# aggregation

Published articles for aggregation.

This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles.

## 【kube-apiserver】CRD / aggregation / 扩展边界：API 扩展停损线

DevFeed: [【kube-apiserver】CRD / aggregation / 扩展边界：API 扩展停损线](<https://devfeed.tech/articles/kube-apiserver-crd-aggregation-api-33969.md>)

Original publisher: [Read original article](<https://quant67.com/post/apiserver/13-extension-boundary/13-extension-boundary.html>)

Author: Liao Tonglang

Published: 2026-08-28T00:00:00Z

Content type: article

Language: zh

Sources: [土法炼钢 - 系统与基础设施](<https://devfeed.tech/sources/source-4.md>)

Topics: [Kubernetes](<https://devfeed.tech/topics/kubernetes.md>), [API](<https://devfeed.tech/topics/api.md>), [etcd](<https://devfeed.tech/topics/etcd.md>), [Extension](<https://devfeed.tech/topics/extension.md>), [Server](<https://devfeed.tech/topics/server.md>)

Tags: [aggregation](<https://devfeed.tech/tags/aggregation.md>), [api](<https://devfeed.tech/tags/api.md>), [api-server](<https://devfeed.tech/tags/api-server.md>), [apiserver](<https://devfeed.tech/tags/apiserver.md>), [apiservice](<https://devfeed.tech/tags/apiservice.md>), [authorization](<https://devfeed.tech/tags/authorization.md>), [crd](<https://devfeed.tech/tags/crd.md>), [distributed](<https://devfeed.tech/tags/distributed.md>), [encryption](<https://devfeed.tech/tags/encryption.md>), [etcd](<https://devfeed.tech/tags/etcd.md>), [extension](<https://devfeed.tech/tags/extension.md>), [kubernetes](<https://devfeed.tech/tags/kubernetes.md>), [v1](<https://devfeed.tech/tags/v1.md>), [v1-30-3](<https://devfeed.tech/tags/v1-30-3.md>), [v3-5](<https://devfeed.tech/tags/v3-5.md>), [v3-5-33](<https://devfeed.tech/tags/v3-5-33.md>), [webhook](<https://devfeed.tech/tags/webhook.md>)

### AI overview

This article explains the boundary between Kubernetes CRD and Aggregated API extension paths in kube-apiserver. CRD requests remain within the apiserver and use its storage and admission paths, while Aggregated API requests are proxied to an external Extension Server. The two paths have different failure modes and troubleshooting points, although both can appear as 503 errors or timeouts.

### Source excerpt

厘清 CRD v1 与 Aggregated API 两条扩展路径在 kube-apiserver 中的存储与请求分界：CRD 对象存 etcd、conversion webhook 失败如何体现在 Storage 轴，APIService 则把请求转发到外部 Extension Server 可引发 503。明确 scheduler/controller/kubelet 为扩展停损线之外的数据面与控制循环。

## PostgreSQL, Aggregates and Histograms

DevFeed: [PostgreSQL, Aggregates and Histograms](<https://devfeed.tech/articles/postgresql-aggregates-and-histograms-34535.md>)

Original publisher: [Read original article](<https://tapoueh.org/blog/2014/02/postgresql-aggregates-and-histograms/>)

Author: Dimitri Fontaine PostgreSQL Major Contributor; Author

Published: 2014-02-21T12:25:00Z

Content type: tutorial

Language: en

Sources: [Dimitri Fontaine](<https://devfeed.tech/sources/dimitri-fontaine.md>)

Topics: [PostgreSQL](<https://devfeed.tech/topics/postgresql.md>), [SQL](<https://devfeed.tech/topics/sql.md>), [MongoDB](<https://devfeed.tech/topics/mongodb.md>), [Mathematics](<https://devfeed.tech/topics/mathematics.md>), [dataset](<https://devfeed.tech/topics/dataset.md>)

Tags: [aggregation](<https://devfeed.tech/tags/aggregation.md>), [article](<https://devfeed.tech/tags/article.md>), [console](<https://devfeed.tech/tags/console.md>), [count](<https://devfeed.tech/tags/count.md>), [dataset](<https://devfeed.tech/tags/dataset.md>), [documentation](<https://devfeed.tech/tags/documentation.md>), [function](<https://devfeed.tech/tags/function.md>), [mongodb](<https://devfeed.tech/tags/mongodb.md>), [postgresql](<https://devfeed.tech/tags/postgresql.md>), [query](<https://devfeed.tech/tags/query.md>), [reporting](<https://devfeed.tech/tags/reporting.md>), [sql](<https://devfeed.tech/tags/sql.md>), [statistics](<https://devfeed.tech/tags/statistics.md>), [table](<https://devfeed.tech/tags/table.md>)

### AI overview

A tutorial on using PostgreSQL SQL aggregates and the width_bucket function to build equidepth histograms from NBA game rebound data. It explains how to compute bucket ranges and frequencies, then render a compact histogram in the SQL console.

