public boolean shouldFlush() {
    if (workMemTable == null) {
      return false;
    }
    if (workMemTable.shouldFlush()) {
      WritingMetrics.getInstance().recordMemControlFlushMemTableCount(1);
      return true;
    }
    return false;
  }
Delete data which belongs to the timeseries `deviceId.measurementId` and the timestamp of which
<= 'timestamp' in the deletion. <br>

<p>Delete data in both working MemTable and flushing MemTables.

@return true if data in MemTable is successfully deleted, false otherwise
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/memtable/TsFileProcessor.java