Why Compression (gzip, snappy, lz4) in Kafka? - Purpose & Use Cases

The Big Idea

What if you could send huge data instantly without waiting or wasting space?

The Scenario

Imagine sending a huge pile of letters by mail one by one. It takes a lot of time and costs a lot. You try to write smaller letters by hand, but it's slow and tiring.

The Problem

Manually shrinking data is slow and often messy. It wastes space and bandwidth, making your messages slow to travel and sometimes incomplete or lost.

The Solution

Compression tools like gzip, snappy, and lz4 automatically squeeze data smaller and faster. They make sending and storing data quick and efficient without losing important information.

Before vs After

✗ Before

send(data)  # sending full data without compression

✓ After

send(compress(data))  # sending compressed data automatically

What It Enables

Compression lets you send more data faster and cheaper, making systems like Kafka handle huge streams smoothly.

Real Life Example

When streaming videos or logs in Kafka, compression shrinks the data so it travels quickly and uses less space, helping apps respond faster.

Key Takeaways

Manual data sending is slow and costly.

Compression tools automatically shrink data efficiently.

This speeds up data transfer and saves storage in Kafka systems.

Practice

1. Which of the following compression types is NOT supported by Kafka by default?

easy

A. gzip

B. snappy

C. lz4

D. bzip2

Solution

1. Step 1: Recall Kafka's default compression types

   Kafka supports gzip, snappy, and lz4 compression types by default.

2. Step 2: Identify unsupported compression

   bzip2 is not included in Kafka's default compression options.

3. Final Answer:

   bzip2 -> Option D

4. Quick Check:

   Kafka default compression excludes bzip2 [OK]

Hint: Remember Kafka supports gzip, snappy, and lz4 only [OK]

Common Mistakes:

• Confusing bzip2 as supported compression
• Thinking all common compressions are supported
• Mixing compression codecs with serialization formats

2. Which is the correct way to set gzip compression in Kafka producer configuration?

easy

A. compression.type = 'gzip'

B. compressionType = 'gzip'

C. compression.type = gzip

D. compression = 'gzip'

Solution

1. Step 1: Identify the correct property name

   The Kafka producer config uses 'compression.type' to set compression.

2. Step 2: Check the correct value format

   The value should be a string, so 'gzip' must be in quotes.

3. Final Answer:

   compression.type = 'gzip' -> Option A

4. Quick Check:

   Use compression.type with string value [OK]

Hint: Use compression.type with quotes around value [OK]

Common Mistakes:

• Using wrong property name like compressionType
• Omitting quotes around 'gzip'
• Using compression instead of compression.type

3. Given this Kafka producer config snippet:

props.put("compression.type", "snappy");
props.put("acks", "all");

What is the effect of setting compression.type to snappy?

medium

A. Messages will be sent without compression.

B. Messages will be compressed using Snappy before sending.

C. Messages will be compressed using gzip.

D. Producer will throw an error due to invalid compression.

Solution

1. Step 1: Understand the compression.type setting

   Setting compression.type to 'snappy' means messages are compressed with Snappy codec.

2. Step 2: Confirm no errors expected

   Snappy is a valid compression type, so no errors occur and compression is applied.

3. Final Answer:

   Messages will be compressed using Snappy before sending. -> Option B

4. Quick Check:

   compression.type = snappy means Snappy compression [OK]

Hint: compression.type sets the codec used for message compression [OK]

Common Mistakes:

• Assuming no compression happens
• Confusing snappy with gzip
• Expecting an error for valid compression type

4. You wrote this Kafka producer config:

props.put("compression.type", "lz5");

What is the problem with this configuration?

medium

A. lz5 is not a supported compression type in Kafka.

B. The property name should be compressionType, not compression.type.

C. The value should be uppercase: LZ5.

D. There is no problem; this is valid.

Solution

1. Step 1: Check the compression type value

   Kafka supports gzip, snappy, and lz4 only; lz5 is invalid.

2. Step 2: Confirm property name correctness

   The property name compression.type is correct, so no issue there.

3. Final Answer:

   lz5 is not a supported compression type in Kafka. -> Option A

4. Quick Check:

   Only gzip, snappy, lz4 are valid compression types [OK]

Hint: Use only gzip, snappy, or lz4 for compression.type [OK]

Common Mistakes:

• Using unsupported compression types like lz5
• Changing property name incorrectly
• Assuming case sensitivity matters for compression type

5. You want to optimize Kafka message throughput by choosing a compression type that balances speed and compression ratio. Which compression type should you choose?

hard

A. gzip, because it has the best compression ratio but slower speed.

B. No compression, to avoid any overhead.

C. snappy, because it offers fast compression with reasonable compression ratio.

D. lz4, because it is the slowest but compresses best.

Solution

1. Step 1: Understand compression trade-offs

   gzip compresses well but is slower; snappy is faster with decent compression; lz4 is fast and efficient.

2. Step 2: Identify best balance for throughput

   snappy is known for fast compression speed and reasonable compression ratio, ideal for throughput.

3. Final Answer:

   snappy, because it offers fast compression with reasonable compression ratio. -> Option C

4. Quick Check:

   snappy balances speed and compression well [OK]

Hint: Pick snappy for speed and decent compression [OK]

Common Mistakes:

• Choosing gzip for speed instead of compression ratio
• Thinking lz4 is slowest
• Assuming no compression is fastest overall