Method persist

cachelib/navy/block_cache/SparseMapIndex.cpp:338–391

}

void SparseMapIndex::persist(
    std::optional<std::reference_wrapper<RecordWriter>> rw) const {
  XDCHECK(rw.has_value());
  if (!rw) {
    XLOG(ERR,
         "Cannot persist Block Cache index: No RecordWriter is available.");
    return;
  }

  serialization::IndexBucket bucketMap;
  auto prevPos = rw->get().getCurPos();
  uint64_t persisted = 0;

  for (uint32_t i = 0; i < numBucketMaps_; i++) {
    *bucketMap.bucketId() = i;
    // Convert index entries to thrift objects
    for (const auto& [key, record] : bucketMaps_[i]) {
      serialization::IndexEntry entry;
      entry.key() = key;
      entry.address() = record.address;
      entry.sizeHint() = record.sizeHint;
      entry.totalHits() = record.extra.totalHits;
      entry.currentHits() = record.currentHits;
      bucketMap.entries()->push_back(entry);
    }

    try {
      // Serialize bucket and this may throw exception when it's exceeding the
      // meta data size limit
      serializeProto(bucketMap, rw->get());
      persisted += bucketMap.entries()->size();
    } catch (const std::exception& e) {
      // Log the error and more info on current index
      XLOGF(ERR,
            "Error persisting Block Cache Index: {}, persist() began at pos {} "
            "and current pos {}, trying to add {} entries from bucketMap {}",
            e.what(), prevPos, rw->get().getCurPos(),
            bucketMap.entries()->size(), i);
      auto memFootprint = computeMemFootprintRange();
      XLOGF(ERR,
            "Current Block cache items count: {}, persisted {} items, index "
            "size in memory {} "
            "(max) - {} (min)",
            computeSize(),
            persisted,
            memFootprint.maxUsedBytes,
            memFootprint.minUsedBytes);
      // rethrow to the caller
      throw;
    }
    // Clear contents to reuse memory.
    bucketMap.entries()->clear();
  }
}

void SparseMapIndex::recover(
    std::optional<std::reference_wrapper<RecordReader>> rr) {