leveldb: add compact_prefix method

Signed-off-by: Sage Weil <sage@inktank.com>

diff --git a/src/os/LevelDBStore.h b/src/os/LevelDBStore.h
index 9f8cd52ca9c758b0dbdcf62456d5421a14b801af..83f2ed3b4c4518bafbe8705aaa8ae4d6909d3367 100644 (file)
--- a/src/os/LevelDBStore.h
+++ b/src/os/LevelDBStore.h
@@ -38,6 +38,17 @@ public:
     db->CompactRange(NULL, NULL);
   }
 
+  /// compact leveldb for all keys with a given prefix
+  void compact_prefix(const string& prefix) {
+    // if we combine the prefix with key by adding a '\0' separator,
+    // a char(1) will capture all such keys.
+    string end = prefix;
+    end += (char)1;
+    leveldb::Slice cstart(prefix);
+    leveldb::Slice cend(end);
+    db->CompactRange(&cstart, &cend);
+  }
+
   /**
    * options_t: Holds options which are minimally interpreted
    * on initialization and then passed through to LevelDB.