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

2 / 20

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

Main fork

free space map

table map

visiblilty map

3 / 20

3. Files are logically split into pages?

True

False

4 / 20

4. What is the purpose of the visibility map?

shows referential relationships for tables

provides an audit trail for the database

provides the data decryption key

shows a page to be vacuumed or frozen

5 / 20

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

Search Path

Schema Path

Directory Path

Access Path

6 / 20

6. What is the purpose of the public schema?

restricted schema for postgres internal usage only

default schema for user objects

schema used for heterogeneous replication

no such schema

7 / 20

7. The default Page size is 2k?

False

True

8 / 20

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

False

True

9 / 20

9. Postgres uses a thread based process model?

False

True

10 / 20

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

PGDATA

PGCORE

PGTIPS

PGBASE

11 / 20

11. What is a schema?

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

A memory area used to cache data from LRU chains

12 / 20

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

True

False

13 / 20

13. TOAST tables reside in a seperate schema?

False

True

14 / 20

14. System Catalog tables begin with which prefix?

pg_

sys_

cat_

dba_

15 / 20

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

False

True

16 / 20

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

obj

oid

obj#

oid#

17 / 20

17. What is the purpose of autovacuum?

Performs a backup of WAL logs

Removes stale data from tables and indexes

Deletes old logs and traces on disk

Rebuilds indexes with b level greater than 2

18 / 20

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

True

False

19 / 20

19. What is the point of the pg_global tablespace?

stores user tables that are common to the whole cluster

stores temporary tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores WAL logs used for global replication

20 / 20

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

True

False

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 statements will start a transaction as Read Repeatable?

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

2 / 10

2. The SQL standard specifies three isolation levels?

False

True

3 / 10

3. Which of the below are valid Isolations Levels?

choose 2

Serializable

Rollback Read

Read Committed

Random Scatter

4 / 10

4. What is the acronym used for the attributes that ensure Data consistency, integrity and durability?

SAFE

HIPPA

ACID

SOC2

5 / 10

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

choose 3

Serializable

Read Committed

Read Uncommitted

Repeatable Read

6 / 10

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

True

False

7 / 10

7. 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 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 and commits the change.

8 / 10

8. What is the default Isolation Level?

Serializable

Read Uncommitted

Repeatable Read

Read Committed

9 / 10

9. 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

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

Apply explicit locks

10 / 10

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

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

reading the data directly from file using a text editor such as vi or notepad

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

reading data direct from memory using pg_dirt

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

False

True

2 / 10

2. CLOG files are stored in which directory?

PGDATA/pg_commit

PGDATA/pg_clog

PGDATA/pg_xact

PGDATA/clog

3 / 10

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

False

True

4 / 10

4. indexes do not use row versioning?

False

True

5 / 10

5. In Postgres, tables are often referred to as which of the below?

heap

clog

dump

view

6 / 10

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

MERGE

COMMIT

DELETE

INSERT

7 / 10

7. CLOG Pages are never cached in memory?

False

True

8 / 10

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

False

True

9 / 10

9. a transaction containing a savepoint is will still be considered as only a single transaction?

False

True

10 / 10

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

pg_current_commit_id()

pg_current_xact_id()

pg_current_id()

pg_current_xmin_id()

Your score is

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