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 column in system catalogs servers as the Primary Key

oid#

obj#

oid

obj

2 / 20

2. Files are logically split into pages?

False

True

3 / 20

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

Egor Rogov

Paul Sammy

Sam Altman

Dan Brown

4 / 20

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

Access Path

Search Path

Schema Path

Directory Path

5 / 20

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

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 user tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

7 / 20

7. Which of below are predefined schemas?

choose 2

system

pg_catalog

public

postgres

8 / 20

8. What is the purpose of autovacuum?

Performs a backup of WAL logs

Deletes old logs and traces on disk

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

9 / 20

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

CreateCluster

StartNewPG

Initialize

CreatePGC

10 / 20

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

11 / 20

11. Each Database has its own System Catalog?

False

True

12 / 20

12. A single Postgres Instance can server only one database?

False

True

13 / 20

13. If we create a new tablespace which directory will symbolic links be created from?

pg_tblspc

pg_tabspace

pg_tablespace

pg_symlinks

14 / 20

14. Tablespaces can be used to segregate data based on performance needs?

True

False

15 / 20

15. What is the purpose of the template0 database?

Useful for Postgres support Services to debug issues

No such database

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

Useful for creating development schemas

16 / 20

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

False

True

17 / 20

17. To be able to restore data consistency, Postgres maintains

online redo logs (ORL)

write-ahead log (WAL)

undo segments (UNDO)

rollback segments (RBS)

18 / 20

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

pg_catalog

pg_class

pg_tables

pg_system

19 / 20

19. Which fork is specific for unlogged tables?

visiblilty map

Main fork

Initialization fork

free space map

20 / 20

20. The information_schema schema provides information on Postgres release notes?

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. Which of the below would best describe a dirty read?

a session being able to see uncommited data altered by another session

reading data direct from memory using pg_dirt

reading the data directly from file using a text editor such as vi or notepad

a session being able to see commited data altered by another session

2 / 10

2. Which parameters sets the database default isolation level?

default_isolation_level

transaction_isolation_level

active_transaction_isolation

default_transaction_isolation

3 / 10

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

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

4 / 10

4. 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.

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 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

5 / 10

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

ACID

SAFE

HIPPA

SOC2

6 / 10

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

Read Uncommitted

Read Committed

Repeatable Read

Serializable

7 / 10

7. What is the default Isolation Level?

Repeatable Read

Read Uncommitted

Serializable

Read Committed

8 / 10

8. 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.

9 / 10

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

True

False

10 / 10

10. 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 twice, another transaction modifies this row between these reads issue a rollback.

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 once and modifies this row and commits the change.

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. Which of the below are true about a Pages Item Pointer?

Each pointer uses 4 bytes

Each pointer uses 8 bytes

stored in PGDATA/itemptr directory

Also know as the pages table of contents

2 / 10

2. What does an Item Pointer contain?

choose 3

tuple status

tuple length

tuple xid

tuple offset from the start of the page

3 / 10

3. Page free space can often become fragmented?

True

False

4 / 10

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

xid

xmax

xtime

xmin

5 / 10

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

False

True

6 / 10

6. CLOG files are stored in which directory?

PGDATA/clog

PGDATA/pg_clog

PGDATA/pg_xact

PGDATA/pg_commit

7 / 10

7. Which 2 items does a Virtual XID consist of?

sequential number

checksum

xmin

backend process ID

8 / 10

8. Tuples can also be referred to as columns?

True

False

9 / 10

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

True

False

10 / 10

10. CLOG Pages are never cached in memory?

False

True

Your score is

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