Postgres Quiz Archive

You have 200 seconds to answer 20 Random questions so think fast!

You will need to score 80% or over to pass!

Created by

Paul Sammy

PostgreSQL 14 Internals Chapter 1

A quiz to test the knowledge of those reading and learning from Postgres 14 Internals book by Egor Rogov, covering topics in Chapter 1.

1 / 20

1. What 3 files/forks as a minimum make up a table on disk?

free space map

visiblilty map

Main fork

table map

2 / 20

2. A Postgres cluster consists of 2 or more physical servers accessing one Postgres Instance?

False

True

3 / 20

3. What command is used to create the Postgres cluster?

CreateCluster

CreatePGC

Initialize

StartNewPG

4 / 20

4. What is the purpose of wal writer?

flushes dirty pages to disk.

writes WAL entries to disk

collects usage statistics for the instance.

executes checkpoints

5 / 20

5. Some System Catalog tables are common to all databases in the cluster?

False

True

6 / 20

6. Each Database has its own System Catalog?

True

False

7 / 20

7. Which of below are predefined schemas?

choose 2

pg_catalog

postgres

public

system

8 / 20

8. Who is the Author of the Postgres 14 Internals book?

Paul Sammy

Sam Altman

Dan Brown

Egor Rogov

9 / 20

9. What is the purpose of the visibility map?

provides an audit trail for the database

shows referential relationships for tables

provides the data decryption key

shows a page to be vacuumed or frozen

10 / 20

10. Users should not modify the template0 database

False

True

11 / 20

11. When PostgreSQL is running what can it be referred to as?

Choose 2 option

Aurora

Postgres Server

Quorum

Instance

12 / 20

12. The pg_default tablespace should never be used to create user tables?

True

False

13 / 20

13. What is the purpose of the template0 database?

No such database

Useful for creating development schemas

Useful for Postgres support Services to debug issues

Useful for restoring data from a logical backup or creating a database with a different encoding

14 / 20

14. pg_catalog schema is used to store system catalog tables?

True

False

15 / 20

15. What is the name of the catalog that stores metadata for all cluster objects?

System Catalog

Sysasm Catalog

Sys Catalog

Sysaux Catalog

16 / 20

16. What is the purpose of autovacuum?

Removes stale data from tables and indexes

Deletes old logs and traces on disk

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

17 / 20

17. What is the name of the system catalog table for relations?

pg_catalog

pg_tables

pg_class

pg_system

18 / 20

18. Which fork contains the actual table data?

visiblilty map

free space map

Main fork

table map

19 / 20

19. Which 3 databases exist directly after cluster initialization?

choose 3 options

template0

postgres

sysaux

template1

20 / 20

20. How many rows in a page does Postgres aim to have before considering TOAST?

Your score is

Created by

Paul Sammy

PostgreSQL 14 Internals Chapter 2

A quiz to test the knowledge of those reading and learning from Postgres 14 Internals book by Egor Rogov, covering topics in Chapter 2.

1 / 10

1. Which isolation level in theory could mean an application does not have to consider isolation anomalies?

Read Committed

Serializable

Read Uncommitted

Repeatable Read

2 / 10

2. The more locks a transaction acquires, the better it is isolated from other transactions?

True

False

3 / 10

3. What are some of database features we can use to avoid a non repeatable read?

Select more than 1 answer below:

Replace procedural code with declarative one.

Apply explicit locks

Use a single SQL operator

Issues a rollback after the commit to satisfy repeatable read.

4 / 10

4. Snapshot isolation is preferred but increases the number of required locks?

True

False

5 / 10

5. Based on Snapshot Isolation use of MVCC which of the below are permitted?

choose 3

Read Committed

Serializable

Read Uncommitted

Repeatable Read

6 / 10

6. Lost updates are forbidden by the standard at all isolation levels?

True

False

7 / 10

7. non-repeatable read anomaly occurs when?

A transaction reads one and the same row twice, another transaction modifies this row between these reads and commits the change.

A transaction reads one and the same row once and modifies this row and commits the change.

A transaction reads one and the same row once, another transaction modifies this row between these reads and commits the change.

A transaction reads one and the same row twice, another transaction modifies this row between these reads issue a rollback.

8 / 10

8. A phantom read anomaly occurs when?

The same transaction executes two identical queries returning a set of rows that satisfy a particular condition, while another transaction adds some other rows satisfying this condition and commits.

The same transaction executes two identical queries returning a set of rows that satisfy a particular condition, while another transaction also queries this same data.

The same transactions issues a commit, then a rollback to restore data to its original value

A transactions inserts a null value into a not null columns and commits

9 / 10

9. which of the below statements will start a transaction as Read Repeatable?

BEGIN ISOLATION LEVEL REPEATABLE READ;

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

10 / 10

10. Which of the below are valid Isolations Levels?

choose 2

Serializable

Rollback Read

Read Committed

Random Scatter

Your score is

Created by

Paul Sammy

PostgreSQL 14 Internals Chapter 3

A quiz to test the knowledge of those reading and learning from Postgres 14 Internals book by Egor Rogov, covering topics in Chapter 3.

1 / 10

1. Rows of TOAST tables are handled in such a way that they are never update?

False

True

2 / 10

2. A page along with its tuples is read into the buffer cache with compression transformations to enhance cache efficiency?

True

False

3 / 10

3. at any one time Postgres can have several versions of a row?

True

False

4 / 10

4. a transaction containing a savepoint is will still be considered as only a single transaction?

True

False

5 / 10

5. When a row is created, its xmin value is set to the transaction ID of which command?

INSERT

CREATE

DELETE

COMMIT

6 / 10

6. Page header sizes can be easily displayed using the <choose from answers> extension

pagedetect

pageinspect

pagesize

pageheadinfo

7 / 10

7. If a transaction aborts, all page changes are reverted(rolled back) in place?

False

True

8 / 10

8. Which 2 of the below represent transaction IDs used for row versioning?

xid

xmin

xmax

xtime

9 / 10

9. CLOG Pages are never cached in memory?

False

True

10 / 10

10. To identify different versions of one and the same row, PostgreSQL marks each of them with which two value?

xmin

xmas

xid

xmax

Your score is

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