Skip to main content AWS DynamoDB NoSQL database for scalable data storage. Use when designing table schemas, writing queries, configuring indexes, managing capacity, implementing single-table design, or troubleshooting performance issues.
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AWS DynamoDB
Amazon DynamoDB is a fully managed NoSQL database service providing fast, predictable performance at any scale. It supports key-value and document data structures.
Table of Contents
Core Concepts
Keys
Key Type Description Partition Key (PK) Required. Determines data distribution Sort Key (SK) Optional. Enables range queries within partition Composite Key PK + SK combination
Secondary Indexes
GSI (Global Secondary Index) Different PK/SK, separate throughput, eventually consistent LSI (Local Secondary Index) Same PK, different SK, shares table throughput, strongly consistent option
Capacity Modes Mode Use Case On-Demand Unpredictable traffic, pay-per-request Provisioned Predictable traffic, lower cost, can use auto-scaling
Common Patterns
Create a Table aws dynamodb create-table \
--table-name Users \
--attribute-definitions \
AttributeName=PK,AttributeType=S \
AttributeName=SK,AttributeType=S \
--key-schema \
AttributeName=PK,KeyType=HASH \
AttributeName=SK,KeyType=RANGE \
--billing-mode PAY_PER_REQUEST
import boto3
dynamodb = boto3.resource('dynamodb')
table = dynamodb.create_table(
TableName='Users',
KeySchema=[
{'AttributeName': 'PK', 'KeyType': 'HASH'},
{'AttributeName': 'SK', 'KeyType': 'RANGE'}
],
AttributeDefinitions=[
{'AttributeName': 'PK', 'AttributeType': 'S'},
{'AttributeName': 'SK', 'AttributeType': 'S'}
],
BillingMode='PAY_PER_REQUEST'
)
table.wait_until_exists()
Basic CRUD Operations import boto3
from boto3.dynamodb.conditions import Key, Attr
dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table('Users')
# Put item
table.put_item(
Item={
'PK': 'USER#123',
'SK': 'PROFILE',
'name': 'John Doe',
'email': '[email protected] ',
'created_at': '2024-01-15T10:30:00Z'
}
)
# Get item
response = table.get_item(
Key={'PK': 'USER#123', 'SK': 'PROFILE'}
)
item = response.get('Item')
# Update item
table.update_item(
Key={'PK': 'USER#123', 'SK': 'PROFILE'},
UpdateExpression='SET #name = :name, updated_at = :updated',
ExpressionAttributeNames={'#name': 'name'},
ExpressionAttributeValues={
':name': 'John Smith',
':updated': '2024-01-16T10:30:00Z'
}
)
# Delete item
table.delete_item(
Key={'PK': 'USER#123', 'SK': 'PROFILE'}
)
Query Operations # Query by partition key
response = table.query(
KeyConditionExpression=Key('PK').eq('USER#123')
)
# Query with sort key condition
response = table.query(
KeyConditionExpression=Key('PK').eq('USER#123') & Key('SK').begins_with('ORDER#')
)
# Query with filter
response = table.query(
KeyConditionExpression=Key('PK').eq('USER#123'),
FilterExpression=Attr('status').eq('active')
)
# Query with projection
response = table.query(
KeyConditionExpression=Key('PK').eq('USER#123'),
ProjectionExpression='PK, SK, #name, email',
ExpressionAttributeNames={'#name': 'name'}
)
# Paginated query
paginator = dynamodb.meta.client.get_paginator('query')
for page in paginator.paginate(
TableName='Users',
KeyConditionExpression='PK = :pk',
ExpressionAttributeValues={':pk': {'S': 'USER#123'}}
):
for item in page['Items']:
print(item)
Batch Operations # Batch write (up to 25 items)
with table.batch_writer() as batch:
for i in range(100):
batch.put_item(Item={
'PK': f'USER#{i}',
'SK': 'PROFILE',
'name': f'User {i}'
})
# Batch get (up to 100 items)
dynamodb = boto3.resource('dynamodb')
response = dynamodb.batch_get_item(
RequestItems={
'Users': {
'Keys': [
{'PK': 'USER#1', 'SK': 'PROFILE'},
{'PK': 'USER#2', 'SK': 'PROFILE'}
]
}
}
)
Create GSI aws dynamodb update-table \
--table-name Users \
--attribute-definitions AttributeName=email,AttributeType=S \
--global-secondary-index-updates '[
{
"Create": {
"IndexName": "email-index",
"KeySchema": [{"AttributeName": "email", "KeyType": "HASH"}],
"Projection": {"ProjectionType": "ALL"}
}
}
]'
Conditional Writes from botocore.exceptions import ClientError
# Only put if item doesn't exist
try:
table.put_item(
Item={'PK': 'USER#123', 'SK': 'PROFILE', 'name': 'John'},
ConditionExpression='attribute_not_exists(PK)'
