over+msgmap: do not store filename after DBI->connect

SQLite already knows the filename internally, so avoid having it
as a long-lived Perl SV to save some bytes when there's many
inboxes and open DBs.

1 files changed, 8 insertions, 6 deletions

diff --git a/lib/PublicInbox/Msgmap.pm b/lib/PublicInbox/Msgmap.pm
index e86fb854..38ec7858 100644
--- a/lib/PublicInbox/Msgmap.pm
+++ b/lib/PublicInbox/Msgmap.pm
@@ -229,9 +229,9 @@ sub mid_set {
 
 sub DESTROY {
         my ($self) = @_;
-        delete $self->{dbh};
-        my $f = $self->{filename};
+        my $dbh = $self->{dbh} or return;
         if (($self->{pid} // 0) == $$) {
+                my $f = $dbh->sqlite_db_filename;
                 unlink $f or warn "failed to unlink $f: $!\n";
         }
 }
@@ -239,8 +239,9 @@ sub DESTROY {
 sub atfork_parent {
         my ($self) = @_;
         $self->{pid} or die "not a temporary clone\n";
-        delete $self->{dbh} and die "tmp_clone dbh not prepared for parent";
-        my $dbh = $self->{dbh} = PublicInbox::Over::dbh_new($self, 1);
+        my $dbh = $self->{dbh} and die "tmp_clone dbh not prepared for parent";
+        $self->{filename} = $dbh->sqlite_db_filename;
+        $dbh = $self->{dbh} = PublicInbox::Over::dbh_new($self, 1);
         $dbh->do('PRAGMA synchronous = OFF');
 }
 
@@ -249,9 +250,10 @@ sub atfork_prepare {
         $self->{pid} or die "not a temporary clone\n";
         $self->{pid} == $$ or
                 die "BUG: atfork_prepare not called from $self->{pid}\n";
-        $self->{dbh} or die "temporary clone not open\n";
+        my $dbh = $self->{dbh} or die "temporary clone not open\n";
+
         # must clobber prepared statements
-        %$self = (filename => $self->{filename}, pid => $$);
+        %$self = (filename => $dbh->sqlite_db_filename, pid => $$);
 }
 
 sub skip_artnum {