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 purpose of wal writer?

executes checkpoints

flushes dirty pages to disk.

writes WAL entries to disk

collects usage statistics for the instance.

2 / 20

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

pg_class

pg_catalog

pg_tables

pg_system

3 / 20

3. What is the purpose of the visibility map?

provides an audit trail for the database

provides the data decryption key

shows referential relationships for tables

shows a page to be vacuumed or frozen

4 / 20

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

Sysaux Catalog

Sysasm Catalog

Sys Catalog

System Catalog

5 / 20

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

TOAST

GROW

BAKE

BREAD

6 / 20

6. What is a schema?

Namespace that store all objects of a database

The name used to refer to a super user account

This is the same as a user in Postgres

A memory area used to cache data from LRU chains

7 / 20

7. The default Page size is 2k?

True

False

8 / 20

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

Choose 2 option

Instance

Quorum

Aurora

Postgres Server

9 / 20

9. Each Database has its own System Catalog?

True

False

10 / 20

10. Which of below are predefined schemas?

choose 3

pg_temp

pg_toast

pg_schema

information_schema

11 / 20

11. pg_catalog schema is used to store system catalog tables?

True

False

12 / 20

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

pg_tabspace

pg_tablespace

pg_tblspc

pg_symlinks

13 / 20

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

undo segments (UNDO)

write-ahead log (WAL)

online redo logs (ORL)

rollback segments (RBS)

14 / 20

14. Who is the Author of the Postgres 14 Internals book?

Sam Altman

Paul Sammy

Egor Rogov

Dan Brown

15 / 20

15. What is another name for the postgres process?

postmaster

aurora

postmanager

masterprocess

16 / 20

16. What is the purpose of the template0 database?

No such database

Useful for creating development schemas

Useful for Postgres support Services to debug issues

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

17 / 20

17. What column in system catalogs servers as the Primary Key

oid

oid#

obj#

obj

18 / 20

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

PGBASE

PGCORE

PGTIPS

PGDATA

19 / 20

19. Which of below are predefined schemas?

choose 2

public

pg_catalog

postgres

system

20 / 20

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

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

False

True

2 / 10

2. 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 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.

3 / 10

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

choose 3

Read Uncommitted

Read Committed

Repeatable Read

Serializable

4 / 10

4. What is the default Isolation Level?

Read Uncommitted

Repeatable Read

Serializable

Read Committed

5 / 10

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

True

False

6 / 10

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

Read Uncommitted

Repeatable Read

Serializable

Read Committed

7 / 10

7. non-repeatable read anomaly occurs when?

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.

A transaction reads one and the same row twice, another transaction modifies this row between these reads and commits the change.

8 / 10

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

Select more than 1 answer below:

Apply explicit locks

Use a single SQL operator

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

9 / 10

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

False

True

10 / 10

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

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

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

False

True

2 / 10

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

True

False

3 / 10

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

True

False

4 / 10

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

False

True

5 / 10

5. CLOG contains how many bits for each transaction?

6 / 10

6. Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/pg_subtrans

PGDATA/subtrans

PGDATA/pg_xid

7 / 10

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

temporary XID

magic XID

heap XID

virtual XID

8 / 10

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

COMMIT

CREATE

INSERT

DELETE

9 / 10

9. status of a subtransaction is written into CLOG?

True

False

10 / 10

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

xid

xmin

xmas

xmax

Your score is

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