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 2

pg_catalog

postgres

system

public

2 / 20

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

True

False

3 / 20

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

Choose 2 option

Aurora

Instance

Quorum

Postgres Server

4 / 20

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

True

False

5 / 20

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

free space map

Main fork

table map

visiblilty map

6 / 20

6. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

7 / 20

7. Tablespaces are used to define physical data layout?

False

True

8 / 20

8. Which of below are predefined schemas?

choose 3

information_schema

pg_schema

pg_toast

pg_temp

9 / 20

9. What is the name of the directory that contains the files related to the Postgres cluster?

PGCORE

PGDATA

PGBASE

PGTIPS

10 / 20

10. What is the purpose of the template0 database?

No such database

Useful for Postgres support Services to debug issues

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

Useful for creating development schemas

11 / 20

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

False

True

12 / 20

12. What is the purpose of wal writer?

flushes dirty pages to disk.

executes checkpoints

writes WAL entries to disk

collects usage statistics for the instance.

13 / 20

13. Files are logically split into pages?

True

False

14 / 20

14. Which 3 databases exist directly after cluster initialization?

choose 3 options

postgres

template0

template1

sysaux

15 / 20

15. What is the purpose of the template1 database?

regular database that you can use at your discretion

a template for all the other databases

database used for temporary tables

No such database

16 / 20

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

17 / 20

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

True

False

18 / 20

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

choose 3

indexes

sequences

triggers

tables

19 / 20

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

choose 2

pg_global

pg_default

pg_tablespace

pg_temp

20 / 20

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

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

choose 3

Serializable

Repeatable Read

Read Uncommitted

Read Committed

2 / 10

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

True

False

3 / 10

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

SOC2

HIPPA

SAFE

ACID

4 / 10

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

BEGIN ISOLATION LEVEL REPEATABLE READ;

SET ISO=REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

5 / 10

5. 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.

6 / 10

6. 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 commited data altered by another session

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

7 / 10

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

False

True

8 / 10

8. 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 also queries this same data.

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

9 / 10

9. The SQL standard specifies three isolation levels?

False

True

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?

xmax

xmin

xid

xmas

2 / 10

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

False

True

3 / 10

3. CLOG contains how many bits for each transaction?

4 / 10

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

virtual XID

temporary XID

magic XID

heap XID

5 / 10

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

checksum

backend process ID

sequential number

xmin

6 / 10

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

True

False

7 / 10

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

xid

xmax

xtime

xmin

8 / 10

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

True

False

9 / 10

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

DELETE

CREATE

COMMIT

INSERT

10 / 10

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

archive log

commit log

redo log

transaction log

Your score is

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