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

True

False

2 / 20

2. 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

Useful for creating development schemas

No such database

3 / 20

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

True

False

4 / 20

4. What is a schema?

A memory area used to cache data from LRU chains

This is the same as a user in Postgres

The name used to refer to a super user account

Namespace that store all objects of a database

5 / 20

5. Files are logically split into pages?

True

False

6 / 20

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

False

True

7 / 20

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

Choose 2 option

Aurora

Instance

Postgres Server

Quorum

8 / 20

8. What is the default standard size for a fork file?

1GB

5MB

5GB

1MB

9 / 20

9. What is the purpose of the postgres database?

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

No such database

regular database that you can use at your discretion

a template for all the other database

10 / 20

10. What is the purpose of the public schema?

default schema for user objects

schema used for heterogeneous replication

restricted schema for postgres internal usage only

no such schema

11 / 20

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

12 / 20

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

13 / 20

13. Which of below are predefined schemas?

choose 2

pg_catalog

public

postgres

system

14 / 20

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

True

False

15 / 20

15. What is the point of the pg_global tablespace?

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

stores user tables that are common to the whole cluster

16 / 20

16. What is the purpose of autovacuum?

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

Deletes old logs and traces on disk

Removes stale data from tables and indexes

17 / 20

17. The default Page size is 2k?

False

True

18 / 20

18. Which fork is specific for unlogged tables?

Initialization fork

free space map

Main fork

visiblilty map

19 / 20

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

undo segments (UNDO)

online redo logs (ORL)

write-ahead log (WAL)

rollback segments (RBS)

20 / 20

20. What column in system catalogs servers as the Primary Key

oid#

oid

obj#

obj

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 parameters sets the database default isolation level?

default_transaction_isolation

default_isolation_level

transaction_isolation_level

active_transaction_isolation

2 / 10

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

False

True

3 / 10

3. which of the below statements will start a transaction as Read Repeatable?

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

4 / 10

4. 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 and modifies this row 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.

5 / 10

5. Which of the below are valid Isolations Levels?

choose 2

Random Scatter

Serializable

Read Committed

Rollback Read

6 / 10

6. The SQL standard specifies three isolation levels?

False

True

7 / 10

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

Select more than 1 answer below:

Use a single SQL operator

Apply explicit locks

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

8 / 10

8. What is the default Isolation Level?

Read Committed

Repeatable Read

Read Uncommitted

Serializable

9 / 10

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

False

True

10 / 10

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

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

xmin

xtime

xid

xmax

2 / 10

2. CLOG contains how many bits for each transaction?

3 / 10

3. indexes do not use row versioning?

False

True

4 / 10

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

xmin

backend process ID

sequential number

checksum

5 / 10

5. Postgres table physical data files are always cross compatible across platforms?

False

True

6 / 10

6. Information about subtransactions is stored under?

PGDATA/pg_subtrans

PGDATA/subtrans

PGDATA/pg_xid

PGDATA/pg_min

7 / 10

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

True

False

8 / 10

8. Page free space can often become fragmented?

False

True

9 / 10

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

False

True

10 / 10

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

True

False

Your score is

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