swuferhong commented on code in PR #20513:
URL: https://github.com/apache/flink/pull/20513#discussion_r946253480
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docs/content/docs/dev/table/sql/queries/hints.md:
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@@ -84,4 +84,222 @@ insert into kafka_table1 /*+
OPTIONS('sink.partitioner'='round-robin') */ select
```
+## Join Hints
+
+{{< label Batch >}}
+
+Join hints allow users to manually choose the join strategy in optimizer, and
manually optimize the execution plan to improve the performance of the query.
Now only support in batch mode.
+
+### Join Hints Strategies
+The following Join strategies are currently supported in Flink SQL for batch
job:
+
+
+**BroadCast Join**
+
+
+In this Join strategy, the data on the build side (usually a small table) will
be broadcast to each downstream operator,
+and the data on the probe side (usually a large table) will be sent directly
to the downstream operator with Forward.
+Then the data on the build side (small table) will be built into a Hash Table
for the probe side to query.
+
+**Hash Shuffle Join**
+
+
+In this Join strategy, the data on the Build side and the Probe side will be
shuffled with the join key, and the data
+with the same key will be distributed to the same downstream operator. Then
the data on the build side (smaller table)
Review Comment:
> the same downstream operator
done!
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