Cassandra 写入表的速度很慢（每次插入的写入延迟为 38 毫秒）。我试图通过打开跟踪来找出原因。但是我收到了这个错误，我不明白。请注意，插入本身确实成功。我正在使用 cassandra 1.2.5
错误：“NoneType”对象不可迭代
这是插入：
insert into table1(col1, col2, col3,
col15, col6, col11,
col12, col13, col14,
col7,col8, col10,
col9, col4, col5)
values (6000000, 1, 'name_1', 'name_alias_1',
false,false, 676, 59455,
'REG', 'ADM', 'CRT', 'AST',
{'1000000001', '1000000002', '1000000003', '1000000004'},
'2013-06-26 19:44:36', '2013-06-26 19:44:36');
这是表格说明：
CREATE TABLE table1 (
col1 bigint,
col2 bigint,
col3 text,
col4 timestamp,
col5 timestamp,
col6 boolean,
col7 text,
col8 text,
col9 set<text>,
col10 text,
col11 boolean,
col12 bigint,
col13 int,
col14 text,
col15 text
PRIMARY KEY (col1, col2)
) WITH
bloom_filter_fp_chance=0.010000 AND
caching='KEYS_ONLY' AND
comment='' AND
dclocal_read_repair_chance=0.000000 AND
gc_grace_seconds=864000 AND
read_repair_chance=0.100000 AND
replicate_on_write='true' AND
populate_io_cache_on_flush='false' AND
compaction={'class': 'SizeTieredCompactionStrategy'} AND
compression={'sstable_compression': 'SnappyCompressor'};