Make NewBloomFilterPolicy() use full filter by default (#4735)

Summary:
Full block (use_block_based_builder=false) Bloom filter has clear CPU saving benefits but with limitation of using temp memory when building an SST file proportional to the SST file size. We reduced the chance of having large SST files with multi-level universal compaction. Now we change to a default with better performance.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4735

Differential Revision: D13266674

Pulled By: siying

fbshipit-source-id: 7594a4c3e32568a5a2adce22bb0e46553e55c602

HISTORY.md

@@ -8,6 +8,7 @@
 ### Bug Fixes
 * Fixed Get correctness bug in the presence of range tombstones where merge operands covered by a range tombstone always result in NotFound.
 * Start populating `NO_FILE_CLOSES` ticker statistic, which was always zero previously.
+* The default value of NewBloomFilterPolicy()'s argument use_block_based_builder is changed to false. Note that this new default may cause large temp memory usage when building very large SST files.
 
 ## 5.18.0 (11/12/2018)
 ### New Features

db/db_block_cache_test.cc

@@ -349,7 +349,7 @@ TEST_F(DBBlockCacheTest, IndexAndFilterBlocksStats) {
   // 200 bytes are enough to hold the first two blocks
   std::shared_ptr<Cache> cache = NewLRUCache(200, 0, false);
   table_options.block_cache = cache;
-  table_options.filter_policy.reset(NewBloomFilterPolicy(20));
+  table_options.filter_policy.reset(NewBloomFilterPolicy(20, true));
   options.table_factory.reset(new BlockBasedTableFactory(table_options));
   CreateAndReopenWithCF({"pikachu"}, options);
 

include/rocksdb/filter_policy.h

@@ -145,6 +145,6 @@ class FilterPolicy {
 // ignores trailing spaces, it would be incorrect to use a
 // FilterPolicy (like NewBloomFilterPolicy) that does not ignore
 // trailing spaces in keys.
-extern const FilterPolicy* NewBloomFilterPolicy(int bits_per_key,
+extern const FilterPolicy* NewBloomFilterPolicy(
-    bool use_block_based_builder = true);
+    int bits_per_key, bool use_block_based_builder = false);
 }