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 the postgres database?

a template for all the other database

regular database that you can use at your discretion

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

No such database

2 / 20

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

True

False

3 / 20

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

online redo logs (ORL)

rollback segments (RBS)

write-ahead log (WAL)

undo segments (UNDO)

4 / 20

4. What is the purpose of the template1 database?

No such database

database used for temporary tables

regular database that you can use at your discretion

a template for all the other databases

5 / 20

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

False

True

6 / 20

6. What is the purpose of the visibility map?

shows referential relationships for tables

shows a page to be vacuumed or frozen

provides the data decryption key

provides an audit trail for the database

7 / 20

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

choose 2

pg_temp

pg_default

pg_global

pg_tablespace

8 / 20

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

True

False

9 / 20

9. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Performs a backup of WAL logs

Removes stale data from tables and indexes

Rebuilds indexes with b level greater than 2

10 / 20

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

False

True

11 / 20

11. The default Page size is 2k?

False

True

12 / 20

12. Each Database has its own System Catalog?

True

False

13 / 20

13. How does Postgres know which schema to use if not specified?

Search Path

Directory Path

Access Path

Schema Path

14 / 20

14. What is the point of the pg_global tablespace?

stores user tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores temporary tables that are common to the whole cluster

stores WAL logs used for global replication

15 / 20

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

False

True

16 / 20

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

Choose 2 option

Quorum

Instance

Aurora

Postgres Server

17 / 20

17. What is the name of the mechanism used to store a row bigger than a page size?

BREAD

GROW

BAKE

TOAST

18 / 20

18. What is the purpose of the template0 database?

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

No such database

Useful for Postgres support Services to debug issues

Useful for creating development schemas

19 / 20

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

20 / 20

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

CreatePGC

Initialize

StartNewPG

CreateCluster

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 are valid Isolations Levels?

choose 2

Read Committed

Serializable

Random Scatter

Rollback Read

2 / 10

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

False

True

3 / 10

3. The SQL standard specifies three isolation levels?

True

False

4 / 10

4. 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.

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.

5 / 10

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

False

True

6 / 10

6. Which parameters sets the database default isolation level?

default_transaction_isolation

transaction_isolation_level

active_transaction_isolation

default_isolation_level

7 / 10

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

Select more than 1 answer below:

Replace procedural code with declarative one.

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

Use a single SQL operator

8 / 10

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

True

False

9 / 10

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

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

reading data direct from memory using pg_dirt

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

10 / 10

10. 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.

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. Which 2 items does a Virtual XID consist of?

backend process ID

sequential number

checksum

xmin

2 / 10

2. What does an Item Pointer contain?

choose 3

tuple xid

tuple length

tuple offset from the start of the page

tuple status

3 / 10

3. Page free space can often become fragmented?

False

True

4 / 10

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

True

False

5 / 10

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

xtime

xmin

xmax

xid

6 / 10

6. Tuples can also be referred to as columns?

False

True

7 / 10

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

pg_current_commit_id()

pg_current_id()

pg_current_xmin_id()

pg_current_xact_id()

8 / 10

8. CLOG contains how many bits for each transaction?

9 / 10

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

True

False

10 / 10

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

True

False

Your score is

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