init+index: support --skip-docdata for Xapian

Since we no longer read document data from Xapian, allow users
to opt-out of storing it.

This breaks compatibility with previous releases of
public-inbox, but gives us a ~1.5% space savings on Xapian
storage (and associated I/O and page cache pressure reduction).

1 files changed, 7 insertions, 5 deletions

diff --git a/lib/PublicInbox/Admin.pm b/lib/PublicInbox/Admin.pm
index f5427af7..b8ead6f7 100644
--- a/lib/PublicInbox/Admin.pm
+++ b/lib/PublicInbox/Admin.pm
@@ -48,13 +48,14 @@ sub resolve_repo_dir {
 sub detect_indexlevel ($) {
         my ($ibx) = @_;
 
-        # brand new or never before indexed inboxes default to full
-        return 'full' unless $ibx->over;
-        delete $ibx->{over}; # don't leave open FD lying around
+        my $over = $ibx->over;
+        my $srch = $ibx->search;
+        delete @$ibx{qw(over search)}; # don't leave open FDs lying around
 
+        # brand new or never before indexed inboxes default to full
+        return 'full' unless $over;
         my $l = 'basic';
-        my $srch = $ibx->search or return $l;
-        delete $ibx->{search}; # don't leave open FD lying around
+        return $l unless $srch;
         if (my $xdb = $srch->xdb) {
                 $l = 'full';
                 my $m = $xdb->get_metadata('indexlevel');
@@ -65,6 +66,7 @@ sub detect_indexlevel ($) {
 $ibx->{inboxdir} has unexpected indexlevel in Xapian: $m
 
                 }
+                $ibx->{-skip_docdata} = 1 if $xdb->get_metadata('skip_docdata');
         }
         $l;
 }