This Week in Databend #82

February 22, 2023 · 5 min read

PsiACE

Databend is a modern cloud data warehouse, serving your massive-scale analytics needs at low cost and complexity. Open source alternative to Snowflake. Also available in the cloud: .

Databend is a modern cloud data warehouse, serving your massive-scale analytics needs at low cost and complexity. Open source alternative to Snowflake. Also available in the cloud: https://app.databend.com .

What's New

Check out what we've done this week to make Databend even better for you.

Features & Improvements ✨

AST

select from stage support uri with connection options (#10066)

Catalog

Iceberg/create-catalog (#9017)

Expression

type decimal support agg func min/max (#10085)
add sum/avg for decimal types (#10059)

Pipeline

enrich core pipelines processors (#10098)

Query

create stage, select stage, copy, infer_schema support named file format (#10084)
query result cache (#10042)

Storage

table data cache (#9772)
use drop_table_by_id api in drop all (#10054)
native storage format support nested data types (#9798)

Code Refactoring 🎉

Meta

add compatible layer for upgrade (#10082)
More elegant error handling (#10112, #10114, etc.)

Cluster

support exchange sorting (#10149)

Executor

add check processor graph completed (#10166)

Planner

apply constant folder at physical plan builder (#9889)

Query

use accumulating to impl single state aggregator (#10125)

Storage

adopt OpenDAL's batch delete support (#10150)
adopt OpenDAL query based metadata cache (#10162)

Build/Testing/CI Infra Changes 🔌

release deb repository (#10080)
release with systemd units (#10145)

Bug Fixes 🔧

Expression

no longer return Variant as common super type (#9961)
allow auto cast from string and variant (#10111)

Cluster

fix limit query hang in cluster mode (#10006)

Storage

wrong column statistics when contain tuple type (#10068)
compact not work as expected with add column (#10070)
fix add column min/max stat bug (#10137)

What's On In Databend

Stay connected with the latest news about Databend.

Query Result Cache

In the past week, Databend now supports caching of query results!

             ┌─────────┐ 1  ┌─────────┐ 1
             │         ├───►│         ├───►Dummy───►Downstream
Upstream────►│Duplicate│ 2  │         │ 3
             │         ├───►│         ├───►Dummy───►Downstream
             └─────────┘    │         │
                            │ Shuffle │
             ┌─────────┐ 3  │         │ 2  ┌─────────┐
             │         ├───►│         ├───►│  Write  │
Upstream────►│Duplicate│ 4  │         │ 4  │ Result  │
             │         ├───►│         ├───►│  Cache  │
             └─────────┘    └─────────┘    └─────────┘

Learn More

Table Data Cache

Databend now supports table data cache:

disk cache: raw column(compressed) data of the data block.
in-memory cache(experimental): deserialized column objects of a data block.

For cache-friendly workloads, the performance gains are significant.

Learn More

Deb Source & Systemd Support

Databend now offers the official Deb package source and supports the use of systemd to manage the service.

For DEB822 Source Format:

sudo curl -L -o /etc/apt/sources.list.d/datafuselabs.sources https://repo.databend.rs/deb/datafuselabs.sources
sudo apt update
sudo apt install databend
sudo systemctl start databend-meta
sudo systemctl start databend-query

Learn More

What's Up Next

We're always open to cutting-edge technologies and innovative ideas. You're more than welcome to join the community and bring them to Databend.

Service Activation Progress Report

When starting a Query/Meta node, it is necessary to perform checks and output them explicitly to help the user diagnose faults and confirm status.

Example:

storage check succeed
meta check failed: timeout, no response. endpoints: xxxxxxxx .
status check failed: address already in use.

Issue 10193: Feature: output the necessary progress when starting a query/meta node

Please let us know if you're interested in contributing to this issue, or pick up a good first issue at https://link.databend.rs/i-m-feeling-lucky to get started.