public void appendBucketIndex(PageIndexSortBuckets pisb) {
    for (int i = 0; i < SchemaFileConfig.SEG_SIZE_LST.length; i++) {
      pisb.getBucket(i).addAll(indexBuckets.getBucket(i));
    }
  }
Since records are ordered for write operation, it is reasonable to flush those left siblings of
the active leaf page. The target page would be initiated at the first split within the
operation.

@param page left leaf of the split
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/schemafile/pagemgr/SchemaPageContext.java