Chen Riang's Blog

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Druid Timeout Exception

org.apache.druid.query.QueryTimeoutException

I hit timeout exception from Druid when I performing a big query that require long time to process. org.apache.druid.query.QueryTimeoutException: url [http://xx.xx.xx.xx:8088/druid/v2/] timed o...

Druid Not Enough Buffer Capacity

When running a groupby query with huge aggregation process and follow by sub select query in SQL, I bump into following exception Not enough capacity for even one row! Need[xx] but have[0] So...

Running Apache Druid in Kubernetes

Apache Druid is an open source database that special built for business intelligence queries (OLPA) on large event dataset. It can provide a very low latency data ingestion, flexible data explorati...

Connect Delta Lake with JDBC

In previous blog post, we walk through some basic CRUD operations on Delta Lake. However, if you’re a Java application developer, you might just want to focus on the SQL query logic without having ...

Delta Lake - The Next Gen Data Lake

When we talk about data lake in enterprise, the first term that normally will pop up would be Apache Hadoop. Hadoop seem to be the no brainer solution for most of the company that thinking to maint...

Spark Infer Timestamp data type from JSON

Apache Spark provides a feature to infer data schema based on the incoming data. However, in Spark version 3.1.2, it wrongly interprets the Timestamp field as String data type. 1 2 3 4 5 6 7 8 9 1...

Running Apache Spark standalone cluster in one machine

Apache Spark is a complex framework that provide parallelized in-memory data processing. Often time during development, we just want to focus on creating the business without having to worried abou...

TimeScaleDB

A Supercharged Postgres Database that you should know

Changing database technology is very difficult decision when coming to modernizing a legacy product. Don’t believe me? Try asking your DBA about changing existing database technology and see what y...

Running IntelliJ IDEA in WSLg (Window 11)

I have been using WSL for development for sometime and turn up 80% of my tools has moved to WSL instead of native Window. However, if you’re a WSL heavy user like me, you will surely understand the...

Java 8 Date Time

Java’s date time API can be quite confusing when you’re new to it. Java introduced another new set of date time API to replace the legacy API in version 8. In this article, we will be looking into ...