Cassandra 映射类型读取延迟

首先，感谢所有回答我们所有问题的人

我希望人们能帮我摆脱困境，但我在其中一点上被绊住了

我有6个节点的Apache2.1集群，我创建了一个有3列的表。第一列是文本类型，另外两列是映射类型。当我将数据插入表中并读取数据时..获取一行大约需要20毫秒，但如果我为所有3列创建一个文本类型的表，则只需要5毫秒。请告诉我我是否丢失了..如果是映射类型，为什么需要时间？？ 我对启动映射类型读取延迟感到困惑

以下是cfstats和查询：

表:

PRODUCT_TYPE
SSTable count: 1
SSTables in each level: [1, 0, 0, 0, 0, 0, 0, 0, 0]
Space used (live): 81458
Space used (total): 81458
Space used by snapshots (total): 0
Off heap memory used (total): 87
SSTable Compression Ratio: 0.15090414689301526
Number of keys (estimate): 6
Memtable cell count: 0
Memtable data size: 0
Memtable off heap memory used: 0
Memtable switch count: 0
Local read count: 5
Local read latency: 22.494 ms
Local write count: 0
Local write latency: NaN ms
Pending flushes: 0
Bloom filter false positives: 0
Bloom filter false ratio: 0.00000
Bloom filter space used: 16
Bloom filter off heap memory used: 8
Index summary off heap memory used: 15
Compression metadata off heap memory used: 64
Compacted partition minimum bytes: 73458
Compacted partition maximum bytes: 105778
Compacted partition mean bytes: 91087
Average live cells per slice (last five minutes): 1.0
Maximum live cells per slice (last five minutes): 1.0
Average tombstones per slice (last five minutes): 0.0
Maximum tombstones per slice (last five minutes): 0.0

CREATE TABLE TEST.PRODUCT_TYPE (
type text PRIMARY KEY,
col1 map<int, boolean>,
timestamp_map map<int, timestamp>
) WITH bloom_filter_fp_chance = 0.1
AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
AND comment = ''
AND compaction = {'min_threshold': '4', 'class':                       'org.apache.cassandra.db.compaction.LeveledCompactionStrategy', '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 = 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';


 activity                                                                                                              | timestamp                  | source        | source_elapsed
 -----------------------------------------------------------------------------------------------------------------------+----------------------------+---------------+----------------
                                                                                                    Execute CQL3 query | 2015-06-03 21:57:36.841000 | 10.65.133.202 |              0
                                            Parsing SELECT * from location_eligibility_by_type5; [SharedPool-Worker-1] | 2015-06-03 21:57:36.842000 | 10.65.133.202 |             54
                                                                             Preparing statement [SharedPool-Worker-1] | 2015-06-03 21:57:36.842000 | 10.65.133.202 |             86
                                                                       Computing ranges to query [SharedPool-Worker-1] | 2015-06-03 21:57:36.842000 | 10.65.133.202 |            165
  Submitting range requests on 1537 ranges with a concurrency of 1 (0.0 rows per range expected) [SharedPool-Worker-1] | 2015-06-03 21:57:36.842000 | 10.65.133.202 |            410
                                                             Enqueuing request to /10.65.137.191 [SharedPool-Worker-1] | 2015-06-03 21:57:36.849000 | 10.65.133.202 |           7448
                                                                      Message received from /10.65.133.202 [Thread-15] | 2015-06-03 21:57:36.849000 | 10.65.137.191 |             15
                                      Submitted 1 concurrent range requests covering 1537 ranges [SharedPool-Worker-1] | 2015-06-03 21:57:36.849000 | 10.65.133.202 |           7488
                                                              Sending message to /10.65.137.191 [WRITE-/10.65.137.191] | 2015-06-03 21:57:36.849000 | 10.65.133.202 |           7515
 Executing seq scan across 0 sstables for [min(-9223372036854775808), min(-9223372036854775808)] [SharedPool-Worker-1] | 2015-06-03 21:57:36.850000 | 10.65.137.191 |            105
                                                              Read 1 live and 0 tombstoned cells [SharedPool-Worker-1] | 2015-06-03 21:57:36.866000 | 10.65.137.191 |          16851
                                                              Read 1 live and 0 tombstoned cells [SharedPool-Worker-1] | 2015-06-03 21:57:36.882000 | 10.65.137.191 |          33542
                                                              Read 1 live and 0 tombstoned cells [SharedPool-Worker-1] | 2015-06-03 21:57:36.899000 | 10.65.137.191 |          50206
                                                              Read 1 live and 0 tombstoned cells [SharedPool-Worker-1] | 2015-06-03 21:57:36.915000 | 10.65.137.191 |          66556
                                                              Read 1 live and 0 tombstoned cells [SharedPool-Worker-1] | 2015-06-03 21:57:36.932000 | 10.65.137.191 |          82814
                                                                    Scanned 5 rows and matched 5 [SharedPool-Worker-1] | 2015-06-03 21:57:36.932000 | 10.65.137.191 |          82839
                                                            Enqueuing response to /10.65.133.202 [SharedPool-Worker-1] | 2015-06-03 21:57:36.933000 | 10.65.137.191 |          82878
                                                              Sending message to /10.65.133.202 [WRITE-/10.65.133.202] | 2015-06-03 21:57:36.933000 | 10.65.137.191 |          83054
                                                                     Message received from /10.65.137.191 [Thread-151] | 2015-06-03 21:57:36.944000 | 10.65.133.202 |         102134
                                                         Processing response from /10.65.137.191 [SharedPool-Worker-2] | 2015-06-03 21:57:36.944000 | 10.65.133.202 |         102191
                                                                                                      Request complete | 2015-06-03 21:57:36.948916 | 10.65.133.202 |         107916

