questdb: A Java repository from lganzzzo

What is QuestDB

QuestDB is an open source database designed to make time series lightning fast and easy.

It uses a column-oriented approach, vectorized execution, SIMD instructions, and a whole array of low-latency techniques. The whole code base is built from scratch and without dependencies, in the name of performance. We are 100% free from garbage collection.

QuestDB implements SQL, and augments it for time-series. It exposes a Postgres wire protocol, a high-performance REST API, and even supports ingestion with InfluxDB line protocol. It supports both relational and time-series joins, which makes it easy to correlate data over time. Writes are durably committed to disk, meaning that the data is safe - yet instantly accessible.

Performance figures

Raw figures

Number operations per second per thread. Writes are durable and written to disk.

Operation	64-bit double	32-bit int
Read	120 Million /s	240 Million /s
Write	240 Million /s	480 Million /s

On a CPU with 6 memory channels, QuestDB can scan through 117GB of data per second.

Queries

Execution time on a c5.metal instance using 16 of the 96 threads available.

Query	Runtime
`SELECT sum(double) FROM 1bn`	0.061 secs
`SELECT tag, sum(double) FROM 1bn`	0.179 secs
`SELECT tag, sum(double) FROM 1bn WHERE timestamp='2019'`	0.05 secs

Getting Started

The easiest way to get started is with Docker:

docker run -p 9000:9000 -p 8812:8812 questdb/questdb

You can more information about Docker usage here.

Alternative methods

Connecting to QuestDB

You can interact with QuestDB using:

Web Console listening on port 9000: localhost:9000
Postgres wire, for example with PSQL (alpha) on port 8812
REST API listening on port 9000

Both the HTTP and PostgreSQL servers reference the database in <root_directory>/db.

You can connect to the Postgres server as follows. The default password is quest

psql -h localhost -p 8812 -U admin -W -d qdb

Building from source

(a) Prerequisites

Java 11 64-bit
Maven 3
Node.js 12 / NPM 6

java --version
mvn --version
node --version

(b) Clone the Repository

git clone git@github.com:questdb/questdb.git

(c) Build the Code

cd questdb
mvn clean package -DskipTests

The build should take around 2 minutes. You can remove -DskipTests to run the 3000+ unit tests. The tests take 3-5 minutes to run.

(d) Run QuestDB

# Create a database root directory and run QuestDB
mkdir <root_directory>
java -p core/target/core-5.0.2-SNAPSHOT.jar -m io.questdb/io.questdb.ServerMain -d <root_directory>