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. Users should not modify the template0 database

True

False

2 / 20

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

Sam Altman

Paul Sammy

Dan Brown

Egor Rogov

3 / 20

3. Which of the below objects can be referred to as relations?

choose 3

triggers

tables

indexes

sequences

4 / 20

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

table map

Main fork

visiblilty map

free space map

5 / 20

5. A schema can belong to more than one database?

False

True

6 / 20

6. What is the point of the pg_global tablespace?

stores WAL logs used for global replication

stores temporary tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores user tables that are common to the whole cluster

7 / 20

7. Each tablespaces can only be assigned for use by one database

False

True

8 / 20

8. What is the purpose of the template0 database?

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

Useful for creating development schemas

Useful for Postgres support Services to debug issues

No such database

9 / 20

9. What is the default standard size for a fork file?

5MB

5GB

1MB

1GB

10 / 20

10. TOAST tables reside in a seperate schema?

False

True

11 / 20

11. Which 3 databases exist directly after cluster initialization?

choose 3 options

template0

postgres

template1

sysaux

12 / 20

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

True

False

13 / 20

13. What is the name of the 2 default tablespaces created after initialization?

choose 2

pg_tablespace

pg_temp

pg_default

pg_global

14 / 20

14. How does Postgres know which schema to use if not specified?

Directory Path

Search Path

Access Path

Schema Path

15 / 20

15. Files are logically split into pages?

True

False

16 / 20

16. What is another name for the postgres process?

postmaster

postmanager

masterprocess

aurora

17 / 20

17. What is a schema?

A memory area used to cache data from LRU chains

This is the same as a user in Postgres

The name used to refer to a super user account

Namespace that store all objects of a database

18 / 20

18. What is the purpose of wal writer?

writes WAL entries to disk

collects usage statistics for the instance.

flushes dirty pages to disk.

executes checkpoints

19 / 20

19. What is the name of the mechanism used to store a row bigger than a page size?

TOAST

BAKE

GROW

BREAD

20 / 20

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

pg_tables

pg_class

pg_system

pg_catalog

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

False

True

2 / 10

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

choose 3

Repeatable Read

Read Committed

Read Uncommitted

Serializable

3 / 10

3. non-repeatable read anomaly occurs when?

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.

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.

4 / 10

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

Read Uncommitted

Serializable

Read Committed

Repeatable Read

5 / 10

5. What is the default Isolation Level?

Repeatable Read

Serializable

Read Committed

Read Uncommitted

6 / 10

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

SET ISO=REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

7 / 10

7. 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

Issues a rollback after the commit to satisfy repeatable read.

Use a single SQL operator

8 / 10

8. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Random Scatter

Read Committed

Serializable

9 / 10

9. What is the acronym used for the attributes that ensure Data consistency, integrity and durability?

SOC2

HIPPA

ACID

SAFE

10 / 10

10. 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.

A transactions inserts a null value into a not null columns 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

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. status of a subtransaction is written into CLOG?

False

True

2 / 10

2. Indexes values also support multi versioning with several versions of an index value existing at any point in time?

True

False

3 / 10

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

True

False

4 / 10

4. Tuples can also be referred to as columns?

False

True

5 / 10

5. Which function can we use to find the current transaction ID?

pg_current_id()

pg_current_xmin_id()

pg_current_commit_id()

pg_current_xact_id()

6 / 10

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

True

False

7 / 10

7. psql provides a special mode that allows you to continue a transaction after a failure?

False

True

8 / 10

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

CREATE

COMMIT

INSERT

DELETE

9 / 10

9. CLOG files are stored in which directory?

PGDATA/pg_clog

PGDATA/pg_commit

PGDATA/pg_xact

PGDATA/clog

10 / 10

10. CLOG contains how many bits for each transaction?

Your score is

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