tracked_synced_size_limit -> pre_sync_size

db/db_impl/db_impl.cc

@@ -1398,12 +1398,9 @@ Status DBImpl::SyncWAL() {
       auto& log = *it;
       assert(!log.getting_synced);
       log.getting_synced = true;
-      if (it->number == current_log_number) {
-        // The current log can be appended while we sync it. Such appends are
-        // not necessarily synced so we need to figure out the size guaranteed
-        // to be synced ahead of time.
-        log.tracked_synced_size_limit = log.writer->file()->GetFileSize();
-      }
+      // Size is expected to be monotonically increasing.
+      assert(log.writer->file()->GetFileSize() >= log.pre_sync_size);
+      log.pre_sync_size = log.writer->file()->GetFileSize();
       logs_to_sync.push_back(log.writer);
     }
 
@@ -1479,9 +1476,7 @@ Status DBImpl::MarkLogsSynced(uint64_t up_to, bool synced_dir) {
     assert(wal.getting_synced);
     if (immutable_db_options_.track_and_verify_wals_in_manifest &&
         wal.writer->file()->GetFileSize() > 0) {
-      uint64_t tracked_synced_size = std::min(
-          wal.tracked_synced_size_limit, wal.writer->file()->GetFileSize());
-      synced_wals.AddWal(wal.number, WalMetadata(tracked_synced_size));
+      synced_wals.AddWal(wal.number, WalMetadata(wal.pre_sync_size));
     }
 
     if (logs_.size() > 1) {
@@ -1491,7 +1486,6 @@ Status DBImpl::MarkLogsSynced(uint64_t up_to, bool synced_dir) {
       it = logs_.erase(it);
     } else {
       wal.getting_synced = false;
-      wal.tracked_synced_size_limit = UINT64_MAX;
       ++it;
     }
   }

db/db_impl/db_impl.h

@@ -1599,10 +1599,10 @@ class DBImpl : public DB {
     log::Writer* writer;  // own
     // true for some prefix of logs_
     bool getting_synced = false;
-    // This can be used to limit the synced size tracked in MANIFEST. It is
-    // useful for files that undergo append during sync, in which case the file
-    // size at tracking time is not necessarily all synced.
-    uint64_t tracked_synced_size_limit = UINT64_MAX;
+    // The size of the file before the sync happens. This amount is guaranteed
+    // to be persisted even if appends happen during sync so it can be used for
+    // tracking the synced size in MANIFEST.
+    uint64_t pre_sync_size = 0;
   };
 
   // PurgeFileInfo is a structure to hold information of files to be deleted in

db/db_impl/db_impl_compaction_flush.cc

@@ -96,6 +96,9 @@ IOStatus DBImpl::SyncClosedLogs(JobContext* job_context) {
     auto& log = *it;
     assert(!log.getting_synced);
     log.getting_synced = true;
+    // Size is expected to be monotonically increasing.
+    assert(log.writer->file()->GetFileSize() >= log.pre_sync_size);
+    log.pre_sync_size = log.writer->file()->GetFileSize();
     logs_to_sync.push_back(log.writer);
   }
 

db/db_impl/db_impl_write.cc

@@ -1192,6 +1192,9 @@ Status DBImpl::PreprocessWrite(const WriteOptions& write_options,
       // Note: there does not seem to be a reason to set this early before we
       // actually write to the WAL
       log.getting_synced = true;
+      // Size is expected to be monotonically increasing.
+      assert(log.writer->file()->GetFileSize() >= log.pre_sync_size);
+      log.pre_sync_size = log.writer->file()->GetFileSize();
     }
   } else {
     *need_log_sync = false;