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

BAKE

GROW

TOAST

BREAD

2 / 20

2. pg_catalog schema is used to store system catalog tables?

False

True

3 / 20

3. Which fork is specific for unlogged tables?

Main fork

visiblilty map

free space map

Initialization fork

4 / 20

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

5 / 20

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

pg_tables

pg_catalog

pg_system

pg_class

6 / 20

6. What is the purpose of wal writer?

executes checkpoints

writes WAL entries to disk

collects usage statistics for the instance.

flushes dirty pages to disk.

7 / 20

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

Paul Sammy

Sam Altman

Egor Rogov

Dan Brown

8 / 20

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

choose 3

sequences

triggers

tables

indexes

9 / 20

9. What is another name for the postgres process?

postmaster

aurora

postmanager

masterprocess

10 / 20

10. The default Page size is 2k?

False

True

11 / 20

11. 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

12 / 20

12. What is the purpose of the template1 database?

No such database

database used for temporary tables

regular database that you can use at your discretion

a template for all the other databases

13 / 20

13. Which fork keeps track of available space within pages?

vacuum space map

used space map

wal space map

free space map

14 / 20

14. What is the purpose of the visibility map?

shows referential relationships for tables

shows a page to be vacuumed or frozen

provides an audit trail for the database

provides the data decryption key

15 / 20

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

PGTIPS

PGBASE

PGCORE

PGDATA

16 / 20

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

False

True

17 / 20

17. Which fork contains the actual table data?

Main fork

table map

free space map

visiblilty map

18 / 20

18. If we create a new tablespace which directory will symbolic links be created from?

pg_tablespace

pg_symlinks

pg_tblspc

pg_tabspace

19 / 20

19. Each Database has its own System Catalog?

True

False

20 / 20

20. Which 3 databases exist directly after cluster initialization?

choose 3 options

template0

sysaux

postgres

template1

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_isolation_level

transaction_isolation_level

default_transaction_isolation

active_transaction_isolation

2 / 10

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

BEGIN ISOLATION LEVEL REPEATABLE READ;

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

3 / 10

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

False

True

4 / 10

4. 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 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

5 / 10

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

False

True

6 / 10

6. 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, 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 and commits the change.

7 / 10

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

False

True

8 / 10

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

Serializable

Read Uncommitted

Read Committed

Repeatable Read

9 / 10

9. The SQL standard specifies three isolation levels?

False

True

10 / 10

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

choose 3

Read Committed

Read Uncommitted

Serializable

Repeatable Read

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

CREATE

INSERT

DELETE

COMMIT

2 / 10

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

Each pointer uses 4 bytes

Also know as the pages table of contents

Each pointer uses 8 bytes

stored in PGDATA/itemptr directory

3 / 10

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

True

False

4 / 10

4. CLOG Pages are never cached in memory?

False

True

5 / 10

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

pg_current_xmin_id()

pg_current_commit_id()

pg_current_id()

pg_current_xact_id()

6 / 10

6. When a transaction is committed Postgres uses a special <replace with answer> structure?

commit log

transaction log

archive log

redo log

7 / 10

7. Page free space can often become fragmented?

True

False

8 / 10

8. What does an Item Pointer contain?

choose 3

tuple xid

tuple status

tuple length

tuple offset from the start of the page

9 / 10

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

True

False

10 / 10

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

xmin

xmas

xmax

xid

Your score is

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