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 fork contains the actual table data?

table map

visiblilty map

Main fork

free space map

2 / 20

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

BREAD

TOAST

BAKE

GROW

3 / 20

3. Which 3 databases exist directly after cluster initialization?

choose 3 options

sysaux

postgres

template1

template0

4 / 20

4. What is a schema?

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

The name used to refer to a super user account

This is the same as a user in Postgres

5 / 20

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

6 / 20

6. Each Database has its own System Catalog?

True

False

7 / 20

7. What is the purpose of autovacuum?

Removes stale data from tables and indexes

Deletes old logs and traces on disk

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

8 / 20

8. It is the postmasters job to listener for incoming connections?

False

True

9 / 20

9. What is the purpose of the visibility map?

shows a page to be vacuumed or frozen

shows referential relationships for tables

provides an audit trail for the database

provides the data decryption key

10 / 20

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

table map

visiblilty map

free space map

Main fork

11 / 20

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

False

True

12 / 20

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

choose 3

tables

sequences

triggers

indexes

13 / 20

13. Which of below are predefined schemas?

choose 3

information_schema

pg_temp

pg_toast

pg_schema

14 / 20

14. What is the purpose of wal writer?

writes WAL entries to disk

flushes dirty pages to disk.

collects usage statistics for the instance.

executes checkpoints

15 / 20

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

PGDATA

PGTIPS

PGBASE

PGCORE

16 / 20

16. What is the purpose of the postgres database?

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

regular database that you can use at your discretion

No such database

a template for all the other database

17 / 20

17. Postgres by default has built in connection pooling abilities?

True

False

18 / 20

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

False

True

19 / 20

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

True

False

20 / 20

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

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 are valid Isolations Levels?

choose 2

Serializable

Rollback Read

Random Scatter

Read Committed

2 / 10

2. The SQL standard specifies three isolation levels?

False

True

3 / 10

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

False

True

4 / 10

4. What is the default Isolation Level?

Serializable

Read Committed

Repeatable Read

Read Uncommitted

5 / 10

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

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

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

reading data direct from memory using pg_dirt

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

6 / 10

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

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 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, 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.

8 / 10

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

False

True

9 / 10

9. What are some of database features we can use to avoid a non repeatable read?

Select more than 1 answer below:

Issues a rollback after the commit to satisfy repeatable read.

Use a single SQL operator

Apply explicit locks

Replace procedural code with declarative one.

10 / 10

10. Which parameters sets the database default isolation level?

default_transaction_isolation

transaction_isolation_level

active_transaction_isolation

default_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. index row headers like table row headers contain xmin and xmax fields?

True

False

2 / 10

2. Which 2 items does a Virtual XID consist of?

sequential number

checksum

backend process ID

xmin

3 / 10

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

Each pointer uses 4 bytes

stored in PGDATA/itemptr directory

Each pointer uses 8 bytes

Also know as the pages table of contents

4 / 10

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

True

False

5 / 10

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

False

True

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

xid

xmax

xmas

xmin

9 / 10

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

True

False

10 / 10

10. Information about subtransactions is stored under?

PGDATA/pg_subtrans

PGDATA/pg_xid

PGDATA/pg_min

PGDATA/subtrans

Your score is

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