AWS DynamoDB and Lambda: Scan optimizations / performance

To store api-gateway websocket-connections, I use a dynamoDB-table. When posting to stored connections, I retrieve the connection in a lambda-function via: const dynamodb = new DynamoDB.DocumentClient(); const { Items, Count } = await dynamodb.scan({ TableName: ‘Websocket’ }).promise(); // post to connections This is not really fast; the query takes around 400 – 800ms which could…

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Difference in performance(traversing, adding, removing, getting) between LinkedList and ArrayList using Iterator design pattern

I have been looking deeper into different collection implementations and i wonder if there is any performance difference when implementing iterator on various List types(Like the previously mentioned in the title). As we all know iterating over ArrayList is faster as opposed to LinkedList. However is the case same when we iterate over both using…

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javac not including .png images in lib directory when compiling

I’ve been trying to get this program to work, everything is ok apart from the missing images that are not displayed when i run it. Before execution myprogram has the following directories: lib, src, doc cd /home/vik/myprogram javac -d bin -cp /home/vik/myprogram/lib /home/vik/myprogram/src/com/photoalbum/*/*.java java -cp bin:lib com.photoalbum.start.Main the directory /lib contains only 2 .png images…

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Header file C++

when i’m trying to compile program but it says that i have an error in row when i’m to create a function pow(int base ,int exp),it says that ‘pow’: illegal qualified name in member declaration,here’s my code: Math.h: #pragma once static class Math { public: static int Math::pow(int base,int exp); }; Math.cpp: #include “Math.h” int…

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