
+                if ($threader) {
+                        $threader->thread_msg($mid, $smsg->ts, $xpath, $data);
+                } else {
+                        link_message($self, $smsg, $refs, $old_tid);
+                }
                 $tg->index_text($mid, 1, 'XM');
-                $doc->set_data($smsg->to_doc_data($blob));
+                $doc->set_data($data);
 
                 if (my $altid = $self->{-altid}) {
                         foreach my $alt (@$altid) {
@@ -424,8 +439,8 @@ sub next_thread_id {
         $last_thread_id;
 }
 
-sub link_message {
-        my ($self, $smsg, $old_tid) = @_;
+sub parse_references ($) {
+        my ($smsg) = @_;
         my $doc = $smsg->{doc};
         my $mid = $smsg->mid;
         my $mime = $smsg->{mime};
@@ -436,7 +451,6 @@ sub link_message {
         my @refs = (($hdr->header_raw('References') || '') =~ /<([^>]+)>/g);
         push(@refs, (($hdr->header_raw('In-Reply-To') || '') =~ /<([^>]+)>/g));
 
-        my $tid;
         if (@refs) {
                 my %uniq = ($mid => 1);
                 my @orig_refs = @refs;
@@ -452,25 +466,31 @@ sub link_message {
                         push @refs, $ref;
                 }
         }
+        $smsg->{references} = '<'.join('> <', @refs).'>' if @refs;
+        \@refs
+}
 
-        if (@refs) {
-                $smsg->{references} = '<'.join('> <', @refs).'>';
+sub link_message {
+        my ($self, $smsg, $refs, $old_tid) = @_;
+        my $tid;
+
+        if (@$refs) {
 
                 # first ref *should* be the thread root,
                 # but we can never trust clients to do the right thing
-                my $ref = shift @refs;
+                my $ref = shift @$refs;
                 $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) {
+                foreach $ref (@$refs) {
                         my $ptid = $self->_resolve_mid_to_tid($ref);
                         merge_threads($self, $tid, $ptid);
                 }
         } else {
                 $tid = defined $old_tid ? $old_tid : $self->next_thread_id;
         }
-        $doc->add_term('G' . $tid);
+        $smsg->{doc}->add_term('G' . $tid);
 }
 
 sub index_blob {
@@ -798,4 +818,20 @@ sub DESTROY {
         $_[0]->{lockfh} = undef;
 }
 
