From 2710cb7b8dede64204da3f1d20c905b7040f647b Mon Sep 17 00:00:00 2001
From: Claude <claudius@vdmza.com>
Date: Thu, 11 Jun 2026 11:24:09 -0400
Subject: [PATCH] init

---
 .../apache/beam/sdk/io/parquet/ParquetIO.java | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java b/sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
index feaceeeb4432..f869286b98bd 100644
--- a/sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
+++ b/sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
@@ -1033,6 +1033,8 @@ public abstract static class Sink implements FileIO.Sink<GenericRecord> {
 
     abstract @Nullable ValueProvider<Integer> getMinRowCountForPageSizeCheck();
 
+    abstract @Nullable ValueProvider<Integer> getMaxRowCountForPageSizeCheck();
+
     abstract @Nullable Class<? extends GenericData> getAvroDataModelClass();
 
     abstract Builder toBuilder();
@@ -1056,6 +1058,9 @@ abstract static class Builder {
       abstract Builder setMinRowCountForPageSizeCheck(
           ValueProvider<Integer> minRowCountForPageSizeCheck);
 
+      abstract Builder setMaxRowCountForPageSizeCheck(
+          ValueProvider<Integer> maxRowCountForPageSizeCheck);
+
       abstract Builder setAvroDataModelClass(Class<? extends GenericData> modelClass);
 
       abstract Sink build();
@@ -1130,6 +1135,39 @@ public Sink withMinRowCountForPageSizeCheck(
       return toBuilder().setMinRowCountForPageSizeCheck(minRowCountForPageSizeCheck).build();
     }
 
+    /**
+     * Specify the maximum number of rows to buffer before a page size check is forced. By default
+     * Parquet estimates the next check from the average row size and may defer it (up to {@code
+     * 10000} rows); a run of small rows followed by large rows can then let the column page buffer
+     * overflow {@code Integer.MAX_VALUE} before the deferred check fires. Setting this (e.g. {@code
+     * 1}) caps the interval so a check -- and flush -- happens at least this often regardless of
+     * the estimate. Pair it with {@link #withMinRowCountForPageSizeCheck(int)} to bound the buffer
+     * for tables whose row sizes vary widely.
+     */
+    public Sink withMaxRowCountForPageSizeCheck(int maxRowCountForPageSizeCheck) {
+      checkArgument(
+          maxRowCountForPageSizeCheck > 0, "maxRowCountForPageSizeCheck must be positive");
+      return toBuilder()
+          .setMaxRowCountForPageSizeCheck(
+              ValueProvider.StaticValueProvider.of(maxRowCountForPageSizeCheck))
+          .build();
+    }
+
+    /**
+     * Like {@link #withMaxRowCountForPageSizeCheck(int)}, but accepts a {@link ValueProvider} so
+     * the value can be supplied at runtime (required for classic Dataflow templates).
+     */
+    public Sink withMaxRowCountForPageSizeCheck(
+        ValueProvider<Integer> maxRowCountForPageSizeCheck) {
+      checkNotNull(maxRowCountForPageSizeCheck, "maxRowCountForPageSizeCheck can not be null");
+      if (maxRowCountForPageSizeCheck.isAccessible()) {
+        Integer value = maxRowCountForPageSizeCheck.get();
+        checkNotNull(value, "maxRowCountForPageSizeCheck value cannot be null");
+        checkArgument(value > 0, "maxRowCountForPageSizeCheck must be positive");
+      }
+      return toBuilder().setMaxRowCountForPageSizeCheck(maxRowCountForPageSizeCheck).build();
+    }
+
     /**
      * Define the Avro data model; see {@link AvroParquetWriter.Builder#withDataModel(GenericData)}.
      */
@@ -1170,6 +1208,15 @@ public void open(WritableByteChannel channel) throws IOException {
         }
       }
 
+      ValueProvider<Integer> maxRowCountProvider = getMaxRowCountForPageSizeCheck();
+      if (maxRowCountProvider != null) {
+        Integer maxRowCount = maxRowCountProvider.get();
+        if (maxRowCount != null) {
+          checkArgument(maxRowCount > 0, "maxRowCountForPageSizeCheck must be positive");
+          builder = builder.withMaxRowCountForPageSizeCheck(maxRowCount);
+        }
+      }
+
       if (modelClass != null) {
         try {
           builder.withDataModel(buildModelObject(modelClass));