Summary
The Pub/Sub sink configuration table documents the following defaults for the flush fields:
| Field |
Documented Default |
Flush.Messages |
0 |
Flush.Bytes |
0 |
Flush.Frequency |
"0s" |
However, the actual PubSub sink batching defaults are:
- Up to 100 messages per batch
- Up to 1 MiB per batch
- Flushed every 10ms
This is a meaningful difference — the documented defaults suggest single-message (unbatched) behavior, which is inaccurate for PubSub. Note that Kafka and Webhook do default to single-message batches, so PubSub's behavior should be clearly distinguished.
The new no-linger batching sink also matches these PubSub defaults.
What should be updated
- Correct the default values in the
pubsub_sink_config field table on the Changefeed Sinks page
- Clarify that PubSub's defaults differ from those of Kafka and Webhook sinks
Related
- DOC-17404 — Update changefeed default batching recommendations (general batching guidance; should be consistent with this fix)
Jira issue: DOC-17832
Summary
The Pub/Sub sink configuration table documents the following defaults for the flush fields:
Flush.Messages0Flush.Bytes0Flush.Frequency"0s"However, the actual PubSub sink batching defaults are:
This is a meaningful difference — the documented defaults suggest single-message (unbatched) behavior, which is inaccurate for PubSub. Note that Kafka and Webhook do default to single-message batches, so PubSub's behavior should be clearly distinguished.
The new no-linger batching sink also matches these PubSub defaults.
What should be updated
pubsub_sink_configfield table on the Changefeed Sinks pageRelated
Jira issue: DOC-17832