Md. Sany Ahmed sany2k8

Impala Partition Refresh – Complete, Practical Guide

This document explains why Impala requires partition refresh operations, what exactly happens internally, what breaks if you skip them, and all available strategies to make newly written Parquet data queryable and performant.

This is written to be understandable for new engineers, while still being accurate for production systems.

1. The Core Problem Impala Solves

1. What Spark Is (And Is Not)

Spark is NOT:

just a SQL engine
just a query engine

Spark IS:

A general-purpose distributed data processing engine capable of ETL, analytics, and machine learning.

1. What Impala Is (And Is Not)

Impala is NOT:

a storage engine
a file format
a batch processing system

Impala IS:

1. First Principle: What a Hive Table Really Is

A Hive table is NOT:

a storage engine
a file format
a database that owns data

A Hive table IS:

1. Example Dataset (Logical View)

Assume this dataset coming from an ingestion job:

order_id	country	product	amount
1	US	Book	120
2	IN	Pen	20
3	US	Book	300
4	IN	Pencil	10

🧭 Big Data Ecosystem Overview

This document explains how the main components of the Hadoop-based Big Data ecosystem connect and work together: Hue, Hive, Impala, HDFS, Spark (PySpark), HBase, Iceberg, Parquet, ORC, Oozie, and Teradata.

🧱 Core Components and Their Roles

Component	Type	Purpose

Typos & Corrections

Original Text (on page)	Issue	Suggested Correction
“List sroted pods”	Typo	“List sorted pods”
“List pods using a different output”	Wording unclear	Could be: “List pods with different output formats”
“View all cotainers logs…”	Typo	“View all containers logs…”
“locahost-port”	Typo	“localhost-port”
“hosts-port”	Wording	Better: “host-port”
**“

Search Type	Speed	Accuracy	Flexibility	Storage	Best For
Exact Match	⭐⭐⭐⭐⭐	⭐⭐⭐⭐⭐	⭐	⭐⭐⭐⭐⭐	IDs, codes, filters
Pattern Match	⭐⭐⭐⭐	⭐⭐⭐	⭐⭐⭐	⭐⭐⭐⭐	Autocomplete, prefixes
Full-Text	⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐	Documents, articles
Vector / Semantic	⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐⭐⭐	⭐⭐	Recommendations, concepts
Fuzzy	⭐⭐	⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐	Typos, data cleaning

	flowchart TD

	%% =============================
	%% Global Layout Tweaks
	%% =============================

	%% Make arrows thicker and more visible
	linkStyle default stroke-width:2px,stroke:#555,opacity:0.9;

	-- CREATE EXTENSION IF NOT EXISTS postgis;
	-- CREATE EXTENSION IF NOT EXISTS pgvector;

	------------------------------ Exercise 1 ------------------------------
	-- Table setup
	CREATE TABLE products (
	id SERIAL PRIMARY KEY,
	sku VARCHAR(20) UNIQUE,
	name VARCHAR(200),
	category VARCHAR(50),