Artem Krylysov

Posts tagged with golang

Let's build a Full-Text Search engine

Full-Text Search is one of those tools people use every day without realizing it. If you ever googled "golang coverage report" or tried to find "indoor wireless camera" on an e-commerce website, you used some kind of full-text search.

Full-Text Search (FTS) is a technique for searching text in a collection of documents. A document can refer to a web page, a newspaper article, an email message, or any structured text.

Today we are going to build our own FTS engine. By the end of this post, we'll be able to search across millions of documents in less than a millisecond. We'll start with simple search queries like "give me all documents that contain the word cat" and we'll extend the engine to support more sophisticated boolean queries.

String interning in Go

String interning is a technique of storing only one copy of each unique string in memory. It can significantly reduce memory usage for applications that store many duplicated strings.

Handling C++ exceptions in Go

Cgo is a mechanism that allows Go packages call C code. The Go compiler enables cgo for every .go source file that imports a special pseudo package "C". The text in the comment before the import "C" line is treated as a C code. You can include headers, define functions, types and variables - everything a normal C code can do:

package main

#include <stdio.h>

void foo(int x) {
    printf("x: %d\n", x);
import "C"

func main() { // x: 123

Profiling and optimizing Go web applications


This post was updated on 2021-04-25.

Go has a powerful built-in profiler that supports CPU, memory, goroutine and block (contention) profiling.

Enabling the profiler #

Go provides a low-level profiling API runtime/pprof, but if you are developing a long-running service, it's more convenient to work with a high-level net/http/pprof package.

All you need to enable the profiler is to import net/http/pprof and it will automatically register the required HTTP handlers:

package main

import (
    _ "net/http/pprof"

func hiHandler(w http.ResponseWriter, r *http.Request) {

func main() {
    http.HandleFunc("/", hiHandler)
    http.ListenAndServe(":8080", nil)