我有一个关于Cassandra的问题。目前，通过column1排序，18位uuid上的“entities\u by\u time”是可以的，但是uuid升序到19位排序时有问题。请帮帮我。
cqlsh:minds> select * from entities_by_time where key='activity:user:990192934408163330' order by column1 desc limit 10;
key | column1 | value
----------------------------------+--------------------+--------------------
activity:user:990192934408163330 | 999979571363188746 | 999979571363188746
activity:user:990192934408163330 | 999979567064027139 | 999979567064027139
activity:user:990192934408163330 | 999979562764865555 | 999979562764865555
activity:user:990192934408163330 | 999979558465703953 | 999979558465703953
activity:user:990192934408163330 | 999979554170736649 | 999979554170736649
activity:user:990192934408163330 | 999979549871575047 | 999979549871575047
activity:user:990192934408163330 | 999979545576607752 | 999979545576607752
activity:user:990192934408163330 | 999979541290029073 | 999979541290029073
activity:user:990192934408163330 | 999979536990867461 | 999979536990867461
activity:user:990192934408163330 | 999979532700094475 | 999979532700094475
cqlsh:minds> select * from entities_by_time where key='activity:user:990192934408163330' order by column1 asc limit 10;
key | column1 | value
----------------------------------+---------------------+---------------------
activity:user:990192934408163330 | 1000054880351555598 | 1000054880351555598
activity:user:990192934408163330 | 1000054884671688706 | 1000054884671688706
activity:user:990192934408163330 | 1000054888966656017 | 1000054888966656017
activity:user:990192934408163330 | 1000054893257429005 | 1000054893257429005
activity:user:990192934408163330 | 1000054897552396308 | 1000054897552396308
activity:user:990192934408163330 | 1000054901843169290 | 1000054901843169290
activity:user:990192934408163330 | 1000054906138136577 | 1000054906138136577
activity:user:990192934408163330 | 1000054910433103883 | 1000054910433103883
activity:user:990192934408163330 | 1000054914723876869 | 1000054914723876869
activity:user:990192934408163330 | 1000054919010455568 | 1000054919010455568
CREATE TABLE minds.entities_by_time (
key text,
column1 text,
value text,
PRIMARY KEY (key, column1)
) WITH COMPACT STORAGE
AND CLUSTERING ORDER BY (column1 ASC)
AND bloom_filter_fp_chance = 0.01
AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}
AND comment = ''
AND compaction = {'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy', 'max_threshold': '32', 'min_threshold': '4'}
AND compression = {'enabled': 'false'}
AND crc_check_chance = 1.0
AND dclocal_read_repair_chance = 0.0
AND default_time_to_live = 0
AND gc_grace_seconds = 864000
AND max_index_interval = 2048
AND memtable_flush_period_in_ms = 0
AND min_index_interval = 128
AND read_repair_chance = 0.1
AND speculative_retry = '99PERCENTILE';通过查询发现，在Cassandra，1007227353832624141少于963426376394739730。为什么？
1条答案
按热度按时间oyxsuwqo1#
打得好克里斯！表定义说明了一切！我重新创建了您的表，并在两个方向上运行查询排序：
所以对于你的问题。。。
在Cassandra，1007227353832624141小于963426376394739730。为什么？
简单地说，因为9>1，这就是原因。
您的表定义在
column1，它是文本/utf8字符串，而不是数字。本质上，cassandra是以它知道的唯一方式对字符串进行排序的-按ascii betial顺序，而不是字母数字顺序。将你的数字存储为数字，排序将以更可预测的方式进行。