sunchao commented on a change in pull request #34659:
URL: https://github.com/apache/spark/pull/34659#discussion_r826414621
##########
File path:
sql/core/src/main/java/org/apache/spark/sql/execution/datasources/parquet/VectorizedRleValuesReader.java
##########
@@ -210,48 +213,358 @@ private void readBatchInternal(
} else if (rowId > rangeEnd) {
state.nextRange();
} else {
- // the range [rowId, rowId + n) overlaps with the current row range in
state
+ // The range [rowId, rowId + n) overlaps with the current row range in
state
long start = Math.max(rangeStart, rowId);
long end = Math.min(rangeEnd, rowId + n - 1);
- // skip the part [rowId, start)
+ // Skip the part [rowId, start)
int toSkip = (int) (start - rowId);
if (toSkip > 0) {
skipValues(toSkip, state, valueReader, updater);
rowId += toSkip;
leftInPage -= toSkip;
}
- // read the part [start, end]
+ // Read the part [start, end]
n = (int) (end - start + 1);
switch (mode) {
case RLE:
if (currentValue == state.maxDefinitionLevel) {
- updater.readValues(n, offset, values, valueReader);
- } else {
- nulls.putNulls(offset, n);
+ updater.readValues(n, state.valueOffset, values, valueReader);
+ state.valueOffset += n;
+ } else if (!state.isRequired && currentValue ==
state.maxDefinitionLevel - 1) {
+ // Only add null if this represents a null element, but not for
the case where a
+ // struct itself is null
+ nulls.putNulls(state.valueOffset, n);
+ state.valueOffset += n;
}
+ defLevels.putInts(state.levelOffset, n, currentValue);
break;
case PACKED:
for (int i = 0; i < n; ++i) {
- if (currentBuffer[currentBufferIdx++] ==
state.maxDefinitionLevel) {
- updater.readValue(offset + i, values, valueReader);
+ int value = currentBuffer[currentBufferIdx++];
+ if (value == state.maxDefinitionLevel) {
+ updater.readValue(state.valueOffset++, values, valueReader);
} else {
- nulls.putNull(offset + i);
+ // Only add null if this represents a null element, but not
for the case where a
+ // struct itself is null
+ nulls.putNull(state.valueOffset++);
}
+ defLevels.putInt(state.levelOffset + i, value);
}
break;
}
- offset += n;
+ state.levelOffset += n;
leftInBatch -= n;
rowId += n;
leftInPage -= n;
currentCount -= n;
+ defLevels.addElementsAppended(n);
+ }
+ }
+
+ state.rowsToReadInBatch = leftInBatch;
+ state.valuesToReadInPage = leftInPage;
+ state.rowId = rowId;
+ }
+
+ public void readBatchNested(
+ ParquetReadState state,
+ WritableColumnVector repLevels,
+ VectorizedRleValuesReader defLevelsReader,
+ WritableColumnVector defLevels,
+ WritableColumnVector values,
+ VectorizedValuesReader valueReader,
+ ParquetVectorUpdater updater) {
+ readBatchNestedInternal(state, repLevels, defLevelsReader, defLevels,
values, values, true,
+ valueReader, updater);
+ }
+
+ public void readIntegersNested(
+ ParquetReadState state,
+ WritableColumnVector repLevels,
+ VectorizedRleValuesReader defLevelsReader,
+ WritableColumnVector defLevels,
+ WritableColumnVector values,
+ WritableColumnVector nulls,
+ VectorizedValuesReader valueReader) {
+ readBatchNestedInternal(state, repLevels, defLevelsReader, defLevels,
values, nulls, false,
+ valueReader, new ParquetVectorUpdaterFactory.IntegerUpdater());
+ }
+
+ /**
+ * Keep reading repetition level values from the page until either: 1) we've
read enough
+ * top-level rows to fill the current batch, or 2) we've drained the data
page completely.
+ *
+ * @param valuesReused whether 'values' vector is reused for 'nulls'
+ */
+ public void readBatchNestedInternal(
+ ParquetReadState state,
+ WritableColumnVector repLevels,
+ VectorizedRleValuesReader defLevelsReader,
+ WritableColumnVector defLevels,
+ WritableColumnVector values,
+ WritableColumnVector nulls,
+ boolean valuesReused,
+ VectorizedValuesReader valueReader,
+ ParquetVectorUpdater updater) {
+
+ int leftInBatch = state.rowsToReadInBatch;
+ int leftInPage = state.valuesToReadInPage;
+ long rowId = state.rowId;
+
+ DefLevelProcessor defLevelProcessor = new
DefLevelProcessor(defLevelsReader, state, defLevels,
+ values, nulls, valuesReused, valueReader, updater);
+
+ while ((leftInBatch > 0 || !state.lastListCompleted) && leftInPage > 0) {
+ if (currentCount == 0 && !readNextGroup()) break;
+
+ // Values to read in the current RLE/PACKED block, must be <= what's
left in the page
+ int valuesLeftInBlock = Math.min(leftInPage, currentCount);
+
+ // The current row range start and end
+ long rangeStart = state.currentRangeStart();
+ long rangeEnd = state.currentRangeEnd();
+
+ switch (mode) {
+ case RLE:
+ // This RLE block is consist of top-level rows, so we'll need to
check
+ // if the rows should be skipped according to row indexes.
