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

False

True

2 / 20

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

3 / 20

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

choose 3

sequences

indexes

tables

triggers

4 / 20

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

True

False

5 / 20

5. Postgres uses a thread based process model?

True

False

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 directory that contains the files related to the Postgres cluster?

PGDATA

PGBASE

PGTIPS

PGCORE

8 / 20

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

False

True

9 / 20

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

Main fork

table map

free space map

visiblilty map

10 / 20

10. What is the purpose of wal writer?

flushes dirty pages to disk.

collects usage statistics for the instance.

executes checkpoints

writes WAL entries to disk

11 / 20

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

write-ahead log (WAL)

rollback segments (RBS)

online redo logs (ORL)

undo segments (UNDO)

12 / 20

12. What is a schema?

A memory area used to cache data from LRU chains

The name used to refer to a super user account

Namespace that store all objects of a database

This is the same as a user in Postgres

13 / 20

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

True

False

14 / 20

14. If we create a new tablespace which directory will symbolic links be created from?

pg_tblspc

pg_symlinks

pg_tablespace

pg_tabspace

15 / 20

15. Users should not modify the template0 database

False

True

16 / 20

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

False

True

17 / 20

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

choose 2

pg_tablespace

pg_global

pg_temp

pg_default

18 / 20

18. Postgres server spawns a new backend session for each connection?

False

True

19 / 20

19. Tablespaces are used to define physical data layout?

False

True

20 / 20

20. Which of below are predefined schemas?

choose 2

postgres

system

public

pg_catalog

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

choose 3

Read Uncommitted

Read Committed

Repeatable Read

Serializable

2 / 10

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

Read Uncommitted

Serializable

Read Committed

Repeatable Read

3 / 10

3. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Random Scatter

Serializable

Read Committed

4 / 10

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

True

False

5 / 10

5. Which parameters sets the database default isolation level?

transaction_isolation_level

active_transaction_isolation

default_transaction_isolation

default_isolation_level

6 / 10

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

False

True

7 / 10

7. 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

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 data direct from memory using pg_dirt

8 / 10

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

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.

9 / 10

9. 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.

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.

10 / 10

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

False

True

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 function can we use to find the current transaction ID?

pg_current_id()

pg_current_xmin_id()

pg_current_commit_id()

pg_current_xact_id()

2 / 10

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

redo log

transaction log

commit log

archive log

3 / 10

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

False

True

4 / 10

4. A page along with its tuples is read into the buffer cache with compression transformations to enhance cache efficiency?

True

False

5 / 10

5. Page free space can often become fragmented?

True

False

6 / 10

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

True

False

7 / 10

7. CLOG contains how many bits for each transaction?

8 / 10

8. indexes do not use row versioning?

False

True

9 / 10

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

True

False

10 / 10

10. status of a subtransaction is written into CLOG?

True

False

Your score is

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