This means that our users around the world can now get free Let’s Encrypt certificates for domains containing characters outside of the ASCII set, which is built primarily for the English language.
Let’s Encrypt only signs end-entity certificates with RSA intermediates. We will add the ability to have end-entity certs signed by an ECDSA intermediate.
The QUIC working group has just been chartered, and will meet for the first time in Seoul. This working group is taking Google’s pre-standardization QUIC protocol that has been deployed in production for several years, and will use it as a starting point to develop a UDP-based, stream-multiplexing, encrypted transport protocol with standardized congestion control, TLS 1.3 by default, a mapping for HTTP/2 semantics over QUIC, and multipath extensions. This is the IETF’s first standardized always-encrypted transport protocol, so careful consideration of applicability and operational capabilities will be key for success.
Zlib version 1.2.7.1 was released in early 2013 and added the ability to use a predefined “dictionary” to prefill the lookback window for LZ77. This seemed promising since we could “warm up” the lookback window with field names and other common strings. We ran a few tests using the Python Zlib library with a naive predefined dictionary consisting of an arbitrary Pin JSON blob. The compression savings increased from ~50% to ~66% at what appeared to be relatively little cost.
另外他們做了 read-only 的 benchmark (畢竟這是重點)。圖片資料有點糊，但可以看出 y 軸是 Queries/sec。而 x 軸上則用文字給了些說明，黃色是 TokuDB，紅色是本來的 InnoDB Compression，剩下的都是不同的字典集的成果：
Below is a graph from our presentation which showed a read-only version of our production workload at concurrency of 256, 128, 32, 16, 8, 4 and 1 clients. TokuDB is in yellow, InnoDB page compression is in red and the other lines are column compression with a variety of dictionaries.
整體效率都比之前高不少，尤其是當 concurrent query 的數量偏高的時候差距會很大。
而這個功能將會納入未來的 Percona 版本，對於在 MySQL 裡面會塞 JSON 或是 XML 的人應該會很有幫助：
We worked with Percona to create a specification for column compression with an optional predefined dictionary and then contracted with Percona to build the feature.
*) Change: HTTP/2 clients can now start sending request body
immediately; the "http2_body_preread_size" directive controls size of
the buffer used before nginx will start reading client request body.
Originally the kernel allocated a 32-bit bitmask to define these capabilities. A few years ago it was expanded to 64. There are currently around 38 capabilities defined.
With just 12 ms of round-trip latency between US East (Ohio) and US East (Northern Virginia), you can make good use of unique AWS features such as S3 Cross-Region Replication, Cross-Region Read Replicas for Amazon Aurora, Cross-Region Read Replicas for MySQL, and Cross-Region Read Replicas for PostgreSQL.
其中有個特別的地方在於 us-east-{1,2} 之間傳輸的費用會以 Inter-AZ 計費，而非以跨 region 計費。大概是希望讓大家有動力多放些東西過去，畢竟 us-east-1 實在太大，穩定性超有名的關係 XDDD：
Data transfer between the two Regions is priced at the Inter-AZ price ($0.01 per GB), making your cross-region use cases even more economical.
An index_col_name specification can end with ASC or DESC. These keywords are permitted for future extensions for specifying ascending or descending index value storage. Currently, they are parsed but ignored; index values are always stored in ascending order.
所以當 8.0 建立了 a_desc_b_asc (a DESC, b ASC) 這樣的 index，可以看到對於不同 ORDER BY 時效能的差異：(一千萬筆資料)
有些變快可以理解，但有些結果不太清楚造成的原因...
Anyway，對於變慢的兩個 query，他提了一個不算解法的解法，就是加上對應的 index XDDD：
If user wants to avoid filesorts for Query 5 and Query 6, he/she can alter the table to add a key (a ASC, b ASC) . Further to this, if the user wants to avoid backward index scans too, he/she can add both ( a ASC, b DESC) and (a DESC, b DESC).
