database/sql: rollback is freezing if rows not be closed

[kshvakov]

What version of Go are you using (go version)?

go version devel +b225051 Mon Jun 5 02:35:47 2017 +0000 linux/amd64

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/kshvakov/gopath"
GORACE=""
GOROOT="/home/kshvakov/go"
GOTOOLDIR="/home/kshvakov/go/pkg/tool/linux_amd64"
GCCGO="/usr/bin/gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build025114464=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
PKG_CONFIG="pkg-config"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"

What did you do?

package main

import (
	"database/sql"
	"fmt"
	"log"

	_ "github.com/lib/pq"
)

func main() {
	connect, err := sql.Open("postgres", "postgres://[email protected]:5432/example?sslmode=disable")
	checkErr(err)
	if tx, err := connect.Begin(); err == nil {
		if _, err = tx.Query("SELECT 1"); err == nil {
			// rows.Close()
			fmt.Println("rollback")
			tx.Rollback()
			fmt.Println("rollback: done!")
		}
		_, err = tx.Query("SELECT 1")
		fmt.Println(err)
	}
}

func checkErr(err error) {
	if err != nil {
		log.Fatal(err)
	}
}

What did you expect to see?

rollback
rollback: done!
sql: Transaction has already been committed or rolled back

What did you see instead?

rollback

[odeke-em]

/cc @kardianos

[gopherbot]

CL https://golang.org/cl/44812 mentions this issue.

[kardianos]

I agree that this is an issue, though a case could be made this is a coding error. I've send the above CL which would alter the behavior so the Rows will be closed if the parent Tx is closed in any way while it is open.