### Source excerpt

In our previous article Aggregating NBA data, PostgreSQL vs MongoDB we spent time comparing the pretty new MongoDB Aggregation Framework with the decades old SQL aggregates. Today, let's showcase more of those SQL aggregates, producing a nice histogram right from our SQL console.

## Aggregating NBA data, PostgreSQL vs MongoDB

DevFeed: [Aggregating NBA data, PostgreSQL vs MongoDB](<https://devfeed.tech/articles/aggregating-nba-data-postgresql-vs-mongodb-34534.md>)

Original publisher: [Read original article](<https://tapoueh.org/blog/2014/02/aggregating-nba-data-postgresql-vs-mongodb/>)

Author: Dimitri Fontaine PostgreSQL Major Contributor; Author

Published: 2014-02-17T22:40:00Z

Content type: comparison

Language: en

Sources: [Dimitri Fontaine](<https://devfeed.tech/sources/dimitri-fontaine.md>)

Topics: [PostgreSQL](<https://devfeed.tech/topics/postgresql.md>), [MongoDB](<https://devfeed.tech/topics/mongodb.md>), [SQL](<https://devfeed.tech/topics/sql.md>), [Databases](<https://devfeed.tech/topics/databases.md>), [data](<https://devfeed.tech/topics/data.md>)

Tags: [aggregate](<https://devfeed.tech/tags/aggregate.md>), [aggregation](<https://devfeed.tech/tags/aggregation.md>), [databases](<https://devfeed.tech/tags/databases.md>), [mongodb](<https://devfeed.tech/tags/mongodb.md>), [postgresql](<https://devfeed.tech/tags/postgresql.md>), [sql](<https://devfeed.tech/tags/sql.md>)

### AI overview

This comparison loads NBA statistics from a BSON file into PostgreSQL, designs a normalized relational schema, and expresses a MongoDB aggregation query in SQL. It explains how PostgreSQL views, joins, filtering, grouping, ordering, and limiting can reproduce the referenced aggregation workflow.

### Source excerpt

When reading the article Crunching 30 Years of NBA Data with MongoDB Aggregation I coulnd't help but think that we've been enjoying aggregates in SQL for 3 or 4 decades already. When using PostgreSQL it's even easy to actually add your own aggregates given the SQL command create aggregate.

## The UML Class Diagram

DevFeed: [The UML Class Diagram](<https://devfeed.tech/articles/the-uml-class-diagram-40756.md>)

Original publisher: [Read original article](<https://radek.io/posts/uml-class-diagram/>)

Published: 2011-08-13T00:00:00Z

Content type: tutorial

Language: en

Sources: [Radek Pazdera](<https://devfeed.tech/sources/radek-pazdera.md>)

Topics: [class](<https://devfeed.tech/topics/class.md>), [classes](<https://devfeed.tech/topics/classes.md>), [Inheritance](<https://devfeed.tech/topics/inheritance.md>), [interfaces](<https://devfeed.tech/topics/interfaces.md>), [Software Engineering](<https://devfeed.tech/topics/software-engineering.md>)

Tags: [aggregation](<https://devfeed.tech/tags/aggregation.md>), [cheat-sheet](<https://devfeed.tech/tags/cheat-sheet.md>), [class](<https://devfeed.tech/tags/class.md>), [classes](<https://devfeed.tech/tags/classes.md>), [inheritance](<https://devfeed.tech/tags/inheritance.md>), [interfaces](<https://devfeed.tech/tags/interfaces.md>), [relationships](<https://devfeed.tech/tags/relationships.md>), [software-development](<https://devfeed.tech/tags/software-development.md>)

### AI overview

This article explains UML class diagrams, including how to represent classes, methods, attributes, inheritance, interfaces, associations, aggregation, and composition. It also describes the distinctions among these relationships and their graphical notation.

### Source excerpt

One of the most useful UML diagrams explained.