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. Each Database has its own System Catalog?

False

True

2 / 20

2. What is a schema?

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

This is the same as a user in Postgres

The name used to refer to a super user account

3 / 20

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

False

True

4 / 20

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

obj

obj#

oid

oid#

5 / 20

5. Users should not modify the template0 database

False

True

6 / 20

6. What is the purpose of the public schema?

restricted schema for postgres internal usage only

schema used for heterogeneous replication

default schema for user objects

no such schema

7 / 20

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

8 / 20

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

True

False

9 / 20

9. The default Page size is 2k?

False

True

10 / 20

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

CreatePGC

Initialize

StartNewPG

CreateCluster

11 / 20

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

choose 2

pg_temp

pg_global

pg_tablespace

pg_default

12 / 20

12. What is the purpose of the template1 database?

database used for temporary tables

No such database

a template for all the other databases

regular database that you can use at your discretion

13 / 20

13. What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

Deletes old logs and traces on disk

Performs a backup of WAL logs

14 / 20

14. To understand each other, a client and a server must use one and the same interfacing protocol?

True

False

15 / 20

15. What is the purpose of the template0 database?

Useful for creating development schemas

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

Useful for Postgres support Services to debug issues

No such database

16 / 20

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

pg_tblspc

pg_symlinks

pg_tablespace

pg_tabspace

17 / 20

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

5MB

1GB

5GB

1MB

18 / 20

18. What is the purpose of wal writer?

writes WAL entries to disk

executes checkpoints

collects usage statistics for the instance.

flushes dirty pages to disk.

19 / 20

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

True

False

20 / 20

20. Which fork contains the actual table data?

table map

visiblilty map

free space map

Main fork

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. The SQL standard specifies three isolation levels?

True

False

2 / 10

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

SAFE

ACID

SOC2

HIPPA

3 / 10

3. A phantom read anomaly occurs when?

A transactions inserts a null value into a not null columns and commits

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 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.

4 / 10

4. Which parameters sets the database default isolation level?

default_isolation_level

default_transaction_isolation

transaction_isolation_level

active_transaction_isolation

5 / 10

5. What is the default Isolation Level?

Repeatable Read

Serializable

Read Uncommitted

Read Committed

6 / 10

6. non-repeatable read anomaly occurs when?

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.

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.

7 / 10

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

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

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

8 / 10

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

CREATE EXTENSTION REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

9 / 10

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

True

False

10 / 10

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

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

xmas

xmin

xmax

xid

2 / 10

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

stored in PGDATA/itemptr directory

Also know as the pages table of contents

Each pointer uses 8 bytes

Each pointer uses 4 bytes

3 / 10

3. What does an Item Pointer contain?

choose 3

tuple length

tuple offset from the start of the page

tuple xid

tuple status

4 / 10

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

True

False

5 / 10

5. Page free space can often become fragmented?

False

True

6 / 10

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

False

True

7 / 10

7. CLOG files are stored in which directory?

PGDATA/pg_clog

PGDATA/pg_xact

PGDATA/pg_commit

PGDATA/clog

8 / 10

8. If a transaction is read only which kind of Transaction ID is it allocated?

virtual XID

heap XID

temporary XID

magic XID

9 / 10

9. CLOG contains how many bits for each transaction?

10 / 10

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

False

True

Your score is

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