Questions tagged [caching]
Questions regarding cache algorithms by applications and implementations of information caching by database engines and other information repository and presentation applications.
244
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3
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Optimizing writes over the same entity in relational DB
I am developing a micro service that saves votes to a relational database. I have a use case with an entity that represents an aggregation of votes. I receive events from voters saying that they vote ...
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8
votes
4
answers
3k
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How to perform consistent hashing on any Python object that works with hash()?
I have a Python library that performs a kind of calculation given a parameter-object. A requirement of the parameter object is that it be both hashable and serializable. It's a long calculation, so it ...
- 101
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0
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55
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Cache publishing updates, or clients polling the cache?
Context:
I am working on an application which loads a cache on startup - periodically refreshed. However it turns out that this cache is something which is very general and can be used by other ...
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1
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51
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Is it practical to cache multiple instances of variable API data (updates hourly for each instance) for N users?
I'm using flask with SQLAlchemy on a postgresql database for a mobile app I'm building. My application allows a single user to save lets say up to 5 different locations which are saved in the database....
- 1
12
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6
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1k
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How to avoid violating the SRP in a class to manage caching?
Note: The code sample is written in c#, but that shouldn't matter. I've put c# as a tag because I can't find a more appropiate one. This is about the code structure.
I'm reading Clean Code and trying ...
- 40.5k
0
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1
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107
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Optimal way Implement a Session Cache
I have an App that connects with Salesforce and do different operations. So I'm trying to implement a Session Cache for the Application to avoid repetitive login calls.
So far what I have done is I ...
- 194k
19
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6
answers
32k
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Best practices for unit testing methods that use cache heavily?
I have a number of business logic methods that store and retrieve (with filtering) objects and lists of objects from cache.
Consider
IList<TObject> AllFromCache() { ... }
TObject FetchById(...
- 70.3k
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0
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79
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How to generate idempotency token for remote cache
We are using a client library over Memcache.
This library has a lot of logic for Memcache client and is indispensable in current form.
One of the API of the library is put which internally just uses ...
- 107
14
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5
answers
6k
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How can I efficiently diff a CSV file against a database?
I have an inventory of products stored in Postgres. I need to be able to take a CSV file and get a list of changes—the things in the CSV file that are different to what is in the database. The CSV ...
- 1,250
12
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5
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9k
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What data structure should I use for this caching strategy?
I am working on a .NET 4.0 application, that performs a rather expensive calculation on two doubles returning a double. This calculation is performed for each one of several thousand items. These ...
- 103
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2
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856
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Simple Java Spring Boot Cache for multi-container system
I have a requirement to cache some static data as it is being consumed by our system. There is a static API that gives a map of records and we are fetching the corresponding record based on request.
...
- 1,339
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0
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60
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Effective cache solution to have the newest data in React Native
Goal
We have an app with different articles. I want to cache an article when the user has read it, but make sure that I display the latest data. I came up with this hook:
React.useEffect(() => {
...
- 101
3
votes
4
answers
3k
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How to align on both word size and cache lines in x86
From what it sounds like, a 64 bit processor means aligning to 64 bits, which means if you have unicode utf-8 stored in there, each 8-bit chunk would take up 64 bits of space. That doesn't really make ...
- 767
1
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1
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91
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Contextual Implementation Overhead vs Redundancy
I have an application that has use cases relative to where it is used. A local client and server, where all the server data is in a single location and the client queries that server knowing it is ...
- 68.9k
-1
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1
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256
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Can I call a WCF endpoint from ASP.Net Web API?
I have a web api with controller methods that use rest http(post/get calls).
Clients consume this API with normal httpclient calls and I pass an http response back.
My use case is I have a legacy ...
CommunityBot
- 1
0
votes
0
answers
38
views
Cache graph with hierarchy
I'm looking to build a graph that's tied to any caching system that I can interact with. Its only goal is when an item is deleted, based on its "linked items", to also delete these. A partial rebuild ...
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607
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13
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264k
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So Singletons are bad, then what?
There has been a lot of discussion lately about the problems with using (and overusing) Singletons. I've been one of those people earlier in my career too. I can see what the problem is now, and yet, ...
- 103
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1
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1k
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Can cache be shared among services via Redis/Hazelcast?
