我有Cassandra集群（2个节点），我试图将value列类型更改为Map。
在cqlsh中执行ALTER TABLE "keyspace"."table" ALTER value TYPE Map;后，出现不允许修改的错误。（表为空）

CREATE TABLE "keyspace"."table" (
    key text,
    column1 bigint,
    column2 bigint,
    value text,
    PRIMARY KEY (key, column1, column2)
) WITH COMPACT STORAGE
    AND CLUSTERING ORDER BY (column1 ASC, column2 ASC)
    AND bloom_filter_fp_chance = 0.1
    AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}
    AND comment = ''
    AND compaction = {'class': 'org.apache.cassandra.db.compaction.LeveledCompactionStrategy'}
    AND compression = {'chunk_length_in_kb': '64', 'class': 'org.apache.cassandra.io.compress.SnappyCompressor'}
    AND crc_check_chance = 1.0
    AND dclocal_read_repair_chance = 0.05
    AND default_time_to_live = 0
    AND gc_grace_seconds = 5
    AND max_index_interval = 2048
    AND memtable_flush_period_in_ms = 0
    AND min_index_interval = 128
    AND read_repair_chance = 0.0
    AND speculative_retry = '99PERCENTILE';

[中文版5.0.1| cassandra 3.11.0| CQL质量标准3.4.4|本机协议v4]
是否可以更改此表结构的表？什么原因会导致此问题？
谢谢