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 abort pipeline (#6174)
integration with sentry (#6226)
rewrite predicate and accelerate tpch19 (#6301)

databend meta

support leave a cluster with databend-meta --leave.. (#6181)
add import init cluster support (#6280)

statements

support exists statement (#6166)
statement delete from... (#5691)
order by sub stmt support db.table.col (#6191)

new planner

introduce serializable physical plan (#6191)
support non-equi conditions in hash join (#6145)
decorrelate EXISTS subquery with non-equi condition (#6232)
migrate Create(#5905)/Alter(#6319)/Drop(#6327) UDF

Improvement

improve compatibility with clickhouse http handler (#6148)
limit push down for table fuse_snapshot & proc system$fuse_snapshot (#6167)
split ast statements into multiple mods (#6176)
store grpc addr to node info and auto refresh backends addrs for grpc client (#5495)

Join Performance Improvements

improve left/semi/anti join performance [~80x] (#6241)
improve join results gather [~7x] (#6228)
improve semi/anti join with other conjuncts [~17x] (#6366)

Build/Testing/CI

add tpch stateless-test (#6225)
add async insert test (#5964)

Bug fixes

fix datatype different cause mysql session distroy (#6150)
fix node id truncation when cluster id is escaped (#6193)
fix aggregate count incorrect state place (#6218)
fix grouping check (#6219)
fix output of to_datetime() (#6252)
fix MySQL connection close_wait or fin_wait_2 (#6341)

Tips

Let's learn a weekly tip from Databend.

`DELETE` in Databend

The DELETE statement can delete one or more rows from a table.

Syntax

Databend now supports such syntax:

DELETE FROM table_name
[WHERE search_ condition]

Example

Suppose that the bookstore table currently contains the following data:

bookId	bookName
101	After the death of Don Juan
102	Grown ups
103	The long answer
104	Wartime friends
105	Deconstructed

Now let's delete the book with id = 103:

DELETE from bookstore where bookId = 103;

After deletion, the data in the bookstore table is shown as follows:

bookId	bookName
101	After the death of Don Juan
102	Grown ups
104	Wartime friends
105	Deconstructed

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.


ariesdevil	b41sh	BohuTANG	ClSlaid	cuichenli	dantengsky


drmingdrmer	everpcpc	fkuner	leiysky	lichuang	mergify[bot]


PsiACE	soyeric128	sundy-li	TCeason	TennyZhuang	Xuanwo


xudong963	youngsofun	zhang2014	ZhiHanZ

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 #48