+# remote_* subs are only used by SearchIdxPart and SearchIdxThread:
+sub remote_commit {
+        my ($self) = @_;
+        print { $self->{w} } "commit\n" or die "failed to write commit: $!";
+}
+
+sub remote_close {
+        my ($self) = @_;
+        my $pid = delete $self->{pid} or die "no process to wait on\n";
+        my $w = delete $self->{w} or die "no pipe to write to\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)." exited with: $?";
+}
+
 1;
diff --git a/lib/PublicInbox/SearchIdxPart.pm b/lib/PublicInbox/SearchIdxPart.pm
new file mode 100644
index 00000000..d5a3fd17
--- /dev/null
+++ b/lib/PublicInbox/SearchIdxPart.pm
@@ -0,0 +1,70 @@
+# Copyright (C) 2018 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+package PublicInbox::SearchIdxPart;
+use strict;
+use warnings;
+use base qw(PublicInbox::SearchIdx);
+
+sub new {
+        my ($class, $v2writable, $part, $threader) = @_;
+        my $self = $class->SUPER::new($v2writable->{-inbox}, 1, $part);
+        $self->{threader} = $threader;
+        my ($r, $w);
+        pipe($r, $w) or die "pipe failed: $!\n";
+        my $pid = fork;
+        defined $pid or die "fork failed: $!\n";
+        if ($pid == 0) {
+                foreach my $other (@{$v2writable->{idx_parts}}) {
+                        my $other_w = $other->{w} or next;
+                        close $other_w or die "close other failed: $!\n";
+                }
+                $v2writable = undef;
+                close $w;
+                eval { partition_worker_loop($self, $r) };
+                die "worker $part died: $@\n" if $@;
+                die "unexpected MM $self->{mm}" if $self->{mm};
+                exit;
+        }
+        $self->{pid} = $pid;
+        $self->{w} = $w;
+        close $r;
+        $self;
+}
+
+sub partition_worker_loop ($$) {
+        my ($self, $r) = @_;
+        my $xdb = $self->_xdb_acquire;
+        $xdb->begin_transaction;
+        my $txn = 1;
+        while (my $line = $r->getline) {
+                if ($line eq "commit\n") {
+                        $xdb->commit_transaction if $txn;
+                        $txn = undef;
+                } elsif ($line eq "close\n") {
+                        $self->_xdb_release;
+                        $xdb = $txn = undef;
+                } else {
+                        my ($len, $artnum, $object_id) = split(/ /, $line);
+                        $xdb ||= $self->_xdb_acquire;
+                        if (!$txn) {
+                                $xdb->begin_transaction;
+                                $txn = 1;
+                        }
+                        my $n = read($r, my $msg, $len) or die "read: $!\n";
+                        $n == $len or die "short read: $n != $len\n";
+                        my $mime = PublicInbox::MIME->new(\$msg);
+                        $self->index_blob($mime, $len, $artnum, $object_id);
+                }
+        }
+        warn "$$ still in transaction\n" if $txn;
+        warn "$$ xdb active\n" if $xdb;
+}
+
+# called by V2Writable
+sub index_raw {
+        my ($self, $len, $msgref, $artnum, $object_id) = @_;
+        print { $self->{w} } "$len $artnum $object_id\n", $$msgref or die
+                "failed to write partition $!\n";
+}
+
+1;
diff --git a/lib/PublicInbox/SearchIdxThread.pm b/lib/PublicInbox/SearchIdxThread.pm
new file mode 100644
index 00000000..6471309e
--- /dev/null
+++ b/lib/PublicInbox/SearchIdxThread.pm
@@ -0,0 +1,111 @@
+# Copyright (C) 2018 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+package PublicInbox::SearchIdxThread;
+use strict;
+use warnings;
+use base qw(PublicInbox::SearchIdx);
+use Storable qw(freeze thaw);
+
+sub new {
+        my ($class, $v2ibx) = @_;
+        my $self = $class->SUPER::new($v2ibx, 1, 'all');
+        # create the DB:
+        $self->_xdb_acquire;
+        $self->_xdb_release;
+
+        my ($r, $w);
+        pipe($r, $w) or die "pipe failed: $!\n";
+        binmode $r, ':raw';
+        binmode $w, ':raw';
+        my $pid = fork;
+        defined $pid or die "fork failed: $!\n";
+        if ($pid == 0) {
+                close $w;
+                eval { thread_worker_loop($self, $r) };
+                die "thread worker died: $@\n" if $@;
+                exit;
+        }
+        $self->{w} = $w;
+        $self->{pid} = $pid;
+        close $r;
+
+        $w->autoflush(1);
+
+        # lock on only exists in parent, not in worker
+        my $l = $self->{lock_path} = $self->xdir . '/thread.lock';
+        open my $fh, '>>', $l or die "failed to create $l: $!\n";
+        $self;
+}
+
+sub thread_worker_loop {
+        my ($self, $r) = @_;
+        my $msg;
+        my $xdb = $self->_xdb_acquire;
+        $xdb->begin_transaction;
+        my $txn = 1;
+        while (my $line = $r->getline) {
+                if ($line eq "commit\n") {
+                        $xdb->commit_transaction if $txn;
+                        $txn = undef;
+                } elsif ($line eq "close\n") {
+                        $self->_xdb_release;
+                        $xdb = $txn = undef;
+                } else {
+                        read($r, $msg, $line) or die "read failed: $!\n";
+                        $msg = thaw($msg); # should raise on error
+                        defined $msg or die "failed to thaw buffer\n";
+                        if (!$txn) {
+                                $xdb->begin_transaction;
+                                $txn = 1;
+                        }
+                        eval { $self->thread_msg_real(@$msg) };
+                        warn "failed to index message <$msg->[0]>: $@\n" if $@;
+                }
+        }
+}
+
+# called by a partition worker
+sub thread_msg {
+        my ($self, $mid, $ts, $xpath, $doc_data) = @_;
+        my $w = $self->{w};
+        my $err;
+        my $str = freeze([ $mid, $ts, $xpath, $doc_data ]);
+        my $len = length($str) . "\n";
+
+        # multiple processes write to the same pipe, so use flock
+        $self->_lock_acquire;
+        print $w $len, $str or $err = $!;
+        $self->_lock_release;
+
+        die "print failed: $err\n" if $err;
+}
+
+sub thread_msg_real {
+        my ($self, $mid, $ts, $xpath, $doc_data) = @_;
+        my $smsg = $self->lookup_message($mid);
+        my ($old_tid, $doc_id);
+        if ($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;
+        } else {
+                $smsg = PublicInbox::SearchMsg->new(undef);
+                $smsg->{mid} = $mid;
+        }
+        my $doc = $smsg->{doc};
+        $doc->add_term('XPATH' . $xpath) if defined $xpath;
+        $doc->add_term('XMID' . $mid);
+        $doc->set_data($doc_data);
+        $smsg->{ts} = $ts;
+        my @refs = ($smsg->references =~ /<([^>]+)>/g);
+        $self->link_message($smsg, \@refs, $old_tid);
+        my $db = $self->{xdb};
+        if (defined $doc_id) {
+                $db->replace_document($doc_id, $doc);
+        } else {
+                $doc_id = $db->add_document($doc);
+        }
+}
+
+1;
diff --git a/lib/PublicInbox/SearchMsg.pm b/lib/PublicInbox/SearchMsg.pm
index 25c1abb8..941bfd24 100644
--- a/lib/PublicInbox/SearchMsg.pm
+++ b/lib/PublicInbox/SearchMsg.pm
@@ -29,19 +29,24 @@ sub get_val ($$) {
         Search::Xapian::sortable_unserialise($doc->get_value($col));
 }
 
