Cassandra_Cassandra 使用心得二三说

Cassandra 作为一个比较新兴的数据库，对于大数据量的支持比较好。

但是使用Cassandra 中也有许多需要注意的地方，我来总结一下，本文不定期更新。。。

特点一：

Cassandra 作为一个数据库支持 TTL ，生存时长(expire time)

示例：

1.针对每一条数据：

INSERT INTO latest_temperatures(weatherstation_id,event_time,temperature)
VALUES (’1234ABCD’,’2013-04-03 07:02:00′,’73F’) USING TTL 20;

2.针对表级别设置每条数据的默认生存周期：

创建表

CREATE TABLE test_ttl(
id int PRIMARY KEY,
value text
) WITH 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'}
AND compression = {'sstable_compression': 'org.apache.cassandra.io.compress.LZ4Compressor'}
AND dclocal_read_repair_chance = 0.1
AND default_time_to_live = 30
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';

插入数据：

INSERT INTO test_ttl(id,value)
VALUES (1, '2013-04-03');

校验数据：
SELECT * FROM test.test_ttl;

修改默认的生命时长：
ALTER TABLE test.test_ttl WITH default_time_to_live = 120;

更多有关于生存周期的设计方案，请参考我的博文

特点二：

Cassandra where 中的筛选条件的 column . 一定要在上面预先做索引. 否则是不能作为筛选条件的。

示例

CREATE TABLE test_index(
id int PRIMARY KEY,
value text
) WITH 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'}
AND compression = {'sstable_compression': 'org.apache.cassandra.io.compress.LZ4Compressor'}
AND dclocal_read_repair_chance = 0.1
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 = 0.0
AND speculative_retry = '99.0PERCENTILE';