Databend Open Source Weekly Issue 144

The open source China community team made its first live broadcast, telling the story behind the open source China community in the name of sharing."

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What's On In Databend

Explore Databend's new developments this week and encounter Databend that is closer to your heart.

Learn about Databend's SEQUENCE support

A SEQUENCE is an object used to automatically generate unique numeric identifiers, typically used to assign different identifiers to rows in a table, such as user ID columns. Typically, the sequence starts at a specified value and increments by a specified increment.

Sequences in Databend start at 1 and increment by 1 each time. While sequences guarantee unique values, they do not guarantee continuity.

Usage is as follows:

-- Create a new sequence named staff_id_seq
CREATE SEQUENCE staff_id_seq;

-- Create a new table named staff with columns for staff_id, name, and department
CREATE TABLE staff (
    staff_id INT,
    name VARCHAR(50),
    department VARCHAR(50)
);

-- Insert a new row into the staff table, using the next value from the staff_id_seq sequence for the staff_id column
INSERT INTO staff (staff_id, name, department)
VALUES (NEXTVAL(staff_id_seq), 'John Doe', 'HR');

If you'd like to learn more, feel free to contact the Databend team or check out the resources listed below.

Docs | DDL Commands - Sequence

Support dynamic adjustment of session priority

In a multi-user environment, different query tasks may require different resource allocation priorities. Databend now supports dynamic adjustment of session priority, allowing administrators or users to set the priority of query tasks as needed, thereby optimizing resource usage and improving response time for important tasks.

The syntax is as follows:

SET PRIORITY (HIGH | MEDIUM | LOW) <session_id>

Which <session_id>can show processlistbe obtained by statement.

If you'd like to learn more, feel free to contact the Databend team or check out the resources listed below.

PR 15352 | feat: support adjust query's priority

Code Corner

Let’s explore code snippets or projects in Databend and the surrounding ecosystem.

Open Source Summer 2024 | Go to the Cloud Data Warehouse with Databend

This year is the third year that the Databend community has participated in the Open Source Summer event, and I am very happy to continue to work together with you. As in previous years, we have prepared two projects and welcome you who are interested in cloud data warehouse to explore together.

Open Source Summer 2024 - Databend

Highlights

Here are some noteworthy events, maybe you can find something of interest.

Newly supported geometry functions: ST_XMAX.
Newly supported MAP functions: map_size, map_cat, map_contains_key.
Optimized vacuum drop tableto support parallel execution.
Added http handler v1/login.

What's Up Next

We are always open to cutting-edge technologies and innovative ideas, and welcome you to join the community and inject vitality into Databend.

Support more geometric functions

Geometry functions are a set of functions that handle spatial data types, such as geometric objects such as points, lines, and polygons.

In the last weekly report, we introduced Databend's current geometric function support. In order to better support spatial analysis and geographical data management scenarios, there are still a considerable number of functions for analysis measurement and transformation that need to be implemented.

In the Issue below, we have compiled the functions to be supported and the current progress. Interested students are welcome to participate in related development.

Issue #15413 | Feature: Support geometry functions

If you are interested in this topic, you can try to solve some of the problems or participate in discussions and PR reviews. Alternatively, you can click on https://link.databend.rs/im-feeling-lucky to pick a random question, good luck!

New Contributors

Meet new people in the community. Databend is a better place because of you.

@forsaken628 implemented the map_size function, #15444 .
@hanxuanliang implemented the map_contains_key function, #15465 .

Changelog

Check out the changelog for Databend's daily builds to stay up to date on the latest developments.

Address: https://github.com/datafuselabs/databend/releases

Contributors

A big thank you to the contributors for their great work this week.

Connect With Us

Databend is an open source, flexible, low-cost, new data warehouse based on object storage that can also perform real-time analysis. We look forward to your attention and exploring cloud native data warehouse solutions together to create a new generation of open source Data Cloud.