v2writable: support async git blob retrievals

This seems to speed up --reindex on smallish v2 inboxes by about
30% on both HDD and SSD.  lore/git (~1GB) on an SSD even gives a
30% improvement with 3 shards.  I'm only seeing a ~4% speedup on
LKML with a SATA SSD (which is difficult to repeat because it
takes around 4 hours).

Testing LKML on an HDD will take much more time...

2 files changed, 65 insertions, 55 deletions

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index fe089c8e..1fc57410 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -21,7 +21,7 @@ use PublicInbox::OverIdx;
 use PublicInbox::Spawn qw(spawn);
 use PublicInbox::Git qw(git_unquote);
 use PublicInbox::MsgTime qw(msg_timestamp msg_datestamp);
-our @EXPORT_OK = qw(too_big crlf_adjust log2stack is_ancestor);
+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;
@@ -553,21 +553,11 @@ sub index_sync {
         }
 }
 
-sub too_big ($$) {
-        my ($self, $oid) = @_;
-        my $max_size = $self->{index_max_size} or return;
-        my (undef, undef, $size) = $self->{ibx}->git->check($oid);
-        die "E: bad $oid in $self->{ibx}->{inboxdir}\n" if !defined($size);
-        return if $size <= $max_size;
-        warn "W: skipping $oid ($size > $max_size)\n";
-        1;
-}
-
-sub ck_size { # check_async cb for -index --max-size=...
+sub check_size { # check_async cb for -index --max-size=...
         my ($oid, $type, $size, $arg, $git) = @_;
         (($type // '') eq 'blob') or die "E: bad $oid in $git->{git_dir}";
         if ($size <= $arg->{index_max_size}) {
-                $git->cat_async($oid, \&index_both, $arg);
+                $git->cat_async($oid, $arg->{index_oid}, $arg);
         } else {
                 warn "W: skipping $oid ($size > $arg->{index_max_size})\n";
         }
@@ -630,12 +620,14 @@ sub process_stack {
                         $git->cat_async($oid, \&unindex_both, $self);
                 }
         }
-        $sync->{index_max_size} = $self->{ibx}->{index_max_size};
+        if ($sync->{index_max_size} = $self->{ibx}->{index_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->{index_max_size}) {
-                                $git->check_async($oid, \&ck_size, $arg);
+                                $git->check_async($oid, \&check_size, $arg);
                         } else {
                                 $git->cat_async($oid, \&index_both, $arg);
                         }
diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index f159d39c..6908bd2e 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -18,7 +18,7 @@ use PublicInbox::InboxWritable;
 use PublicInbox::OverIdx;
 use PublicInbox::Msgmap;
 use PublicInbox::Spawn qw(spawn popen_rd);
-use PublicInbox::SearchIdx qw(too_big log2stack crlf_adjust is_ancestor);
+use PublicInbox::SearchIdx qw(log2stack crlf_adjust is_ancestor check_size);
 use IO::Handle; # ->autoflush
 use File::Temp qw(tempfile);
 
@@ -124,7 +124,6 @@ sub new {
         };
         $self->{over}->{-no_sync} = 1 if $v2ibx->{-no_sync};
         $self->{shards} = count_shards($self) || nproc_shards($creat);
-        $self->{index_max_size} = $v2ibx->{index_max_size};
         bless $self, $class;
 }
 
@@ -307,8 +306,8 @@ sub idx_init {
         # do not leak read-only FDs to child processes, we only have these
         # FDs for duplicate detection so they should not be
         # frequently activated.
-        # delete @$ibx{qw(git mm search)};
-        delete $ibx->{$_} foreach (qw(git mm search));
+        delete @$ibx{qw(mm search)};
+        $ibx->git->cleanup;
 
         $self->{parallel} = 0 if ($ibx->{indexlevel}//'') eq 'basic';
         if ($self->{parallel}) {
@@ -863,11 +862,13 @@ sub atfork_child {
 sub reindex_checkpoint ($$) {
         my ($self, $sync) = @_;
 
+        $self->{ibx}->git->cleanup; # *async_wait
+        ${$sync->{need_checkpoint}} = 0;
         $sync->{mm_tmp}->atfork_prepare;
         $self->done; # release lock
 
         if (my $pr = $sync->{-opt}->{-progress}) {
-                $pr->(sprintf($sync->{-regen_fmt}, $sync->{nr}));
+                $pr->(sprintf($sync->{-regen_fmt}, ${$sync->{nr}}));
         }
 
         # allow -watch or -mda to write...
@@ -875,15 +876,14 @@ sub reindex_checkpoint ($$) {
         $sync->{mm_tmp}->atfork_parent;
 }
 
