Spannerのテーブルから全レコード削除する君２

spanner_delete_all_rows_by_multi_pk.go

func deleteAllRowsByMultiPK(ctx context.Context, db *spanner.Client, tableName string, primaryFirstKeyName string, primarySecondKeyName string) {
	var primaryKeys []*spanner.Mutation

	stmt := spanner.Statement{SQL: "SELECT `" + primaryFirstKeyName + "`, `" + primarySecondKeyName + "` 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 primaryFirstKey string
		var primarySecondKey string
		if err := row.Columns(&primaryFirstKey, &primarySecondKey); err != nil {
			panic(err)
		}

		primaryKeys = append(primaryKeys,
			spanner.Delete(tableName, spanner.Key{primaryFirstKey, primarySecondKey}),
		)
	}

	var deleteMutations []*spanner.Mutation
	for i, key := range primaryKeys {
		deleteMutations = append(deleteMutations, key)
		if i%1000 == 0 {
			_, err := db.Apply(ctx, deleteMutations)
			if err != nil {
				panic(err)
			}
			deleteMutations = []*spanner.Mutation{}
		}
	}

	if len(deleteMutations) != 0 {
		_, err := db.Apply(ctx, deleteMutations)
		if err != nil {
			panic(err)
		}
	}
}