|
| 1 | +package mysql |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "database/sql" |
| 6 | + "encoding/csv" |
| 7 | + "fmt" |
| 8 | + "io" |
| 9 | + "reflect" |
| 10 | + "strings" |
| 11 | + |
| 12 | + "github.com/go-sql-driver/mysql" |
| 13 | + "github.com/xo/usql/drivers" |
| 14 | +) |
| 15 | + |
| 16 | +func copyRows(ctx context.Context, db *sql.DB, rows *sql.Rows, table string) (int64, error) { |
| 17 | + localInfileSupported := false |
| 18 | + row := db.QueryRowContext(ctx, "SELECT @@GLOBAL.local_infile") |
| 19 | + err := row.Scan(&localInfileSupported) |
| 20 | + if err == nil && localInfileSupported && !hasBlobColumn(rows) { |
| 21 | + return bulkCopy(ctx, db, rows, table) |
| 22 | + } else { |
| 23 | + return drivers.CopyWithInsert(func(int) string { return "?" })(ctx, db, rows, table) |
| 24 | + } |
| 25 | +} |
| 26 | + |
| 27 | +func bulkCopy(ctx context.Context, db *sql.DB, rows *sql.Rows, table string) (int64, error) { |
| 28 | + mysql.RegisterReaderHandler("data", func() io.Reader { |
| 29 | + return toCsvReader(rows) |
| 30 | + }) |
| 31 | + defer mysql.DeregisterReaderHandler("data") |
| 32 | + tx, err := db.BeginTx(ctx, nil) |
| 33 | + if err != nil { |
| 34 | + return 0, err |
| 35 | + } |
| 36 | + var cnt int64 |
| 37 | + csvSpec := " FIELDS TERMINATED BY ',' " |
| 38 | + stmt := fmt.Sprintf("LOAD DATA LOCAL INFILE 'Reader::data' INTO TABLE %s", |
| 39 | + // if there is a column list, csvSpec goes between the table name and the list |
| 40 | + strings.Replace(table, "(", csvSpec+" (", 1)) |
| 41 | + // if there wasn't a column list in the table spec, csvSpec goes at the end |
| 42 | + if !strings.Contains(table, "(") { |
| 43 | + stmt += csvSpec |
| 44 | + } |
| 45 | + res, err := tx.ExecContext(ctx, stmt) |
| 46 | + if err != nil { |
| 47 | + tx.Rollback() |
| 48 | + } else { |
| 49 | + err = tx.Commit() |
| 50 | + if err == nil { |
| 51 | + cnt, err = res.RowsAffected() |
| 52 | + } |
| 53 | + } |
| 54 | + return cnt, err |
| 55 | +} |
| 56 | + |
| 57 | +func hasBlobColumn(rows *sql.Rows) bool { |
| 58 | + columnTypes, err := rows.ColumnTypes() |
| 59 | + if err != nil { |
| 60 | + return false |
| 61 | + } |
| 62 | + for _, ct := range columnTypes { |
| 63 | + if ct.DatabaseTypeName() == "BLOB" { |
| 64 | + return true |
| 65 | + } |
| 66 | + } |
| 67 | + return false |
| 68 | +} |
| 69 | + |
| 70 | +func toCsvReader(rows *sql.Rows) io.Reader { |
| 71 | + r, w := io.Pipe() |
| 72 | + go writeAsCsv(rows, w) |
| 73 | + return r |
| 74 | +} |
| 75 | + |
| 76 | +// writeAsCsv writes the rows in a CSV format compatible with LOAD DATA INFILE |
| 77 | +func writeAsCsv(rows *sql.Rows, w *io.PipeWriter) { |
| 78 | + defer w.Close() // noop if already closed |
| 79 | + columnTypes, err := rows.ColumnTypes() |
| 80 | + if err != nil { |
| 81 | + w.CloseWithError(err) |
| 82 | + return |
| 83 | + } |
| 84 | + values := make([]interface{}, len(columnTypes)) |
| 85 | + valueRefs := make([]reflect.Value, len(columnTypes)) |
| 86 | + for i := 0; i < len(columnTypes); i++ { |
| 87 | + valueRefs[i] = reflect.New(columnTypes[i].ScanType()) |
| 88 | + values[i] = valueRefs[i].Interface() |
| 89 | + } |
| 90 | + record := make([]string, len(values)) |
| 91 | + csvWriter := csv.NewWriter(w) |
| 92 | + for rows.Next() { |
| 93 | + if err = rows.Err(); err != nil { |
| 94 | + break |
| 95 | + } |
| 96 | + err = rows.Scan(values...) |
| 97 | + if err != nil { |
| 98 | + break |
| 99 | + } |
| 100 | + for i, valueRef := range valueRefs { |
| 101 | + // NB: Does not work for BLOBs. Use regular copy if there are BLOB columns |
| 102 | + record[i] = fmt.Sprintf("%v", valueRef.Elem().Interface()) |
| 103 | + } |
| 104 | + err = csvWriter.Write(record) |
| 105 | + if err != nil { |
| 106 | + break |
| 107 | + } |
| 108 | + } |
| 109 | + if err == nil { |
| 110 | + csvWriter.Flush() |
| 111 | + err = csvWriter.Error() |
| 112 | + } |
| 113 | + w.CloseWithError(err) // same as w.Close(), if err is nil |
| 114 | +} |
0 commit comments