[PATCH] searchidx: improve error message when Xapian fails

[Eric Wong <e@80x24.org>]

Konstantin Ryabitsev <konstantin@linuxfoundation.org> wrote:
> > Exception: Expected block 102325 to be level 2, not 0
> 
> In the process of helping me debug this, Eric pointed out that the
> xapian-db was corrupted. Apparently, this happened while I was copying
> the lkml dir to a safe location for testing purposes. Once I had a
> non-corrupted version of the database, I was able to successfully edit
> the necessary message.

Also, for public reference, using the flock(1) command (or
similar) can be used to safely copy while -mda or -watch
runs:

	flock /path/to/inbox.lock cp -a ....

I suppose this is also possible, to minimize lock time:

	# unlocked copy step
	rsync -a $SRC $DST

	# locked copy using a remote destination to force delta-transmission:
	flock /path/to/inbox.lock rsync -a $SRC $REMOTE_DST

But to make Xapian corruption more apparent in the future:

---------------8<-------------
Subject: [PATCH] searchidx: improve error message when Xapian fails

Make it easier to detect if a partition is corrupt.
---
 lib/PublicInbox/SearchIdx.pm | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index 9985628..7cd67f1 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -117,7 +117,11 @@ sub _xdb_acquire {
 		}
 	}
 	return unless defined $flag;
-	$self->{xdb} = Search::Xapian::WritableDatabase->new($dir, $flag);
+	my $xdb = eval { Search::Xapian::WritableDatabase->new($dir, $flag) };
+	if ($@) {
+		die "Failed opening $dir: ", $@;
+	}
+	$self->{xdb} = $xdb;
 }
 
 sub add_val ($$$) {
-- 
EW