add tickers of read blob valid bytedance#199

Author: yapple

db/version_set.cc

@@ -1275,6 +1275,11 @@ Status Version::fetch_buffer(LazyBuffer* buffer) const {
                  context->data[1]);
   uint64_t sequence = context->data[2];
   auto pair = *reinterpret_cast<DependenceMap::value_type*>(context->data[3]);
+  if (pair.second->fd.GetNumber() != pair.first) {
+    RecordTick(db_statistics_, READ_BLOB_INVALID);
+  } else {
+    RecordTick(db_statistics_, READ_BLOB_VALID);
+  }
   bool value_found = false;
   SequenceNumber context_seq;
   GetContext get_context(cfd_->internal_comparator().user_comparator(), nullptr,

include/rocksdb/statistics.h

@@ -258,6 +258,10 @@ enum Tickers : uint32_t {
   GC_TOUCH_FILES,
   GC_SKIP_GET_BY_SEQ,
   GC_SKIP_GET_BY_FILE,
+
+  READ_BLOB_VALID,
+  READ_BLOB_INVALID,
+
   TICKER_ENUM_MAX
 };
 

monitoring/statistics.cc

@@ -139,6 +139,8 @@ const std::vector<std::pair<Tickers, std::string>> TickersNameMap = {
     {GC_TOUCH_FILES, "rocksdb.num.gc.touch_files"},
     {GC_SKIP_GET_BY_SEQ, "rocksdb.num.gc.skip_by_seqno"},
     {GC_SKIP_GET_BY_FILE, "rocksdb.num.gc.skip_by_file_meta"},
+    {READ_BLOB_VALID, "rocksdb.num.read.blob_valid"},
+    {READ_BLOB_INVALID, "rocksdb.num.read.blob_invalid"},
 };
 
 const std::vector<std::pair<Histograms, std::string>> HistogramsNameMap = {