State stores in Kafka - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a persistent state store named "my-store".

Kafka

StoreBuilder<KeyValueStore<String, String>> storeBuilder = Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore([1]), Serdes.String(), Serdes.String());

Drag options to blanks, or click blank then click option'

A"state-store"

B"store"

C"my-store"

D"kafka-store"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put the store name in quotes.

Using an incorrect store name.

The store name must be a unique string identifier. Here, "my-store" is the correct name.

2fill in blank

medium

Complete the code to add the state store to the topology.

Kafka

topology.[1](storeBuilder);

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AaddStateStore

BaddProcessor

CaddSource

DaddSink

Attempts:

3 left

💡 Hint

Common Mistakes

Using addProcessor instead of addStateStore.

Confusing addSource or addSink with state store methods.

The method addStateStore adds a state store to the topology.

3fill in blank

hard

Fix the error in the code to retrieve the state store from the processor context.

Kafka

KeyValueStore<String, String> store = (KeyValueStore<String, String>) context.[1]("my-store");

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AfetchStateStore

BretrieveStore

CgetStore

DgetStateStore

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect method names that do not exist in the API.

Forgetting to cast the returned object to KeyValueStore.

The correct method to get a state store from the context is getStateStore.

4fill in blank

hard

Fill both blanks to create a RocksDB persistent key-value store with string serializers.

Kafka

StoreBuilder<KeyValueStore<String, String>> storeBuilder = Stores.keyValueStoreBuilder(Stores.[1]KeyValueStore("my-rocks-store"), [2], Serdes.String());

Drag options to blanks, or click blank then click option'

Apersistent

BinMemory

CSerdes.String()

DpersistentRocksDB

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'inMemory' instead of 'persistent' for the store type.

Using wrong serializer for the key.

The method persistentKeyValueStore creates a RocksDB persistent store. The serializer for keys is Serdes.String().

5fill in blank

hard

Fill all three blanks to define a state store, add it to the topology, and retrieve it in a processor.

Kafka

StoreBuilder<KeyValueStore<String, String>> storeBuilder = Stores.keyValueStoreBuilder(Stores.[1]KeyValueStore("store1"), Serdes.String(), [2]);

topology.[3](storeBuilder);

Drag options to blanks, or click blank then click option'

Apersistent

BSerdes.String()

CaddStateStore

DinMemory

Attempts:

3 left

💡 Hint

Common Mistakes

Using inMemory instead of persistent store.

Using wrong serializer for values.

Using addProcessor instead of addStateStore.

Use persistentKeyValueStore to create a persistent store, Serdes.String() for value serializer, and addStateStore to add it to the topology.