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 point of the pg_global tablespace?

stores WAL logs used for global replication

stores temporary tables that are common to the whole cluster

stores user tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

2 / 20

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

False

True

3 / 20

3. What is the purpose of autovacuum?

Removes stale data from tables and indexes

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

Deletes old logs and traces on disk

4 / 20

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

True

False

5 / 20

5. What is the purpose of wal writer?

executes checkpoints

flushes dirty pages to disk.

collects usage statistics for the instance.

writes WAL entries to disk

6 / 20

6. Which of below are predefined schemas?

choose 2

pg_catalog

public

system

postgres

7 / 20

7. Which fork contains the actual table data?

table map

free space map

Main fork

visiblilty map

8 / 20

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

False

True

9 / 20

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

pg_symlinks

pg_tblspc

pg_tabspace

pg_tablespace

10 / 20

10. What is another name for the postgres process?

postmaster

masterprocess

aurora

postmanager

11 / 20

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

System Catalog

Sys Catalog

Sysasm Catalog

Sysaux Catalog

12 / 20

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

obj#

oid#

oid

obj

13 / 20

13. Which of below are predefined schemas?

choose 3

information_schema

pg_toast

pg_schema

pg_temp

14 / 20

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

5MB

1MB

1GB

5GB

15 / 20

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

Egor Rogov

Paul Sammy

Dan Brown

Sam Altman

16 / 20

16. To understand each other, a client and a server must use one and the same interfacing protocol?

True

False

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. How many files or forks on disk will a 10Mb table with no index have?

19 / 20

19. Users should not modify the template0 database

False

True

20 / 20

20. What is the purpose of the public schema?

schema used for heterogeneous replication

no such schema

default schema for user objects

restricted schema for postgres internal usage only

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. 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;

2 / 10

2. 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 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 twice, another transaction modifies this row between these reads issue a rollback.

3 / 10

3. The SQL standard specifies three isolation levels?

True

False

4 / 10

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

True

False

5 / 10

5. 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 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

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.

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

6 / 10

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

Read Committed

Serializable

Repeatable Read

Read Uncommitted

7 / 10

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

True

False

8 / 10

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

Select more than 1 answer below:

Issues a rollback after the commit to satisfy repeatable read.

Apply explicit locks

Replace procedural code with declarative one.

Use a single SQL operator

9 / 10

9. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Random Scatter

Read Committed

Serializable

10 / 10

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

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

False

True

2 / 10

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

Also know as the pages table of contents

Each pointer uses 8 bytes

Each pointer uses 4 bytes

stored in PGDATA/itemptr directory

3 / 10

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

INSERT

CREATE

DELETE

COMMIT

4 / 10

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

pg_current_xmin_id()

pg_current_commit_id()

pg_current_xact_id()

pg_current_id()

5 / 10

5. CLOG files are stored in which directory?

PGDATA/pg_clog

PGDATA/pg_xact

PGDATA/clog

PGDATA/pg_commit

6 / 10

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

True

False

7 / 10

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

True

False

8 / 10

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

False

True

9 / 10

9. Information about subtransactions is stored under?

PGDATA/pg_subtrans

PGDATA/subtrans

PGDATA/pg_min

PGDATA/pg_xid

10 / 10

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

True

False

Your score is

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