Shiny App not responding - r

Question

I have written a well functioning Shiny App, and I want to rewrite the code a little bit, to make it more elegant.
My probem: the App is loading for ages, and when it loads, it does not respond anymore. Strange thing that it is functioning well in the old version of the App.
This is what I have right now (after removing nearly everything):
ui.R:
library(shiny)
function(request){shinyUI(fluidPage(
sidebarLayout(
sidebarPanel(
),
mainPanel(
DT::dataTableOutput("table")
)
)
))}
server.R:
library(shiny)
library(DT)
library(crosstalk)
library(tidyverse)
data <- readRDS("report_summary2.rds")
shinyServer(function(input, output, session) {
computeTable <- function(){data %>% select("Year", "Month", "Date", "Transaction")}
output$table <- DT::renderDataTable({
DT::datatable(
data = computeTable(),
filter = "top",
rownames = FALSE,
options = list(
pageLength = 100
)
)
})
})
Unfortunately I cannot share report_summary.rds, as it contains sensitive information, it has like 500.000 rows and 9 columns in total, so dealing with that should not be the issue.
This was working in the old App version like a charm, but now it loads forever, and if I try to use the filters for dataTable (at the top), the App is not responding anymore.
I've been searching and looking, but could not find anything. Possibly anybody sees something?

Answer 1

You are right after > 400 thousand rows DT becomes slow being a single process (as well as Basic Shiny).
Here are some options:
To store and access data in RDBMS or noSQL.
Use Shiny Pro, which allows to split the load through multiple servers\applications.
Check as well architecture of your application (too much reactivity will slow it down).
And of course run a Profiler to find out where are your real bottle-necks. All other options are
somehow cosmetic: usage of global.R, split data table for
quick\small and bigger\slow parts etc.