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

free space map

visiblilty map

Main fork

table map

2 / 20

2. Files are logically split into pages?

True

False

3 / 20

3. What is the purpose of the template0 database?

No such database

Useful for Postgres support Services to debug issues

Useful for creating development schemas

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

4 / 20

4. What is the purpose of the template1 database?

No such database

a template for all the other databases

regular database that you can use at your discretion

database used for temporary tables

5 / 20

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

False

True

6 / 20

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

online redo logs (ORL)

undo segments (UNDO)

write-ahead log (WAL)

rollback segments (RBS)

7 / 20

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

True

False

8 / 20

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

pg_tabspace

pg_tablespace

pg_symlinks

pg_tblspc

9 / 20

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

postman

init

pginit

postgres

10 / 20

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

1GB

5GB

1MB

5MB

11 / 20

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

pg_catalog

pg_system

pg_tables

pg_class

12 / 20

12. What is the point of the pg_global tablespace?

stores system catalog objects that are common to the whole cluster

stores temporary tables that are common to the whole cluster

stores WAL logs used for global replication

stores user tables that are common to the whole cluster

13 / 20

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

14 / 20

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

Sam Altman

Paul Sammy

Dan Brown

Egor Rogov

15 / 20

15. Which of below are predefined schemas?

choose 2

public

postgres

system

pg_catalog

16 / 20

16. Users should not modify the template0 database

False

True

17 / 20

17. What is the purpose of the public schema?

default schema for user objects

no such schema

schema used for heterogeneous replication

restricted schema for postgres internal usage only

18 / 20

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

True

False

19 / 20

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

True

False

20 / 20

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

vacuum space map

free space map

used space map

wal space map

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

True

False

2 / 10

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

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

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

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

reading data direct from memory using pg_dirt

3 / 10

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

False

True

4 / 10

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

choose 3

Repeatable Read

Read Committed

Read Uncommitted

Serializable

5 / 10

5. At any moment the database system can contain several versions of one and the same row?

True

False

6 / 10

6. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Random Scatter

Rollback Read

Serializable

7 / 10

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

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.

8 / 10

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

True

False

9 / 10

9. What is the default Isolation Level?

Repeatable Read

Read Committed

Serializable

Read Uncommitted

10 / 10

10. A phantom read anomaly occurs when?

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.

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.

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

xmin

xid

xtime

xmax

2 / 10

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

DELETE

INSERT

COMMIT

CREATE

3 / 10

3. virtual IDs exist only in PGDATA/pg_vxid when not cached?

False

True

4 / 10

4. Page free space can often become fragmented?

False

True

5 / 10

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

archive log

commit log

redo log

transaction log

6 / 10

6. Tuples can also be referred to as columns?

False

True

7 / 10

7. indexes do not use row versioning?

False

True

8 / 10

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

Each pointer uses 8 bytes

Also know as the pages table of contents

Each pointer uses 4 bytes

stored in PGDATA/itemptr directory

9 / 10

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

False

True

10 / 10

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

False

True

Your score is

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