Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ACSA - AraBob > Databases > Flashcards

Databases Flashcards

1
Q

Which RDS databases can be configured as multi-AZ or single-AZ?

A
  • SQLServer
  • Oracle
  • MySQL
  • PostgreSQL
  • MariaBD
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which RDS database is always multi-AZ?

A

Amazon Aurora

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Advantages of RDS?

A
  • up and running in minutes (not days)
  • multi-AZ
  • failover capability
  • automated backups
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When do we use RDS?

A
  • for online transaction processing (OTP)*
  • for customer orders
  • for completing large numbers of small transactions in real time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When don’t we want to use RDS?

A
  • OLAP (Online Analytical Processing)
  • complex queries
  • large amounts of data
  • data analysis

Instead, use a data warehouse like Redshift, which is optimized for Online Analytics Processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does Multi-AZ RDS work?

A
  • creates an exact copy of your production database in another AZ
  • AWS handles the replication for you
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens in RDS with an Unplanned Failure or maintenance?

A
  • If AWS notices that you lose your primary DB, there is an automatic failover by updating the DNS to point to the secondary DB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Multi-AZ for?**

A
  • disaster recovery

- NOT improving performance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are Read Replicas for?

A
  • for improving performance
  • a read-only copy of your database
  • for querying and read-heavy workloads
  • NOT for DR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Can Read Replicas be Multi-AZ?

A

Yes,

- can be in different regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How many read replicas can you have per DB?

A

5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Read Replica basics

A
  • a read-only copy of your primary DB in the same AZ, cross-AZ, or cross-region
  • used to increase or scale read performance
  • great for read-heavy workloads
  • takes the load off your primary DB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Amazon Aurora?

A
  • Amazon’s proprietary DB
  • MySQL & PostgreSQL
  • combines speed & availability at a low price point
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How much faster is Aurora than mySQL or PostgreSQL?

A
  • 5x faster than mySQL

- 3x faster than PostgreSQL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Aurora Basics

A
  • Storage Auto Scaling - starts with 10 GB. Scales in 10 GB increments up to 128 TB.
  • Compute can scale up to 96 vCPUs and 768 GB of memory.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How redundant is Aurora?*

A

2 copies of your data are stored in each AZ, with a minimum of 3 AZs
- it’s really redundant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Scaling Aurora

A

it’s designed to transparently handle the loss of 2 copies of data w/o affecting database write availability and 3 copies of data w/o affecting read availability

18
Q

How is Aurora self-healing?*

A
  • Aurora data blocks and disks are continuously scanned for errors and repaired automatically
19
Q

Aurora Replica limits by type*

A

Aurora Replicas - up to 15 Aurora replicas

  • MYSQL Replicas - up to 5 read replicas
  • PostGres Replicas - up to 5 read replicas
20
Q

Aurora Backups*

A
  • automated backups always enabled
  • backups do not impact database performance
  • can take snapshots (does not impact performance)
  • can share snapshots with other AWS accounts
21
Q

Aurora Serverless *

A
  • on demand
  • auto-scaling
  • for the MySQL and PostGres editions of Aurora
  • automatically starts up, shuts down, scales capacity up and down
22
Q

What is Aurora Serverless for?

A
  • infrequent, intermittent, unpredictable workloads

- for questions on exam where you need the performance of Aurora but have spiky workloads

23
Q

Dynamo DB

A
  • Fully managed
  • A fast & flexible noSQL database for all applications that need consistent, single-digit-millisecond latency at any scale
  • Supports document and key-value data models
24
Q

Dynamo DB use cases

A
  • mobile
  • web
  • gaming
  • ad-tech
  • IoT, etc.
25
Q

Dynamo Facts

A
  1. stored on SSD storage
  2. spread across 3 geographically distinct data centers
  3. eventually consistent reads (by default)
  4. strongly consistent reads (as an option)
26
Q

Eventually Consistent Reads *

A

consistency between all copies of the database is achieved within 1 second

27
Q

Strongly Consistent Reads *

A

returns a result that reflects all writes that received a successful response prior to the read.

28
Q

Dynamo DB Accelerator (DAX)

A
  • fully managed, highly available, in-memory cache
  • 10x performance improvement
  • reduces request time from milliseconds to microseconds, even under load
  • no need for developers to manage caching logic
  • compatible with Dynamo Db API calls
29
Q

Dynamo DB On-Demand Capacity

A
  • pay-per-request pricing
  • balances cost & performance
  • pay more per request than with provisioned capacity
  • use for new product launches
30
Q

Dynamo Security

A
  • encryption at rest with KMS
  • site-to-site VPN
  • DirectConnect (DX)
  • IAM policies and roles
  • fine-grained access
  • Cloud Watch & Cloud Trail
  • VPC endpoints
31
Q

Dynamo DB Transactions *

A

ACID:

  • Atomic - all changes to the DB must be performed successfully, or not at all
  • Consistent - data must be in a consistent state before and after the transaction
  • Isolated - No other processes can change the data while the transaction is running
  • Durable - the changes made by a transaction must persist.
32
Q

How do you use ACID w/ Dynamo DB?

A
  • by using transactions
  • transactions provide atomicity, consistency, isolation and durability across 1 or more tables within a single AWS account or region
33
Q

Use Cases for Transactions in DynamoDB*

A
  • apps that need coordinated inserts, deletes or updates to multiple items as part of a single logical business operation
  • financial transactions, managing orders
  • building multi-player game engines
  • coordinating actions across distributed services
  • up to 25 items or 4 MB of data per transaction
34
Q

What does ACID boil down to?*

A

All or nothing. No partially successful updates.

35
Q

3 options for reads

A
  • eventual consistency
  • strong consistency
  • transactional
36
Q

2 options for writes:

A
  • standard

- transactional

37
Q

Dynamo On-Demand Backup & Restore

A
  • full backups at any time
  • zero impact on table performance or availability
  • consistent w/i seconds & retained until deleted
  • operates in the same region as the source table
38
Q

Dynamo Point in Time Recovery (PITR)

A
  • restore to any point in the last 35 days
  • incremental backups
  • not turned on by default
  • latest restorable point - 5 minutes in the past
39
Q

Dynamo DB Streams

A
  • time-ordered sequence of item-level changes in a table
  • FIFO
  • every time your data changes it comes w/ a sequence number
  • for inserts, updates and deletes
  • stored for 24 hours
  • broken into shards
  • can combine Lambda functions for functionality like stored procedures
40
Q

Shards

A

collections of stream records with sequential numbers

41
Q

Dynamo Global Tables

A

a way of replicating your Dynamo DB tables from one region to another

  • managed multi-master, multi-region replication
  • great for globally distributed applications*
  • based on Dynamo DB streams (must be enabled to use Global tables)
  • multi-region redundancy for recovery or high availability*
  • no need to re-write your app, just go into the console and turn it on*
  • replication latency under 1 second

ACSA - AraBob (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions