pubsub: Memory growth observed while sending messages with ordering keys

[srikanthvukkadapu]

Client

PubSub v1.10.1

Environment

Ubuntu 20.04

Go Environment

go 1.16

Expected behavior

memory growth should not be observed while sending messages using transient ordering keys (ordering keys which have a limited life span)

Actual behavior

Memory growth is observed while sending messages using Topic.Publish method with ordering keys. Attaching the proof report image. It looks like the maps s.bundlers and s.outstanding of PublishScheduler are growing.

Should the increment of outstanding s.outstanding[key]++ be done when the key is found in the map only as it is already initialised to 1 when it is not found in the map.

google-cloud-go/pubsub/internal/scheduler/publish_scheduler.go

Line 147 in 71c0469

s.outstanding[key]++

[hongalex]

Someone else actually pointed out this issue and will be resolved by #4282.