xcpdb: support resharding v2 repos

v2 repos are sometimes created on machines where CPU
parallelization exceeds the capability of the storage devices.

In that case, users may reshard the Xapian DB to any smaller,
positive integer to avoid excessive overhead and contention when
bottlenecked by slow storage.

Resharding can also be used to increase shard count after
hardware upgrades.

1 files changed, 1 insertions, 0 deletions

diff --git a/MANIFEST b/MANIFEST
index 5085bff8..a750e09e 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -258,3 +258,4 @@ t/view.t
 t/watch_filter_rubylang.t
 t/watch_maildir.t
 t/watch_maildir_v2.t
+t/xcpdb-reshard.t