AWS DynamoDB

Dynomo DB

RCU/WCU calculate

* round up

RCU 4KB / unit
WCU 1KB / unit

Partition calculate

Strongly Consistent Read VS Eventually COnsistent REad

default Eventually
will impact RCU

Throttling/hotspot
ProvisionedThroughputExceededExceptions

Operation

put Item

replace

Update Item

update as you indicate

Conditional Writes

Delete Item

Delete Table

Batch Write Item

25 put / delete in one call
16MB written
400KB per item
retry?

Get Item

Projection Expression

Batch Get Item

100 items
16MB
faster than query

Table

Query

partitionKey =
SortKey (=, <, <=, >, >=, Between, Begin)
FilterExpression

Returns
1MB
Limit

Pagination

secondary index?

Scan

scan the entire table, inefficient
1MB
pagination

Parallel scans
Projection Ecpression
FilterExpression

Local Secondary Index

defianed ata table createion time

Global Secondary Index

modify as you go

Concurrency

optimistic locking/concurrency database

DAX DynamoDB Accelerator

TTL
additional cluster
cache the hot key
low latency
solve hot key prolbem

stream

lambda
24 h data retention

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