Yihui Xie • 3/29/2026

The Surprising Slowness of `textConnection()` in R

This article investigates why textConnection() in R is surprisingly slow, using a case where quarto render took 35 seconds vs rmarkdown's 0.5 seconds for long output. Profiling revealed garbage collection consumed 56% of runtime, caused by textConnection appending lines via c() in a loop, leading to O(n^2) allocations and copies. The fix is using file() connections instead, which delegate buffering to the OS. The article provides technical debugging insights and performance optimization for R programming.

0 comments

#performance #profiling #Garbage Collection