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

transient fuse table (#5968)
support field comment (#5952)
stop parsing at insert statement (#6048)
configurable repr of float denormals in output formats (#6065)
integrate cluster select query with new processor (#4544)

optimizer

decorrelate EXISTS subquery (#6073)
support push down filter through cross apply (#6079)

functions

support ifnull (#5921)
support multi_if (#6039)
support date_sub (#6050)
support to_nullable and assume_not_null (#6055)
support coalesce (#5922)

clickhouse handle

support settings (#5945)
improve output format (#6027)
support set database. (#6097)

new planner

show statements (#6013)
show users/roles statement (#6016)
migrate grant (#6049)
migrate revoke (#6066)
migrate copy (#6074)
migrate insert statement (#5897)
support query log for new planner (#6053)
support SELECT ... FROM ... { AT TIMESTAMP } (#6056)

Improvement

stop supporting multiple statements (#6052)
make uuid return uuid values for each row (#6114)
add more meta cluster status (#6083)
cache panic of http handlers (#6090)
adjust table snapshot timestamp precision to micro second (#6144)

Bug fixes

fix de_csv with escaped quoted (#6008)
consider NULL for binary op in type checker (#6043)
fix error of EXISTS subquery (#6073)
transient object storage IO operation fault handling (#6045)
remove a wrong cut parser in subquery (#6111)

Tips

Let's learn a weekly tip from Databend.

Cluster key

Cluster key is intended to improve query performance by physically clustering data together.

For example, when you set a column as your cluster key for a table, the table data will be physically sorted by the column you set. This will maximize the query performance if your most queries are filtered by the column.

Sets a cluster key when creating a table

CREATE TABLE <name> ... CLUSTER BY ( <expr1> [ , <expr2> ... ] )

Changes the cluster key for a table

ALTER TABLE <name> CLUSTER BY ( <expr1> [ , <expr2> ... ] )

Deletes the cluster key for a table

ALTER TABLE <name> DROP CLUSTER KEY

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	AngleNet	b41sh	BohuTANG	cadl	dantengsky


drmingdrmer	everpcpc	fkuner	hantmac	junnplus	leiysky


lichuang	mergify[bot]	PsiACE	RinChanNOWWW	soyeric128	sundy-li


TCeason	TennyZhuang	TianLangStudio	Veeupup	wfxr	wubx


Xuanwo	xudong963	youngsofun	yuuch	zhang2014	zhyass

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 #47