Tag Archives: global

新的 DNS Resolver:9.9.9.9

看到新的 DNS Resolver 服務,也拿到了還不錯的 IP address,9.9.9.9:「New “Quad9” DNS service blocks malicious domains for everyone」,服務網站是「Quad 9 | Internet Security and Privacy in a Few Easy Steps」,主打宣稱過濾已知的危險站台... 由政府單位、IBM 以及 Packet Clearing House 成立的: The Global Cyber Alliance (GCA)—an organization founded by law … Continue reading

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MySQL 總算要拔掉 mysql_query_cache 了

半官方的 MySQL blog 上宣佈了拔掉 mysql_query_cache 的計畫:「MySQL 8.0: Retiring Support for the Query Cache」。 作者開頭引用了 ProxySQL 的人對 MySQL Query Cache 的說明: Although MySQL Query Cache was meant to improve performance, it has serious scalability issues and it can easily become a … Continue reading

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Google 弄出來的 Grumpy:把 Python 2.7 的程式碼轉成 Go...

Google 放出 Grumpy,可以把 Python 2.7 的程式碼轉成 Go:「Grumpy: Go running Python!」。 下面看到一個留言頗有趣的: This sad to see that Grumpy is mean to be a replacement of CPython 2.7 instead of CPython 3.x . I presume the code from youtube was written in … Continue reading

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Dropbox 在全球建機房加速...

Dropbox 為了加速傳輸,在全球到處建機房降低 latency:「Infrastructure Update: Pushing the edges of our global performance」。 就他們測試發現,透過 proxy server 降低 latency 的效果很不錯: We’ve tested and applied this configuration in various markets in Europe and Asia. In France, for example, median download speeds are 40% faster … Continue reading

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關閉 MySQL 的 Query Cache

MySQL 的 Query Cache 是目前已知效能不好的主要因素之一 (global mutex lock 的緣故),在正式環境裡的 best practice 一般都是關閉,之前測過也是一開下去效能就會狂掉... 而 Percona 的人在討論要怎麼樣才能完全關閉 MySQL 的 Query Cache:「Is Your Query Cache Really Disabled?」,而他們發現只有在 query_cache_type 與 query_cache_size 都設為 0,而且重開 MySQL 才能完全避免 global mutex lock: [W]e can see it is not … Continue reading

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Netflix 開發的 Delayed Queue

原來這個叫做 Delayed Queue,難怪之前用其他關鍵字都找不到什麼資料... (就不講其他關鍵字了 XD) Netflix 發表了他們自己所開發的 Delayed Queue:「Distributed delay queues based on Dynomite」。 本來的架構是用 Cassandra + Zookeeper 來做: Traditionally, we have been using a Cassandra based queue recipe along with Zookeeper for distributed locks, since Cassandra is the de … Continue reading

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Percona 對 mysql_query_cache 的測試 (以 Magento 為例)

Percona 的人以現在的觀點來看 mysql_query_cache:「The MySQL query cache: Worst enemy or best friend?」。 起因主要也是懷疑 query cache 是 global mutex 在現在的硬體架構 (主要是 CPU 數量成長) 應該是個負面的影響,但不確定影響多少: The query cache is well known for its contentions: a global mutex has to be acquired for any … Continue reading

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DynamoDB 的 Online Indexing 與 Reserved Capacity

剛剛看到 DynamoDB 的新功能以及購買 Reserved Capacity 的計費模式:「Amazon DynamoDB Update – Online Indexing & Reserved Capacity Improvements」。 可以動態增加 Global Secondary Indexes 有點像是「總算可以 ALTER TABLE 了!!!」的感覺 XDDD 而 Reserved Capacity 好像是第一次把 Capacity 類的費用 commit 化?我記得 EBS 沒有這種計費...

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Amazon DynamoDB 筆記

Amazon DynamoDB 頁面上的介紹: Amazon DynamoDB is a fast and flexible NoSQL database service for all applications that need consistent, single-digit millisecond latency at any scale. 資料型態的部份就跳過去了,這篇筆記的重點在於 index 的部份 (了解他如何 scale),尤其是對 RDBMS 有了解的人要如何從他所設計的架構理解 DynamoDB 的 index。 理論基礎是 Amazon 在 2007 年丟出的論文「Dynamo: … Continue reading

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