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杂七杂八的,随手记录。

Design Trade-offs for a Robust Dynamic Hybrid Hash Join

本文为摘录(或转载),侵删,原文为: attachments/pdf/f/p2257-jahangiri.pdf

1 ABSTRACT

  • 探索分片数量对 HHJ 性能的影响
  • propose a new lower bound for number of partitions
  • design and evaluate different partition insertion techniques to maximize memory utilization with the lest CPU cost

2 INTRODUCTION

  • HHJ: Hybrid Hash Join

OceanBase 707M tpmC

Ulimit conflict with PAM and Systemd

本文为摘录(或转载),侵删,原文为: https://mydbops.wordpress.com/2017/12/10/ulimit-conflict-with-pam-and-systemd%E2%80%8B%E2%80%8B%E2%80%8B/#content

1 ulimit 是做什么的

User limits command, limit the use of system-wide resources.

2 ulimit 从哪里读取配置文件

  • 从下面的文件、目录中读取配置文件

Stream Control Transmission Protocol (SCTP)

本文为摘录(或转载),侵删,原文为: https://www.linuxjournal.com/article/9749

1 SCTP Associations

SCTP 的联合 (association) 类似于 TCP 的连接 (connection) , 但又有不同:

调优"四剑客"的实战演练,福尔摩斯•K带你轻松优化性能

Table of Contents

本文为摘录(或转载),侵删,原文为: https://mp.weixin.qq.com/s?__biz=MjM5NjgwMDMxMg==&mid=2652164045&idx=1&sn=305c8d05c0b8b41827a9d4062c44a4a8&chksm=bd03dd9a8a74548c907bc3f1ffac82db0207e14bdd6c2398fa798187b9ea449371a9f0ec1f6f&mpshare=1&scene=1&srcid=1205yZcXcCHhOMmAZpuiFyFo&sharer_sharetime=1688349494576&sharer_shareid=a1eb8d286d4dcd42a0c884a984d12f54#rd

1 几个重要的库

  • KWR
    KES 自动负载信息库(Automatic Workload Repertories),每小时自动采集性能指标生成快照,建立数据库时间模型、IO 模型、等待事件、TOP SQL 和操作系统统计等性能指标,为数据库性能调优提供指导。

All Major C++17 Features You Should Know

Cardinality Estimation in DBMS: A Comprehensive Benchmark Evaluation

本文为摘录(或转载),侵删,原文为: attachments/pdf/2/p752-zhu.pdf

1 ABSTRACT

  • we compare the effectiveness of CardEst methods in a real DBMS

  • We establish a new benchmark for CardEst, which:

    • contains a new complex realworld dataset STATS and
    • a diverse query workload STATS-CEB.
  • We integrate multiple most representative CardEst methods into PostgreSQL,

cgroup memo

1 Threads (Tasks (threads) versus processes)

cgroup v1 可以单独操作进程中的线程, man cgroups :

In cgroups v1, a distinction is drawn between processes and tasks. In this view, a process can con‐ sist of multiple tasks (more commonly called threads, from a user-space perspective, and called such in the remainder of this man page). In cgroups v1, it is possible to independently manipulate the cgroup memberships of the threads in a process.

Columnar Formats for Schemaless LSM-based Document Stores

本文为摘录(或转载),侵删,原文为: attachments/pdf/f/p2085-alkowaileet.pdf

这篇论文探讨了文档存储数据库系统的数据模型灵活性限制其在列式关系数据库中进行分析工作负载的表现。作者提出了几种基于 Log-Structured Merge (LSM) tree 事件的技术,旨在将数据存储在列式布局中。他们扩展了 Dremel 格式并引入一个新的列式布局来组织和存储数据。论文还强调了在文档存储中使用查询编译技术的潜力,并介绍了他们在 Apache AsterixDB 中的实现和评估。实验结果显示了显著的性能增益,并在最小程度上影响了摄入性能。