Can cache be shared among services via Redis/Hazelcast?
I have a few microservices A, B, C etc. The Microservice C is mainly for helping other services. Service C periodically updates cache - so that ...
- 166
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1
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67
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Should cached data be kept separate from primary tables?
I have a table in an SQL database for storing information about some business object that looks something like this (details changed so as not to give away what company I work for):
CREATE TABLE ...
- 32.5k
-1
votes
1
answer
30
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Options to maintain queue of resources that will be uniquely returned
I need to maintain a queue of resources in a cache such that when multiple clients try to pop elements from the queue concurrently, each element would be uniquely returned to only one of the clients. ...
- 13.8k
0
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1
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231
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Low Latency for multi-million record database in a web app [closed]
As a forewarning, this is for a school project with other school teammates, so my question is just for the sake of learning best practices. We are creating a recommendation system web app which ...
- 3,169
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0
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98
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Should I use ETag Cache on all HTTP Responses?
I was wondering if there is any downside to using E-Tag cache for every request and response.
To be more specific, I'm building a data heavy SPA connected to a Laravel API and the client insists that ...
- 103
-1
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2
answers
162
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Should I make all my business logic depend on the data that comes from the cache?
One of my web services hits a few hundred thousand visits per day where most of the operations are CRUD and we are thinking to get a cache sitting in front of our SQL database.
I have had implemented ...
- 45.4k
8
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2
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4k
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Caching by in-memory dictionaries. Are we doing it all wrong?
This approach is pretty much the accepted way to do anything in our company.
A simple example
When a piece of data for a customer is requested from a service, we fetch all the data for that customer(...
- 2,754
1
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2
answers
270
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How do I decide an initial in-memory cache size given my DB size and expected load throughput?
(Purely for learning purposes)
Say the DB contains 1 billion rows with 200 bytes per row = 200 GB of data.
The traffic at peak is 1000 requests/s, with each request asking for one DB row.
What cache ...
CommunityBot
- 1
0
votes
2
answers
357
views
What are the differences between memory coherence and cache coherence?
https://en.wikipedia.org/wiki/Memory_coherence says:
Memory coherence is an issue that affects the design of computer
systems in which two or more processors or cores share a common area
of memory.[1]...
- 111
10
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4
answers
1k
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Are there CPUs that perform this possible L1 cache write optimization?
When the CPU with an L1 cache does a write, what normally happens is that (assuming that the cache line that it is writing to is already in the L1 cache) the cache (in addition to updating the data) ...
- 191
3
votes
1
answer
970
views
Best strategy to flush Redis cache used in a distributed environment
Current setup:
We follow the cache-first strategy right now.
Always fetch from the cache first.
If absent in cache, fetch from DB and update the cache.
Cache TTL is 30 min. After this, the cache-key ...
- 68.9k
7
votes
3
answers
8k
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Is caching Access Tokens on the back end of a Web Application a good idea? (access_token storage best practices)
Let's suppose we have a Web Application that uses an Open Id Connect service provider, the Web Application uses the Authorization Code flow to get access to a different API, and therefore gets an ...
CommunityBot
- 1
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votes
2
answers
316
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Taking load off of Rest API with Cloudflare Cache?
I have a server running on AWS which serves data, that is not changing too often (think about a CMS system) to multiple clients.
This service is critical for most of the client apps, thus I want to ...
- 68.9k
0
votes
1
answer
149
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Is it possible for the CPU to read or write to the cache, while I/O device is reading main memory?
If an I/O device is reading the main memory (directly) then is it possible for the CPU to access the cache?
I think it's possible for the CPU to access the cache in case of a hit. But in case of a ...
- 40.5k
-2
votes
1
answer
228
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Recommended way of caching weather information
I'm developing an application that will show some weather information based on the user's location. Since the weather forecast is just a very small feature of the app that complements the main ones, I ...
- 56.2k
0
votes
1
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46
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What is the added value of using cache control header on top of CDN for a web application?
I'm a developer on a website which has a server which serves HTML and another server which handles API requests. I use a CDN to cache both the HTML and API responses. I feel that it gives me all the ...
