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 is a schema?

Namespace that store all objects of a database

This is the same as a user in Postgres

A memory area used to cache data from LRU chains

The name used to refer to a super user account

2 / 20

2. What is the name of the 2 default tablespaces created after initialization?

choose 2

pg_default

pg_global

pg_tablespace

pg_temp

3 / 20

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

4 / 20

4. Which fork contains the actual table data?

visiblilty map

Main fork

table map

free space map

5 / 20

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

Egor Rogov

Dan Brown

Paul Sammy

Sam Altman

6 / 20

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

False

True

7 / 20

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

choose 3

triggers

sequences

tables

indexes

8 / 20

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

False

True

9 / 20

9. Which fork is specific for unlogged tables?

Main fork

visiblilty map

Initialization fork

free space map

10 / 20

10. TOAST tables reside in a seperate schema?

False

True

11 / 20

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

False

True

12 / 20

12. What is the purpose of the visibility map?

shows a page to be vacuumed or frozen

shows referential relationships for tables

provides an audit trail for the database

provides the data decryption key

13 / 20

13. 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 temporary tables that are common to the whole cluster

stores WAL logs used for global replication

14 / 20

14. Which of below are predefined schemas?

choose 3

information_schema

pg_toast

pg_schema

pg_temp

15 / 20

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

Main fork

free space map

table map

visiblilty map

16 / 20

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

True

False

17 / 20

17. Files are logically split into pages?

True

False

18 / 20

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

19 / 20

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

Choose 2 option

Postgres Server

Instance

Aurora

Quorum

20 / 20

20. 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 creating development schemas

Useful for Postgres support Services to debug issues

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?

A transactions inserts a null value into a not null columns 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.

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.

2 / 10

2. The SQL standard specifies three isolation levels?

False

True

3 / 10

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

True

False

4 / 10

4. What is the default Isolation Level?

Read Committed

Read Uncommitted

Serializable

Repeatable Read

5 / 10

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

choose 3

Read Committed

Read Uncommitted

Repeatable Read

Serializable

6 / 10

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

False

True

7 / 10

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

False

True

8 / 10

8. 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.

Use a single SQL operator

Issues a rollback after the commit to satisfy repeatable read.

Apply explicit locks

9 / 10

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

True

False

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

reading data direct from memory using pg_dirt

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 of the below are true about a Pages Item Pointer?

stored in PGDATA/itemptr directory

Also know as the pages table of contents

Each pointer uses 4 bytes

Each pointer uses 8 bytes

2 / 10

2. Rows of TOAST tables are handled in such a way that they are never update?

True

False

3 / 10

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

True

False

4 / 10

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

pg_current_id()

pg_current_xact_id()

pg_current_commit_id()

pg_current_xmin_id()

5 / 10

5. A page along with its tuples is read into the buffer cache with compression transformations to enhance cache efficiency?

False

True

6 / 10

6. The page header is located in the highest address?

True

False

7 / 10

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

xid

xmas

xmin

xmax

8 / 10

8. Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/pg_xid

PGDATA/pg_subtrans

PGDATA/subtrans

9 / 10

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

magic XID

heap XID

temporary XID

virtual XID

10 / 10

10. CLOG Pages are never cached in memory?

True

False

Your score is

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