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Amazon Redshift 壓縮率的改善

Amazon Redshift 對壓縮率的改善:「Data Compression Improvements in Amazon Redshift Bring Compression Ratios Up to 4x」。

首先是引入了 Zstandard

First, we added support for the Zstandard compression algorithm, which offers a good balance between a high compression ratio and speed in build 1.0.1172. When applied to raw data in the standard TPC-DS, 3 TB benchmark, Zstandard achieves 65% reduction in disk space. Zstandard is broadly applicable.


Second, we’ve improved the automation of compression on tables created by the CREATE TABLE AS, CREATE TABLE or ALTER TABLE ADD COLUMN commands. Starting with Build 1.0.1161, Amazon Redshift automatically chooses a default compression for the columns created by those commands. Automated compression happens when we estimate that we can reduce disk space without degrading query performance. Our customers have seen up to 40% reduction in disk space.


Third, we’ve been optimizing our internal on-disk data structures. Our preview customers averaged a 7% reduction in disk space usage with this improvement. This feature is delivered starting with Build 1.0.1271.


Finally, we have enhanced the ANALYZE COMPRESSION command to estimate disk space reduction.

不過其他幾個產品線的使用方式更成熟 (像是 Amazon Athena 這類產品),不知道會不會讓 Amazon Redshift 慢慢退出第一線...

Ubuntu 上找不到 apt-add-repository 的解法

剛剛在弄 Linode 上的 Ubuntu 時要裝 PPA,發現沒有 apt-add-repository 可以用,找了一下資料發現這不是系統一定會安裝的軟體,所以要自己手動安裝:

apt-get install python-software-properties

裝完後就可以繼續裝 PPA 了。