Cassanda，可用的RAM最大 [英] Cassanda, the available RAM is used to a maximum

问题描述

我想对大约10万行进行一次简单的查询。
我有32GB RAM（20GB是免费的）。 Cassandra使用了这么多的内存，可用的RAM被用于最大程度，并且进程被终止。
如何优化Cassandra？我已经阅读了关于调整Java资源和改变Java堆大小，但我仍然没有解决方案。

I want to make a simple query over approximately 10 mio rows. I have 32GB RAM (20GB is free). And Cassandra is using so much memory, that the available RAM is used to a maximum, and the process is killed. How can I optimize Cassandra? I have read about "Tuning Java resources" and changing the Java heap sizing, but I still have no solution.

推荐答案

Cassandra会用尽系统上可用的内存。这是一个贪婪的过程，将使用任何可用的内存进行缓存，类似于内核页面缓存的工作方式。不要担心，如果Cassandra正在使用您的所有主机内存，它将只在缓存中，如果必要将被释放到其他进程。

Cassandra will use up as much memory as is available to it on the system. It's a greedy process and will use any available memory for caching, similar to the way the kernel page cache works. Don't worry if Cassandra is using all your hosts memory, it will just be in cache and will be released to other processes if necessary.

如果您的查询遭受超时，这可能是从单个分区读取过多的数据，以致查询不会在read_request_timeout_in_ms下返回。如果是这种情况，您应该考虑使您的分区大小更小。

If your query is suffering from timeouts this will probably be from reading too much data from a single partition so that the query doesn't return in under read_request_timeout_in_ms. If this is the case you should look at making your partition sizes smaller.

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