index: --sequential-shard works incrementally

We should never reindex all data in Xapian unless --reindex is
specified on the command-line.  This means users who put
publicInbox.indexSequentialShard in their config file won't have
to put up with a full reindex at every invocation, only when
they specify --reindex.

We'll also cleanup the progress output to not emit non-sensical
ranges where the starting number is higher than the end.

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index dfcb489723d29a6faf0283efb133585e4a5949e6..8148439aca5e6dd3dc015f33849e4d890460eea3 100644 (file)
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -1197,20 +1197,20 @@ sub index_xap_only { # git->cat_async callback
 
 sub index_xap_step ($$$;$) {
        my ($self, $sync, $beg, $step) = @_;
-       my $ibx = $self->{ibx};
-       my $all = $ibx->git;
-       my $over = $ibx->over;
-       my $batch_bytes = batch_bytes($self);
-       $step //= $self->{shards};
        my $end = $sync->{art_end};
+       return if $beg > $end; # nothing to do
+
+       $step //= $self->{shards};
+       my $ibx = $self->{ibx};
        if (my $pr = $sync->{-opt}->{-progress}) {
                $pr->("Xapian indexlevel=$ibx->{indexlevel} ".
                        "$beg..$end (% $step)\n");
        }
+       my $batch_bytes = batch_bytes($self);
        for (my $num = $beg; $num <= $end; $num += $step) {
-               my $smsg = $over->get_art($num) or next;
+               my $smsg = $ibx->over->get_art($num) or next;
                $smsg->{v2w} = $self;
-               $all->cat_async($smsg->{blob}, \&index_xap_only, $smsg);
+               $ibx->git->cat_async($smsg->{blob}, \&index_xap_only, $smsg);
                if ($self->{transact_bytes} >= $batch_bytes) {
                        ${$sync->{nr}} = $num;
                        reindex_checkpoint($self, $sync);
@@ -1252,8 +1252,9 @@ sub index_epoch ($$$) {
 }
 
 sub xapian_only {
-       my ($self, $opt, $sync) = @_;
+       my ($self, $opt, $sync, $art_beg) = @_;
        my $seq = $opt->{sequentialshard};
+       $art_beg //= 0;
        local $self->{parallel} = 0 if $seq;
        $self->idx_init($opt); # acquire lock
        if (my $art_end = $self->{ibx}->mm->max) {
@@ -1267,9 +1268,11 @@ sub xapian_only {
                $sync->{art_end} = $art_end;
                if ($seq || !$self->{parallel}) {
                        my $shard_end = $self->{shards} - 1;
-                       index_xap_step($self, $sync, $_) for (0..$shard_end);
+                       for (0..$shard_end) {
+                               index_xap_step($self, $sync, $art_beg + $_)
+                       }
                } else { # parallel (maybe)
-                       index_xap_step($self, $sync, 0, 1);
+                       index_xap_step($self, $sync, $art_beg, 1);
                }
        }
        $self->{ibx}->git->cat_async_wait;
@@ -1288,6 +1291,7 @@ sub index_sync {
        return unless defined $latest;
 
        my $seq = $opt->{sequentialshard};
+       my $art_beg; # the NNTP article number we start xapian_only at
        my $idxlevel = $self->{ibx}->{indexlevel};
        local $self->{ibx}->{indexlevel} = 'basic' if $seq;
 
@@ -1311,6 +1315,12 @@ sub index_sync {
                $self->{mm}->{dbh}->begin_work;
                $sync->{mm_tmp} =
                        $self->{mm}->tmp_clone($self->{ibx}->{inboxdir});
+
+               # xapian_only works incrementally w/o --reindex
+               if ($seq && !$opt->{reindex}) {
+                       $art_beg = $sync->{mm_tmp}->max;
+                       $art_beg++ if defined($art_beg);
+               }
        }
        if ($sync->{index_max_size} = $self->{ibx}->{index_max_size}) {
                $sync->{index_oid} = \&index_oid;
@@ -1325,10 +1335,10 @@ sub index_sync {
                $pr->('all.git '.sprintf($sync->{-regen_fmt}, $$nr)) if $pr;
        }
 
-       if ($seq) { # deal with Xapian shards sequentially
+       # deal with Xapian shards sequentially
+       if ($seq && delete($sync->{mm_tmp})) {
                $self->{ibx}->{indexlevel} = $idxlevel;
-               delete $sync->{mm_tmp};
-               xapian_only($self, $opt, $sync);
+               xapian_only($self, $opt, $sync, $art_beg);
        }
 
        # reindex does not pick up new changes, so we rerun w/o it: