最大限度.宽行的大小? [英] Max. size of wide rows?

问题描述

理论上，Cassandra 允许在宽行中最多包含 20 亿列.

Theoretically, Cassandra allows up to 2 billion columns in a wide row.

我听说实际上高达 50.000 cols/50 MB 就可以了；50.000-100.000 cols/100 MB 可以，但需要一些调整；并且每行的列数不应超过 100.000/100 MB.原因是这会给堆带来压力.

I have heard that in reality up to 50.000 cols/50 MB are fine; 50.000-100.000 cols/100 MB are OK but require some tuning; and that one should never go above 100.000/100 MB columns per row. The reason being that this will put pressure on the heap.

这有什么道理吗?

推荐答案

在 Cassandra 中，最大单元格数单个分区中(行 x 列)为 20 亿.

In Cassandra, the maximum number of cells (rows x columns) in a single partition is 2 billion.

此外，单个列值可能不会大于 2GB，但实际上，MB 的个位数"是更合理的限制，因为没有流式传输或随机访问 blob 值.

Additionally, a single column value may not be larger than 2GB, but in practice, "single digits of MB" is a more reasonable limit, since there is no streaming or random access of blob values.

大于 100Mb 的分区会对堆造成巨大压力.

Partitions greater than 100Mb can cause significant pressure on the heap.

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