产品类型
表计数：1
每个级别中的SSTables:[1,0,0,0,0,0,0,0]
使用空间（现场）：81458
使用空间（总计）：81458
快照使用的空间（总计）：0
使用的堆外内存（总数）：87
SSTable压缩比：0.15090414689301526
钥匙数量（估计）：6个
Memtable单元格计数：0
Memtable数据大小：0
已使用Memtable堆外内存：0
Memtable开关计数：0
本地读取计数：5
本地读取延迟：22.494毫秒
本地写入计数：0
本地写入延迟：毫秒
挂起的刷新：0
Bloom筛选器误报：0
布卢姆过滤器错误率：0.00000
使用的布卢姆过滤器空间：16
使用的Bloom筛选器堆外内存：8
使用的索引摘要堆外内存：15
使用的压缩元数据堆外内存：64
压缩分区最小字节数：73458
压缩分区最大字节数：105778
压缩分区平均字节数：91087
平均每片活细胞数（过去五分钟）：1.0
每片最大活细胞数（过去五分钟）：1.0
每片平均墓碑数（过去五分钟）：0.0
每片最大墓碑数（过去五分钟）：0.0
创建表TEST.PRODUCT\u TYPE(
键入文本主键，
col1地图，
时间戳映射
)使用bloom_过滤器时，fp_概率=0.1
和缓存=“{”键“：“所有”，“每个分区的行“：“无”}”
和注释=“”
压缩={'min_threshold'：'4'，'class'：'org.apache.cassandra.db.compression.LeveledCompactionStrategy'，'max_threshold'：'32'}
压缩={'sstable_compression'：'org.apache.cassandra.io.compress.LZ4Compressor'}
和dclocal\u read\u repair\u chance=0.1
并且默认的\u time\u to\u live=0
gc_grace_秒=864000
最大指数间隔=2048
和memtable_flush_period_in_ms=0
最小索引间隔=128
并读取_repair_chance=0.0
推测性_重试='99.0百分位'；
活动|时间戳|源|源|已过
-----------------------------------------------------------------------------------------------------------------------+----------------------------+---------------+----------------
执行CQL3查询| 2015-06-03 21:57:36.841000 | 10.65.133.202 | 0
按类型5分析从位置选择*；[SharedPool-Worker-1]| 2015-06-03 21:57:36.842000 | 10.65.133.202 | 54
编制报表[SharedPool-Worker-1]| 2015-06-03 21:57:36.842000 | 10.65.133.202 | 86
要查询的计算范围[SharedPool-Worker-1]| 2015-06-03 21:57:36.842000 | 10.65.133.202 | 165
提交1537个范围上的范围请求，并发性为1（预期每个范围0.0行）[SharedPool-Worker-1]| 2015-06-03 21:57:36.842000 | 10.65.133.202 | 410
排队请求至/10.65.137.191[共享工具-工人-1]| 2015-06-03 21:57:36.849000 | 10.65.133.202 | 7448
从/10.65.133.202[线程-15]收到的消息| 2015-06-03 21:57:36.849000 | 10.65.137.191 | 15
提交了1份涉及1537个范围的并发范围请求[SharedPool-Worker-1]| 2015-06-03 21:57:36.849000 | 10.65.133.202 | 7488
将消息发送到/10.65.137.191[写入-/10.65.137.191]| 2015-06-03 21:57:36.849000 | 10.65.133.202 | 7515
针对[min（-9223372036854775808）、min（-9223372036854775808）][SharedPool-Worker-1]| 2015-06-03 21:57:36.850000 | 10.65.137.191 | 105跨0个sstables执行序列扫描
阅读1个活细胞和0个墓碑细胞[SharedPool-Worker-1]| 2015-06-03 21:57:36.866000 | 10.65.137.191 | 16851
阅读1个活细胞和0个墓碑细胞[SharedPool-Worker-1]| 2015-06-03 21:57:36.882000 | 10.65.137.191 | 33542
阅读1个活细胞和0个墓碑细胞[SharedPool-Worker-1]| 2015-06-03 21:57:36.899000 | 10.65.137.191 | 50206
阅读1个活细胞和0个墓碑细胞[SharedPool-Worker-1]| 2015-06-03 21:57:36.915000 | 10.65.137.191 | 66556
阅读1个活细胞和0个墓碑细胞[SharedPool-Worker-1]| 2015-06-03 21:57:36.932000 | 10.65.137.191 | 82814
扫描了5行并匹配了5[SharedPool-Worker-1]| 2015-06-03 21:57:36.932000 | 10.65.137.191 | 82839
排队响应/10.65.133.202[SharedPool-Worker-1]| 2015-06-03 21:57:36.933000 | 10.65.137.191 | 82878
正在向/10.65.133发送消息。
create table no_collections(id int, value text, primary key (id));
create table with_collections(id int, value set<text>, primary key (id));