+ if (currentValue == 0) {
+ if (leftInBatch == 0) {
+ state.lastListCompleted = true;
+ } else {
+ // # of rows to read in the block, must be <= what's left in the
current batch
+ int n = Math.min(leftInBatch, valuesLeftInBlock);
+
+ if (rowId + n < rangeStart) {
+ // Need to skip all rows in [rowId, rowId + n)
+ defLevelProcessor.skipValues(n);
+ rowId += n;
+ currentCount -= n;
+ leftInPage -= n;
+ } else if (rowId > rangeEnd) {
+ // The current row index already beyond the current range:
move to the next range
+ // and repeat
+ state.nextRange();
+ } else {
+ // The range [rowId, rowId + n) overlaps with the current row
range
+ long start = Math.max(rangeStart, rowId);
+ long end = Math.min(rangeEnd, rowId + n - 1);
+
+ // Skip the rows in [rowId, start)
+ int toSkip = (int) (start - rowId);
+ if (toSkip > 0) {
+ defLevelProcessor.skipValues(toSkip);
+ rowId += toSkip;
+ currentCount -= toSkip;
+ leftInPage -= toSkip;
+ }
+
+ // Read the rows in [start, end]
+ n = (int) (end - start + 1);
+
+ if (n > 0) {
+ repLevels.appendInts(n, 0);
+ defLevelProcessor.readValues(n);
+ }
+
+ rowId += n;
+ currentCount -= n;
+ leftInBatch -= n;
+ leftInPage -= n;
+ }
+ }
+ } else {
+ // Not a top-level row: just read all the repetition levels in the
block if the row
+ // should be included according to row indexes, else skip the rows.
+ if (!state.shouldSkip) {
+ repLevels.appendInts(valuesLeftInBlock, currentValue);
+ }
+ state.numBatchedDefLevels += valuesLeftInBlock;
+ leftInPage -= valuesLeftInBlock;
+ currentCount -= valuesLeftInBlock;
+ }
+ break;
+ case PACKED:
+ int i = 0;
+
+ for (; i < valuesLeftInBlock; i++) {
+ int currentValue = currentBuffer[currentBufferIdx + i];
+ if (currentValue == 0) {
+ if (leftInBatch == 0) {
+ state.lastListCompleted = true;
+ break;
+ } else if (rowId < rangeStart) {
+ // This is a top-level row, therefore check if we should skip
it with row indexes
+ // the row is before the current range, skip it
+ defLevelProcessor.skipValues(1);
+ } else if (rowId > rangeEnd) {
+ // The row is after the current range, move to the next range
and compare again
+ state.nextRange();
+ break;
+ } else {
+ // The row is in the current range, decrement the row counter
and read it
+ leftInBatch--;
+ repLevels.appendInt(0);
+ defLevelProcessor.readValues(1);
+ }
+ rowId++;
+ } else {
+ if (!state.shouldSkip) {
+ repLevels.appendInt(currentValue);
+ }
+ state.numBatchedDefLevels += 1;
+ }
+ }
+
+ leftInPage -= i;
+ currentCount -= i;
+ currentBufferIdx += i;
+ break;
+ }
+ }
+
+ // Process all the batched def levels
+ defLevelProcessor.finish();
+
+ state.rowsToReadInBatch = leftInBatch;
+ state.valuesToReadInPage = leftInPage;
+ state.rowId = rowId;
+ }
+
+ private static class DefLevelProcessor {
+ private final VectorizedRleValuesReader reader;
+ private final ParquetReadState state;
+ private final WritableColumnVector defLevels;
+ private final WritableColumnVector values;
+ private final WritableColumnVector nulls;
+ private final boolean valuesReused;
+ private final VectorizedValuesReader valueReader;
+ private final ParquetVectorUpdater updater;
+
+ DefLevelProcessor(
+ VectorizedRleValuesReader reader,
+ ParquetReadState state,
+ WritableColumnVector defLevels,
+ WritableColumnVector values,
+ WritableColumnVector nulls,
+ boolean valuesReused,
+ VectorizedValuesReader valueReader,
+ ParquetVectorUpdater updater) {
+ this.reader = reader;
+ this.state = state;
+ this.defLevels = defLevels;
+ this.values = values;
+ this.nulls = nulls;
+ this.valuesReused = valuesReused;
+ this.valueReader = valueReader;
+ this.updater = updater;
+ }
+
+ void readValues(int n) {
+ if (!state.shouldSkip) {
+ state.numBatchedDefLevels += n;
Review comment:
This is to enable batch reading on the definition levels & values as
much as possible. For instance, if we have the following triplets:
| repetition level | definition level | values |
----------------|---------------|--------
| 3 | 1 | 0 |
| 2 | 1 | 1 |
| 3 | 1 | 2 |
| 2 | 1 | 3 |
| 3 | 1 | 4 |
| 2 | 1 | 5 |
First we'd have to read the repetition levels, which must be encoded with
bit-packing and therefore have to be read one by one. On the other hand, the
definition levels are probably encoded in RLE and therefore, together with the
values, can be read in one batch.
If we don't use this, then we'd have to call `reader.readValues` for each
repetition level read here, which is more expensive I think.
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