/images/avatar.jpg
杂七杂八的,随手记录。

Performance of 10 G Ethernet Using Commodity Hardware

Performance Tip of the Week

本文为摘录(或转载),侵删,原文为: https://abseil.io/fast

1 #9: Optimizations past their prime

1.1 Best practices

– 可能的情况下编写清晰、惯用的代码
Prefer writing clear, idiomatic code whenever possible. It is not only easier to read and debug, but in the long run, also easier for the compiler to optimize.

Prefix Filter: Better Than Bloom

Table of Contents

本文为摘录(或转载),侵删,原文为: ../pdf/d/p1311-even.pdf

1 Abstract

2 INTRODUCTION

  • What is a filter

    属于近似查询 (approximate membership query), 用于判断独具是否在集合中。

    • 如果输入在集合中,则必定输出 Yes
    • 如果不在集合中,则输出 Yes 的概率不能多于 \(\Sigma\)
  • What are filters used for
    • 与精确查询相比
      • 更省资源, 与数据量无关,而与 Σ (误报率)有关
      • 适于放在内存中,用于真正操作之前来过滤掉无效数据
        • 比如 join

QueryFormer: A Tree Transformer Model for Query Plan Representation

Table of Contents

本文为摘录(或转载),侵删,原文为: attachments/pdf/0/p1658-zhao.pdf

QueryFormer:

  • learning-based query planer representation model
  • with tree-structured Transformer architecture

-integrate histograms from database into query plan encoding

1 INTRODUCTION

  • Physical Query Plan As DAG (Directed Acyclic Graph)

    Figure 1: Example query and query plan

    Figure 1: Example query and query plan

    • node 表示操作
    • edge 表示方向
    • 子节点先执行,执行结果给父节点作为输入
  • Physical Query Plan 作为机器学习的输入,用以数据库优化