From 43a593a6d921acbf79ccac0abad35c093faac175 Mon Sep 17 00:00:00 2001
From: sdong <siying.d@fb.com>
Date: Fri, 28 Mar 2014 16:57:04 -0700
Subject: [PATCH] Change default value of some Options

Summary: Since we are optimizing for server workloads, some default values are not optimized any more. We change some of those values that I feel it's less prone to regression bugs.

Test Plan: make all check

Reviewers: dhruba, haobo, ljin, igor, yhchiang

Reviewed By: igor

CC: leveldb, MarkCallaghan

Differential Revision: https://reviews.facebook.net/D16995
---
 db/db_test.cc             |  5 +++++
 include/rocksdb/options.h |  8 ++++----
 util/options.cc           | 14 +++++++-------
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/db/db_test.cc b/db/db_test.cc
index ee70871a2..0f007f791 100644
--- a/db/db_test.cc
+++ b/db/db_test.cc
@@ -306,6 +306,7 @@ class DBTest {
 
   DBTest() : option_config_(kDefault),
              env_(new SpecialEnv(Env::Default())) {
+    last_options_.max_background_flushes = 0;
     filter_policy_ = NewBloomFilterPolicy(10);
     dbname_ = test::TmpDir() + "/db_test";
     ASSERT_OK(DestroyDB(dbname_, Options()));
@@ -371,6 +372,8 @@ class DBTest {
   // Return the current option configuration.
   Options CurrentOptions() {
     Options options;
+    options.paranoid_checks = false;
+    options.max_background_flushes = 0;
     switch (option_config_) {
       case kHashSkipList:
         options.prefix_extractor.reset(NewFixedPrefixTransform(1));
@@ -431,6 +434,7 @@ class DBTest {
         options.compaction_style = kCompactionStyleUniversal;
         break;
       case kCompressedBlockCache:
+        options.allow_mmap_writes = true;
         options.block_cache_compressed = NewLRUCache(8*1024*1024);
         break;
       case kInfiniteMaxOpenFiles:
@@ -5306,6 +5310,7 @@ TEST(DBTest, ReadCompaction) {
     options.filter_policy = nullptr;
     options.block_size = 4096;
     options.no_block_cache = true;
+    options.disable_seek_compaction = false;
 
     Reopen(&options);
 
diff --git a/include/rocksdb/options.h b/include/rocksdb/options.h
index bd51669a2..54b4ef38f 100644
--- a/include/rocksdb/options.h
+++ b/include/rocksdb/options.h
@@ -146,7 +146,7 @@ struct Options {
   // If any of the writes to the database fails (Put, Delete, Merge, Write),
   // the database will switch to read-only mode and fail all other
   // Write operations.
-  // Default: false
+  // Default: true
   bool paranoid_checks;
 
   // Use the specified object to interact with the environment,
@@ -199,7 +199,7 @@ struct Options {
   // on target_file_size_base and target_file_size_multiplier for level-based
   // compaction. For universal-style compaction, you can usually set it to -1.
   //
-  // Default: 1000
+  // Default: 5000
   int max_open_files;
 
   // Control over blocks (user data is stored in a set of blocks, and
@@ -436,7 +436,7 @@ struct Options {
   // Without a separate pool, long running major compaction jobs could
   // potentially block memtable flush jobs of other db instances, leading to
   // unnecessary Put stalls.
-  // Default: 0
+  // Default: 1
   int max_background_flushes;
 
   // Specify the maximal size of the info log file. If the log file
@@ -562,7 +562,7 @@ struct Options {
   // Allow the OS to mmap file for reading sst tables. Default: false
   bool allow_mmap_reads;
 
-  // Allow the OS to mmap file for writing. Default: true
+  // Allow the OS to mmap file for writing. Default: false
   bool allow_mmap_writes;
 
   // Disable child process inherit open files. Default: true
diff --git a/util/options.cc b/util/options.cc
index aa1a4c64e..5c5bab557 100644
--- a/util/options.cc
+++ b/util/options.cc
@@ -35,14 +35,14 @@ Options::Options()
       compaction_filter_factory_v2(new DefaultCompactionFilterFactoryV2()),
       create_if_missing(false),
       error_if_exists(false),
-      paranoid_checks(false),
+      paranoid_checks(true),
       env(Env::Default()),
       info_log(nullptr),
       info_log_level(INFO),
       write_buffer_size(4 << 20),
       max_write_buffer_number(2),
       min_write_buffer_number_to_merge(1),
-      max_open_files(1000),
+      max_open_files(5000),
       block_cache(nullptr),
       block_cache_compressed(nullptr),
       block_size(4096),
@@ -53,8 +53,8 @@ Options::Options()
       whole_key_filtering(true),
       num_levels(7),
       level0_file_num_compaction_trigger(4),
-      level0_slowdown_writes_trigger(8),
-      level0_stop_writes_trigger(12),
+      level0_slowdown_writes_trigger(20),
+      level0_stop_writes_trigger(24),
       max_mem_compaction_level(2),
       target_file_size_base(2 * 1048576),
       target_file_size_multiplier(1),
@@ -69,10 +69,10 @@ Options::Options()
       db_stats_log_interval(1800),
       db_log_dir(""),
       wal_dir(""),
-      disable_seek_compaction(false),
+      disable_seek_compaction(true),
       delete_obsolete_files_period_micros(6 * 60 * 60 * 1000000UL),
       max_background_compactions(1),
-      max_background_flushes(0),
+      max_background_flushes(1),
       max_log_file_size(0),
       log_file_time_to_roll(0),
       keep_log_file_num(1000),
@@ -91,7 +91,7 @@ Options::Options()
       purge_redundant_kvs_while_flush(true),
       allow_os_buffer(true),
       allow_mmap_reads(false),
-      allow_mmap_writes(true),
+      allow_mmap_writes(false),
       is_fd_close_on_exec(true),
       skip_log_error_on_recovery(false),
       stats_dump_period_sec(3600),