cgo error or something else?

Hi, I am using oracle times ten database and my code is as follow:

func main() {
        godrv.SetAutoCommit(false)
        db, err := sql.Open("goracle", os.Getenv("ORACLE_DSN"))
        if err != nil {
                log.Println(err)
                os.Exit(1)
        }
        db.SetMaxOpenConns(128)
        db.SetMaxIdleConns(64)
        // 10 go routine insert
        runtime.GOMAXPROCS(4)
        var wg sync.WaitGroup
        log.Println(time.Now())
        var numInsert = 2500
        for i := 0; i < 4; i++ {
                wg.Add(1)
                go func() {
                        tx, err := db.Begin()
                        exit(err)
                        stmt, err := tx.Prepare("INSERT INTO users VALUES(?)")
                        defer stmt.Close()
                        for i := 0; i < numInsert; i++ {
                                _, err = stmt.Exec(time.Now().UnixNano())
                                exit(err)
                        }
                        err = tx.Commit()
                        exit(err)
                        wg.Done()
                }()
        }
        wg.Wait()
        log.Println(time.Now())
}

If I set numInsert to 250, it will not raise any error. But while it's set to 2500 or more, the error is like this:

I am not sure if it's due to my misuse of goracle or any other error. I think the code is simple as it is. BTW, if I start more than 4 go routines to insert data into database, it raised the same error which really confused me. Would you help?

I dived into the source code and found this:

// MakeDSN makea a data source name given the host port and SID.
func MakeDSN(host string, port int, sid, serviceName string) string {
    var format, conn string
    if sid != "" {
        conn = sid
        format = ("(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=" +
            "(PROTOCOL=TCP)(HOST=%s)(PORT=%d)))(CONNECT_DATA=(SID=%s)))")
    } else {
        conn = serviceName
        format = ("(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=" +
            "(PROTOCOL=TCP)(HOST=%s)(PORT=%d)))(CONNECT_DATA=" +
            "(SERVICE_NAME=%s)))")
    }
    if format == "" {
        return ""
    }
    return fmt.Sprintf(format, host, port, conn)
}

Well, is the program connected to database via tcp? Maybe I prefer the OCI(direct access database via shared memory) way which I found my conf file contains

lol. Actually I do not know much about oracle times ten database. Anyway, I just hope that it could work stable because it is used in production :-)

[tgulacsi]

I think you're right, the default connection method is through TCP, thus each connection implies an OS thread (with at least 8kb memory), thus too much of them means a lot of memory - this matches the panic message, which is in malloc.

You can use your hand crafted/stolen from output of tnsping DSN as you wish, as
'username/password@(DESCRIPTION=....)'.

Well, I have 128G ram on my server and it should be enough no matter if it is through tcp, right?

I simply want to use the godrv but seems godrv does not use the MakeDSN function to construct the DSN. So, any changes can I make ?

My code has been changed to this:

But error is the same:

If I only start one go routine, it will also raise the same error.
But if I do the same job in a for loop, nothing is wrong.
Unfortunately, we have to support multi go routines, like, many users login in the mean time or something else.

[tgulacsi]

No, your first report was about setRowCount, this latter is at getBindInfo. But both are at malloc.goc.

Which version of go do you use? The latest stable is 1.2.1, and that has something else at line 73 (http://golang.org/src/pkg/runtime/malloc.goc) - can you try with the latest go?

I am using the latest stable go.

[tgulacsi]

I'm just shooting blindly, as I cannot reproduce this issue (no TimesTen here), but what about runtime.LockOSThread() ?

Another blind shot could be trying github.com/tgulacsi/gocilib - that's C code is not written by me :)