70 lines
1.3 KiB
Go
70 lines
1.3 KiB
Go
package resources
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import (
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"context"
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"database/sql"
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"log"
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)
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func QueryDeadlock(ctx context.Context, db *sql.DB) {
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rows, _ := db.QueryContext(ctx, "SELECT id, name FROM users")
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defer rows.Close()
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for rows.Next() {
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var id int
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var name string
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_ = rows.Scan(&id, &name)
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rowsAddrs, _ := db.QueryContext(
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ctx,
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"SELECT address FROM addresses WHERE user_id = $1",
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id,
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)
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defer rowsAddrs.Close()
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var addr string
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_ = rowsAddrs.Scan(&addr)
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log.Println(id, name, addr)
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}
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}
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func QueryDeadlockFixOne(ctx context.Context, db *sql.DB) {
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type Res struct {
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ID int
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Name string
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Addr string
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}
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var values []Res
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rows, _ := db.QueryContext(ctx, "SELECT id, name FROM users")
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for rows.Next() {
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var res Res
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_ = rows.Scan(&res.ID, &res.Name)
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values = append(values, res)
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}
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rows.Close()
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for _, v := range values {
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_ = db.QueryRowContext(
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ctx, "SELECT address FROM addresses WHERE user_id = $1", v.ID,
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).Scan(&v.Addr)
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log.Println(v)
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}
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}
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func QueryDeadlockFixTwo(ctx context.Context, db *sql.DB) {
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rows, _ := db.QueryContext(
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ctx,
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"SELECT u.id, u.name, a.address FROM users AS u, addresses as a WHERE u.id == a.user_id",
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)
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defer rows.Close()
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for rows.Next() {
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var id int
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var name string
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var addr string
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_ = rows.Scan(&id, &name, &addr)
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log.Println(id, name, addr)
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}
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}
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