Question

最近,在单列家庭单行的几栏中,我进行了高效检索。目前,我正在使用Papops作为Casses AP。问题在于,如果我想从几个方面提一下一下,那是怎么办的。如果我能够一劳永逸地从家里打一栏,那将是容易的。

例如,我有一个家庭,拥有大量的一栏。其中一部分具有共同的预先规定,请说“组/组/组”,其中xxx为识别符号。还有一些一栏,称为“a”、“b”、“c”。现在,我想把这两栏放在一起,因此,我必须确定两块雕像,并两次打电话。

如何从效率的角度解决这一问题? Cassandra Somehow cache a section family which was recentrecoveryd and calls RecumnsFromRow for the second time will not make searching it?

Answer 1

由于您已推出自己的复合专栏名称,你基本上不得不发出多次接听。

这并不是一个可怕的大型交易效率的明智之举,因为这些栏目是同一个栏目,如果你正确选择你的比较器,就应当是一个单一磁盘。其后在同一行次的问询应打到非洲顾问办磁盘(OS级,与Casses公司无关)。

为经常查阅全部内容的小行设计了罗条ach(如序列物体或类似物体)。他们实际上将给像这样的大行施加大量的记忆压力。我建议为这一家庭安排留有残疾的囚室。

If you find you need to, you can do some additional tweaking via making the following adjustments: - turn down read_repair_chance - enable result pinning : https://github.com/apache/cassandra/blob/cassandra-0.7.0/conf/cassandra.yaml#L229-236

This will let your 0S S file system cache work more efficiently since the same hosts will be handling the same queries, and the subsequent slices will be operating on sections of the row ideally in the same SSTable and thus in FS cache.

(Shameless plug - but actually quite helpful in these situations) Also, consider a free download OpsCenter (http://www.datastax.com/opscenter), and watch the metrics for the column family as you experiment with the different options. This will give you an idea of the most efficient way to structure your queries specifically for your data.

Answer 2

Cassandra确实有选择性的浏览量,但如果你的浏览量非常大,这很可能造成很多记忆的代价,因此,也许不可取。

(在您的储存配置中,用row子、输电管、螺旋式螺旋式螺旋式螺旋_save_Term_in_seconds和前载荷-row_cache proeprties)对 per进行配置。)

http://wiki.apache.org/cassandra/StorageConfiguration says:

The row cache saves even more time, but must store the whole values of its rows, so it is extremely space-intensive. It s best to only use the row cache if you have hot rows or static rows.

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