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 of below are predefined schemas?

choose 3

pg_schema

pg_temp

information_schema

pg_toast

2 / 20

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

Access Path

Search Path

Schema Path

Directory Path

3 / 20

3. TOAST tables reside in a seperate schema?

True

False

4 / 20

4. What is the purpose of the template0 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

No such database

5 / 20

5. System Catalog tables begin with which prefix?

pg_

sys_

cat_

dba_

6 / 20

6. What is a schema?

This is the same as a user in Postgres

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

The name used to refer to a super user account

7 / 20

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

False

True

8 / 20

8. Which fork is specific for unlogged tables?

free space map

Initialization fork

Main fork

visiblilty map

9 / 20

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

10 / 20

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

False

True

11 / 20

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

pg_tables

pg_system

pg_catalog

pg_class

12 / 20

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

Choose 2 option

Postgres Server

Quorum

Instance

Aurora

13 / 20

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

True

False

14 / 20

14. What is the point of the pg_global tablespace?

stores WAL logs used for global replication

stores user tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores temporary tables that are common to the whole cluster

15 / 20

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

1GB

1MB

5GB

5MB

16 / 20

16. What is the purpose of the public schema?

schema used for heterogeneous replication

no such schema

restricted schema for postgres internal usage only

default schema for user objects

17 / 20

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

rollback segments (RBS)

undo segments (UNDO)

write-ahead log (WAL)

online redo logs (ORL)

18 / 20

18. Which of below are predefined schemas?

choose 2

postgres

public

system

pg_catalog

19 / 20

19. A single Postgres Instance can server only one database?

False

True

20 / 20

20. What is the purpose of the template1 database?

database used for temporary tables

regular database that you can use at your discretion

No such database

a template for all the other databases

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

True

False

2 / 10

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

Read Uncommitted

Repeatable Read

Serializable

Read Committed

3 / 10

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

HIPPA

SAFE

ACID

SOC2

4 / 10

4. Which parameters sets the database default isolation level?

default_isolation_level

transaction_isolation_level

default_transaction_isolation

active_transaction_isolation

5 / 10

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

False

True

6 / 10

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

True

False

7 / 10

7. 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

8 / 10

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

choose 3

Read Uncommitted

Serializable

Read Committed

Repeatable Read

9 / 10

9. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Serializable

Rollback Read

Random Scatter

10 / 10

10. non-repeatable read anomaly occurs when?

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

A transaction reads one and the same row once, another transaction modifies this row between these reads and commits the change.

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 header is located in the highest address?

False

True

2 / 10

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

DELETE

CREATE

COMMIT

INSERT

3 / 10

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

True

False

4 / 10

4. What does an Item Pointer contain?

choose 3

tuple offset from the start of the page

tuple status

tuple length

tuple xid

5 / 10

5. Information about subtransactions is stored under?

PGDATA/pg_subtrans

PGDATA/subtrans

PGDATA/pg_min

PGDATA/pg_xid

6 / 10

6. If a transaction is read only which kind of Transaction ID is it allocated?

magic XID

temporary XID

heap XID

virtual XID

7 / 10

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

xmin

xmax

xtime

xid

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. Which function can we use to find the current transaction ID?

pg_current_xmin_id()

pg_current_xact_id()

pg_current_commit_id()

pg_current_id()

10 / 10

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

True

False

Your score is

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