Databend Weekly

Databend is an open source elastic and reliable Modern Cloud Data Warehouse, it offers blazing fast query and combines elasticity, simplicity, low cost of the cloud, built to make the Data Cloud easy.

Big changes

Below is a list of some major changes that we don't want you to miss.

Features

support date_add for new parser (#5419)
add metrics in metasrv (#5208)

Migrate to new planner

support limit for new planner (#5301)
support TRY_CAST, EXTRACT and INTERVAL (#5362)
enhance GROUP BY semantic check (#5431)

Work around JOIN

support using and natural (#5423)

RFC

Config Backward Compatibility

Improvement

avoid ub and delete unnecessary unsafe (#5338)
fix get function unnecessary double column loop (#5349)
display friendly error if not started with valid flags (#5443)

Build / Testing / CI

Sql logic test framework (#5416)

Bug fixes

fix some cases in aggregator plan (#5307)
fix wrong result of memory table engine (#5364)
fix server hang when processor panic (#5394)

Tips

Let's learn a weekly tip from Databend.

Analyze User Retention With Databend

User retention helps you analyze how many users return to your product or service. Let's go through an example and see how to analyze it in Databend.

Create a Table

CREATE TABLE events(`user_id` INT, `login_date` DATE);

Now we have a table with the following fields:

user_id - a unique identifier for user
login_date - user login date

User Retention Analysis

It's easy and performance to use Databend Retention Function to do the user retention analysis.

SELECT
    sum(r[0]) AS r1,
    sum(r[1]) AS r2,
    sum(r[2]) AS r3
FROM
(
    SELECT
        user_id,
        retention(login_date = '2022-05-15', login_date = '2022-05-16', login_date = '2022-05-17') AS r
    FROM events
    GROUP BY user_id
);

Learn more:

Changelogs

You can check the changelogs of Databend nightly to learn about our latest developments.

Contributors

Thanks a lot to the contributors for their excellent work this week.


andylokandy	ariesdevil	b41sh	BohuTANG	drmingdrmer	everpcpc


fkuner	junnplus	leiysky	lichuang	mergify[bot]	RinChanNOWWW


sundy-li	TCeason	usamoi	weakish	wubx	Xuanwo


xudong963	ygf11	youngsofun	ZeaLoVe	zhang2014

Meet Us

Please join the DatafuseLabs Community if you are interested in Databend.

We are looking forward to seeing you try our code. We have a strong team behind you to ensure a smooth experience in trying our code for your projects. If you are a hacker passionate about database internals, feel free to play with our code.

You can submit issues for any problems you find. We also highly appreciate any of your pull requests.

This week in Databend #42