Artem Krylysov

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 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.

A few months ago I released the first version of an embedded on-disk key-value store written in Go. The store is about 10 times faster than LevelDB for random lookups. I'll explain why it's faster, but first let's talk about the reason why I decided to create my own key-value store.

Running Go on AWS Lambda is not something totally new - developers figured out how to launch Go binaries from Python a while ago, but it wasn't convenient and had some performance implications.

A few days ago Amazon announced an official Go support for AWS Lambda.

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() {
    C.foo(C.int(123)) // x: 123
}

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

package main

import (
    "net/http"
    _ "net/http/pprof"
)

func hiHandler(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("hi"))
}

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