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

Search Path

Directory Path

Schema Path

Access Path

2 / 20

2. How many files or forks on disk will a 10Mb table with no index have?

3 / 20

3. Which 3 databases exist directly after cluster initialization?

choose 3 options

template1

postgres

sysaux

template0

4 / 20

4. To understand each other, a client and a server must use one and the same interfacing protocol?

False

True

5 / 20

5. Users should not modify the template0 database

False

True

6 / 20

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

True

False

7 / 20

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

pg_symlinks

pg_tablespace

pg_tabspace

pg_tblspc

8 / 20

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

False

True

9 / 20

9. Which fork contains the actual table data?

Main fork

free space map

visiblilty map

table map

10 / 20

10. Which fork is specific for unlogged tables?

Initialization fork

free space map

Main fork

visiblilty map

11 / 20

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

rollback segments (RBS)

undo segments (UNDO)

online redo logs (ORL)

write-ahead log (WAL)

12 / 20

12. What column in system catalogs servers as the Primary Key

obj#

obj

oid#

oid

13 / 20

13. What is a schema?

Namespace that store all objects of a database

A memory area used to cache data from LRU chains

The name used to refer to a super user account

This is the same as a user in Postgres

14 / 20

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

True

False

15 / 20

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

GROW

TOAST

BREAD

BAKE

16 / 20

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

Choose 2 option

Aurora

Quorum

Postgres Server

Instance

17 / 20

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

CreatePGC

Initialize

CreateCluster

StartNewPG

18 / 20

18. TOAST tables reside in a seperate schema?

False

True

19 / 20

19. Which fork keeps track of available space within pages?

vacuum space map

wal space map

free space map

used space map

20 / 20

20. What is the purpose of the public schema?

default schema for user objects

schema used for heterogeneous replication

no such schema

restricted schema for postgres internal usage only

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

False

True

2 / 10

2. 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

3 / 10

3. Which parameters sets the database default isolation level?

default_transaction_isolation

active_transaction_isolation

default_isolation_level

transaction_isolation_level

4 / 10

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

True

False

5 / 10

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

Read Uncommitted

Repeatable Read

Read Committed

Serializable

6 / 10

6. The SQL standard specifies three isolation levels?

True

False

7 / 10

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

True

False

8 / 10

8. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Random Scatter

Rollback Read

Serializable

9 / 10

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

False

True

10 / 10

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

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

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?

True

False

2 / 10

2. UPDATE can be regarded as which 2 separate operations?

COMMIT

MERGE

INSERT

DELETE

3 / 10

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

True

False

4 / 10

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

CREATE

INSERT

DELETE

COMMIT

5 / 10

5. What does an Item Pointer contain?

choose 3

tuple status

tuple xid

tuple length

tuple offset from the start of the page

6 / 10

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

True

False

7 / 10

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

True

False

8 / 10

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

Each pointer uses 4 bytes

Also know as the pages table of contents

stored in PGDATA/itemptr directory

Each pointer uses 8 bytes

9 / 10

9. CLOG files are stored in which directory?

PGDATA/clog

PGDATA/pg_xact

PGDATA/pg_clog

PGDATA/pg_commit

10 / 10

10. status of a subtransaction is written into CLOG?

True

False

Your score is

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