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. Users should not modify the template0 database

True

False

2 / 20

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

False

True

3 / 20

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

PGTIPS

PGCORE

PGDATA

PGBASE

4 / 20

4. What is the process first launched at server start?

init

postman

postgres

pginit

5 / 20

5. The default Page size is 2k?

False

True

6 / 20

6. What is the purpose of autovacuum?

Performs a backup of WAL logs

Deletes old logs and traces on disk

Removes stale data from tables and indexes

Rebuilds indexes with b level greater than 2

7 / 20

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

Initialize

CreateCluster

StartNewPG

CreatePGC

8 / 20

8. Each Database has its own System Catalog?

False

True

9 / 20

9. What is a schema?

The name used to refer to a super user account

Namespace that store all objects of a database

A memory area used to cache data from LRU chains

This is the same as a user in Postgres

10 / 20

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

11 / 20

11. Which of below are predefined schemas?

choose 2

public

system

pg_catalog

postgres

12 / 20

12. What is the purpose of the postgres database?

No such database

regular database that you can use at your discretion

a template for all the other database

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

13 / 20

13. What is the purpose of the public schema?

default schema for user objects

restricted schema for postgres internal usage only

schema used for heterogeneous replication

no such schema

14 / 20

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

visiblilty map

free space map

Main fork

table map

15 / 20

15. Tablespaces are used to define physical data layout?

False

True

16 / 20

16. What is the purpose of wal writer?

writes WAL entries to disk

collects usage statistics for the instance.

flushes dirty pages to disk.

executes checkpoints

17 / 20

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

18 / 20

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

BAKE

GROW

TOAST

BREAD

19 / 20

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

True

False

20 / 20

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

pg_class

pg_system

pg_tables

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

False

True

2 / 10

2. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Rollback Read

Serializable

Random Scatter

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 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.

4 / 10

4. 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

5 / 10

5. Which parameters sets the database default isolation level?

default_transaction_isolation

transaction_isolation_level

default_isolation_level

active_transaction_isolation

6 / 10

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

choose 3

Read Committed

Read Uncommitted

Repeatable Read

Serializable

7 / 10

7. What is the default Isolation Level?

Read Committed

Serializable

Repeatable Read

Read Uncommitted

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.

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 transactions issues a commit, then a rollback to restore data to its original value

9 / 10

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

True

False

10 / 10

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

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. Page free space can often become fragmented?

True

False

2 / 10

2. indexes do not use row versioning?

True

False

3 / 10

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

False

True

4 / 10

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

False

True

5 / 10

5. Each page has a layer that usually consists of?

choose 2

free space

undo segment

page header

flashback block

6 / 10

6. psql provides a special mode that allows you to continue a transaction after a failure?

True

False

7 / 10

7. CLOG contains how many bits for each transaction?

8 / 10

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

False

True

9 / 10

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

DELETE

MERGE

COMMIT

INSERT

10 / 10

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

False

True

Your score is

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