FlushProcess

Summary:
Abstract out FlushProcess and take it out of DBImpl.
This also includes taking DeletionState outside of DBImpl.

Currently this diff is only doing the refactoring. Future work includes:
1. Decoupling flush_process.cc, make it depend on less state
2. Write flush_process_test, which will mock out everything that FlushProcess depends on and test it in isolation

Test Plan: make check

Reviewers: rven, yhchiang, sdong, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27561

Makefile

@@ -143,7 +143,8 @@ TESTS = \
 	cuckoo_table_builder_test \
 	cuckoo_table_reader_test \
 	cuckoo_table_db_test \
-	write_batch_with_index_test
+	write_batch_with_index_test \
+	flush_job_test
 
 TOOLS = \
         sst_dump \
@@ -412,6 +413,9 @@ ttl_test: utilities/ttl/ttl_test.o $(LIBOBJECTS) $(TESTHARNESS)
 write_batch_with_index_test: utilities/write_batch_with_index/write_batch_with_index_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) utilities/write_batch_with_index/write_batch_with_index_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)
 
+flush_job_test: db/flush_job_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) db/flush_job_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)
+
 dbformat_test: db/dbformat_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/dbformat_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
 

db/column_family.cc

@@ -20,6 +20,7 @@
 #include <limits>
 
 #include "db/db_impl.h"
+#include "db/job_context.h"
 #include "db/version_set.h"
 #include "db/internal_stats.h"
 #include "db/compaction_picker.h"
@@ -71,15 +72,15 @@ ColumnFamilyHandleImpl::ColumnFamilyHandleImpl(ColumnFamilyData* cfd,
 
 ColumnFamilyHandleImpl::~ColumnFamilyHandleImpl() {
   if (cfd_ != nullptr) {
-    DBImpl::DeletionState deletion_state;
+    JobContext job_context;
     mutex_->Lock();
     if (cfd_->Unref()) {
       delete cfd_;
     }
-    db_->FindObsoleteFiles(deletion_state, false, true);
+    db_->FindObsoleteFiles(&job_context, false, true);
     mutex_->Unlock();
-    if (deletion_state.HaveSomethingToDelete()) {
-      db_->PurgeObsoleteFiles(deletion_state);
+    if (job_context.HaveSomethingToDelete()) {
+      db_->PurgeObsoleteFiles(job_context);
     }
   }
 }

db/db_filesnapshot.cc

@@ -42,7 +42,7 @@ Status DBImpl::DisableFileDeletions() {
 }
 
 Status DBImpl::EnableFileDeletions(bool force) {
-  DeletionState deletion_state;
+  JobContext job_context;
   bool should_purge_files = false;
   {
     MutexLock l(&mutex_);
@@ -55,15 +55,15 @@ Status DBImpl::EnableFileDeletions(bool force) {
     if (disable_delete_obsolete_files_ == 0)  {
       Log(db_options_.info_log, "File Deletions Enabled");
       should_purge_files = true;
-      FindObsoleteFiles(deletion_state, true);
+      FindObsoleteFiles(&job_context, true);
     } else {
       Log(db_options_.info_log,
           "File Deletions Enable, but not really enabled. Counter: %d",
           disable_delete_obsolete_files_);
     }
   }
   if (should_purge_files)  {
-    PurgeObsoleteFiles(deletion_state);
+    PurgeObsoleteFiles(job_context);
   }
   LogFlush(db_options_.info_log);
   return Status::OK();