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

system

pg_catalog

public

postgres

2 / 20

2. TOAST tables reside in a seperate schema?

False

True

3 / 20

3. Which fork contains the actual table data?

Main fork

free space map

visiblilty map

table map

4 / 20

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

5 / 20

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

PGDATA

PGTIPS

PGBASE

PGCORE

6 / 20

6. Which fork is specific for unlogged tables?

free space map

visiblilty map

Initialization fork

Main fork

7 / 20

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

pg_catalog

pg_tables

pg_class

pg_system

8 / 20

8. How many files or forks on disk will a 10Mb table with no index have?

9 / 20

9. What is the purpose of the template1 database?

database used for temporary tables

No such database

regular database that you can use at your discretion

a template for all the other databases

10 / 20

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

Sys Catalog

Sysasm Catalog

Sysaux Catalog

System Catalog

11 / 20

11. The default Page size is 2k?

False

True

12 / 20

12. Which of below are predefined schemas?

choose 3

pg_schema

pg_toast

information_schema

pg_temp

13 / 20

13. Each Database has its own System Catalog?

True

False

14 / 20

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

False

True

15 / 20

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

False

True

16 / 20

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

False

True

17 / 20

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

rollback segments (RBS)

write-ahead log (WAL)

online redo logs (ORL)

undo segments (UNDO)

18 / 20

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

choose 3

triggers

indexes

sequences

tables

19 / 20

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

True

False

20 / 20

20. What is the purpose of the template0 database?

Useful for Postgres support Services to debug issues

Useful for creating development schemas

No such database

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

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. Which parameters sets the database default isolation level?

transaction_isolation_level

default_isolation_level

default_transaction_isolation

active_transaction_isolation

3 / 10

3. 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, 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.

4 / 10

4. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Serializable

Random Scatter

Read Committed

5 / 10

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

choose 3

Repeatable Read

Read Uncommitted

Read Committed

Serializable

6 / 10

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

False

True

7 / 10

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

Read Uncommitted

Serializable

Repeatable Read

Read Committed

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 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 adds some other rows satisfying this condition and commits.

9 / 10

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

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

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

reading data direct from memory using pg_dirt

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

10 / 10

10. The SQL standard specifies three isolation levels?

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

True

False

2 / 10

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

True

False

3 / 10

3. The page header is located in the highest address?

True

False

4 / 10

4. If a transaction aborts, all page changes are reverted(rolled back) in place?

True

False

5 / 10

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

INSERT

DELETE

CREATE

COMMIT

6 / 10

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

checksum

xmin

backend process ID

sequential number

7 / 10

7. virtual IDs exist only in PGDATA/pg_vxid when not cached?

False

True

8 / 10

8. CLOG files are stored in which directory?

PGDATA/pg_commit

PGDATA/pg_clog

PGDATA/clog

PGDATA/pg_xact

9 / 10

9. CLOG Pages are never cached in memory?

True

False

10 / 10

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

True

False

Your score is

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