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?

Directory Path

Schema Path

Search Path

Access Path

2 / 20

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

oid#

obj

obj#

oid

3 / 20

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

vacuum space map

free space map

used space map

wal space map

4 / 20

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

table map

visiblilty map

free space map

Main fork

5 / 20

5. What is the purpose of the visibility map?

shows referential relationships for tables

shows a page to be vacuumed or frozen

provides the data decryption key

provides an audit trail for the database

6 / 20

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

True

False

7 / 20

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

choose 3

indexes

tables

triggers

sequences

8 / 20

8. Which fork is specific for unlogged tables?

Main fork

Initialization fork

visiblilty map

free space map

9 / 20

9. Each Database has its own System Catalog?

False

True

10 / 20

10. Tablespaces are used to define physical data layout?

True

False

11 / 20

11. pg_catalog schema is used to store system catalog tables?

True

False

12 / 20

12. 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

13 / 20

13. Which of below are predefined schemas?

choose 2

public

system

pg_catalog

postgres

14 / 20

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

15 / 20

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

True

False

16 / 20

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

Initialize

CreatePGC

StartNewPG

CreateCluster

17 / 20

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

pg_class

pg_system

pg_catalog

pg_tables

18 / 20

18. Users should not modify the template0 database

False

True

19 / 20

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

5GB

1GB

1MB

5MB

20 / 20

20. What is the purpose of wal writer?

executes checkpoints

writes WAL entries to disk

flushes dirty pages to disk.

collects usage statistics for the instance.

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 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.

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

2 / 10

2. non-repeatable read anomaly occurs when?

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 twice, 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 once, another transaction modifies this row between these reads and commits the change.

3 / 10

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

False

True

4 / 10

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

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

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

reading data direct from memory using pg_dirt

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

5 / 10

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

SOC2

SAFE

HIPPA

ACID

6 / 10

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

False

True

7 / 10

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

False

True

8 / 10

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

False

True

9 / 10

9. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Serializable

Random Scatter

Rollback Read

10 / 10

10. What is the default Isolation Level?

Serializable

Read Uncommitted

Repeatable Read

Read Committed

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. Page free space can often become fragmented?

False

True

2 / 10

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

DELETE

CREATE

INSERT

COMMIT

3 / 10

3. Postgres table physical data files are always cross compatible across platforms?

False

True

4 / 10

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

False

True

5 / 10

5. CLOG files are stored in which directory?

PGDATA/clog

PGDATA/pg_commit

PGDATA/pg_xact

PGDATA/pg_clog

6 / 10

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

True

False

7 / 10

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

True

False

8 / 10

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

False

True

9 / 10

9. indexes do not use row versioning?

False

True

10 / 10

10. The page header stores checksum and the sizes of the other parts of the page?

False

True

Your score is

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