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

What is the purpose of the template0 database?

Useful for Postgres support Services to debug issues

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

No such database

Useful for creating development schemas

2 / 20

What is the name of the catalog that stores metadata for all cluster objects?

Sysaux Catalog

System Catalog

Sys Catalog

Sysasm Catalog

3 / 20

Which of below are predefined schemas?

choose 2

public

postgres

system

pg_catalog

4 / 20

Which of below are predefined schemas?

choose 3

pg_temp

pg_schema

information_schema

pg_toast

5 / 20

Postgres uses a thread based process model?

True

False

6 / 20

A single Postgres Instance can server only one database?

True

False

7 / 20

Postgres by default has built in connection pooling abilities?

True

False

8 / 20

What is the purpose of autovacuum?

Deletes old logs and traces on disk

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

Performs a backup of WAL logs

9 / 20

A schema can belong to more than one database?

False

True

10 / 20

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

11 / 20

Which fork is specific for unlogged tables?

free space map

Initialization fork

Main fork

visiblilty map

12 / 20

What is the purpose of the visibility map?

provides the data decryption key

shows a page to be vacuumed or frozen

provides an audit trail for the database

shows referential relationships for tables

13 / 20

Each Database has its own System Catalog?

False

True

14 / 20

What is the purpose of the postgres database?

No such database

regular database that you can use at your discretion

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

a template for all the other database

15 / 20

What column in system catalogs servers as the Primary Key

obj#

oid#

oid

obj

16 / 20

Each tablespaces can only be assigned for use by one database

False

True

17 / 20

What is the default standard size for a fork file?

5MB

1MB

5GB

1GB

18 / 20

Who is the Author of the Postgres 14 Internals book?

Dan Brown

Sam Altman

Paul Sammy

Egor Rogov

19 / 20

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

True

False

20 / 20

Postgres server spawns a new backend session for each connection?

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

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

False

True

2 / 10

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

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

3 / 10

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

False

True

4 / 10

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

True

False

5 / 10

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

False

True

6 / 10

A phantom read anomaly occurs when?

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

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.

7 / 10

Which parameters sets the database default isolation level?

active_transaction_isolation

transaction_isolation_level

default_isolation_level

default_transaction_isolation

8 / 10

The SQL standard specifies three isolation levels?

True

False

9 / 10

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

Read Uncommitted

Read Committed

Repeatable Read

Serializable

10 / 10

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 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 issue a rollback.

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

The page header stores checksum and the sizes of the other parts of the page?

True

False

2 / 10

Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/pg_subtrans

PGDATA/pg_xid

PGDATA/subtrans

3 / 10

Each page has a layer that usually consists of?

choose 2

page header

flashback block

undo segment

free space

4 / 10

UPDATE can be regarded as which 2 separate operations?

INSERT

MERGE

DELETE

COMMIT

5 / 10

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

heap XID

magic XID

temporary XID

virtual XID

6 / 10

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

False

True

7 / 10

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

True

False

8 / 10

CLOG contains how many bits for each transaction?

9 / 10

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

False

True

10 / 10

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

commit log

transaction log

redo log

archive log

Your score is

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