[ABANDON] Support for single-primary, multi-secondary processes

CMakeLists.txt

@@ -489,6 +489,7 @@ set(SOURCES
         db/db_impl_debug.cc
         db/db_impl_experimental.cc
         db/db_impl_readonly.cc
+        db/db_impl_secondary.cc
         db/db_info_dumper.cc
         db/db_iter.cc
         db/dbformat.cc
@@ -874,6 +875,7 @@ if(WITH_TESTS)
         db/db_options_test.cc
         db/db_properties_test.cc
         db/db_range_del_test.cc
+        db/db_secondary_test.cc
         db/db_sst_test.cc
         db/db_statistics_test.cc
         db/db_table_properties_test.cc

HISTORY.md

@@ -6,6 +6,7 @@
 * RocksDB may choose to preopen some files even if options.max_open_files != -1. This may make DB open slightly longer.
 * For users of dictionary compression with ZSTD v0.7.0+, we now reuse the same digested dictionary when compressing each of an SST file's data blocks for faster compression speeds.
 * For all users of dictionary compression who set `cache_index_and_filter_blocks == true`, we now store dictionary data used for decompression in the block cache for better control over memory usage. For users of ZSTD v1.1.4+ who compile with -DZSTD_STATIC_LINKING_ONLY, this includes a digested dictionary, which is used to increase decompression speed.
+* Introduce a new IOError subcode, PathNotFound, to indicate trying to open a nonexistent file or directory for read.
 
 ### Public API Change
 * CompactionPri = kMinOverlappingRatio also uses compensated file size, which boosts file with lots of tombstones to be compacted first.

Makefile

@@ -443,6 +443,7 @@ TESTS = \
 	db_merge_operator_test \
 	db_options_test \
 	db_range_del_test \
+	db_secondary_test \
 	db_sst_test \
 	db_tailing_iter_test \
 	db_io_failure_test \
@@ -548,6 +549,7 @@ TESTS = \
 	range_tombstone_fragmenter_test \
 	range_del_aggregator_test \
 	sst_file_reader_test \
+	db_secondary_test \
 
 PARALLEL_TEST = \
 	backupable_db_test \
@@ -1558,6 +1560,9 @@ range_tombstone_fragmenter_test: db/range_tombstone_fragmenter_test.o db/db_test
 sst_file_reader_test: table/sst_file_reader_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)
 
+db_secondary_test: db/db_secondary_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 #-------------------------------------------------
 # make install related stuff
 INSTALL_PATH ?= /usr/local

TARGETS

@@ -98,6 +98,7 @@ cpp_library(
         "db/db_impl_files.cc",
         "db/db_impl_open.cc",
         "db/db_impl_readonly.cc",
+        "db/db_impl_secondary.cc",
         "db/db_impl_write.cc",
         "db/db_info_dumper.cc",
         "db/db_iter.cc",

db/db_impl.h

@@ -1176,13 +1176,16 @@ class DBImpl : public DB {
   // and log_empty_. Refer to the definition of each variable below for more
   // details.
   InstrumentedMutex log_write_mutex_;
+
+ protected:
   // State below is protected by mutex_
   // With two_write_queues enabled, some of the variables that accessed during
   // WriteToWAL need different synchronization: log_empty_, alive_log_files_,
   // logs_, logfile_number_. Refer to the definition of each variable below for
   // more description.
   mutable InstrumentedMutex mutex_;
 
+ private:
   std::atomic<bool> shutting_down_;
   // This condition variable is signaled on these conditions:
   // * whenever bg_compaction_scheduled_ goes down to 0
@@ -1213,8 +1216,12 @@ class DBImpl : public DB {
   // read and writes are protected by log_write_mutex_ instead. This is to avoid
   // expesnive mutex_ lock during WAL write, which update log_empty_.
   bool log_empty_;
+
+ protected:
   ColumnFamilyHandleImpl* default_cf_handle_;
   InternalStats* default_cf_internal_stats_;
+
+ private:
   std::unique_ptr<ColumnFamilyMemTablesImpl> column_family_memtables_;
   struct LogFileNumberSize {
     explicit LogFileNumberSize(uint64_t _number)
@@ -1281,12 +1288,16 @@ class DBImpl : public DB {
   WriteBatch cached_recoverable_state_;
   std::atomic<bool> cached_recoverable_state_empty_ = {true};
   std::atomic<uint64_t> total_log_size_;
+
+ protected:
   // only used for dynamically adjusting max_total_wal_size. it is a sum of
   // [write_buffer_size * max_write_buffer_number] over all column families
   uint64_t max_total_in_memory_state_;
   // If true, we have only one (default) column family. We use this to optimize
   // some code-paths
   bool single_column_family_mode_;
+
+ private:
   // If this is non-empty, we need to delete these log files in background
   // threads. Protected by db mutex.
   autovector<log::Writer*> logs_to_free_;
@@ -1499,12 +1510,14 @@ class DBImpl : public DB {
 
   std::string db_absolute_path_;
 
+ protected:
   // The options to access storage files
   const EnvOptions env_options_;
 
   // Additonal options for compaction and flush
   EnvOptions env_options_for_compaction_;
 
+ private:
   // Number of running IngestExternalFile() calls.
   // REQUIRES: mutex held
   int num_running_ingest_file_;

db/db_impl_open.cc

@@ -405,7 +405,6 @@ Status DBImpl::Recover(
   }
 
   if (s.ok()) {
-    SequenceNumber next_sequence(kMaxSequenceNumber);
     default_cf_handle_ = new ColumnFamilyHandleImpl(
         versions_->GetColumnFamilySet()->GetDefault(), this, &mutex_);
     default_cf_internal_stats_ = default_cf_handle_->cfd()->internal_stats();
@@ -468,6 +467,7 @@ Status DBImpl::Recover(
     if (!logs.empty()) {
       // Recover in the order in which the logs were generated
       std::sort(logs.begin(), logs.end());
+      SequenceNumber next_sequence(kMaxSequenceNumber);
       s = RecoverLogFiles(logs, &next_sequence, read_only);
       if (!s.ok()) {
         // Clear memtables if recovery failed
@@ -629,8 +629,7 @@ Status DBImpl::RecoverLogFiles(const std::vector<uint64_t>& log_numbers,
     // to be skipped instead of propagating bad information (like overly
     // large sequence numbers).
     log::Reader reader(immutable_db_options_.info_log, std::move(file_reader),
-                       &reporter, true /*checksum*/, log_number,
-                       false /* retry_after_eof */);
+                       &reporter, true /*checksum*/, log_number);
 
     // Determine if we should tolerate incomplete records at the tail end of the
     // Read all the records and add to a memtable

db/db_impl_readonly.cc

@@ -159,7 +159,6 @@ Status DB::OpenForReadOnly(
   *dbptr = nullptr;
   handles->clear();
 
-  SuperVersionContext sv_context(/* create_superversion */ true);
   DBImplReadOnly* impl = new DBImplReadOnly(db_options, dbname);
   impl->mutex_.Lock();
   Status s = impl->Recover(column_families, true /* read only */,
@@ -176,6 +175,7 @@ Status DB::OpenForReadOnly(
       handles->push_back(new ColumnFamilyHandleImpl(cfd, impl, &impl->mutex_));
     }
   }
+  SuperVersionContext sv_context(/* create_superversion */ true);
   if (s.ok()) {
     for (auto cfd : *impl->versions_->GetColumnFamilySet()) {
       sv_context.NewSuperVersion();