当数据库很大时，Cassandra查询速度非常慢

我有一张有4500万把钥匙的桌子。 压缩策略是LCS。 单节点Cassandra版本2.0.5。 没有键或行缓存

查询速度非常慢。当数据库较小时，它们的速度要快好几倍

activity                                                                                       | timestamp    | source      | source_elapsed
-----------------------------------------------------------------------------------------------+--------------+-------------+----------------
                                                                            execute_cql3_query | 17:47:07,891 | 10.72.9.151 |              0
Parsing select * from object_version_info where key = 'test10-Client9_99900' LIMIT 10000; | 17:47:07,891 | 10.72.9.151 |             80
                                                                           Preparing statement | 17:47:07,891 | 10.72.9.151 |            178
                                  Executing single-partition query on object_version_info | 17:47:07,893 | 10.72.9.151 |           2513
                                                                  Acquiring sstable references | 17:47:07,893 | 10.72.9.151 |           2539
                                                                   Merging memtable tombstones | 17:47:07,893 | 10.72.9.151 |           2597
                                                     Bloom filter allows skipping sstable 1517 | 17:47:07,893 | 10.72.9.151 |           2652
                                                     Bloom filter allows skipping sstable 1482 | 17:47:07,893 | 10.72.9.151 |           2677
                                         Partition index with 0 entries found for sstable 1268 | 17:47:08,560 | 10.72.9.151 |         669935
                                                   Seeking to partition beginning in data file | 17:47:08,560 | 10.72.9.151 |         669956
                     Skipped 0/3 non-slice-intersecting sstables, included 0 due to tombstones | 17:47:09,411 | 10.72.9.151 |        1520279
                                                    Merging data from memtables and 1 sstables | 17:47:09,411 | 10.72.9.151 |        1520302
                                                            Read 1 live and 0 tombstoned cells | 17:47:09,411 | 10.72.9.151 |        1520351
                                                                              Request complete | 17:47:09,411 | 10.72.9.151 |        1520615

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读取该跟踪非常困难，您能将其放入代码块吗？您能发布

bin/nodetool cfhistograms object\u version\u info

的输出吗？格式化方面运气不好。但如果将跟踪复制并粘贴到编辑器中，效果会更好。是否有任何查询进行表扫描？cf直方图显示：偏移量=8/单元格计数=46986498和偏移量=446/分区大小=46986498。其他一切都是零。