public void ensureMemoryStatus() {
    if (releaseFlushStrategy.isExceedReleaseThreshold()) {
      releaseSemaphore.release();
    }
  }
Check the current memory usage. If the release threshold is exceeded, trigger the task to
perform an internal and external memory swap to release the memory.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/memory/ReleaseFlushMonitor.java