Connection pooling in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a connection pool with a maximum of 10 connections.

GraphQL

const pool = new Pool({ max: [1] });

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A10

B5

C20

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Setting max to 1 limits to a single connection, which is not pooling.

Using too high a number can overload the database.

The max property sets the maximum number of connections in the pool. Here, 10 is the correct value.

2fill in blank

medium

Complete the code to acquire a client from the connection pool.

GraphQL

const client = await pool.[1]();

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AgetClient

Bconnect

Cacquire

Dopen

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent methods like 'getClient' causes errors.

Forgetting to await the async method leads to unresolved promises.

The connect() method is used to get a client from the pool.

3fill in blank

hard

Fix the error in releasing the client back to the pool.

GraphQL

client.[1]();

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Adisconnect

Bclose

Crelease

Dend

Attempts:

3 left

💡 Hint

Common Mistakes

Calling 'end' closes the connection permanently, defeating pooling.

Forgetting to release causes connection leaks.

The release() method returns the client to the pool for reuse.

4fill in blank

hard

Fill both blanks to create a query using a pooled client and release it after.

GraphQL

const client = await pool.[1]();
const res = await client.query('SELECT * FROM users');
client.[2]();

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Aconnect

Brelease

Cend

Ddisconnect

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'end' or 'disconnect' closes the connection permanently.

Not releasing the client causes connection exhaustion.

You must connect() to get the client and release() it after the query.

5fill in blank

hard

Fill all three blanks to configure a pool with max 15 connections, idle timeout 30000 ms, and statement timeout 5000 ms.

GraphQL

const pool = new Pool({ max: [1], idleTimeoutMillis: [2], statement_timeout: [3] });

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

A15

B30000

C5000

D10000

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up timeout values or using wrong property names.

Setting max too low or too high can cause performance issues.

The max sets max connections, idleTimeoutMillis sets idle timeout, and statement_timeout sets statement timeout in milliseconds.