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...

Posted by ChenRiang on October 10, 2021

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...

Posted by ChenRiang on October 10, 2021

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...

Posted by ChenRiang on October 9, 2021

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 ...

Posted by ChenRiang on September 17, 2021

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...

Posted by ChenRiang on September 9, 2021

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...

Posted by ChenRiang on August 29, 2021

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...

Posted by ChenRiang on August 25, 2021

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...

Posted by ChenRiang on August 17, 2021

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...

Posted by ChenRiang on August 5, 2021

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 ...

Posted by ChenRiang on July 19, 2021