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 single Postgres Instance can server only one database?

True

False

2 / 20

A schema can belong to more than one database?

False

True

3 / 20

What is the point of the pg_global tablespace?

stores WAL logs used for global replication

stores user tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores temporary tables that are common to the whole cluster

4 / 20

Which 3 databases exist directly after cluster initialization?

choose 3 options

sysaux

template1

template0

postgres

5 / 20

Each Database has its own System Catalog?

True

False

6 / 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

7 / 20

What is another name for the postgres process?

masterprocess

postmaster

aurora

postmanager

8 / 20

What column in system catalogs servers as the Primary Key

obj

obj#

oid

oid#

9 / 20

What is the purpose of autovacuum?

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

Deletes old logs and traces on disk

10 / 20

Each tablespaces can only be assigned for use by one database

True

False

11 / 20

Which fork keeps track of available space within pages?

used space map

vacuum space map

free space map

wal space map

12 / 20

Postgres uses a thread based process model?

True

False

13 / 20

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

pg_class

pg_catalog

pg_system

pg_tables

14 / 20

What command is used to create the Postgres cluster?

CreateCluster

StartNewPG

CreatePGC

Initialize

15 / 20

What is the purpose of the public schema?

default schema for user objects

no such schema

restricted schema for postgres internal usage only

schema used for heterogeneous replication

16 / 20

TOAST tables reside in a seperate schema?

True

False

17 / 20

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

False

True

18 / 20

Which of below are predefined schemas?

choose 2

public

postgres

system

pg_catalog

19 / 20

What is the default standard size for a fork file?

1MB

5MB

5GB

1GB

20 / 20

Files are logically split into pages?

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

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

True

False

2 / 10

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

choose 3

Read Uncommitted

Read Committed

Repeatable Read

Serializable

3 / 10

The SQL standard specifies three isolation levels?

False

True

4 / 10

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

Read Uncommitted

Read Committed

Repeatable Read

Serializable

5 / 10

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

True

False

6 / 10

Which of the below are valid Isolations Levels?

choose 2

Serializable

Rollback Read

Random Scatter

Read Committed

7 / 10

Which parameters sets the database default isolation level?

default_isolation_level

default_transaction_isolation

transaction_isolation_level

active_transaction_isolation

8 / 10

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

False

True

9 / 10

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

Select more than 1 answer below:

Replace procedural code with declarative one.

Apply explicit locks

Use a single SQL operator

Issues a rollback after the commit to satisfy repeatable read.

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 issue a rollback.

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 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.

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?

False

True

2 / 10

indexes do not use row versioning?

True

False

3 / 10

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

False

True

4 / 10

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

magic XID

temporary XID

heap XID

virtual XID

5 / 10

What does an Item Pointer contain?

choose 3

tuple xid

tuple status

tuple offset from the start of the page

tuple length

6 / 10

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

Also know as the pages table of contents

Each pointer uses 8 bytes

stored in PGDATA/itemptr directory

Each pointer uses 4 bytes

7 / 10

status of a subtransaction is written into CLOG?

True

False

8 / 10

virtual IDs exist only in PGDATA/pg_vxid when not cached?

True

False

9 / 10

UPDATE can be regarded as which 2 separate operations?

INSERT

DELETE

COMMIT

MERGE

10 / 10

CLOG contains how many bits for each transaction?

Your score is

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