Spannerのテーブルから全レコード削除する君

spanner_delete_all_rows.go

func deleteAllRows(ctx context.Context, db *spanner.Client, tableName string, primaryKeyName string) {
	var primaryKeys []string

	stmt := spanner.Statement{SQL: `SELECT ` + primaryKeyName + ` FROM ` + tableName}
	iter := db.Single().Query(ctx, stmt)
	defer iter.Stop()
	for {
		row, err := iter.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			panic(err)
		}
		var primaryKey string
		if err := row.Columns(&primaryKey); err != nil {
			panic(err)
		}

		primaryKeys = append(primaryKeys, primaryKey)
	}

	var deleteKeys []string
	for i, key := range primaryKeys {
		deleteKeys = append(deleteKeys, key)
		if i%1000 == 0 {
			if _, err := db.ReadWriteTransaction(
				ctx,
				func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
					stmt := spanner.Statement{SQL: `DELETE FROM ` + tableName + ` WHERE ` + primaryKeyName + ` IN UNNEST (@param)`,
						Params: map[string]interface{}{"param": deleteKeys},
					}
					_, err := txn.Update(ctx, stmt)
					return err
				},
			); err != nil {
				panic(err)
			}

			deleteKeys = []string{}
		}
	}

	if len(deleteKeys) != 0 {
		if _, err := db.ReadWriteTransaction(
			ctx,
			func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
				stmt := spanner.Statement{SQL: `DELETE ` + tableName + ` WHERE ` + primaryKeyName + ` IN UNNEST (@param)`,
					Params: map[string]interface{}{"param": deleteKeys},
				}
				_, err := txn.Update(ctx, stmt)
				return err
			},
		); err != nil {
			panic(err)
		}
	}
}