cqlsh:stackoverflow> select * from no_collections ;

 id | value
----+-------------
  1 | foo,bar,baz
  2 | xxx,yyy,zzz
  3 | aaa,bbb,ccc

(3 rows)
cqlsh:stackoverflow> select * from with_collections ;

 id | value
----+-----------------------
  1 | {'bar', 'baz', 'foo'}
  2 | {'xxx', 'yyy', 'zzz'}
  3 | {'aaa', 'bbb', 'ccc'}

(3 rows)

cqlsh:stackoverflow> TRACING ON ;
Now Tracing is enabled
cqlsh:stackoverflow> select * from with_collections where id=3;

 id | value
----+-----------------------
  3 | {'aaa', 'bbb', 'ccc'}

(1 rows)

Tracing session: 7c3d4ed0-09c8-11e5-b4cd-2988e70b20cb

activity                                                                                            | timestamp                  | source    | source_elapsed
-------------------------------------------------------------------------------------------------+----------------------------+-----------+----------------
                                                                              Execute CQL3 query | 2015-06-03 11:13:58.717000 | 127.0.0.1 |              0
                        Parsing select * from with_collections where id=3; [SharedPool-Worker-1] | 2015-06-03 11:13:58.718000 | 127.0.0.1 |             72
                                                       Preparing statement [SharedPool-Worker-1] | 2015-06-03 11:13:58.718000 | 127.0.0.1 |            218
                      Executing single-partition query on with_collections [SharedPool-Worker-3] | 2015-06-03 11:13:58.718000 | 127.0.0.1 |            547
                                              Acquiring sstable references [SharedPool-Worker-3] | 2015-06-03 11:13:58.718000 | 127.0.0.1 |            556
                                               Merging memtable tombstones [SharedPool-Worker-3] | 2015-06-03 11:13:58.719000 | 127.0.0.1 |            574
 Skipped 0/0 non-slice-intersecting sstables, included 0 due to tombstones [SharedPool-Worker-3] | 2015-06-03 11:13:58.719000 | 127.0.0.1 |            636
                                Merging data from memtables and 0 sstables [SharedPool-Worker-3] | 2015-06-03 11:13:58.719000 | 127.0.0.1 |            644
                                        Read 1 live and 0 tombstoned cells [SharedPool-Worker-3] | 2015-06-03 11:13:58.719000 | 127.0.0.1 |            673
                                                                                Request complete | 2015-06-03 11:13:58.717847 | 127.0.0.1 |            847

cqlsh:stackoverflow> select * from no_collections where id=3;

 id | value
----+-------------
  3 | aaa,bbb,ccc

(1 rows)

Tracing session: 7e9ac6d0-09c8-11e5-b4cd-2988e70b20cb

 activity                                                                                        | timestamp                  | source    | source_elapsed
-------------------------------------------------------------------------------------------------+----------------------------+-----------+----------------
                                                                              Execute CQL3 query | 2015-06-03 11:14:02.685000 | 127.0.0.1 |              0
                          Parsing select * from no_collections where id=3; [SharedPool-Worker-1] | 2015-06-03 11:14:02.686000 | 127.0.0.1 |             77
                                                       Preparing statement [SharedPool-Worker-1] | 2015-06-03 11:14:02.686000 | 127.0.0.1 |            209
                        Executing single-partition query on no_collections [SharedPool-Worker-3] | 2015-06-03 11:14:02.686000 | 127.0.0.1 |            525
                                              Acquiring sstable references [SharedPool-Worker-3] | 2015-06-03 11:14:02.686000 | 127.0.0.1 |            534
                                               Merging memtable tombstones [SharedPool-Worker-3] | 2015-06-03 11:14:02.687000 | 127.0.0.1 |            553
 Skipped 0/0 non-slice-intersecting sstables, included 0 due to tombstones [SharedPool-Worker-3] | 2015-06-03 11:14:02.687000 | 127.0.0.1 |            598
                                Merging data from memtables and 0 sstables [SharedPool-Worker-3] | 2015-06-03 11:14:02.688000 | 127.0.0.1 |            606
                                        Read 1 live and 0 tombstoned cells [SharedPool-Worker-3] | 2015-06-03 11:14:02.688000 | 127.0.0.1 |            630
                                                                                Request complete | 2015-06-03 11:14:02.685789 | 127.0.0.1 |            789