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. To be able to restore data consistency, Postgres maintains

rollback segments (RBS)

write-ahead log (WAL)

online redo logs (ORL)

undo segments (UNDO)

2 / 20

2. Which fork contains the actual table data?

visiblilty map

table map

Main fork

free space map

3 / 20

3. Which 3 databases exist directly after cluster initialization?

choose 3 options

sysaux

postgres

template0

template1

4 / 20

4. Which fork is specific for unlogged tables?

Initialization fork

free space map

Main fork

visiblilty map

5 / 20

5. Users should not modify the template0 database

True

False

6 / 20

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

pg_tablespace

pg_symlinks

pg_tblspc

pg_tabspace

7 / 20

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

pg_tables

pg_catalog

pg_system

pg_class

8 / 20

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

9 / 20

9. What is the process first launched at server start?

init

postgres

pginit

postman

10 / 20

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

False

True

11 / 20

11. Postgres server spawns a new backend session for each connection?

False

True

12 / 20

12. What is the purpose of the template0 database?

No such database

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

Useful for Postgres support Services to debug issues

Useful for creating development schemas

13 / 20

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

used space map

vacuum space map

wal space map

free space map

14 / 20

14. 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

15 / 20

15. The default Page size is 2k?

True

False

16 / 20

16. What is the purpose of the public schema?

schema used for heterogeneous replication

default schema for user objects

no such schema

restricted schema for postgres internal usage only

17 / 20

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

True

False

18 / 20

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

False

True

19 / 20

19. Which of below are predefined schemas?

choose 2

system

public

postgres

pg_catalog

20 / 20

20. What is the name of the directory that contains the files related to the Postgres cluster?

PGTIPS

PGCORE

PGDATA

PGBASE

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. 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 once and modifies this row 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.

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 also queries this same data.

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

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

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.

3 / 10

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

CREATE EXTENSTION REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

4 / 10

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

choose 3

Repeatable Read

Read Committed

Serializable

Read Uncommitted

5 / 10

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

Serializable

Repeatable Read

Read Uncommitted

Read Committed

6 / 10

6. Which parameters sets the database default isolation level?

transaction_isolation_level

active_transaction_isolation

default_transaction_isolation

default_isolation_level

7 / 10

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

True

False

8 / 10

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

Select more than 1 answer below:

Use a single SQL operator

Issues a rollback after the commit to satisfy repeatable read.

Apply explicit locks

Replace procedural code with declarative one.

9 / 10

9. Which of the below are valid Isolations Levels?

choose 2

Serializable

Read Committed

Rollback Read

Random Scatter

10 / 10

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

True

False

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

True

False

2 / 10

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

True

False

3 / 10

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

Also know as the pages table of contents

stored in PGDATA/itemptr directory

Each pointer uses 4 bytes

Each pointer uses 8 bytes

4 / 10

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

xmin

xmax

xmas

xid

5 / 10

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

choose 2

page header

flashback block

free space

undo segment

6 / 10

6. CLOG contains how many bits for each transaction?

7 / 10

7. CLOG Pages are never cached in memory?

False

True

8 / 10

8. Tuples can also be referred to as columns?

True

False

9 / 10

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

False

True

10 / 10

10. Page free space can often become fragmented?

True

False

Your score is

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