AWS Lambda上的DynamoDB扫描速度较慢可能是由于网络延迟或配置不当引起的。以下是一些解决方法和代码示例,可以帮助提高Lambda上DynamoDB扫描的速度:
batchGet
方法一次从表中获取多个项目,或者使用batchWrite
方法一次写入多个项目。import boto3
def batch_get_items(table_name, keys):
dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table(table_name)
response = table.batch_get_item(
RequestItems={
table_name: {
'Keys': keys
}
}
)
return response['Responses'][table_name]
scan
方法的ExclusiveStartKey
参数来指定下一页的起始位置。import boto3
def scan_items(table_name, filter_expression=None, projection_expression=None):
dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table(table_name)
response = table.scan(
FilterExpression=filter_expression,
ProjectionExpression=projection_expression
)
items = response['Items']
while 'LastEvaluatedKey' in response:
response = table.scan(
FilterExpression=filter_expression,
ProjectionExpression=projection_expression,
ExclusiveStartKey=response['LastEvaluatedKey']
)
items.extend(response['Items'])
return items
import boto3
def increase_lambda_memory(event, context):
dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table('your_table_name')
# Perform DynamoDB operations
import boto3
import redis
def get_cached_item(key):
r = redis.Redis(host='your_redis_host', port=your_redis_port, db=0)
item = r.get(key)
if item is None:
dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table('your_table_name')
response = table.get_item(Key={'key': key})
item = response['Item']
# Cache the item in Redis for future use
r.set(key, item)
return item
通过使用上述方法和代码示例,您应该能够提高在AWS Lambda上使用DynamoDB进行扫描的速度。