How to speed up rendering of html documents

[RKonstantinR]

Description

In my case I generate html files based on a quarto document and then take pictures of them using webshot2.

Вut quarto_render function has a large overhead for render and saving the html file.

For example, this code runs in 0.014 sec.

tictoc::tic()
library(dplyr)

mtcars %>% select(params$col_name)
tictoc::toc()

But render an html file already takes about 4 seconds.

tic(msg = "Render")
quarto_render("repex_html.qmd", quiet = TRUE)
toc()
Render: 4.064 sec elapsed

repex_html.qmd

---
title: "repex_html"
format: html
params: 
    col_name: "cyl"
---

```{r}

library(dplyr)

mtcars %>% select(params$col_name)

```

Is there a way to speed up rendering?

[cderv]

Quarto runs R as part of its processing but also does a lot of other things, and that takes time.

I would say a fair comparaison would already be to compare with R run in a new background process.

> tictoc::tic()
> res <- callr::r_safe(function() {
+     params = list()
+     params$col_name = "cyl"
+     library(dplyr)
+     mtcars %>% select(params$col_name)
+     })
> tictoc::toc()
1.52 sec elapsed

Then there will be at least knitr and rmarkdown layer running, with a Pandoc conversion. This adds more second

> tictoc::tic()
> res <- callr::r_safe(function() {
+     rmarkdown::render("test2.qmd")
+     })
> tictoc::toc()
3.01 sec elapsed

Quarto does then do a lots of processing before and after pandoc renders, which adds some timing

> tictoc::tic()
> quarto::quarto_render("test2.qmd", quiet = TRUE)
> tictoc::toc()
4.88 sec elapsed

On my environment, 2 sec more.

We are tracking performance and always trying to improve. Though, you won't be able to make a quarto rendering going as fast as just running R code in a R console.

Quarto offers some options to manage execution to freeze or cache outputs : https://quarto.org/docs/projects/code-execution.html
But this will not make a lot of difference if you computation code is already quick.

Hope it helps

[RKonstantinR]

Thanks for reply.

Apparently, in my case, the best solution would be to check data relevance before rendering.