public static void init() {
    if (walModelFixedMemory != null) {
      return;
    }
    try {
      // Allocate memory for the fixed memory block of WAL
      walModelFixedMemory =
          PipeDataNodeResourceManager.memory()
              .forceAllocateForModelFixedMemoryBlock(
                  (long)
                      (PipeDataNodeResourceManager.memory().getTotalNonFloatingMemorySizeInBytes()
                          * PIPE_CONFIG.getPipeDataStructureWalMemoryProportion()),
                  PipeMemoryBlockType.WAL);
    } catch (Exception e) {
      LOGGER.error("Failed to initialize WAL model fixed memory block", e);
      walModelFixedMemory =
          PipeDataNodeResourceManager.memory()
              .forceAllocateForModelFixedMemoryBlock(0, PipeMemoryBlockType.WAL);
    }
  }
This cache is used by {@link WALEntryPosition}.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/utils/WALInsertNodeCache.java