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. Which fork keeps track of available space within pages?

wal space map

vacuum space map

free space map

used space map

2 / 20

2. What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

Performs a backup of WAL logs

Deletes old logs and traces on disk

3 / 20

3. Which fork is specific for unlogged tables?

Initialization fork

Main fork

free space map

visiblilty map

4 / 20

4. What is the purpose of the visibility map?

provides the data decryption key

shows a page to be vacuumed or frozen

provides an audit trail for the database

shows referential relationships for tables

5 / 20

5. It is the postmasters job to listener for incoming connections?

True

False

6 / 20

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

True

False

7 / 20

7. Postgres by default has built in connection pooling abilities?

False

True

8 / 20

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

Schema Path

Search Path

Directory Path

Access Path

9 / 20

9. What is the purpose of wal writer?

executes checkpoints

writes WAL entries to disk

collects usage statistics for the instance.

flushes dirty pages to disk.

10 / 20

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

Choose 2 option

Instance

Postgres Server

Aurora

Quorum

11 / 20

11. What is a schema?

The name used to refer to a super user account

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

This is the same as a user in Postgres

12 / 20

12. TOAST tables reside in a seperate schema?

True

False

13 / 20

13. System Catalog tables begin with which prefix?

dba_

cat_

pg_

sys_

14 / 20

14. What is the purpose of the template0 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

No such database

15 / 20

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

16 / 20

16. Users should not modify the template0 database

False

True

17 / 20

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

free space map

visiblilty map

Main fork

table map

18 / 20

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

False

True

19 / 20

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

CreatePGC

Initialize

StartNewPG

CreateCluster

20 / 20

20. Files are logically split into pages?

True

False

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. 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 also queries this same data.

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 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

2 / 10

2. Data Consistency is best handled at the application layer rather than at the database layer?

True

False

3 / 10

3. non-repeatable read anomaly occurs when?

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 and commits the change.

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

4 / 10

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

HIPPA

SOC2

ACID

SAFE

5 / 10

5. What is the default Isolation Level?

Repeatable Read

Read Committed

Read Uncommitted

Serializable

6 / 10

6. Which parameters sets the database default isolation level?

default_transaction_isolation

transaction_isolation_level

active_transaction_isolation

default_isolation_level

7 / 10

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

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

8 / 10

8. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Serializable

Random Scatter

Rollback Read

9 / 10

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

True

False

10 / 10

10. The SQL standard specifies three isolation levels?

False

True

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

False

True

2 / 10

2. index row headers like table row headers contain xmin and xmax fields?

True

False

3 / 10

3. CLOG Pages are never cached in memory?

True

False

4 / 10

4. indexes do not use row versioning?

True

False

5 / 10

5. Page free space can often become fragmented?

True

False

6 / 10

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

True

False

7 / 10

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

xid

xtime

xmin

xmax

8 / 10

8. When a transaction is committed Postgres uses a special <replace with answer> structure?

transaction log

archive log

commit log

redo log

9 / 10

9. Each page has a layer that usually consists of?

choose 2

free space

page header

flashback block

undo segment

10 / 10

10. status of a subtransaction is written into CLOG?

False

True

Your score is

Cookie	Duration	Description
cookielawinfo-checkbox-analytics	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
cookielawinfo-checkbox-functional	11 months	The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
cookielawinfo-checkbox-necessary	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
cookielawinfo-checkbox-others	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
cookielawinfo-checkbox-performance	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
viewed_cookie_policy	11 months	The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.