*sql.DB invalid memory address or nil pointer dereference #150
Comments
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We need the following information:
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go version go1.1.2 darwin/amd64 |
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I think the panic shouldn't occur with v1.0.3, which is a bugfix release we released yesterday ( But I'm investigating further, the stacktrace looks really strange to me. The panic is caused by a v1.0.3 can at least prevent the nil-pointer panic, since it checks |
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Can you reproduce this error? |
/Users/jinke/golang/src/cds_spider/newCar/koubei/log.go func AddOk(source string, count int) error {
row := dbpool.DB.QueryRow("SELECT * FROM cheduoshao_spider_status.koubei WHERE source=? AND spider_date=?", source, gcode.Date())
var (
id, quantity int
sources, spider_date string
)
row.Scan(&id, &sources, &quantity, &spider_date)
if id == 0 {
stmt, err := dbpool.DB.Prepare("INSERT cheduoshao_spider_status.koubei SET source=?, quantity=?, spider_date=?")
if err != nil {
return err
}
defer stmt.Close()
_, err = stmt.Exec(source, 1, gcode.Date())
if err != nil {
return err
}
} else {
dbpool.DB.Exec("UPDATE main.koubei SET quantity=? WHERE id=?", quantity+1, id)
}
return nil
}dbpool.DB.Exec("UPDATE main.koubei SET quantity=? WHERE id=?", quantity+1, id) IS ERROR |
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Seem to have not found such a situation before, my system is OS X 10.9 |
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Check if |
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I tried a few times more, I just delete the old version, go get it again |
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I think I was able to reproduce this bug. Once again, this bug is related to https://codereview.appspot.com/14920046 / Go issue 5718 (or #98, #142). v1.0.3 includes #143, which at least avoids the panics. v1.1, which will be released in a few hours, will include #151, which improves this a bit more. I'd suggest to either manually patch your Go version with https://codereview.appspot.com/14920046 or avoid And a note to your code above: Here is how I would modify your code above: func AddOk(source string, count int) error {
var (
id, quantity int
sources, spider_date string
)
if err := dbpool.DB.QueryRow("SELECT * FROM cheduoshao_spider_status.koubei WHERE source=? AND spider_date=?", source, gcode.Date()).Scan(&id, &sources, &quantity, &spider_date); err != nil {
return err
}
if id == 0 {
if _, err =: dbpool.DB.Exec("INSERT cheduoshao_spider_status.koubei SET source=?, quantity=?, spider_date=?", source, 1, gcode.Date()); err != nil {
return err
}
} else {
if _, err =: dbpool.DB.Exec("UPDATE main.koubei SET quantity=? WHERE id=?", quantity+1, id); err != nil {
return err
}
}
return nil
} |
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Ok,Thanks! |
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I'm having too this problem, go version is This is the function _getJSON, that returns a JSON-Encoded string of the results: |
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@danilopolani Your db is nil. |
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Why should it be nil? I have a db var outside the functions Then it is called in |
Then, db is local variable of main, not global variable Without you provide complete reproducible code, no one can point out |
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@methane, you were right, I had to change |
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Just ran into same issue. Surprised that this was issue. |
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@danilopolani @methane you guys saved my time |
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@danilopolani You are right, thank you very much for your help, I have been searching for this problem for a long time, thank you |
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running into same issue.. how do i use @danilopolani solution? |
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Thanks @methane @danilopolani I made the same mistake, luckily I found this discussion. |
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OMG, I could have never imagined the solution was about variables scoping. |
*sql.DB invalid memory address or nil pointer dereference Source solution: go-sql-driver/mysql#150 (comment)
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2021 and you saved my day too! |
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@methane |
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more over 2024, the same story... |
//The file /Users/jinke/golang/src/cds_spider/common/dbpool/mysql.go
//The file /Users/jinke/golang/src/cds_spider/newCar/koubei/koubei.go
"stmt, err := dbpool.DB.Prepare" is Error invalid memory address or nil pointer dereference
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