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

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

BREAD

TOAST

BAKE

GROW

2 / 20

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

False

True

3 / 20

3. A schema can belong to more than one database?

False

True

4 / 20

4. When PostgreSQL is running what can it be referred to as?

Choose 2 option

Postgres Server

Instance

Quorum

Aurora

5 / 20

5. What is another name for the postgres process?

postmanager

aurora

masterprocess

postmaster

6 / 20

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

False

True

7 / 20

7. Each tablespaces can only be assigned for use by one database

True

False

8 / 20

8. To be able to restore data consistency, Postgres maintains

undo segments (UNDO)

rollback segments (RBS)

online redo logs (ORL)

write-ahead log (WAL)

9 / 20

9. What is the purpose of the template1 database?

database used for temporary tables

regular database that you can use at your discretion

a template for all the other databases

No such database

10 / 20

10. If we create a new tablespace which directory will symbolic links be created from?

pg_tablespace

pg_symlinks

pg_tblspc

pg_tabspace

11 / 20

11. 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

12 / 20

12. What is the purpose of wal writer?

flushes dirty pages to disk.

executes checkpoints

writes WAL entries to disk

collects usage statistics for the instance.

13 / 20

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

14 / 20

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

False

True

15 / 20

15. Which 3 databases exist directly after cluster initialization?

choose 3 options

template0

template1

postgres

sysaux

16 / 20

16. What is the purpose of the postgres database?

a template for all the other database

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

No such database

regular database that you can use at your discretion

17 / 20

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

PGBASE

PGDATA

PGTIPS

PGCORE

18 / 20

18. 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 temporary tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

19 / 20

19. System Catalog tables begin with which prefix?

sys_

cat_

pg_

dba_

20 / 20

20. The default Page size is 2k?

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

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

True

False

2 / 10

2. 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.

Use a single SQL operator

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

3 / 10

3. The SQL standard specifies three isolation levels?

True

False

4 / 10

4. Which parameters sets the database default isolation level?

default_transaction_isolation

active_transaction_isolation

transaction_isolation_level

default_isolation_level

5 / 10

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

False

True

6 / 10

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

Serializable

Repeatable Read

Read Uncommitted

Read Committed

7 / 10

7. non-repeatable read anomaly occurs when?

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.

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.

8 / 10

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

choose 3

Read Committed

Repeatable Read

Read Uncommitted

Serializable

9 / 10

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

True

False

10 / 10

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.

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

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

False

True

2 / 10

2. Page header sizes can be easily displayed using the <choose from answers> extension

pagesize

pagedetect

pageinspect

pageheadinfo

3 / 10

3. CLOG files are stored in which directory?

PGDATA/pg_xact

PGDATA/pg_commit

PGDATA/pg_clog

PGDATA/clog

4 / 10

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

xid

xmax

xmin

xmas

5 / 10

5. at any one time Postgres can have several versions of a row?

False

True

6 / 10

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

stored in PGDATA/itemptr directory

Each pointer uses 8 bytes

Each pointer uses 4 bytes

Also know as the pages table of contents

7 / 10

7. Postgres table physical data files are always cross compatible across platforms?

True

False

8 / 10

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

True

False

9 / 10

9. Information about subtransactions is stored under?

PGDATA/pg_subtrans

PGDATA/pg_xid

PGDATA/pg_min

PGDATA/subtrans

10 / 10

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

False

True

Your score is

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