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

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

True

False

2 / 20

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

TOAST

BAKE

GROW

BREAD

3 / 20

What is the purpose of the postgres database?

regular database that you can use at your discretion

a template for all the other database

No such database

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

4 / 20

What is a schema?

The name used to refer to a super user account

A memory area used to cache data from LRU chains

This is the same as a user in Postgres

Namespace that store all objects of a database

5 / 20

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

6 / 20

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

True

False

7 / 20

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

System Catalog

Sysasm Catalog

Sysaux Catalog

Sys Catalog

8 / 20

What command is used to create the Postgres cluster?

CreateCluster

Initialize

CreatePGC

StartNewPG

9 / 20

What is the purpose of wal writer?

executes checkpoints

writes WAL entries to disk

flushes dirty pages to disk.

collects usage statistics for the instance.

10 / 20

Which 3 databases exist directly after cluster initialization?

choose 3 options

template1

template0

postgres

sysaux

11 / 20

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

choose 3

sequences

triggers

tables

indexes

12 / 20

What is the purpose of the visibility map?

provides the data decryption key

provides an audit trail for the database

shows referential relationships for tables

shows a page to be vacuumed or frozen

13 / 20

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

choose 2

pg_global

pg_tablespace

pg_default

pg_temp

14 / 20

Postgres server spawns a new backend session for each connection?

True

False

15 / 20

What is another name for the postgres process?

aurora

masterprocess

postmanager

postmaster

16 / 20

Which of below are predefined schemas?

choose 3

pg_toast

pg_temp

information_schema

pg_schema

17 / 20

How does Postgres know which schema to use if not specified?

Schema Path

Directory Path

Access Path

Search Path

18 / 20

TOAST tables reside in a seperate schema?

True

False

19 / 20

A schema can belong to more than one database?

False

True

20 / 20

What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Deletes old logs and traces on disk

Removes stale data from tables and indexes

Performs a backup of WAL logs

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

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 and modifies this row 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 twice, another transaction modifies this row between these reads issue a rollback.

2 / 10

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

HIPPA

SOC2

SAFE

ACID

3 / 10

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

False

True

4 / 10

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.

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.

5 / 10

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

False

True

6 / 10

Which parameters sets the database default isolation level?

active_transaction_isolation

default_transaction_isolation

default_isolation_level

transaction_isolation_level

7 / 10

The SQL standard specifies three isolation levels?

False

True

8 / 10

Which of the below would best describe a dirty read?

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

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

reading data direct from memory using pg_dirt

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

9 / 10

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

False

True

10 / 10

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

True

False

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

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

redo log

transaction log

archive log

commit log

2 / 10

Page free space can often become fragmented?

False

True

3 / 10

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

xid

xmas

xmax

xmin

4 / 10

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

True

False

5 / 10

Information about subtransactions is stored under?

PGDATA/pg_subtrans

PGDATA/subtrans

PGDATA/pg_xid

PGDATA/pg_min

6 / 10

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

False

True

7 / 10

CLOG contains how many bits for each transaction?

8 / 10

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

pg_current_id()

pg_current_commit_id()

pg_current_xmin_id()

pg_current_xact_id()

9 / 10

status of a subtransaction is written into CLOG?

False

True

10 / 10

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

INSERT

COMMIT

DELETE

CREATE

Your score is

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