Show More DB Stats in info logs

Summary:
DB Stats now are truncated if there are too many CFs. Extend the buffer size to allow more to be printed out. Also, separate out malloc to another log line.
Closes https://github.com/facebook/rocksdb/pull/1439

Differential Revision: D4100943

Pulled By: yiwu-arbug

fbshipit-source-id: 79f7218

db/db_impl.cc

@@ -634,13 +634,20 @@ void DBImpl::MaybeDumpStats() {
       default_cf_internal_stats_->GetStringProperty(
           *db_property_info, DB::Properties::kDBStats, &stats);
     }
-    if (immutable_db_options_.dump_malloc_stats) {
-      DumpMallocStats(&stats);
-    }
     Log(InfoLogLevel::WARN_LEVEL, immutable_db_options_.info_log,
         "------- DUMPING STATS -------");
     Log(InfoLogLevel::WARN_LEVEL, immutable_db_options_.info_log, "%s",
         stats.c_str());
+    if (immutable_db_options_.dump_malloc_stats) {
+      stats.clear();
+      DumpMallocStats(&stats);
+      if (!stats.empty()) {
+        Log(InfoLogLevel::WARN_LEVEL, immutable_db_options_.info_log,
+            "------- Malloc STATS -------");
+        Log(InfoLogLevel::WARN_LEVEL, immutable_db_options_.info_log, "%s",
+            stats.c_str());
+      }
+    }
 #endif  // !ROCKSDB_LITE
 
     PrintStatistics();

util/posix_logger.h

@@ -80,7 +80,7 @@ class PosixLogger : public Logger {
         bufsize = sizeof(buffer);
         base = buffer;
       } else {
-        bufsize = 30000;
+        bufsize = 65536;
         base = new char[bufsize];
       }
       char* p = base;