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. pg_catalog schema is used to store system catalog tables?

True

False

2 / 20

2. Which fork is specific for unlogged tables?

Main fork

free space map

Initialization fork

visiblilty map

3 / 20

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

GROW

BREAD

TOAST

BAKE

4 / 20

4. System Catalog tables begin with which prefix?

sys_

pg_

cat_

dba_

5 / 20

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

True

False

6 / 20

6. A Postgres cluster consists of 2 or more physical servers accessing one Postgres Instance?

False

True

7 / 20

7. Who is the Author of the Postgres 14 Internals book?

Dan Brown

Sam Altman

Egor Rogov

Paul Sammy

8 / 20

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

9 / 20

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

True

False

10 / 20

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

choose 3

tables

sequences

indexes

triggers

11 / 20

11. Files are logically split into pages?

True

False

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

This is the same as a user in Postgres

Namespace that store all objects of a database

13 / 20

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

False

True

14 / 20

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

True

False

15 / 20

15. The default Page size is 2k?

True

False

16 / 20

16. Which of below are predefined schemas?

choose 2

pg_catalog

system

public

postgres

17 / 20

17. What is the purpose of the template0 database?

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

Useful for Postgres support Services to debug issues

No such database

Useful for creating development schemas

18 / 20

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

Main fork

free space map

table map

visiblilty map

19 / 20

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

choose 2

pg_global

pg_default

pg_tablespace

pg_temp

20 / 20

20. What is the purpose of the public schema?

schema used for heterogeneous replication

no such schema

default schema for user objects

restricted schema for postgres internal usage only

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

Serializable

Repeatable Read

Read Uncommitted

Read Committed

2 / 10

2. The SQL standard specifies three isolation levels?

True

False

3 / 10

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

True

False

4 / 10

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

Select more than 1 answer below:

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

Replace procedural code with declarative one.

Use a single SQL operator

5 / 10

5. Which parameters sets the database default isolation level?

default_isolation_level

default_transaction_isolation

active_transaction_isolation

transaction_isolation_level

6 / 10

6. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Random Scatter

Read Committed

Serializable

7 / 10

7. 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 adds some other rows satisfying this condition and commits.

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 also queries this same data.

8 / 10

8. 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 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 issue a rollback.

9 / 10

9. What is the default Isolation Level?

Read Uncommitted

Read Committed

Repeatable Read

Serializable

10 / 10

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

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

False

True

2 / 10

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

True

False

3 / 10

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

False

True

4 / 10

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

False

True

5 / 10

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

CREATE

DELETE

COMMIT

INSERT

6 / 10

6. Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/pg_subtrans

PGDATA/pg_xid

PGDATA/subtrans

7 / 10

7. UPDATE can be regarded as which 2 separate operations?

COMMIT

DELETE

MERGE

INSERT

8 / 10

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

pg_current_xact_id()

pg_current_commit_id()

pg_current_id()

pg_current_xmin_id()

9 / 10

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

False

True

10 / 10

10. status of a subtransaction is written into CLOG?

False

True

Your score is

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