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 column in system catalogs servers as the Primary Key

obj#

oid#

obj

oid

2 / 20

What is the purpose of the public schema?

default schema for user objects

schema used for heterogeneous replication

no such schema

restricted schema for postgres internal usage only

3 / 20

The information_schema schema provides information on Postgres release notes?

True

False

4 / 20

Users should not modify the template0 database

True

False

5 / 20

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

PGTIPS

PGCORE

PGBASE

PGDATA

6 / 20

Which fork contains the actual table data?

visiblilty map

free space map

Main fork

table map

7 / 20

What is the purpose of autovacuum?

Deletes old logs and traces on disk

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

8 / 20

Tablespaces are used to define physical data layout?

True

False

9 / 20

Postgres by default has built in connection pooling abilities?

True

False

10 / 20

A single Postgres Instance can server only one database?

True

False

11 / 20

Each Database has its own System Catalog?

False

True

12 / 20

A schema can belong to more than one database?

True

False

13 / 20

System Catalog tables begin with which prefix?

sys_

pg_

dba_

cat_

14 / 20

It is the postmasters job to listener for incoming connections?

False

True

15 / 20

What is the default standard size for a fork file?

5GB

5MB

1GB

1MB

16 / 20

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

BAKE

BREAD

TOAST

GROW

17 / 20

What is another name for the postgres process?

masterprocess

aurora

postmaster

postmanager

18 / 20

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

False

True

19 / 20

Which of below are predefined schemas?

choose 2

public

postgres

pg_catalog

system

20 / 20

What is the point of the pg_global tablespace?

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

stores user tables that are common to the whole cluster

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

Which parameters sets the database default isolation level?

active_transaction_isolation

default_isolation_level

transaction_isolation_level

default_transaction_isolation

2 / 10

The SQL standard specifies three isolation levels?

False

True

3 / 10

Which of the below would best describe a dirty read?

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

a session being able to see commited 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

4 / 10

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

choose 3

Read Committed

Read Uncommitted

Repeatable Read

Serializable

5 / 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.

6 / 10

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

Select more than 1 answer below:

Use a single SQL operator

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

Apply explicit locks

7 / 10

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

SOC2

SAFE

ACID

HIPPA

8 / 10

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

False

True

9 / 10

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

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

10 / 10

What is the default Isolation Level?

Read Uncommitted

Serializable

Read Committed

Repeatable Read

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

CREATE

INSERT

DELETE

COMMIT

2 / 10

Page free space can often become fragmented?

True

False

3 / 10

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

heap XID

magic XID

temporary XID

virtual XID

4 / 10

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

False

True

5 / 10

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

False

True

6 / 10

status of a subtransaction is written into CLOG?

False

True

7 / 10

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

xmin

xid

xmax

xmas

8 / 10

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

True

False

9 / 10

Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/subtrans

PGDATA/pg_subtrans

PGDATA/pg_xid

10 / 10

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

True

False

Your score is

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