Support ttl in Universal Compaction (facebook#6071)

Summary:
`options.ttl` is now supported in universal compaction, similar to how periodic compactions are implemented in PR facebook#5970 .
Setting `options.ttl` will simply set `options.periodic_compaction_seconds` to execute the periodic compactions code path.
Discarded PR facebook#4749 in lieu of this.

This is a short term work-around/hack of falling back to periodic compactions when ttl is set.
Pull Request resolved: facebook#6071

Test Plan: Added a unit test.

Differential Revision: D18668336

Pulled By: sagar0

fbshipit-source-id: e75f5b81ba949f77ef9eff05e44bb1c757f58612

HISTORY.md

@@ -18,6 +18,7 @@
 * Full and partitioned filters in the block-based table use an improved Bloom filter implementation, enabled with format_version 5 (or above) because previous releases cannot read this filter. This replacement is faster and more accurate, especially for high bits per key or millions of keys in a single (full) filter. For example, the new Bloom filter has a lower false positive rate at 16 bits per key than the old one at 100 bits per key.
 * Added AVX2 instructions to USE_SSE builds to accelerate the new Bloom filter and XXH3-based hash function on compatible x86_64 platforms (Haswell and later, ~2014).
 * Support options.ttl with options.max_open_files = -1. File's oldest ancester time will be written to manifest. If it is availalbe, this information will be used instead of creation_time in table properties.
+* Setting options.ttl for universal compaction now has the same meaning as setting periodic_compaction_seconds.
 
 ### Performance Improvements
 * For 64-bit hashing, RocksDB is standardizing on a slightly modified preview version of XXH3. This function is now used for many non-persisted hashes, along with fastrange64() in place of the modulus operator, and some benchmarks show a slight improvement.

db/column_family.cc

@@ -367,6 +367,18 @@ ColumnFamilyOptions SanitizeOptions(const ImmutableDBOptions& db_options,
     }
   }
 
+  // TTL compactions would work similar to Periodic Compactions in Universal in
+  // most of the cases. So, if ttl is set, execute the periodic compaction
+  // codepath.
+  if (result.compaction_style == kCompactionStyleUniversal && result.ttl != 0) {
+    if (result.periodic_compaction_seconds != 0) {
+      result.periodic_compaction_seconds =
+          std::min(result.ttl, result.periodic_compaction_seconds);
+    } else {
+      result.periodic_compaction_seconds = result.ttl;
+    }
+  }
+
   return result;
 }
 

db/db_options_test.cc

@@ -606,6 +606,35 @@ TEST_F(DBOptionsTest, SanitizeDelayedWriteRate) {
   ASSERT_EQ(31 * 1024 * 1024, dbfull()->GetDBOptions().delayed_write_rate);
 }
 
+TEST_F(DBOptionsTest, SanitizeUniversalTTLCompaction) {
+  Options options;
+  options.compaction_style = kCompactionStyleUniversal;
+
+  options.ttl = 0;
+  options.periodic_compaction_seconds = 0;
+  Reopen(options);
+  ASSERT_EQ(0, dbfull()->GetOptions().ttl);
+  ASSERT_EQ(0, dbfull()->GetOptions().periodic_compaction_seconds);
+
+  options.ttl = 0;
+  options.periodic_compaction_seconds = 100;
+  Reopen(options);
+  ASSERT_EQ(0, dbfull()->GetOptions().ttl);
+  ASSERT_EQ(100, dbfull()->GetOptions().periodic_compaction_seconds);
+
+  options.ttl = 100;
+  options.periodic_compaction_seconds = 0;
+  Reopen(options);
+  ASSERT_EQ(100, dbfull()->GetOptions().ttl);
+  ASSERT_EQ(100, dbfull()->GetOptions().periodic_compaction_seconds);
+
+  options.ttl = 100;
+  options.periodic_compaction_seconds = 500;
+  Reopen(options);
+  ASSERT_EQ(100, dbfull()->GetOptions().ttl);
+  ASSERT_EQ(100, dbfull()->GetOptions().periodic_compaction_seconds);
+}
+
 TEST_F(DBOptionsTest, SanitizeFIFOPeriodicCompaction) {
   Options options;
   options.compaction_style = kCompactionStyleFIFO;

include/rocksdb/advanced_options.h

@@ -647,7 +647,6 @@ struct AdvancedColumnFamilyOptions {
   bool report_bg_io_stats = false;
 
   // Files older than TTL will go through the compaction process.
-  // Supported in Level and FIFO compaction.
   // Pre-req: This needs max_open_files to be set to -1.
   // In Level: Non-bottom-level files older than TTL will go through the
   //           compation process.