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 3 databases exist directly after cluster initialization?

choose 3 options

template0

postgres

template1

sysaux

2 / 20

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

False

True

3 / 20

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

False

True

4 / 20

4. TOAST tables reside in a seperate schema?

False

True

5 / 20

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

free space map

used space map

vacuum space map

wal space map

6 / 20

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

choose 2

pg_global

pg_default

pg_temp

pg_tablespace

7 / 20

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

postman

postgres

pginit

init

8 / 20

8. What is the purpose of the postgres database?

a template for all the other database

No such database

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

regular database that you can use at your discretion

9 / 20

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

obj

oid#

oid

obj#

10 / 20

10. Postgres uses a thread based process model?

False

True

11 / 20

11. Which of below are predefined schemas?

choose 3

pg_schema

pg_temp

information_schema

pg_toast

12 / 20

12. Which of below are predefined schemas?

choose 2

system

public

postgres

pg_catalog

13 / 20

13. What is a schema?

Namespace that store all objects of a database

A memory area used to cache data from LRU chains

This is the same as a user in Postgres

The name used to refer to a super user account

14 / 20

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

True

False

15 / 20

15. What is the purpose of wal writer?

collects usage statistics for the instance.

executes checkpoints

writes WAL entries to disk

flushes dirty pages to disk.

16 / 20

16. What is the purpose of the public schema?

no such schema

restricted schema for postgres internal usage only

schema used for heterogeneous replication

default schema for user objects

17 / 20

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

18 / 20

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

Search Path

Access Path

Schema Path

Directory Path

19 / 20

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

online redo logs (ORL)

write-ahead log (WAL)

rollback segments (RBS)

undo segments (UNDO)

20 / 20

20. The default Page size is 2k?

False

True

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. Which parameters sets the database default isolation level?

transaction_isolation_level

active_transaction_isolation

default_isolation_level

default_transaction_isolation

2 / 10

2. 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;

3 / 10

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

Serializable

Read Uncommitted

Repeatable Read

Read Committed

4 / 10

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

choose 3

Serializable

Read Committed

Read Uncommitted

Repeatable Read

5 / 10

5. 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

reading data direct from memory using pg_dirt

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

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

6 / 10

6. 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.

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 also queries this same data.

7 / 10

7. What are some of database features we can use to avoid a non repeatable read?

Select more than 1 answer below:

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

Use a single SQL operator

Replace procedural code with declarative one.

8 / 10

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

True

False

9 / 10

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

False

True

10 / 10

10. 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 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.

A transaction reads one and the same row twice, another transaction modifies this row between these reads issue a rollback.

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. Tuples can also be referred to as columns?

False

True

2 / 10

2. Page free space can often become fragmented?

False

True

3 / 10

3. If a transaction aborts, all page changes are reverted(rolled back) in place?

True

False

4 / 10

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

COMMIT

INSERT

CREATE

DELETE

5 / 10

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

False

True

6 / 10

6. Which 2 items does a Virtual XID consist of?

sequential number

backend process ID

xmin

checksum

7 / 10

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

xid

xmax

xmin

xmas

8 / 10

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

transaction log

redo log

archive log

commit log

9 / 10

9. Each page has a layer that usually consists of?

choose 2

undo segment

flashback block

page header

free space

10 / 10

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

virtual XID

heap XID

magic XID

temporary XID

Your score is

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