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

2 / 20

2. What is the purpose of the public schema?

schema used for heterogeneous replication

restricted schema for postgres internal usage only

default schema for user objects

no such schema

3 / 20

3. The default Page size is 2k?

False

True

4 / 20

4. Which fork keeps track of available space within pages?

free space map

used space map

wal space map

vacuum space map

5 / 20

5. 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.

6 / 20

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

choose 2

pg_global

pg_tablespace

pg_temp

pg_default

7 / 20

7. What is the purpose of the postgres database?

regular database that you can use at your discretion

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

a template for all the other database

No such database

8 / 20

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

pg_tabspace

pg_symlinks

pg_tablespace

pg_tblspc

9 / 20

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

True

False

10 / 20

10. Each Database has its own System Catalog?

False

True

11 / 20

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

PGBASE

PGTIPS

PGDATA

PGCORE

12 / 20

12. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Performs a backup of WAL logs

Removes stale data from tables and indexes

Rebuilds indexes with b level greater than 2

13 / 20

13. What is the default standard size for a fork file?

1GB

1MB

5GB

5MB

14 / 20

14. A single Postgres Instance can server only one database?

False

True

15 / 20

15. What is the purpose of the visibility map?

shows referential relationships for tables

shows a page to be vacuumed or frozen

provides the data decryption key

provides an audit trail for the database

16 / 20

16. Files are logically split into pages?

True

False

17 / 20

17. TOAST tables reside in a seperate schema?

True

False

18 / 20

18. What is the process first launched at server start?

postman

postgres

pginit

init

19 / 20

19. The information_schema schema provides information on Postgres release notes?

True

False

20 / 20

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

False

True

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

True

False

2 / 10

2. 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.

3 / 10

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

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

4 / 10

4. A phantom read anomaly occurs when?

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.

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

A transactions inserts a null value into a not null columns and commits

5 / 10

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

choose 3

Serializable

Read Committed

Repeatable Read

Read Uncommitted

6 / 10

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

SAFE

ACID

SOC2

HIPPA

7 / 10

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

Repeatable Read

Read Committed

Read Uncommitted

Serializable

8 / 10

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

False

True

9 / 10

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

True

False

10 / 10

10. The SQL standard specifies three isolation levels?

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. CLOG Pages are never cached in memory?

True

False

2 / 10

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

heap XID

magic XID

temporary XID

virtual XID

3 / 10

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

Each pointer uses 4 bytes

Each pointer uses 8 bytes

Also know as the pages table of contents

stored in PGDATA/itemptr directory

4 / 10

4. Rows of TOAST tables are handled in such a way that they are never update?

True

False

5 / 10

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

False

True

6 / 10

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

pg_current_xmin_id()

pg_current_xact_id()

pg_current_id()

pg_current_commit_id()

7 / 10

7. The page header is located in the highest address?

True

False

8 / 10

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

False

True

9 / 10

9. A page along with its tuples is read into the buffer cache with compression transformations to enhance cache efficiency?

True

False

10 / 10

10. CLOG files are stored in which directory?

PGDATA/clog

PGDATA/pg_commit

PGDATA/pg_xact

PGDATA/pg_clog

Your score is

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