- 32.5k
-1
votes
1
answer
113
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Design review for a Cache aside system
I am maintaining a system where a list of string ids are stored against a container (using the term here as a generic entity) object. The database used is MySQL and the table structure looks like this....
CommunityBot
- 1
-4
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1
answer
260
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Design a login system
I have a task of designing login system with the requirement below:
If the user login over three times, lock account for the first 5 minutes. The next failed 3 times login-in will lock the user ...
- 13.8k
1
vote
0
answers
135
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Near Real-Time Data Aggregation using Complex Queries
We are working on a multi-tenant SaaS product that has a ledger of all tenant customer transactions, which we use to track invoice states on a line-item level. This particular application will result ...
- 227
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votes
4
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193
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Where is network data stored while awaiting to be written to disk?
I think download rates may depend on these 3 factors: the Network Infrastructure (router, VPN, network card, towers), the RAM or cache, the Final Storage (HDD or SDD or whatnot).
So we take this as an ...
- 1,765
-1
votes
1
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95
views
Strategy to make sure relevant cache records are expired on data update
In our database, we have around 150 different tables. However, there are a handful of them that are key, as in they get referenced pretty much everywhere. We also have quite a few reports that we pull ...
CommunityBot
- 1
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2
answers
1k
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Website redirect in cache to old website
So I've developed a website for a client, however he used to use this url with a re-direct to 'another' site of his. I had the re-direct cancelled, but whoever visited their old website before, still ...
CommunityBot
- 1
0
votes
1
answer
40
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Fast sliding cache counter
We have an email system that handles incoming and outgoing emails, the risk is that we get so called feedback loops, a bounce email is answered with another bounce etc. We have safeguards in place to ...
- 70.3k
3
votes
1
answer
478
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ASP.NET MVC Caching of ViewModels
My question is regarding caching and ViewModels in ASP.NET (Core) MVC.
I have a service which injects a Repository<T> which is used to fetch domain models from the database. The service layer ...
- 68.9k
1
vote
3
answers
3k
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Redis write-through cache vs write-behind cache (message queue?)
I have a simple use case:
Newsfeeds aggregated based on posts that are linked to geopoints
Users can comment on feed posts
Users can like feed posts and comments
I'm certain that Redis as a cache ...
- 806
3
votes
1
answer
160
views
Design that hides cache as an implementation detail
I have a type which is fairly heavy (maintains an off-heap object), and which can be uniquely derived from a String. It requires cleanup, so of course the type has a close() method, but it is used in ...
CommunityBot
- 1
0
votes
0
answers
84
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Handle big data sets in a web application in combination with real-time communication between web-clients
We have the following use case to be developing:
A web application that shows a data table / data grid with up to 100000 rows and 30-50 columns. Each column is filterable and sortable. The web ...
- 125
2
votes
2
answers
144
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Where to place an in-memory cache to handle repetitive bursts of database queries from several downstream sources, all within a few milliseconds span
I'm working on a Java service that runs on Google Cloud Platform and utilizes a MySQL database via Cloud SQL. The database stores simple relationships between users, accounts they belong to, and ...
- 425
1
vote
2
answers
261
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How to cache duplicate fetch and save calls that are fired within the same second
I have a service which provides an endpoint that fetches from another service, saves, and returns an record.
Here are the details:
The caller calls the endpoint using an identifier (say a customer's ...
- 13.8k
7
votes
3
answers
820
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Best way to reduce database writes?
I couldn't find a similar enough thread, so i'm making a new one. My question is about reducing database writes. Context is that I have an application which increments a number in a database every ...
- 12.3k
-2
votes
2
answers
216
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Caching expensive sql queries on first page load
I have a web application with an express/node backend using typeorm and PostgreSQL. The home page in my app is a query with lots of inner joins that shows the user a complex report. This query takes ...
- 11.8k
0
votes
1
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529
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Caching or in-memory table in Azure for performance
I am building an Angular web application that retrieves part of its data from a Azure SQL Database table via APIs developed in Azure Functions (with Azure API Management at the API Gateway). The data ...
- 153
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1
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115
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Writing a data-oriented ECS update loop that handles multiple components
So I have an engine in progress that's structured like this:
entities are simple ids (unsigned short)
components are stored in pools which are static members
systems are stored by the manager, and ...
