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. Postgres by default has built in connection pooling abilities?

True

False

2 / 20

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

postman

postgres

init

pginit

3 / 20

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

free space map

used space map

vacuum space map

wal space map

4 / 20

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

oid

oid#

obj#

obj

5 / 20

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

choose 2

pg_temp

pg_default

pg_global

pg_tablespace

6 / 20

6. Which fork contains the actual table data?

free space map

visiblilty map

Main fork

table map

7 / 20

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

False

True

8 / 20

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

True

False

9 / 20

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

True

False

10 / 20

10. What is the purpose of the visibility map?

shows a page to be vacuumed or frozen

provides an audit trail for the database

provides the data decryption key

shows referential relationships for tables

11 / 20

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

False

True

12 / 20

12. What is the purpose of autovacuum?

Removes stale data from tables and indexes

Performs a backup of WAL logs

Deletes old logs and traces on disk

Rebuilds indexes with b level greater than 2

13 / 20

13. Postgres uses a thread based process model?

True

False

14 / 20

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

choose 3

sequences

triggers

indexes

tables

15 / 20

15. Which of below are predefined schemas?

choose 3

pg_toast

information_schema

pg_schema

pg_temp

16 / 20

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

pg_tables

pg_catalog

pg_class

pg_system

17 / 20

17. The default Page size is 2k?

True

False

18 / 20

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

True

False

19 / 20

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

True

False

20 / 20

20. Users should not modify the template0 database

True

False

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 of the below are valid Isolations Levels?

choose 2

Read Committed

Serializable

Rollback Read

Random Scatter

2 / 10

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

choose 3

Serializable

Repeatable Read

Read Uncommitted

Read Committed

3 / 10

3. 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 commited data altered by another session

reading data direct from memory using pg_dirt

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

4 / 10

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

True

False

5 / 10

5. which of the below statements will start a transaction as Read Repeatable?

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

CREATE EXTENSTION REPEATABLE_READ;

6 / 10

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

Repeatable Read

Read Committed

Serializable

Read Uncommitted

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 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 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. 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 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.

The same transactions issues a commit, then a rollback to restore data to its original value

10 / 10

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

True

False

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

xmas

xmin

xmax

xid

2 / 10

2. In Postgres, tables are often referred to as which of the below?

heap

clog

dump

view

3 / 10

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

sequential number

checksum

backend process ID

xmin

4 / 10

4. Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/pg_xid

PGDATA/pg_subtrans

PGDATA/subtrans

5 / 10

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

True

False

6 / 10

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

Each pointer uses 8 bytes

Each pointer uses 4 bytes

stored in PGDATA/itemptr directory

Also know as the pages table of contents

7 / 10

7. CLOG contains how many bits for each transaction?

8 / 10

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

False

True

9 / 10

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

xid

xmax

xmin

xtime

10 / 10

10. 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()

Your score is

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