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. It is the postmasters job to listener for incoming connections?

False

True

2 / 20

2. Which 3 databases exist directly after cluster initialization?

choose 3 options

sysaux

template1

postgres

template0

3 / 20

3. What is the purpose of wal writer?

executes checkpoints

flushes dirty pages to disk.

collects usage statistics for the instance.

writes WAL entries to disk

4 / 20

4. Which fork is specific for unlogged tables?

Initialization fork

free space map

Main fork

visiblilty map

5 / 20

5. System Catalog tables begin with which prefix?

pg_

cat_

dba_

sys_

6 / 20

6. What command is used to create the Postgres cluster?

StartNewPG

Initialize

CreatePGC

CreateCluster

7 / 20

7. What is the purpose of the visibility map?

provides the data decryption key

provides an audit trail for the database

shows referential relationships for tables

shows a page to be vacuumed or frozen

8 / 20

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

True

False

9 / 20

9. What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Deletes old logs and traces on disk

Performs a backup of WAL logs

Removes stale data from tables and indexes

10 / 20

10. What is the purpose of the postgres database?

No such database

regular database that you can use at your discretion

a template for all the other database

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

11 / 20

11. The default Page size is 2k?

False

True

12 / 20

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

Main fork

table map

visiblilty map

free space map

13 / 20

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

PGDATA

PGBASE

PGTIPS

PGCORE

14 / 20

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

rollback segments (RBS)

undo segments (UNDO)

online redo logs (ORL)

write-ahead log (WAL)

15 / 20

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

Choose 2 option

Instance

Aurora

Quorum

Postgres Server

16 / 20

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

vacuum space map

free space map

used space map

wal space map

17 / 20

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

True

False

18 / 20

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

True

False

19 / 20

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

False

True

20 / 20

20. Files are logically split into pages?

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. non-repeatable read anomaly occurs when?

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

2 / 10

2. What is the default Isolation Level?

Serializable

Read Committed

Read Uncommitted

Repeatable Read

3 / 10

3. Which of the below would best describe a dirty read?

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

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

4 / 10

4. A phantom read anomaly occurs when?

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

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.

5 / 10

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

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

6 / 10

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

True

False

7 / 10

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

True

False

8 / 10

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

SAFE

SOC2

HIPPA

ACID

9 / 10

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

choose 3

Read Uncommitted

Serializable

Read Committed

Repeatable Read

10 / 10

10. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Read Committed

Serializable

Random Scatter

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. CLOG contains how many bits for each transaction?

2 / 10

2. Tuples can also be referred to as columns?

False

True

3 / 10

3. CLOG Pages are never cached in memory?

True

False

4 / 10

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

clog

dump

heap

view

5 / 10

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

False

True

6 / 10

6. CLOG files are stored in which directory?

PGDATA/pg_clog

PGDATA/clog

PGDATA/pg_xact

PGDATA/pg_commit

7 / 10

7. Information about subtransactions is stored under?

PGDATA/pg_subtrans

PGDATA/pg_min

PGDATA/subtrans

PGDATA/pg_xid

8 / 10

8. 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

9 / 10

9. What does an Item Pointer contain?

choose 3

tuple length

tuple status

tuple xid

tuple offset from the start of the page

10 / 10

10. indexes do not use row versioning?

True

False

Your score is

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