[RocksDB] Add OnCompactionStart to CompactionFilter class

Summary: This is to give application compaction filter a chance to access context information of a specific compaction run. For example, depending on whether a compaction goes through all data files, the application could do things differently.

Test Plan: make check

Reviewers: dhruba, kailiu, sdong

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13683

db/db_impl.cc

@@ -101,6 +101,13 @@ struct DBImpl::CompactionState {
       : compaction(c),
         total_bytes(0) {
   }
+
+  // Create a client visible context of this compaction
+  CompactionFilter::Context GetFilterContext() {
+    CompactionFilter::Context context;
+    context.is_full_compaction = compaction->IsFullCompaction();
+    return context;
+  }
 };
 
 struct DBImpl::DeletionState {
@@ -166,9 +173,8 @@ Options SanitizeOptions(const std::string& dbname,
   if (result.soft_rate_limit > result.hard_rate_limit) {
     result.soft_rate_limit = result.hard_rate_limit;
   }
-  if (result.compaction_filter &&
-      result.compaction_filter_factory->CreateCompactionFilter().get()) {
-    Log(result.info_log, "Both filter and factory specified. Using filter");
+  if (result.compaction_filter) {
+    Log(result.info_log, "Compaction filter specified, ignore factory");
   }
   if (result.prefix_extractor) {
     // If a prefix extractor has been supplied and a PrefixHashRepFactory is
@@ -1927,6 +1933,7 @@ inline SequenceNumber DBImpl::findEarliestVisibleSnapshot(
 }
 
 Status DBImpl::DoCompactionWork(CompactionState* compact) {
+  assert(compact);
   int64_t imm_micros = 0;  // Micros spent doing imm_ compactions
   Log(options_.info_log,
       "Compacting %d@%d + %d@%d files, score %.2f slots available %d",
@@ -1987,10 +1994,12 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) {
   auto compaction_filter = options_.compaction_filter;
   std::unique_ptr<CompactionFilter> compaction_filter_from_factory = nullptr;
   if (!compaction_filter) {
-    compaction_filter_from_factory = std::move(
-        options_.compaction_filter_factory->CreateCompactionFilter());
+    auto context = compact->GetFilterContext();
+    compaction_filter_from_factory =
+      options_.compaction_filter_factory->CreateCompactionFilter(context);
     compaction_filter = compaction_filter_from_factory.get();
   }
+
   for (; input->Valid() && !shutting_down_.Acquire_Load(); ) {
     // Prioritize immutable compaction work
     // TODO: remove memtable flush from normal compaction work

db/db_test.cc

@@ -2430,7 +2430,7 @@ class ChangeFilter : public CompactionFilter {
 class KeepFilterFactory : public CompactionFilterFactory {
   public:
     virtual std::unique_ptr<CompactionFilter>
-    CreateCompactionFilter() override {
+    CreateCompactionFilter(const CompactionFilter::Context& context) override {
       return std::unique_ptr<CompactionFilter>(new KeepFilter());
     }
 
@@ -2442,7 +2442,7 @@ class KeepFilterFactory : public CompactionFilterFactory {
 class DeleteFilterFactory : public CompactionFilterFactory {
   public:
     virtual std::unique_ptr<CompactionFilter>
-    CreateCompactionFilter() override {
+    CreateCompactionFilter(const CompactionFilter::Context& context) override {
       return std::unique_ptr<CompactionFilter>(new DeleteFilter());
     }
 
@@ -2456,7 +2456,7 @@ class ChangeFilterFactory : public CompactionFilterFactory {
     explicit ChangeFilterFactory(int argv) : argv_(argv) {}
 
     virtual std::unique_ptr<CompactionFilter>
-    CreateCompactionFilter() override {
+    CreateCompactionFilter(const CompactionFilter::Context& context) override {
       return std::unique_ptr<CompactionFilter>(new ChangeFilter(argv_));
     }
 

db/version_set.cc

@@ -2467,6 +2467,10 @@ Compaction* VersionSet::PickCompactionUniversal(int level, double score) {
   // remember this currently undergoing compaction
   compactions_in_progress_[level].insert(c);
 
+  // Record whether this compaction includes all sst files.
+  // For now, it is only relevant in universal compaction mode.
+  c->is_full_compaction_ = (c->inputs_[0].size() == current_->files_[0].size());
+
   return c;
 }
 
