PARQUET-1750: Reduce Memory Usage of RowRanges Class (#735)
* PARQUET-1750: Reduce Memory Usage of RowRanges Class
* Remove pre-initialized size constructor and add List constructor
Co-authored-by: David Mollitor <dmollitor@apache.org>
diff --git a/parquet-column/src/main/java/org/apache/parquet/internal/filter2/columnindex/RowRanges.java b/parquet-column/src/main/java/org/apache/parquet/internal/filter2/columnindex/RowRanges.java
index 7753507..cf6a1ca 100644
--- a/parquet-column/src/main/java/org/apache/parquet/internal/filter2/columnindex/RowRanges.java
+++ b/parquet-column/src/main/java/org/apache/parquet/internal/filter2/columnindex/RowRanges.java
@@ -91,27 +91,50 @@
}
}
- static final RowRanges EMPTY = new RowRanges();
+ static final RowRanges EMPTY = new RowRanges(Collections.emptyList());
- /*
- * Creates a new RowRanges object with the single range [0, rowCount - 1].
- */
- static RowRanges createSingle(long rowCount) {
- RowRanges ranges = new RowRanges();
- ranges.add(new Range(0, rowCount - 1));
- return ranges;
+ private final List<Range> ranges;
+
+ private RowRanges() {
+ this(new ArrayList<>());
}
- /*
- * Creates a new RowRanges object with the following ranges.
+ private RowRanges(Range range) {
+ this(Collections.singletonList(range));
+ }
+
+ private RowRanges(List<Range> ranges) {
+ this.ranges = ranges;
+ }
+
+ /**
+ * Creates an immutable RowRanges object with the single range [0, rowCount -
+ * 1].
+ *
+ * @param rowCount a single row count
+ * @return an immutable RowRanges
+ */
+ static RowRanges createSingle(long rowCount) {
+ return new RowRanges(new Range(0L, rowCount - 1L));
+ }
+
+ /**
+ * Creates a mutable RowRanges object with the following ranges:
+ * <pre>
* [firstRowIndex[0], lastRowIndex[0]],
* [firstRowIndex[1], lastRowIndex[1]],
* ...,
* [firstRowIndex[n], lastRowIndex[n]]
+ * </pre>
* (See OffsetIndex.getFirstRowIndex and OffsetIndex.getLastRowIndex for details.)
*
* The union of the ranges are calculated so the result ranges always contain the disjunct ranges. See union for
* details.
+ *
+ * @param rowCount row count
+ * @param pageIndexes pageIndexes
+ * @param offsetIndex offsetIndex
+ * @return a mutable RowRanges
*/
static RowRanges create(long rowCount, PrimitiveIterator.OfInt pageIndexes, OffsetIndex offsetIndex) {
RowRanges ranges = new RowRanges();
@@ -192,11 +215,6 @@
return result;
}
- private final List<Range> ranges = new ArrayList<>();
-
- private RowRanges() {
- }
-
/*
* Adds a range to the end of the list of ranges. It maintains the disjunct ascending order(*) of the ranges by
* trying to union the specified range to the last ranges in the list. The specified range shall be larger(*) than
