backupccl: add missing ctx cancel check

adityamaru · adityamaru · commit 6fabaf837bba · 2023-09-25T15:30:16.000-04:00
In #111159 we deduced from the stacks a situation in which the goroutine draining `spanCh` had exited due to a context cancelation but the writer was not listening for a ctx cancelation. This manifests as a stuck restore when using the non-default make simple import spans implementation. Fixes: #111159 Release note: None
diff --git a/pkg/ccl/backupccl/restore_span_covering.go b/pkg/ccl/backupccl/restore_span_covering.go
@@ -519,7 +519,11 @@ func generateAndSendImportSpans(
 			return err
 		}
 		for _, sp := range importSpans {
-			spanCh <- sp
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			case spanCh <- sp:
+			}
 		}
 		return nil
 	}

Original file line number	Diff line number	Diff line change
`@@ -519,7 +519,11 @@ func generateAndSendImportSpans(`
`519`	`519`	`return err`
`520`	`520`	`}`
`521`	`521`	`for _, sp := range importSpans {`
`522`		`- spanCh <- sp`
	`522`	`+ select {`
	`523`	`+ case <-ctx.Done():`
	`524`	`+ return ctx.Err()`
	`525`	`+ case spanCh <- sp:`
	`526`	`+ }`
`523`	`527`	`}`
`524`	`528`	`return nil`
`525`	`529`	`}`