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

Postgres by default has built in connection pooling abilities?

True

False

2 / 20

Postgres uses a thread based process model?

False

True

3 / 20

What is the purpose of wal writer?

collects usage statistics for the instance.

flushes dirty pages to disk.

executes checkpoints

writes WAL entries to disk

4 / 20

Which fork contains the actual table data?

visiblilty map

free space map

Main fork

table map

5 / 20

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

Main fork

free space map

table map

visiblilty map

6 / 20

What is a schema?

The name used to refer to a super user account

Namespace that store all objects of a database

This is the same as a user in Postgres

A memory area used to cache data from LRU chains

7 / 20

System Catalog tables begin with which prefix?

pg_

sys_

cat_

dba_

8 / 20

Each tablespaces can only be assigned for use by one database

False

True

9 / 20

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

10 / 20

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

pg_system

pg_tables

pg_catalog

pg_class

11 / 20

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

choose 3

indexes

sequences

triggers

tables

12 / 20

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

choose 2

pg_temp

pg_global

pg_default

pg_tablespace

13 / 20

To be able to restore data consistency, Postgres maintains

undo segments (UNDO)

online redo logs (ORL)

rollback segments (RBS)

write-ahead log (WAL)

14 / 20

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

TOAST

BREAD

GROW

BAKE

15 / 20

Postgres server spawns a new backend session for each connection?

False

True

16 / 20

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

Schema Path

Directory Path

Access Path

Search Path

17 / 20

What is the point of the pg_global tablespace?

stores user tables that are common to the whole cluster

stores WAL logs used for global replication

stores system catalog objects that are common to the whole cluster

stores temporary tables that are common to the whole cluster

18 / 20

A schema can belong to more than one database?

False

True

19 / 20

What command is used to create the Postgres cluster?

CreateCluster

Initialize

StartNewPG

CreatePGC

20 / 20

What column in system catalogs servers as the Primary Key

obj#

oid

oid#

obj

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

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

choose 3

Read Committed

Repeatable Read

Serializable

Read Uncommitted

2 / 10

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

False

True

3 / 10

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 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 transactions issues a commit, then a rollback to restore data to its original value

4 / 10

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

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

5 / 10

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

False

True

6 / 10

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

False

True

7 / 10

Which of the below would best describe a dirty read?

reading data direct from memory using pg_dirt

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

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

8 / 10

The SQL standard specifies three isolation levels?

False

True

9 / 10

What is the default Isolation Level?

Read Uncommitted

Serializable

Repeatable Read

Read Committed

10 / 10

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

Serializable

Repeatable Read

Read Committed

Read Uncommitted

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

CLOG Pages are never cached in memory?

True

False

2 / 10

The page Special Space is located at the start of the page with highest address

True

False

3 / 10

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

xid

xmax

xmin

xmas

4 / 10

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

magic XID

temporary XID

virtual XID

heap XID

5 / 10

CLOG files are stored in which directory?

PGDATA/clog

PGDATA/pg_clog

PGDATA/pg_commit

PGDATA/pg_xact

6 / 10

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

pg_current_commit_id()

pg_current_xact_id()

pg_current_xmin_id()

pg_current_id()

7 / 10

Which 2 of the below represent transaction IDs used for row versioning?

xid

xtime

xmin

xmax

8 / 10

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

False

True

9 / 10

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

True

False

10 / 10

If a transaction aborts, all page changes are reverted(rolled back) in place?

False

True

Your score is

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