fhueske commented on code in PR #28737:
URL: https://github.com/apache/flink/pull/28737#discussion_r3596814685
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docs/content/docs/sql/reference/queries/joins.md:
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@@ -300,6 +300,74 @@ The main difference between above Temporal Table DDL and
Temporal Table Function
- The temporal table DDL can be defined in SQL but temporal table function can
not;
- Both temporal table DDL and temporal table function support temporal join
versioned table, but only temporal table function can temporal join the latest
version of any table/view.
+LATERAL SNAPSHOT Join
+--------------
+
+{{< label Streaming >}}
+
+A `LATERAL SNAPSHOT` join is a *stream enrichment* join that augments an
append-only table (the *probe* side) with the current state of an updating
table (the *build* side).
+Unlike an [event-time temporal join](#event-time-temporal-join), it does not
correlate each probe-side row with a specific historical version of the build
side.
+Instead, every probe-side row is joined with the build-side state that is
current at the time the row is processed, similar to a [processing-time
temporal join](#processing-time-temporal-join), but with well-defined behavior
at query start-up.
Review Comment:
This refers to the note about the processing-time temporal table join:
> The reason why the FOR SYSTEM_TIME AS OF syntax used in temporal join with
latest version of any table/view is not support is only the semantic
consideration, because the join processing for left stream doesn’t wait for the
complete snapshot of temporal table, this may mislead users in production
environment.
I'll expand the point a bit.
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