I have a 3 node cluster with replication factor : 2.
考虑的列族有 default_time_to_live = 3600 哪个是使用alter table设置的： cqlsh:summary> alter table match with default_time_to_live=3600;
将数据插入columnfamily并立即查询后，选择ttl（column_name），我得到的结果不正确 .
cqlsh:summary> select ttl(end_time) from match limit 5;
ttl（end_time）
3132
5342
5342
1802
1802
（5排）
Keyspace定义：
CREATE KEYSPACE summary WITH replication = {'class': 'NetworkTopologyStrategy', 'DC1': '2'} AND durable_writes = true;
列族定义：
CREATE TABLE summary.match (
match_name text,
start_time bigint,
end_time bigint,
PRIMARY KEY (match_name, start_time)) WITH CLUSTERING ORDER BY (start_time ASC)
AND bloom_filter_fp_chance = 0.01
AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
AND comment = ''
AND compaction = {'min_threshold': '4', 'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy', 'max_threshold': '32'}
AND compression = {'sstable_compression':'org.apache.cassandra.io.compress.LZ4Compressor'}
AND dclocal_read_repair_chance = 0.1
AND default_time_to_live = 3600
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 = 0.0
AND speculative_retry = '99.0PERCENTILE';
使用：Cassandra 2.1.0 | CQL规范3.2.0
它不应该低于3600吗？ 5342 的TTL值在哪里？
问题： default_time_to_live 值如何生效？
1 回答
这不是问题 . 群集中节点的时间戳不同步 .
运行
ntpdate -bu <ntp server>以同步每个节点中的时钟 . 然后TTL正如预期的那样到来 .一些阅读为什么同步时间对于cassandra很重要 .
https://blog.logentries.com/2014/03/synchronizing-clocks-in-a-cassandra-cluster-pt-1-the-problem/
https://ria101.wordpress.com/2011/02/08/cassandra-the-importance-of-system-clocks-avoiding-oom-and-how-to-escape-oom-meltdown/