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 is specific for unlogged tables?

visiblilty map

Main fork

Initialization fork

free space map

2 / 20

2. Tablespaces are used to define physical data layout?

False

True

3 / 20

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

choose 3

tables

indexes

triggers

sequences

4 / 20

4. What is a schema?

This is the same as a user in Postgres

Namespace that store all objects of a database

The name used to refer to a super user account

A memory area used to cache data from LRU chains

5 / 20

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

False

True

6 / 20

6. What is the point of the pg_global tablespace?

stores system catalog objects that are common to the whole cluster

stores user tables that are common to the whole cluster

stores WAL logs used for global replication

stores temporary tables that are common to the whole cluster

7 / 20

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

online redo logs (ORL)

rollback segments (RBS)

undo segments (UNDO)

write-ahead log (WAL)

8 / 20

8. TOAST tables reside in a seperate schema?

False

True

9 / 20

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

StartNewPG

CreateCluster

Initialize

CreatePGC

10 / 20

10. What is the name of the catalog that stores metadata for all cluster objects?

Sysasm Catalog

Sys Catalog

System Catalog

Sysaux Catalog

11 / 20

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

Main fork

free space map

visiblilty map

table map

12 / 20

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

False

True

13 / 20

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

14 / 20

14. Which fork contains the actual table data?

table map

Main fork

free space map

visiblilty map

15 / 20

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

False

True

16 / 20

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

True

False

17 / 20

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

True

False

18 / 20

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

BREAD

BAKE

GROW

TOAST

19 / 20

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

True

False

20 / 20

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

5GB

5MB

1MB

1GB

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 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.

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?

False

True

3 / 10

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

True

False

4 / 10

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

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

SET ISO=REPEATABLE_READ;

5 / 10

5. Which parameters sets the database default isolation level?

active_transaction_isolation

default_transaction_isolation

transaction_isolation_level

default_isolation_level

6 / 10

6. 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.

Issues a rollback after the commit to satisfy repeatable read.

Use a single SQL operator

Apply explicit locks

7 / 10

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

choose 3

Serializable

Read Committed

Read Uncommitted

Repeatable Read

8 / 10

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

Repeatable Read

Read Uncommitted

Serializable

Read Committed

9 / 10

9. Which of the below are valid Isolations Levels?

choose 2

Random Scatter

Serializable

Rollback Read

Read Committed

10 / 10

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

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

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

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. The page Special Space is located at the start of the page with highest address

True

False

2 / 10

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

False

True

3 / 10

3. a transaction containing a savepoint is will still be considered as only a single transaction?

False

True

4 / 10

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

True

False

5 / 10

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

False

True

6 / 10

6. Information about subtransactions is stored under?

PGDATA/subtrans

PGDATA/pg_min

PGDATA/pg_xid

PGDATA/pg_subtrans

7 / 10

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

xid

xmin

xmax

xtime

8 / 10

8. status of a subtransaction is written into CLOG?

False

True

9 / 10

9. CLOG contains how many bits for each transaction?

10 / 10

10. Page free space can often become fragmented?

False

True

Your score is

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