Cassandra Query on secondary index：ReadTimeout：code = 1200

Question

我正在使用[cqlsh 5.0.1 | Cassandra 2.2.1 | CQL规范3.3.0 |本机协议v4]版本。我有复制因子2节点卡桑德拉簇为2

$ nodetool status test_keyspace 
Datacenter: datacenter1 
======================= 
Status=Up/Down 
|/ State=Normal/Leaving/Joining/Moving 
-- Address  Load  Tokens  Owns (effective) Host ID       Rack 
UN 10.xxx.4.xxx 85.32 GB 256   100.0%   xxxx-xx-xx-xx-xx    rack1 
UN 10.xxx.4.xxx 80.99 GB 256   100.0%   x-xx-xx-xx-xx     rack1 

[I已经取代数，其中x]

这是密钥空间认定中。

cqlsh> describe test_keyspace; 

CREATE KEYSPACE test_keyspace WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '2'} AND durable_writes = true; 

CREATE TABLE test_keyspace.test_table (
    id text PRIMARY KEY, 
    listids map<int, timestamp> 
) 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'; 
CREATE INDEX list_index ON test_keyspace.test_table (keys(listids)); 

id是独一无二的，listids's键具有基数接近1000我在此键空间上百万的记录。

我想要得到具有特定键的记录数以及这些记录的列表。我想这个查询从cqlsh：

select count(1) from test_table where listids contains key 12; 

几秒钟后得到这个错误：在cqlshrc和cassandra.yaml

ReadTimeout: code=1200 [Coordinator node timed out waiting for replica nodes' responses] message="Operation timed out - received only 0 responses." info={'received_responses': 0, 'required_responses': 1, 'consistency': 'ONE'} 

我已经修改超时参数。

cat /etc/cassandra/conf/cassandra.yaml | grep read_request_timeout_in_ms 
#read_request_timeout_in_ms: 5000 
read_request_timeout_in_ms: 300000 

cat ~/.cassandra/cqlshrc 
[connection] 
timeout = 36000 
request_timeout = 36000 
client_timeout = 36000 

当我检查/var/log/cassandra/system.log我只拿到了这个 -

WARN [SharedPool-Worker-157] 2016-07-25 11:56:22,010 SelectStatement.java:253 - Aggregation query used without partition key 

我使用的Java客户端形成我的代码。 Java客户端也获得了很多读取超时。一种解决方案可能是重塑我的数据，但这需要更多时间（虽然我不确定）。有人可以建议快速解决这个问题吗？

添加统计：

$ nodetool cfstats test_keyspace 
Keyspace: test_keyspace 
    Read Count: 5928987886 
    Read Latency: 3.468279416568199 ms. 
    Write Count: 1590771056 
    Write Latency: 0.02020026287239664 ms. 
    Pending Flushes: 0 
     Table (index): test_table.list_index 
     SSTable count: 9 
     Space used (live): 9664953448 
     Space used (total): 9664953448 
     Space used by snapshots (total): 4749 
     Off heap memory used (total): 1417400 
     SSTable Compression Ratio: 0.822577888909709 
     Number of keys (estimate): 108 
     Memtable cell count: 672265 
     Memtable data size: 30854168 
     Memtable off heap memory used: 0 
     Memtable switch count: 0 
     Local read count: 1718274 
     Local read latency: 63.356 ms 
     Local write count: 1031719451 
     Local write latency: 0.015 ms 
     Pending flushes: 0 
     Bloom filter false positives: 369 
     Bloom filter false ratio: 0.00060 
     Bloom filter space used: 592 
     Bloom filter off heap memory used: 520 
     Index summary off heap memory used: 144 
     Compression metadata off heap memory used: 1416736 
     Compacted partition minimum bytes: 73 
     Compacted partition maximum bytes: 2874382626 
     Compacted partition mean bytes: 36905317 
     Average live cells per slice (last five minutes): 5389.0 
     Maximum live cells per slice (last five minutes): 51012 
     Average tombstones per slice (last five minutes): 2.0 
     Maximum tombstones per slice (last five minutes): 2759 

     Table: test_table 
     SSTable count: 559 
     Space used (live): 62368820540 
     Space used (total): 62368820540 
     Space used by snapshots (total): 4794 
     Off heap memory used (total): 817427277 
     SSTable Compression Ratio: 0.4856571513639344 
     Number of keys (estimate): 96692796 
     Memtable cell count: 2587248 
     Memtable data size: 27398085 
     Memtable off heap memory used: 0 
     Memtable switch count: 558 
     Local read count: 5927272991 
     Local read latency: 3.788 ms 
     Local write count: 559051606 
     Local write latency: 0.037 ms 
     Pending flushes: 0 
     Bloom filter false positives: 4905594 
     Bloom filter false ratio: 0.00023 
     Bloom filter space used: 612245816 
     Bloom filter off heap memory used: 612241344 
     Index summary off heap memory used: 196239565 
     Compression metadata off heap memory used: 8946368 
     Compacted partition minimum bytes: 43 
     Compacted partition maximum bytes: 1916 
     Compacted partition mean bytes: 173 
     Average live cells per slice (last five minutes): 1.0 
     Maximum live cells per slice (last five minutes): 1 
     Average tombstones per slice (last five minutes): 1.0 
     Maximum tombstones per slice (last five minutes): 1 

Answer 1

您可以重新设计你的表格，或在多个较小的查询拆分查询。

您正在选择使用二级索引而不使用分区键（即警告告诉你什么）。这样做，你基本上执行全表扫描。您的节点必须查看每个分区才能满足您的请求。

不更改数据模型的解决方案是遍历所有分区，并为每个分区运行一次查询。

select count(*) from test_table where id = 'somePartitionId' and listids contains key 12; 

这样，你的节点就知道你正在寻找这些信息的分区。然后您必须在客户端汇总这些查询的结果。

Answer 2

我面临同样的问题。尝试 1）＃也可以设置为None来禁用：client_timeout = None在家庭.cassandra中的cqlshrc中。没有帮助。

2）增加超时*在ym.cassandra.yaml

timeout_in_ms没也有帮助。最后，我决定在我的java代码中的select子句上运行循环并收到计数。 12万行在7秒内给了我数。它很快。

Cluster cluster = Cluster.builder() 
      .addContactPoints(serverIp) 
      .build(); 

    session = cluster.connect(keyspace); 


    String cqlStatement = "SELECT count(*) FROM imadmin.device_appclass_attributes"; 
    //String cqlStatement = "SELECT * FROM system_schema.keyspaces"; 
    for (Row row : session.execute(cqlStatement)) { 
     System.out.println(row.toString()); 
    }