miscidx: switch to lazy transactions

This fixes a sporadic failure on a 1/2 core VM where
"git cat-file --batch" hasn't started up by the time
$cleanup->() destroys the ALL.git directory in t/lei.t
(but not t/lei-oneshot.t).

This happens because dwaitpid() runs inside the event loop
asynchronously and we were able to return to the client before
the cat-file process could even start.

I could not reproduce this failure on my usual 4-core
workstation via "schedtool -a 0x1" to force the entire
test to use a single core.

Lazy transactions matches OverIdx and SearchIdx behavior, and
I've verified this lets us avoid problems with old Xapian
versions (on CentOS 7.x) which failed to set FD_CLOEXEC.

1 files changed, 0 insertions, 4 deletions

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 0104f87a..7f9342b0 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -623,10 +623,6 @@ shard[$i] bad echo:$echo != $i waiting for txn commit
                         $dbh->commit;
                         $dbh->begin_work;
                 }
-                if ($midx) {
-                        $self->git->batch_prepare;
-                        $midx->begin_txn;
-                }
         }
         $self->{total_bytes} += $self->{transact_bytes};
         $self->{transact_bytes} = 0;