Bugfix for issue 33; reduce lock contention in Get(), parallel benchmarks.

- Fix for issue 33 (non-null-terminated result from
  leveldb_property_value())

- Support for running multiple instances of a benchmark in parallel.

- Reduce lock contention on Get():
  (1) Do not hold the lock while searching memtables.
  (2) Shard block and table caches 16-ways.

  Benchmark for evaluating this change:
  $ db_bench --benchmarks=fillseq1,readrandom --threads=$n
  (fillseq1 is a small hack to make sure fillseq runs once regardless
  of number of threads specified on the command line).



git-svn-id: https://leveldb.googlecode.com/svn/trunk@49 62dab493-f737-651d-591e-8d6aee1b9529

1 files changed, 1 insertions, 0 deletions

diff --git a/util/histogram.h b/util/histogram.h
index f72f122..32484c0 100644
--- a/util/histogram.h
+++ b/util/histogram.h
@@ -16,6 +16,7 @@ class Histogram {
 
   void Clear();
   void Add(double value);
+  void Merge(const Histogram& other);
 
   std::string ToString() const;