bigquery: max staleness cannot be retreived/updated

[nonmanager]

Client

https://pkg.go.dev/cloud.google.com/go/bigquery@v1.60.0

Code

e.g.

package main

import (
	"context"
	"fmt"
	"os"
	"time"

	"cloud.google.com/go/bigquery"
)

func main() {
	// Part 1: read current MaxStaleness
	ctx := context.TODO()
	client, _ := bigquery.NewClient(ctx, "my_project")
	table := client.Dataset("my_dataset").Table("my_materialized_view_with_staleness")
	md, _ := table.Metadata(ctx)
	fmt.Printf("%v\n", md.MaterializedView.MaxStaleness)

	// Part 2: update MaxStaleness to 5 hours
	tm := bigquery.TableMetadataToUpdate{
		MaterializedView: md.MaterializedView,
	}
	tm.MaterializedView.MaxStaleness = bigquery.IntervalValueFromDuration(5 * time.Hour)
	_, err := table.Update(ctx, tm, md.ETag)
	if err != nil {
		fmt.Fprintf(os.Stderr, "oops: %v\n", err)
		os.Exit(1)
	}
}

Expected behavior

When run against a MV that has max_staleness set, the code should:

• print the current max staleness interval (for example, 0-0 0 0:30:0)
• update the interval to 0-0 0 5:0:0

Actual behavior

The code:

• prints out <nil> as the current value of MaxStaleness (the actual value, set via SQL, is visible in BQ Studio)
• executes the update, but the MV is unchaged

Additional context

By inspecting the client code, I've observed that the Table returned by the v2 API does return the current max staleness in the root Table.maxStaleness field. However, the client uses Table.materializedView.maxStaleness, which is always empty in the server response.

When it comes to writing, I couldn't get the BigQuery API to change the existing max staleness value. Setting Table.maxStaleness explicitly (instead of Table.materializedView.maxStaleness) in the client library did not work.

By the way, the CDC feature has its own max staleness setting (which applies to tables, not MVs), so I wonder if these two are conflated somewhere in the API/client.

Relevant PR by @alvarowolfx (introduces max staleness to the client).