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 name of the directory that contains the files related to the Postgres cluster?

PGBASE

PGCORE

PGTIPS

PGDATA

2 / 20

2. Which fork is specific for unlogged tables?

Initialization fork

free space map

Main fork

visiblilty map

3 / 20

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

True

False

4 / 20

4. What is the purpose of the visibility map?

shows a page to be vacuumed or frozen

provides an audit trail for the database

shows referential relationships for tables

provides the data decryption key

5 / 20

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

postman

pginit

postgres

init

6 / 20

6. Each tablespaces can only be assigned for use by one database

True

False

7 / 20

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

choose 2

pg_temp

pg_tablespace

pg_global

pg_default

8 / 20

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

online redo logs (ORL)

write-ahead log (WAL)

rollback segments (RBS)

undo segments (UNDO)

9 / 20

9. Each Database has its own System Catalog?

True

False

10 / 20

10. Users should not modify the template0 database

False

True

11 / 20

11. Which of below are predefined schemas?

choose 2

public

system

pg_catalog

postgres

12 / 20

12. Tablespaces are used to define physical data layout?

True

False

13 / 20

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

True

False

14 / 20

14. What is the purpose of the template1 database?

regular database that you can use at your discretion

database used for temporary tables

No such database

a template for all the other databases

15 / 20

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

False

True

16 / 20

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

System Catalog

Sys Catalog

Sysaux Catalog

Sysasm Catalog

17 / 20

17. What is a schema?

This is the same as a user in Postgres

Namespace that store all objects of a database

The name used to refer to a super user account

A memory area used to cache data from LRU chains

18 / 20

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

True

False

19 / 20

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

Main fork

visiblilty map

table map

free space map

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

True

False

2 / 10

2. 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.

Apply explicit locks

Use a single SQL operator

3 / 10

3. Which parameters sets the database default isolation level?

transaction_isolation_level

default_isolation_level

active_transaction_isolation

default_transaction_isolation

4 / 10

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

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

reading data direct from memory using pg_dirt

5 / 10

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

Read Committed

Repeatable Read

Serializable

Read Uncommitted

6 / 10

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

False

True

7 / 10

7. non-repeatable read anomaly occurs when?

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.

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

8 / 10

8. Lost updates are forbidden by the standard at all isolation levels?

True

False

9 / 10

9. What is the default Isolation Level?

Read Committed

Read Uncommitted

Repeatable Read

Serializable

10 / 10

10. 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

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. Indexes values also support multi versioning with several versions of an index value existing at any point in time?

True

False

2 / 10

2. The page header stores checksum and the sizes of the other parts of the page?

False

True

3 / 10

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

redo log

archive log

transaction log

commit log

4 / 10

4. CLOG files are stored in which directory?

PGDATA/pg_xact

PGDATA/pg_commit

PGDATA/pg_clog

PGDATA/clog

5 / 10

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

Each pointer uses 8 bytes

stored in PGDATA/itemptr directory

Also know as the pages table of contents

Each pointer uses 4 bytes

6 / 10

6. Tuples can also be referred to as columns?

False

True

7 / 10

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

sequential number

xmin

checksum

backend process ID

8 / 10

8. Which function can we use to find the current transaction ID?

pg_current_id()

pg_current_commit_id()

pg_current_xact_id()

pg_current_xmin_id()

9 / 10

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

True

False

10 / 10

10. Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/pg_xid

PGDATA/pg_subtrans

PGDATA/subtrans

Your score is

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