@@ -2921,6 +2925,7 @@ Compaction::Compaction(int level, int out_level, uint64_t target_file_size,
       parent_index_(-1),
       score_(0),
       bottommost_level_(false),
+      is_full_compaction_(false),
       level_ptrs_(std::vector<size_t>(number_levels)) {
   edit_ = new VersionEdit(number_levels_);
   for (int i = 0; i < number_levels_; i++) {

db/version_set.h

@@ -589,6 +589,9 @@ class Compaction {
   // Is this compaction creating a file in the bottom most level?
   bool BottomMostLevel() { return bottommost_level_; }
 
+  // Does this compaction include all sst files?
+  bool IsFullCompaction() { return is_full_compaction_; }
+
  private:
   friend class Version;
   friend class VersionSet;
@@ -624,6 +627,8 @@ class Compaction {
 
   // Is this compaction creating a file in the bottom most level?
   bool bottommost_level_;
+  // Does this compaction include all sst files?
+  bool is_full_compaction_;
 
   // level_ptrs_ holds indices into input_version_->levels_: our state
   // is that we are positioned at one of the file ranges for each

include/rocksdb/compaction_filter.h

@@ -16,8 +16,14 @@ class Slice;
 
 class CompactionFilter {
  public:
-  virtual ~CompactionFilter() {}
 
+  // Context information of a compaction run
+  struct Context {
+    // Does this compaction run include all data files
+    bool is_full_compaction;
+  };
+
+  virtual ~CompactionFilter() {}
 
   // The compaction process invokes this
   // method for kv that is being compacted. A return value
@@ -44,26 +50,28 @@ class CompactionFilter {
 // Each compaction will create a new CompactionFilter allowing the
 // application to know about different campactions
 class CompactionFilterFactory {
-  public:
-    virtual ~CompactionFilterFactory() { };
-    virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter() = 0;
+ public:
+  virtual ~CompactionFilterFactory() { };
 
-    // Returns a name that identifies this compaction filter factory.
-    virtual const char* Name() const = 0;
+  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+    const CompactionFilter::Context& context) = 0;
+
+  // Returns a name that identifies this compaction filter factory.
+  virtual const char* Name() const = 0;
 };
 
 // Default implementaion of CompactionFilterFactory which does not
 // return any filter
 class DefaultCompactionFilterFactory : public CompactionFilterFactory {
-  public:
-    virtual std::unique_ptr<CompactionFilter>
-    CreateCompactionFilter() override {
-      return std::unique_ptr<CompactionFilter>(nullptr);
-    }
+ public:
+  virtual std::unique_ptr<CompactionFilter>
+  CreateCompactionFilter(const CompactionFilter::Context& context) override {
+    return std::unique_ptr<CompactionFilter>(nullptr);
+  }
 
-    virtual const char* Name() const override {
-      return "DefaultCompactionFilterFactory";
-    }
+  virtual const char* Name() const override {
+    return "DefaultCompactionFilterFactory";
+  }
 };
 
 }  // namespace rocksdb

utilities/ttl/db_ttl.h

@@ -236,12 +236,15 @@ class TtlCompactionFilterFactory : public CompactionFilterFactory {
     : ttl_(ttl),
       user_comp_filter_factory_(comp_filter_factory) { }
 
-    virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter() {
+    virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+        const CompactionFilter::Context& context) {
       return std::unique_ptr<TtlCompactionFilter>(
-          new TtlCompactionFilter(
-            ttl_,
-            nullptr,
-            std::move(user_comp_filter_factory_->CreateCompactionFilter())));
+        new TtlCompactionFilter(
+          ttl_,
+          nullptr,
+          std::move(user_comp_filter_factory_->CreateCompactionFilter(context))
+        )
+      );
     }
 
     virtual const char* Name() const override {

utilities/ttl/ttl_test.cc

@@ -284,7 +284,8 @@ class TtlTest {
       }
 
       virtual std::unique_ptr<CompactionFilter>
-      CreateCompactionFilter() override {
+      CreateCompactionFilter(
+          const CompactionFilter::Context& context) override {
         return std::unique_ptr<CompactionFilter>(
             new TestFilter(kSampleSize_, kNewValue_));
       }