Tag Archives: db

用 Percona Toolkit 備份的 MySQL 可以直接還原到 Amazon RDS 上

AWS 宣佈 Amazon RDS for MySQL 支援從 Percona Toolkit 備份出來的檔案還原了:「Easily restore an Amazon RDS MySQL database from your MySQL backup」。 Starting today you can easily restore a new Amazon RDS for MySQL database instance from a backup of your existing … Continue reading

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Amazon Athena 可以透過 ODBC 連接了

Amazon Athena 支援 ODBC 了 (先前直接連結只支援 JDBC):「Amazon Athena adds support for querying data using an ODBC driver」。 With the availability of a new ODBC driver, you can now connect popular business intelligence tools to Athena. This allows you to report … Continue reading

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從 Cassandra 到 ScyllaDB 的轉移方式好像跟以前不太一樣了...

在「New Docs: Four Phases to Migrate from Apache Cassandra to Scylla」這邊看到 ScyllaDB 官方提供 Cassandra 轉移到 ScyllaDB 的說明,跟以前好像差蠻多的... 以前 ScyllaDB 可以直接加入到 Cassandra 的 cluster (一時間沒找到資料,但在「can not add node with cassandra ami · Issue #107 · scylladb/scylla-cluster-tests」可以看到當時的痕跡),現在給的方法是在資料庫不相容時的轉移方式 (像是從 MySQL 轉換到 PostgreSQL 這種),是暗示已經沒辦法這樣做了嗎? … Continue reading

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大型 WordPress 站台會用到的 LudicrousDB (以及 HyperDB)

最近收到 HyperDB 的 mailing list 信件 (開頭是「[HyperDB] How can I set up HyperDB with latest version.」這封),有人提到 HyperDB 很久沒更新了... 結果在信理看到有人回了「stuttter/ludicrousdb」這個專案: LudicrousDB is an advanced database interface for WordPress that supports replication, failover, load balancing, & partitioning 兩個專案都是抽換掉 WordPress 在處理 database 的 … Continue reading

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在 MOPCON 2017 的 Unconference「MySQL to NoSQL & Search Engine」

把投影片傳到 Speaker Deck 上了:「MySQL to NoSQL & Search Engine」。 這是在介紹 noplay/python-mysql-replication 這個軟體,我在示範時用的 python script 有增加 blocking 參數讓他保持一直讀取 MySQL replication stream: from pymysqlreplication import BinLogStreamReader mysql_settings = {'host': '127.0.0.1', 'port': 3306, 'user': 'root', 'passwd': ''} stream = BinLogStreamReader(connection_settings = mysql_settings, server_id=100, … Continue reading

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Amazon Aurora (MySQL) 推出的 Asynchronous Key Prefetch

Amazon Aurora (MySQL) 推出新的效能改善,可以改善 JOIN 時的效能:「Amazon Aurora (MySQL) Speeds Join Queries by More than 10x with Asynchronous Key Prefetch」。 看起來像是某個情況的 optimization,將可能的 random access 換成 sequential access 而得到大量的效能: This feature applies to queries that require use of the Batched Key Access … Continue reading

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InnoDB 的 MVCC 繁忙時的效能問題

在 Facebook 上看到 Percona 的人修正了 InnoDB 的 MVCC 在繁忙時會有 的效能問題: 在 MySQL 官方的 bug tracking system 是「InnoDB's MVCC has O(N^2) behaviors」這個,可以看到給的重製範例是在 transaction 內大量塞 INSERT 進去後,另外一個 transaction 使用 secondary index 就會受到影響。 裡面也有提到「Secondary index updates make consistent reads do O(N^2) undo page … Continue reading

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Amazon Aurora 也支援 PostgreSQL 了

AWS 宣佈 Amazon Aurora 也支援 PostgreSQL 了,相容於 9.6.3 的版本 (應該就是改自這個版本):「Now Available – Amazon Aurora with PostgreSQL Compatibility」。 效能上一樣有提昇,不過數字參考用: On the performance side, you can expect up to 3x the throughput that you’d get if you ran PostgreSQL on your own … Continue reading

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有 Lazy Connection 功能的 PDO object

在「Aura.Sql」這邊看到有提供 Lazy Connection 的 PDO object,而且是繼承自本來的 PDO object: Provides an extension to the native PDO along with a profiler and connection locator. Because ExtendedPdo is an extension of the native PDO, code already using the native PDO or typehinted to … Continue reading

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Amazon RDS 的 RI 也支援彈性計價了

AWS 宣佈 RDS 的 RI 也支援彈性計價了:「Amazon RDS Reserved Instances Offer Instance Size Flexibility」。 也就是說跟 EC2 的 RI 方式切齊,買 db.m4.2xlarge 的 RI 後,可以用在兩台 db.m4.xlarge 上: For example, let’s say you purchased a db.m4.2xlarge MySQL RI in US East (N. Virginia). The … Continue reading

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