@Override
  public boolean equals(Object obj) {
    if (obj == this) {
      return true;
    }
    if (obj == null) {
      return false;
    }
    if (!(obj instanceof MemTableInfo)) {
      return false;
    }
    MemTableInfo other = (MemTableInfo) obj;
    return this.memTableId == other.memTableId
        && Objects.equals(this.tsFilePath, other.tsFilePath)
        && this.firstFileVersionId == other.firstFileVersionId;
  }
MemTableInfo records brief info of one memTable, including memTable id, tsFile path, and .wal
file version id of its first {@link WALEntry}.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/checkpoint/MemTableInfo.java