DynamoDB overviewlearning manual
Published on 2023-04-20 00:10:05 · 中文 · بالعربية · Español · हिंदीName · 日本語 · Русский язык · 中文繁體
DynamoDB allows users to create databases that can store and retrieve any amount of data and provide any amount of traffic. It automatically distributes data and traffic across servers to dynamically manage each customer's request and maintain fast performance.
DynamoDB 與 RDBMS
DynamoDB uses a NoSQL model, which means it uses a non-relational system. The following table highlights the differences between DynamoDB and RDBMS-
advantage
The two main advantages of DynamoDB are scalability and flexibility. It does not enforce specific data sources and structures, allowing users to work with almost anything in a uniform way.
It is also designed to support a wide range of functions ranging from lighter tasks and operations to demanding enterprise functions. It also allows simple use of multiple languages: Ruby, Java, Python, C#, Erlang, PHP, and Perl.
limit
DynamoDB does have certain limitations, however, these limitations do not necessarily cause huge problems or hinder solid development.
You can review them from the following points-
Capacity Unit Size - Read capacity units are single, consistent reads of items up to 4KB per second. For items up to 1KB, the write capacity unit is one write per second.
Provisioned throughput min/max - All tables and global secondary indexes have at least one read and one write capacity unit. The maximum value depends on the region. In the US, 40K reads and writes are still the upper limit per table (80K per account), the upper limit is 10K per table in other regions, and the account limit is 20K.
Provisioned throughput increases and decreases - You can increase it as often as you want, but the reduction is still limited to no more than four per table per day.
Table size and number per account - There is no limit on table size, but accounts have a limit of 256 tables unless you ask for a higher cap.
Secondary indexes per table - Five local indexes and five global indexes are allowed.
Projected secondary index properties per table - DynamoDB allows 20 attributes.
Partition key length and value - They have a minimum length of 1 byte and a maximum length of 2048 bytes, however, DynamoDB has no limit on values.
Sort Key Length and Values - It has a minimum length of 1 byte and a maximum length of 1024 bytes, and has no restrictions on values unless its table uses a local secondary index.
Table and secondary index names - Names must be at least 3 characters long and up to 255. They use the following characters: AZ, az, 0-9, "_ ", "-", and ".".
Property name - Minimum one character, maximum 64KB, except for keys and certain attributes.
Reserved words - DynamoDB does not block the use of reserved words as names.
Expression length - Expression strings have a 4KB limit. Property expressions have a 255-byte limit. The substitution variable for an expression has a 2MB limit.