AWS DynamoDB
Amazon DynamoDB, a fully managed NoSQL data storage and retrieval service, makes it easy and cost-effective for any size request traffic to store and retrieve any amount.
Provides predictable, fast performance and seamless scaling
DynamoDB allows customers to outsource the administrative burdens of scaling and operating distributed databases to AWS. Customers don’t have to worry about setup and configuration, software patching or cluster scaling.
DynamoDB tables don’t have fixed schemas. Each item in the table may have a different number or combination of attributes.
DynamoDB synchronizes data replication across three facilities within an AWS Region. This ensures high availability and data longevity.
DynamoDB allows for fast in-place updates. A single API call can increment or decrease a numeric attribute in a row.
DynamoDB uses trusted cryptographic methods to authenticate users and prevent unauthorized access to data.
With SSD (solid State Drive) storage and automatic 3-way replicating, durability, performance, reliability and security are all built-in.
DynamoDB supports two types of primary keys: Partition Key (previously known as the Hash key). A simple primary key that consists of one attribute
The partition key value is used to input an internal hash function. The output of the hash function determines where the item will be stored.
There can be no two tables with the same partition key value.
Partition Key and Sort key (previously known as the Hash and Range keys) A composite primary key is made up of two attributes. The first attribute is called the partition key, while the second attribute refers to the sort key.
The partition key value is used to input an internal hash function. The output of the hash function determines where the item will be stored.
All items with the same partition key will be stored together in sorted order based on their sort key value.
The combination of the sort key and partition key must be unique
It is possible to have two items with the same partition key value. However, those two items must have distinct sort key values.
DynamoDB Secondary Indexes add flexibility to queries without affecting performance.
Items are automatically kept as sparse objects. Items will only appear in an Index if they exist in a table on which the index was defined. This makes queries against an index efficient.
DynamoDB’s single-digit millisecond latency and throughput make it an excellent choice for gaming, adtech, and many other applications.
DynamoDB Consistency can be used to offload large amounts of reads for frequently changed data. ElastiCache and DAX can both be used in front DynamoDB
Each DynamoDB table automatically stores in the three geographically dispersed locations to ensure its durability.
Read consistency refers to the way and when a successful write or update of data items is reflected in subsequent read operations of the same item.
DynamoDB lets you specify whether the read should eventually be consistent or strong consistent at the time of your request.
Usually, consistency across all copies can be achieved within a second
A consistent read may not reflect the results from a recent write.
After a brief time, repeat the read to return the latest data.
DynamoDB uses eventually consistent readings by default.
Strongly Consistent ReadersA strong, consistent read will return a result that reflects all the writes that received a positive response before the read
Consistent reads are twice as expensive as eventually consistent ones
However, Strongly Consistent Readings have their disadvantages. A network outage or delay might mean that a strongly consistent read is not possible. DynamoDB might return an error 500 (HTTP 500) in this instance.
High latency t may be a result of consistent readings.