-sub reindex_oid ($$$) {
-        my ($self, $sync, $oid) = @_;
-        return if too_big($self, $oid);
-        my ($num, $mid0, $len);
-        my $msgref = $self->{ibx}->git->cat_file($oid, \$len);
-        return if $len == 0; # purged
-        my $mime = PublicInbox::Eml->new($$msgref);
+sub index_oid { # cat_async callback
+        my ($bref, $oid, $type, $size, $arg) = @_;
+        return if $size == 0; # purged
+        my ($num, $mid0);
+        my $mime = PublicInbox::Eml->new($$bref);
         my $mids = mids($mime->header_obj);
         my $chash = content_hash($mime);
+        my $self = $arg->{v2w};
 
         if (scalar(@$mids) == 0) {
                 warn "E: $oid has no Message-ID, skipping\n";
@@ -891,12 +891,12 @@ sub reindex_oid ($$$) {
         }
 
         # {unindexed} is unlikely
-        if ((my $unindexed = $sync->{unindexed}) && scalar(@$mids) == 1) {
+        if ((my $unindexed = $arg->{unindexed}) && scalar(@$mids) == 1) {
                 $num = delete($unindexed->{$mids->[0]});
                 if (defined $num) {
                         $mid0 = $mids->[0];
                         $self->{mm}->mid_set($num, $mid0);
-                        delete($sync->{unindexed}) if !keys(%$unindexed);
+                        delete($arg->{unindexed}) if !keys(%$unindexed);
                 }
         }
         if (!defined($num)) { # reuse if reindexing (or duplicates)
@@ -907,12 +907,12 @@ sub reindex_oid ($$$) {
                 }
         }
         $mid0 //= do { # is this a number we got before?
-                $num = $sync->{mm_tmp}->num_for($mids->[0]);
+                $num = $arg->{mm_tmp}->num_for($mids->[0]);
                 defined($num) ? $mids->[0] : undef;
         };
         if (!defined($num)) {
                 for (my $i = $#$mids; $i >= 1; $i--) {
-                        $num = $sync->{mm_tmp}->num_for($mids->[$i]);
+                        $num = $arg->{mm_tmp}->num_for($mids->[$i]);
                         if (defined($num)) {
                                 $mid0 = $mids->[$i];
                                 last;
@@ -920,7 +920,7 @@ sub reindex_oid ($$$) {
                 }
         }
         if (defined($num)) {
-                $sync->{mm_tmp}->num_delete($num);
+                $arg->{mm_tmp}->num_delete($num);
         } else { # never seen
                 $num = $self->{mm}->mid_insert($mids->[0]);
                 if (defined($num)) {
@@ -939,16 +939,16 @@ sub reindex_oid ($$$) {
                 warn "E: $oid <", join('> <', @$mids), "> is a duplicate\n";
                 return;
         }
-        $sync->{nr}++;
+        ++${$arg->{nr}};
         my $smsg = bless {
-                raw_bytes => $len,
+                raw_bytes => $size,
                 num => $num,
                 blob => $oid,
                 mid => $mid0,
         }, 'PublicInbox::Smsg';
-        $smsg->populate($mime, $sync);
-        if (do_idx($self, $msgref, $mime, $smsg)) {
-                reindex_checkpoint($self, $sync);
+        $smsg->populate($mime, $arg);
+        if (do_idx($self, $bref, $mime, $smsg)) {
+                ${$arg->{need_checkpoint}} = 1;
         }
 }
 
@@ -1065,11 +1065,14 @@ sub sync_prepare ($$$) {
         # our code and blindly injects "d" file history into git repos
         if (my @leftovers = keys %{delete($sync->{D}) // {}}) {
                 warn('W: unindexing '.scalar(@leftovers)." leftovers\n");
+                my $arg = { v2w => $self };
+                my $all = $self->{ibx}->git;
                 for my $oid (@leftovers) {
                         $oid = unpack('H*', $oid);
                         $self->{current_info} = "leftover $oid";
-                        unindex_oid($self, $oid);
+                        $all->cat_async($oid, \&unindex_oid, $arg);
                 }
+                $all->cat_async_wait;
         }
         return 0 if (!$regen_max && !keys(%{$self->{unindex_range}}));
 
@@ -1077,7 +1080,7 @@ sub sync_prepare ($$$) {
         # it's a problem and we need to notice it via die()
         my $pad = length($regen_max) + 1;
         $sync->{-regen_fmt} = "% ${pad}u/$regen_max\n";
-        $sync->{nr} = 0;
+        $sync->{nr} = \(my $nr = 0);
         return -1 if $sync->{reindex};
         $regen_max + $self->{mm}->num_highwater() || 0;
 }
@@ -1091,13 +1094,13 @@ sub unindex_oid_remote ($$$) {
         }
 }
 
-sub unindex_oid ($$;$) {
-        my ($self, $oid, $unindexed) = @_;
+sub unindex_oid ($$;$) { # git->cat_async callback
+        my ($bref, $oid, $type, $size, $sync) = @_;
+        my $self = $sync->{v2w};
+        my $unindexed = $sync->{in_unindex} ? $sync->{unindexed} : undef;
         my $mm = $self->{mm};
-        my $msgref = $self->{ibx}->git->cat_file($oid);
-        my $mime = PublicInbox::Eml->new($msgref);
-        my $mids = mids($mime->header_obj);
-        $mime = $msgref = undef;
+        my $mids = mids(PublicInbox::Eml->new($bref)->header_obj);
+        undef $$bref;
         my $over = $self->{over};
         foreach my $mid (@$mids) {
                 my %gone;
@@ -1125,17 +1128,20 @@ sub unindex_oid ($$;$) {
 # a mirror because the source used -purge or -edit
 sub unindex ($$$$) {
         my ($self, $sync, $git, $unindex_range) = @_;
-        my $unindexed = $sync->{unindexed} ||= {}; # $mid0 => $num
+        my $unindexed = $sync->{unindexed} //= {}; # $mid0 => $num
         my $before = scalar keys %$unindexed;
         # order does not matter, here:
         my @cmd = qw(log --raw -r
                         --no-notes --no-color --no-abbrev --no-renames);
         my $fh = $git->popen(@cmd, $unindex_range);
+        my $all = $self->{ibx}->git;
+        local $sync->{in_unindex} = 1;
         while (<$fh>) {
                 /\A:\d{6} 100644 $OID ($OID) [AM]\tm$/o or next;
-                unindex_oid($self, $1, $unindexed);
+                $all->cat_async($1, \&unindex_oid, $sync);
         }
         close $fh or die "git log failed: \$?=$?";
+        $all->cat_async_wait;
 
         return unless $sync->{-opt}->{prune};
         my $after = scalar keys %$unindexed;
@@ -1171,17 +1177,25 @@ sub index_epoch ($$$) {
         }
         defined(my $stk = $sync->{stacks}->[$i]) or return;
         $sync->{stacks}->[$i] = undef;
+        my $all = $self->{ibx}->git;
         while (my ($f, $at, $ct, $oid) = $stk->pop_rec) {
                 $self->{current_info} = "$i.git $oid";
                 if ($f eq 'm') {
-                        $sync->{autime} = $at;
-                        $sync->{cotime} = $ct;
-                        reindex_oid($self, $sync, $oid);
+                        my $arg = { %$sync, autime => $at, cotime => $ct };
+                        if ($sync->{index_max_size}) {
+                                $all->check_async($oid, \&check_size, $arg);
+                        } else {
+                                $all->cat_async($oid, \&index_oid, $arg);
+                        }
                 } elsif ($f eq 'd') {
-                        unindex_oid($self, $oid);
+                        $all->cat_async($oid, \&unindex_oid, $sync);
+                }
+                if (${$sync->{need_checkpoint}}) {
+                        reindex_checkpoint($self, $sync);
                 }
         }
-        delete @$sync{qw(autime cotime)};
+        $all->check_async_wait;
+        $all->cat_async_wait;
         update_last_commit($self, $git, $i, $stk->{latest_cmt});
 }
 
@@ -1197,9 +1211,11 @@ sub index_sync {
         fill_alternates($self, $epoch_max);
         $self->{over}->rethread_prepare($opt);
         my $sync = {
+                need_checkpoint => \(my $bool = 0),
                 unindex_range => {}, # EPOCH => oid_old..oid_new
                 reindex => $opt->{reindex},
-                -opt => $opt
+                -opt => $opt,
+                v2w => $self,
         };
         $sync->{ranges} = sync_ranges($self, $sync, $epoch_max);
         if (sync_prepare($self, $sync, $epoch_max)) {
@@ -1211,14 +1227,16 @@ sub index_sync {
                 $self->{mm}->{dbh}->begin_work;
                 $sync->{mm_tmp} = $self->{mm}->tmp_clone;
         }
-
+        if ($sync->{index_max_size} = $self->{ibx}->{index_max_size}) {
+                $sync->{index_oid} = \&index_oid;
+        }
         # work forwards through history
         index_epoch($self, $sync, $_) for (0..$epoch_max);
         $self->done;
 
         if (my $nr = $sync->{nr}) {
                 my $pr = $sync->{-opt}->{-progress};
-                $pr->('all.git '.sprintf($sync->{-regen_fmt}, $nr)) if $pr;
+                $pr->('all.git '.sprintf($sync->{-regen_fmt}, $$nr)) if $pr;
         }
         $self->{over}->rethread_done($opt);