)
except ClientError as e:
if e.response['Error']['Code'] == 'ConditionalCheckFailedException':
print("Item already exists")
# Optimistic locking with version
table.update_item(
Key={'PK': 'USER#123', 'SK': 'PROFILE'},
UpdateExpression='SET #name = :name, version = version + :inc',
ConditionExpression='version = :current_version',
ExpressionAttributeNames={'#name': 'name'},
ExpressionAttributeValues={
':name': 'New Name',
':inc': 1,
':current_version': 5
}
)
CLI Reference
Table Operations Command Description aws dynamodb create-tableCreate table aws dynamodb describe-tableGet table info aws dynamodb update-tableModify table/indexes aws dynamodb delete-tableDelete table aws dynamodb list-tablesList all tables
Item Operations Command Description aws dynamodb put-itemCreate/replace item aws dynamodb get-itemRead single item aws dynamodb update-itemUpdate item attributes aws dynamodb delete-itemDelete item aws dynamodb queryQuery by key aws dynamodb scanFull table scan
Batch Operations Command Description aws dynamodb batch-write-itemBatch write (25 max) aws dynamodb batch-get-itemBatch read (100 max) aws dynamodb transact-write-itemsTransaction write aws dynamodb transact-get-itemsTransaction read
Best Practices
Data Modeling
Design for access patterns — know your queries before designing
Use composite keys — PK for grouping, SK for sorting/filtering
Prefer query over scan — scans are expensive
Use sparse indexes — only items with index attributes are indexed
Consider single-table design for related entities
Performance
Distribute partition keys evenly — avoid hot partitions
Use batch operations to reduce API calls
Enable DAX for read-heavy workloads
Use projections to reduce data transfer
Cost Optimization
Use on-demand for variable workloads
Use provisioned + auto-scaling for predictable workloads
Set TTL for expiring data
Archive to S3 for cold data
Troubleshooting
Throttling Symptom: ProvisionedThroughputExceededException
Hot partition (uneven key distribution)
Burst traffic exceeding capacity
GSI throttling affecting base table
# Use exponential backoff
import time
from botocore.config import Config
config = Config(
retries={
'max_attempts': 10,
'mode': 'adaptive'
}
)
dynamodb = boto3.resource('dynamodb', config=config)
Hot Partitions # Check consumed capacity by partition
aws cloudwatch get-metric-statistics \
--namespace AWS/DynamoDB \
--metric-name ConsumedReadCapacityUnits \
--dimensions Name=TableName,Value=Users \
--start-time $(date -d '1 hour ago' -u +%Y-%m-%dT%H:%M:%SZ) \
--end-time $(date -u +%Y-%m-%dT%H:%M:%SZ) \
--period 60 \
--statistics Sum
Add randomness to partition keys
Use write sharding
Distribute access across partitions
Query Returns No Items
Verify key values exactly match (case-sensitive)
Check key types (S, N, B)
Confirm table/index name
Review filter expressions (they apply AFTER read)
Scan Performance Issue: Scans are slow and expensive
Use parallel scan for large tables
Create GSI for the access pattern
Use filter expressions to reduce returned data
# Parallel scan
import concurrent.futures
def scan_segment(segment, total_segments):
return table.scan(
Segment=segment,
TotalSegments=total_segments
)
with concurrent.futures.ThreadPoolExecutor() as executor:
results = list(executor.map(
lambda s: scan_segment(s, 4),
range(4)
))
References Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Set up and use 1Password CLI (op). Use when installing the CLI, enabling desktop app integration, signing in (single or multi-account), or reading/injecting/running secrets via op.
CLI to manage emails via IMAP/SMTP. Use `himalaya` to list, read, write, reply, forward, search, and organize emails from the terminal. Supports multiple accounts and message composition with MML (MIME Meta Language).
Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Set up and use 1Password CLI (op). Use when installing the CLI, enabling desktop app integration, signing in (single or multi-account), or reading/injecting/running secrets via op.
CLI to manage emails via IMAP/SMTP. Use `himalaya` to list, read, write, reply, forward, search, and organize emails from the terminal. Supports multiple accounts and message composition with MML (MIME Meta Language).