Tweak the LevelDB options a bit.

Author: pphaneuf

configure.ac

@@ -27,7 +27,7 @@ PKG_CHECK_MODULES([json_c], [json-c])
 
 # Checks for header files.
 AC_HEADER_RESOLV
-AC_CHECK_HEADERS([arpa/inet.h fcntl.h limits.h netinet/in.h stddef.h stdint.h stdlib.h string.h sys/socket.h sys/time.h unistd.h])
+AC_CHECK_HEADERS([arpa/inet.h fcntl.h limits.h netinet/in.h stddef.h stdint.h stdlib.h string.h sys/socket.h sys/time.h unistd.h leveldb/filter_policy.h])
 AC_CHECK_HEADER([event2/event.h],,
                 [AC_MSG_ERROR([libevent headers could not be found])])
 AC_CHECK_HEADER([gflags/gflags.h],,
@@ -36,6 +36,8 @@ AC_CHECK_HEADER([glog/logging.h],,
                 [AC_MSG_ERROR([glog headers could not be found])])
 AC_CHECK_HEADER([google/protobuf/message.h],,
                 [AC_MSG_ERROR([protobuf headers could not be found])])
+AC_CHECK_HEADER([leveldb/db.h],,
+                [AC_MSG_ERROR([leveldb headers could not be found])])
 AC_CHECK_HEADER([ldns/ldns.h],, [missing_ldns=yes])
 
 # Check for working GTest/GMock.

cpp/log/leveldb_db-inl.h

@@ -14,6 +14,10 @@
 #include "monitoring/latency.h"
 #include "util/util.h"
 
+DEFINE_int32(leveldb_max_open_files, 0,
+             "number of open files that can be used by leveldb");
+DEFINE_int32(leveldb_bloom_filter_bits_per_key, 0,
+             "number of open files that can be used by leveldb");
 
 namespace {
 
@@ -29,6 +33,20 @@ const char kTreeHeadPrefix[] = "sth-";
 const char kMetaPrefix[] = "meta-";
 
 
+#ifdef HAVE_LEVELDB_FILTER_POLICY_H
+std::unique_ptr<const leveldb::FilterPolicy> BuildFilterPolicy() {
+  std::unique_ptr<const leveldb::FilterPolicy> retval;
+
+  if (FLAGS_leveldb_bloom_filter_bits_per_key > 0) {
+    retval.reset(CHECK_NOTNULL(leveldb::NewBloomFilterPolicy(
+        FLAGS_leveldb_bloom_filter_bits_per_key)));
+  }
+
+  return retval;
+}
+#endif
+
+
 std::string FormatSequenceNumber(const int64_t seq) {
   return std::to_string(seq);
 }
@@ -47,11 +65,25 @@ const size_t LevelDB<Logged>::kTimestampBytesIndexed = 6;
 
 template <class Logged>
 LevelDB<Logged>::LevelDB(const std::string& dbfile)
-    : contiguous_size_(0), latest_tree_timestamp_(0) {
+    :
+#ifdef HAVE_LEVELDB_FILTER_POLICY_H
+      filter_policy_(BuildFilterPolicy()),
+#endif
+      contiguous_size_(0),
+      latest_tree_timestamp_(0) {
   LOG(INFO) << "Opening " << dbfile;
   cert_trans::ScopedLatency latency(latency_by_op_ms.GetScopedLatency("open"));
   leveldb::Options options;
   options.create_if_missing = true;
+  if (FLAGS_leveldb_max_open_files > 0) {
+    options.max_open_files = FLAGS_leveldb_max_open_files;
+  }
+#ifdef HAVE_LEVELDB_FILTER_POLICY_H
+  options.filter_policy = filter_policy_.get();
+#else
+  CHECK_EQ(FLAGS_leveldb_bloom_filter_bits_per_key, 0)
+      << "this version of leveldb does not have bloom filter support";
+#endif
   leveldb::DB* db;
   leveldb::Status status(leveldb::DB::Open(options, dbfile, &db));
   CHECK(status.ok()) << status.ToString();
@@ -286,8 +318,9 @@ void LevelDB<Logged>::BuildIndex() {
   // this should not be necessarily, but just to be sure...
   std::lock_guard<std::mutex> lock(lock_);
 
-  std::unique_ptr<leveldb::Iterator> it(
-      db_->NewIterator(leveldb::ReadOptions()));
+  leveldb::ReadOptions options;
+  options.fill_cache = false;
+  std::unique_ptr<leveldb::Iterator> it(db_->NewIterator(options));
   CHECK(it);
   it->Seek(kEntryPrefix);
 

cpp/log/leveldb_db.h

@@ -1,7 +1,12 @@
 #ifndef CERTIFICATE_LEVELDB_DB_H
 #define CERTIFICATE_LEVELDB_DB_H
 
+#include "config.h"
+
 #include <leveldb/db.h>
+#ifdef HAVE_LEVELDB_FILTER_POLICY_H
+#include <leveldb/filter_policy.h>
+#endif
 #include <map>
 #include <memory>
 #include <mutex>
@@ -63,6 +68,11 @@ class LevelDB : public Database<Logged> {
   void InsertEntryMapping(int64_t sequence_number, const std::string& hash);
 
   mutable std::mutex lock_;
+#ifdef HAVE_LEVELDB_FILTER_POLICY_H
+  // filter_policy_ must be valid for at least as long as db_ is, so
+  // keep this order.
+  const std::unique_ptr<const leveldb::FilterPolicy> filter_policy_;
+#endif
   std::unique_ptr<leveldb::DB> db_;
 
   int64_t contiguous_size_;