Data Structures in PG
1 Hash & TapeSet
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2 Slot & tuple
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本文为摘录(或转载),侵删,原文为: attachments/pdf/f/p2257-jahangiri.pdf
HHJ: Hybrid Hash Join
本文为摘录(或转载),侵删,原文为: https://github.com/powa-team/powa
Workload Analyzer.
Hyprland is cool, but it may not work smoothly on default Google Chrome. The borders appear distorted and blurry.
To resolve this issue, simply open the Chrome settings, navigate to appearance (chrome://settings/appearance), and enable “Use system title bar and borders.” Afterwards, restart the browser.
This happens when use GTK theme as shown in above screenshot. Use classic them as a worksaround…
本文为摘录(或转载),侵删,原文为: ../../../Work/pg_gpdb/src/backend/utils/time/sharedsnapshot.c
在 Greenplum 中,作为切片计划的一部分,许多 PostgreSQL 进程(qExecs,QE)在单个段数据库上运行,作为同一用户 SQL 语句的一部分。属于特定用户在特定段数据库上的所有 qExecs 需要具有一致的可见性。为此,使用了一种称为“共享本地快照”(Shared Local Snapshot)的思想。共享内存数据结构 SharedSnapshotSlot 在特定数据库实例上的会话的统一流程(gang processes)之间共享会话和事务信息。这些流程被称为 SegMate 进程组。
GP 提供了 gpcheckcat 用于在集群内检查系统表。
| 检查项 || 描述 || Utility 模式 || 复合查询 || 错误等级 | |———————|————————————————————————-|————|——|——| | pg_class || Check pg_class entry that does not have any correspond pg_attribute entry || Y || N || NOREPAIR | | namespace || Check for schemas with a missing schema definition || Y || N || NOREPAIR | | unique_index_violation || Check for violated unique indexes || N || Y || NOREPAIR | | duplicate || Check for duplicate entries || N || Y || | | missing_extraneous || Cross consistency check for missing or extraneous entries || N || Y || | | inconsistent || Cross consistency check for coordinator segment inconsistency || N || || | | foreign_key || Check foreign keys || N || || | | || || || || |