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 the purpose of wal writer?

executes checkpoints

writes WAL entries to disk

flushes dirty pages to disk.

collects usage statistics for the instance.

2 / 20

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

3 / 20

3. What is the purpose of the visibility map?

provides the data decryption key

shows a page to be vacuumed or frozen

provides an audit trail for the database

shows referential relationships for tables

4 / 20

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

visiblilty map

table map

free space map

Main fork

5 / 20

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

used space map

wal space map

free space map

vacuum space map

6 / 20

6. What is the purpose of the public schema?

default schema for user objects

restricted schema for postgres internal usage only

no such schema

schema used for heterogeneous replication

7 / 20

7. What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

Deletes old logs and traces on disk

Performs a backup of WAL logs

8 / 20

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

pginit

postman

init

postgres

9 / 20

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

False

True

10 / 20

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

False

True

11 / 20

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

Initialize

CreateCluster

CreatePGC

StartNewPG

12 / 20

12. What is the name of the catalog that stores metadata for all cluster objects?

Sys Catalog

Sysaux Catalog

Sysasm Catalog

System Catalog

13 / 20

13. Each Database has its own System Catalog?

False

True

14 / 20

14. Postgres by default has built in connection pooling abilities?

False

True

15 / 20

15. What is another name for the postgres process?

masterprocess

postmaster

postmanager

aurora

16 / 20

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

True

False

17 / 20

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

True

False

18 / 20

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

choose 3

tables

triggers

indexes

sequences

19 / 20

19. Tablespaces can be used to segregate data based on performance needs?

True

False

20 / 20

20. Which of below are predefined schemas?

choose 3

pg_schema

information_schema

pg_toast

pg_temp

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 statements will start a transaction as Read Repeatable?

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

2 / 10

2. A phantom read anomaly occurs when?

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.

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

3 / 10

3. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Serializable

Random Scatter

Read Committed

4 / 10

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

Select more than 1 answer below:

Issues a rollback after the commit to satisfy repeatable read.

Replace procedural code with declarative one.

Use a single SQL operator

Apply explicit locks

5 / 10

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

False

True

6 / 10

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

True

False

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 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.

8 / 10

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

choose 3

Repeatable Read

Serializable

Read Committed

Read Uncommitted

9 / 10

9. 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

10 / 10

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

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

commit log

redo log

archive log

transaction log

2 / 10

2. Page header sizes can be easily displayed using the <choose from answers> extension

pagesize

pagedetect

pageheadinfo

pageinspect

3 / 10

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

xmin

xid

xmas

xmax

4 / 10

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

CREATE

DELETE

INSERT

COMMIT

5 / 10

5. indexes do not use row versioning?

True

False

6 / 10

6. CLOG Pages are never cached in memory?

True

False

7 / 10

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

view

dump

clog

heap

8 / 10

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

stored in PGDATA/itemptr directory

Each pointer uses 4 bytes

Each pointer uses 8 bytes

Also know as the pages table of contents

9 / 10

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

choose 2

page header

free space

undo segment

flashback block

10 / 10

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

True

False

Your score is

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