Compression (gzip, snappy, lz4) in Kafka - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of compression in Kafka?

Compression reduces the size of messages sent over the network and stored on disk, improving throughput and saving storage space.

beginner

Name three compression codecs supported by Kafka.

Kafka supports gzip, snappy, and lz4 compression codecs.

intermediate

How does gzip compression compare to snappy in Kafka?

Gzip offers higher compression ratio but is slower, while snappy is faster but compresses less effectively.

intermediate

What is a key advantage of lz4 compression in Kafka?

Lz4 provides a good balance of fast compression and decompression speed with reasonable compression ratio, making it suitable for real-time data streams.

beginner

How do you enable compression for Kafka producers?

Set the producer configuration property 'compression.type' to 'gzip', 'snappy', or 'lz4' to enable compression.

Which Kafka compression codec typically offers the fastest compression speed?

A snappy

B gzip

C none

D lz4

lz4 is designed for fast compression and decompression, faster than snappy and gzip.

What is the default compression type in Kafka if none is specified?

A gzip

B none

C lz4

D snappy

By default, Kafka producers do not compress messages unless 'compression.type' is set.

Which compression codec is best when you want the smallest message size regardless of speed?

A gzip

B snappy

C lz4

D none

Gzip compresses data more tightly than snappy or lz4 but is slower.

How does compression affect Kafka network usage?

A Decreases network usage

B Increases network usage

C No effect on network usage

D Depends on message size only

Compression reduces the size of messages, lowering network bandwidth usage.

Which Kafka compression codec is recommended for real-time streaming with low latency?

A gzip

B snappy

C lz4

D none

Lz4 offers fast compression and decompression suitable for low latency streaming.

Explain the differences between gzip, snappy, and lz4 compression codecs in Kafka.

Think about speed versus compression size trade-offs.

Describe how to enable compression on a Kafka producer and why you might want to do it.

Consider configuration and benefits.

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