-sub load_expand {
-        my ($self) = @_;
-        my $doc = $self->{doc};
-        my $data = $doc->get_data or return;
-        $self->{ts} = get_val($doc, &PublicInbox::Search::TS);
-        utf8::decode($data);
-        my ($subj, $from, $refs, $to, $cc, $blob) = split(/\n/, $data);
+sub load_from_data ($$) {
+        my ($self) = $_[0]; # data = $_[1]
+        my ($subj, $from, $refs, $to, $cc, $blob) = split(/\n/, $_[1]);
         $self->{subject} = $subj;
         $self->{from} = $from;
         $self->{references} = $refs;
         $self->{to} = $to;
         $self->{cc} = $cc;
         $self->{blob} = $blob;
+}
+
+sub load_expand {
+        my ($self) = @_;
+        my $doc = $self->{doc};
+        my $data = $doc->get_data or return;
+        $self->{ts} = get_val($doc, &PublicInbox::Search::TS);
+        utf8::decode($data);
+        load_from_data($self, $data);
         $self;
 }
 
@@ -50,17 +55,9 @@ sub load_doc {
         my $data = $doc->get_data or return;
         my $ts = get_val($doc, &PublicInbox::Search::TS);
         utf8::decode($data);
-        my ($subj, $from, $refs, $to, $cc, $blob) = split(/\n/, $data);
-        bless {
-                doc => $doc,
-                subject => $subj,
-                ts => $ts,
-                from => $from,
-                references => $refs,
-                to => $to,
-                cc => $cc,
-                blob => $blob,
-        }, $class;
+        my $self = bless { doc => $doc, ts => $ts }, $class;
+        load_from_data($self, $data);
+        $self
 }
 
