事务实现原理和Write Ahead Logging(WAL) • 分布式事务和两阶段提交的原理 Greenplum两阶段提交协议的实现 Greenplum两阶段提交协议的优化 ## 事务的属性:ACID |属性|含义|数据库系统的实现| |---|---|---| |Atomic原子性|事务中的操作要么全部正确执行，要么完全不执行。|Write Ahead Logging，分布式事务：两阶段提交协议| Control、两阶段加锁（Two Phase Locking，2PL）、乐观并发控制（OCC）| |Durability持久性|一个事务在提交之后，该事务对数据库的改变是持久的。|Write Ahead Logging + 存储管理| ## Disk-Oriented DBMS Components ![Image](/uploads/documents/d/0/2/e/d02e834dcabe 事务提交，所修改的数据页没有刷回至持久存储，如果发生断电或者系统崩溃。 ☐ Steal: Buffer Pool中未提交的事务所修改的脏页刷回到持久存储，如果发生断电或者系统崩溃。 ## Solution: Logging ## No-Force → Redo Log 事务提交时, 数据页不需要刷回持久存储, 为了保证持久性, 先把Redo Log写入日志文件。Redo log记录修改数据对象的新值(After

PostgreSQL WAL日志解析与应用 王硕 山东瀚高基础软件股份有限公司 ## CONTENTS Part 01 WAL 日志简介 Part 02 WAL 日志工作原理 Part 03 利用 WAL 日志我们可以做什么？ ## Part 01 WAL 日志简介 www.highgo.com ## Write Ahead Log Files - WAL 日志一般存储在$ .jpg) - WAL 日志文件XLOG 文件是一个逻辑概念，每一个XLOG 文件，大小为4G(16*256)，由256个segment组成； • Segment由2048个Block组成，其大小为16M； - Block为WAL日志的最小单位，其大小8k，由PageHeaderData、XlogRecord、XLogRecData组成。 ## Write Ahead Log Files [Image](/uploads/documents/d/5/8/a/d58a5f37b8956629f5ab2ca83436c8eb/p5_1.jpg) X1ogRecord XLOG XLogRecData ## Write Ahead Log Files 00a0 0000 068d 0000 c388 0156 0000 0000 0a00 0000 4cca 61d7 3000 000a 0060 0020 7f01

## Mix Assertion, Logging, Unit Testing and Fuzzing with ZeroErr Build Safer Modern C++ Application Speaker: Xiaofan Sun Date: Sep 19, 2024 ## Self-Introduction • Got my Ph.D. from UC, Riverside last std::unique_ptr Class from third-party library: llvm::Value* ## Logging the Data // LOG(INFO) << Data; // ASSERT(a > b, "A > B is not true", a, b); std::ostream& operator<<(std::ostream& out, llvm::Value* data); ## Logging the Data • Namespace pollution • Hard to implement with template • No extensibility • No customization

Build a lightweight logging and tracing tool with Apache Arrow, Parquet and DataFusion 朱霜 2023.06.18 6.17-6.18 @Shanghai ## Content 1. Introduction 2. Duo - Observability duet: Logging and Tracing • What Public Observability duet: Logging and Tracing Rust ☆26 ♀2 ### Duo - Observability duet: Logging and Tracing https://github.com/duo-rs/duo ## duo-rs/duo Observability duet: Logging and Tracing ![Image] /p4_1.jpg)  ## Logging and Tracing Stack LOGBACK glog ![Image](/uploads/documents/5/a/9/c/5a9c811da5ae6e775136bfe193ee771d/p5_2

45 12. Generator Page — Type 0x09 ..... 46 12.1. Creating Lots Of Sequences ..... 52 13. Write Ahead Log Page — Type 0x0a ..... 58 Appendix A: Fbdump ..... 60 Appendix B: Document history ... pages in the database are in use and which are free. Up until Firebird 3.0, the next page is a Write Ahead Log page (page type 0x0a) but this page is wasted space, if present, and will most likely be dropped activate a shadow, or have the Firebird engine activate one automatically. Unfortunately, if a database write stores corrupt data in the database, the shadow file(s) will be identically corrupted. Because shadow

Resource Consumption ..... 631 19.5. Write Ahead Log ..... 640 19.6. Replication ..... 651 19.7. Query Planning ..... 658 19.8. Error Reporting and Logging ..... 665 19.9. Run-time Statistics the Write-Ahead Log ..... 878 28.1. Reliability ..... 878 28.2. Data Checksums ..... 880 28.3. Write-Ahead Logging (WAL) ..... 880 28.4. Asynchronous Commit ..... 881 28.5. WAL Configuration Configuration ..... 882 28.6. WAL Internals ..... 885 29. Logical Replication ..... 887 29.1. Publication ..... 887 29.2. Subscription ..... 888 29.3. Row Filters ..... 894 29.4

• Integrations • 1. Kyuubi On Apache Kudu • Monitoring • 1. Monitoring Kyuubi - Logging System • 2. Monitoring Kyuubi - Server Metrics • 3. Trouble Shooting • SQL References k-3.2.0-bin-hadoop3.2/conf HADOOP_CONF_DIR: Starting org.apache.kyuubi.server.KyuubiServer, logging to /Users/kentyao/svn-kyuubi/v1.3.1-incubating-rc0/apache-kyuubi-1.3.1-incubating-bin/logs/kyuubi-kentyao-org catalog, databases(namespaces) as below. ##### 3.4.2. Operations Now, we can use the SQL editor to write queries to interact with Kyuubi server through the connection. DESC NAMESPACE DEFAULT; ![Image]

WHAT IS JITTING? - INSTEAD OF AHEAD-OF-TIME (AOT), AKA "THE NORM": IT'S LIKE THE APPLICATION (/LIBRARY) IS THE COMPILER... ## WHAT IS JITTING? - INSTEAD OF AHEAD-OF-TIME (AOT), AKA "THE COMPILER... - JUST-IN-TIME (JIT) IS COMPILATION AT THE POINT OF NEED ## WHAT IS JITTING? - INSTEAD OF AHEAD-OF-TIME (AOT), AKA "THE NORM": IT'S LIKE THE APPLICATION (/LIBRARY) IS THE COMPILER..

k-3.2.0-bin-hadoop3.2/conf HADOOP_CONF_DIR: Starting org.apache.kyuubi.server.KyuubiServer, logging to /Users/kentyao/svn-kyuubi/v1.3.1-incubating-rc0/apache-kyuubi-1.3.1-incubating-bin/logs/kyuubi-kentyao-org b/edcb82f29677ddeddcb04c6254f16939/p39_1.jpg) ## Operations Now, we can use the SQL editor to write queries to interact with Kyuubi server through the connection. ## DESC NAMESPACE DEFAULT; ![Ima b/edcb82f29677ddeddcb04c6254f16939/p43_1.jpg) Tips: zoom up if the pic looks small And we can write simple or complex SQL to manipulate data, for example, here is the query 41 generated by TPCDS dsqgen

3.8+) on UNIX. It supports HTTP/1.0 and HTTP/1.1. ## Extended Documentation • Usage • Access Logging • Using Behind a Reverse Proxy. • Design • Differences from zope.server • waitress API • Arguments https://github.com/Pylons/waitress/pull/242 - Stop early and close the app_iter when attempting to write to a closed socket due to a client disconnect. This should notify a long-lived streaming response (2012-01-08) ## Bug Fixes • Remove performance-sapping call to pull_trigger in the channel's write_soon method added mistakenly in 0.6. ### 0.6 (2012-01-07) Bug Fixes - A logic error prevented the