[doc] Add changelog merging into changelog-producer

docs/content/maintenance/write-performance.md

@@ -160,12 +160,3 @@ You can use fine-grained-resource-management of Flink to increase committer heap
 1. Configure Flink Configuration `cluster.fine-grained-resource-management.enabled: true`. (This is default after Flink 1.18)
 2. Configure Paimon Table Options: `sink.committer-memory`, for example 300 MB, depends on your `TaskManager`.
    (`sink.committer-cpu` is also supported)
-
-## Changelog Compaction
-
-If Flink's checkpoint interval is short (for example, 30 seconds) and the number of buckets is large,
-each snapshot may produce lots of small changelog files.
-Too many files may put a burden on the distributed storage cluster.
-
-In order to compact small changelog files into large ones, you can set the table option `changelog.precommit-compact = true`.
-Default value of this option is false, if true, it will add a compact coordinator and worker operator after the writer operator, which copies changelog files into large ones.

docs/content/primary-key-table/changelog-producer.md

@@ -130,3 +130,14 @@ efficient as the input changelog producer and the latency to produce changelog m
 
 Full-compaction changelog-producer supports `changelog-producer.row-deduplicate` to avoid generating -U, +U
 changelog for the same record.
+
+## Changelog Merging
+
+For `input`, `lookup`, `full-compaction` 'changelog-producer'.
+
+If Flink's checkpoint interval is short (for example, 30 seconds) and the number of buckets is large, each snapshot may
+produce lots of small changelog files. Too many files may put a burden on the distributed storage cluster.
+
+In order to compact small changelog files into large ones, you can set the table option `changelog.precommit-compact = true`.
+Default value of this option is false, if true, it will add a compact coordinator and worker operator after the writer
+operator, which copies changelog files into large ones.