 # :bytes and :lines metadata in RFC 3977
diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 41bfb8d1..cb74ab1a 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -6,7 +6,8 @@ package PublicInbox::V2Writable;
 use strict;
 use warnings;
 use Fcntl qw(:flock :DEFAULT);
-use PublicInbox::SearchIdx;
+use PublicInbox::SearchIdxPart;
+use PublicInbox::SearchIdxThread;
 use PublicInbox::MIME;
 use PublicInbox::Git;
 use PublicInbox::Import;
@@ -32,7 +33,8 @@ sub new {
                 im => undef, #  PublicInbox::Import
                 xap_rw => undef, # PublicInbox::V2SearchIdx
                 xap_ro => undef,
-
+                partitions => 4,
+                transact_bytes => 0,
                 # limit each repo to 1GB or so
                 rotate_bytes => int((1024 * 1024 * 1024) / $PACKING_FACTOR),
         };
@@ -55,29 +57,39 @@ sub add {
         my $cmt = $im->add($mime, $check_cb) or return;
         $cmt = $im->get_mark($cmt);
         my $oid = $im->{last_object_id};
-        my $size = $im->{last_object_size};
-
-        my $idx = $self->search_idx;
-        $idx->index_both($mime, $size, $oid);
-        $idx->{xdb}->set_metadata('last_commit', $cmt);
-        my $n = $self->{transact_bytes} += $size;
-        if ($n > PublicInbox::SearchIdx::BATCH_BYTES) {
+        my ($len, $msgref) = @{$im->{last_object}};
+
+        my $nparts = $self->{partitions};
+        my $part = hex(substr($oid, 0, 8)) % $nparts;
+        my $idx = $self->idx_part($part);
+        my $all = $self->{all};
+        my $num = $all->index_mm($mime);
+        $idx->index_raw($len, $msgref, $num, $oid);
+        my $n = $self->{transact_bytes} += $len;
+        if ($n > (PublicInbox::SearchIdx::BATCH_BYTES * $nparts)) {
                 $self->checkpoint;
         }
 
         $mime;
 }
 
-sub search_idx {
-        my ($self) = @_;
-        $self->{idx} ||= eval {
-                my $idx = PublicInbox::SearchIdx->new($self->{-inbox}, 1);
-                my $mm = $idx->_msgmap_init;
-                $idx->_xdb_acquire->begin_transaction;
-                $self->{transact_bytes} = 0;
-                $mm->{dbh}->begin_work;
-                $idx
-        };
+sub idx_part {
+        my ($self, $part) = @_;
+        my $idx = $self->{idx_parts};
+        return $idx->[$part] if $idx; # fast path
+
+        # first time initialization:
+        my $all = $self->{all} = 
+                PublicInbox::SearchIdxThread->new($self->{-inbox});
+
+        # need to create all parts before initializing msgmap FD
+        my $max = $self->{partitions} - 1;
+        $idx = $self->{idx_parts} = [];
+        for my $i (0..$max) {
+                push @$idx, PublicInbox::SearchIdxPart->new($self, $i, $all);
+        }
+        $all->_msgmap_init->{dbh}->begin_work;
+        $idx->[$part];
 }
 
 sub remove {
@@ -99,23 +111,37 @@ sub done {
         my ($self) = @_;
         my $im = $self->{im};
         $im->done if $im; # PublicInbox::Import::done
-        $self->searchidx_checkpoint;
+        $self->searchidx_checkpoint(0);
 }
 
 sub checkpoint {
         my ($self) = @_;
         my $im = $self->{im};
         $im->checkpoint if $im; # PublicInbox::Import::checkpoint
-        $self->searchidx_checkpoint;
+        $self->searchidx_checkpoint(1);
 }
 
 sub searchidx_checkpoint {
-        my ($self) = @_;
-        my $idx = delete $self->{idx} or return;
+        my ($self, $more) = @_;
+
+        # order matters, we can only close {all} after all partitions
+        # are done because the partitions also write to {all}
+
+        my $parts = $self->{idx_parts};
+        foreach my $idx (@$parts) {
+                $idx->remote_commit;
+                $idx->remote_close unless $more;
+        }
 
-        $idx->{mm}->{dbh}->commit;
-        $idx->{xdb}->commit_transaction;
-        $idx->_xdb_release;
+        if (my $all = $self->{all}) {
+                $all->{mm}->{dbh}->commit;
+                if ($more) {
+                        $all->{mm}->{dbh}->begin_work;
+                }
+                $all->remote_commit;
+                $all->remote_close unless $more;
+        }
+        $self->{transact_bytes} = 0;
 }
 
 sub git_init {
@@ -158,7 +184,7 @@ sub importer {
                 } else {
                         $self->{im} = undef;
                         $im->done;
-                        $self->searchidx_checkpoint;
+                        $self->searchidx_checkpoint(1);
                         $im = undef;
                         my $git_dir = $self->git_init(++$self->{max_git});
                         my $git = PublicInbox::Git->new($git_dir);