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. Which of below are predefined schemas?

choose 3

pg_toast

pg_temp

information_schema

pg_schema

2 / 20

2. What is the purpose of the visibility map?

provides an audit trail for the database

provides the data decryption key

shows referential relationships for tables

shows a page to be vacuumed or frozen

3 / 20

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

Paul Sammy

Egor Rogov

Sam Altman

Dan Brown

4 / 20

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

free space map

table map

Main fork

visiblilty map

5 / 20

5. What is the purpose of the template0 database?

No such database

Useful for Postgres support Services to debug issues

Useful for creating development schemas

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

6 / 20

6. What is the purpose of wal writer?

writes WAL entries to disk

executes checkpoints

flushes dirty pages to disk.

collects usage statistics for the instance.

7 / 20

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

8 / 20

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

9 / 20

9. What is a schema?

This is the same as a user in Postgres

Namespace that store all objects of a database

The name used to refer to a super user account

A memory area used to cache data from LRU chains

10 / 20

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

postgres

init

postman

pginit

11 / 20

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

choose 2

pg_global

pg_temp

pg_default

pg_tablespace

12 / 20

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

False

True

13 / 20

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

False

True

14 / 20

14. What is another name for the postgres process?

aurora

postmanager

masterprocess

postmaster

15 / 20

15. System Catalog tables begin with which prefix?

cat_

sys_

dba_

pg_

16 / 20

16. What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Performs a backup of WAL logs

Removes stale data from tables and indexes

Deletes old logs and traces on disk

17 / 20

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

5MB

5GB

1GB

1MB

18 / 20

18. What is the purpose of the public schema?

no such schema

default schema for user objects

restricted schema for postgres internal usage only

schema used for heterogeneous replication

19 / 20

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

True

False

20 / 20

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

pg_class

pg_system

pg_catalog

pg_tables

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. 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

Use a single SQL operator

Issues a rollback after the commit to satisfy repeatable read.

2 / 10

2. The SQL standard specifies three isolation levels?

False

True

3 / 10

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

False

True

4 / 10

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

False

True

5 / 10

5. 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 adds some other rows satisfying this condition 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.

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

6 / 10

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

choose 3

Read Committed

Serializable

Repeatable Read

Read Uncommitted

7 / 10

7. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Rollback Read

Serializable

Random Scatter

8 / 10

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

Read Uncommitted

Serializable

Repeatable Read

Read Committed

9 / 10

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

ACID

SAFE

HIPPA

SOC2

10 / 10

10. Which parameters sets the database default isolation level?

default_isolation_level

default_transaction_isolation

active_transaction_isolation

transaction_isolation_level

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. CLOG files are stored in which directory?

PGDATA/clog

PGDATA/pg_xact

PGDATA/pg_clog

PGDATA/pg_commit

2 / 10

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

heap

clog

dump

view

3 / 10

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

True

False

4 / 10

4. What does an Item Pointer contain?

choose 3

tuple xid

tuple length

tuple status

tuple offset from the start of the page

5 / 10

5. To identify different versions of one and the same row, PostgreSQL marks each of them with which two value?

xmin

xmas

xmax

xid

6 / 10

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

True

False

7 / 10

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

True

False

8 / 10

8. Which of the below are true about a Pages Item Pointer?

Also know as the pages table of contents

Each pointer uses 8 bytes

stored in PGDATA/itemptr directory

Each pointer uses 4 bytes

9 / 10

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

False

True

10 / 10

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

True

False

Your score is

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