v2writable: support "barrier" operation to avoid reforking

[public-inbox.git] / lib / PublicInbox / V2Writable.pm

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 7728b91a542a79727eaed2f627639fdad080cbb0..6e2a8d68cc45f10e129d8f072c4dca45d3914746 100644 (file)
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -113,7 +113,7 @@ sub num_for {
                };
 
                # crap, Message-ID is already known, hope somebody just resent:
-               $self->done; # write barrier, clears $self->{skel}
+               $self->barrier;
                foreach my $m (@$mids) {
                        # read-only lookup now safe to do after above barrier
                        my $existing = $self->lookup_content($mime, $m);
@@ -228,6 +228,37 @@ sub checkpoint {
        $self->searchidx_checkpoint(1);
 }
 
+# issue a write barrier to ensure all data is visible to other processes
+# and read-only ops.  Order of data importance is: git > SQLite > Xapian
+sub barrier {
+       my ($self) = @_;
+
+       # For safety, we ensure git checkpoint is complete before because
+       # the data in git is still more important than what is in Xapian.
+       # Performance may be gained by delaying ->progress call but we
+       # lose safety
+       if (my $im = $self->{im}) {
+               $im->checkpoint;
+               $im->progress('checkpoint');
+       }
+       my $skel = $self->{skel};
+       my $parts = $self->{idx_parts};
+       if ($parts && $skel) {
+               my $dbh = $skel->{mm}->{dbh};
+               $dbh->commit; # SQLite data is second in importance
+
+               # Now deal with Xapian
+               $skel->barrier_init(scalar(@$parts));
+               # each partition needs to issue a barrier command to skel:
+               $_->barrier foreach @$parts;
+
+               $skel->barrier_wait; # wait for each Xapian partition
+
+               $dbh->begin_work;
+       }
+       $self->{transact_bytes} = 0;
+}
+
 sub searchidx_checkpoint {
        my ($self, $more) = @_;
 
@@ -349,6 +380,7 @@ sub lookup_content {
        my $ibx = $self->{-inbox};
 
        my $srch = $ibx->search;
+       $srch->reopen;
        my $cid = content_id($mime);
        my $found;
        $srch->each_smsg_by_mid($mid, sub {