/**
* @return the unused section of the page, or null if fully applied. pagesIndex guaranteed to have
* at least one row after this method returns
*/
private Page updatePagesIndex(Page page) {
checkArgument(page.getPositionCount() > 0);
// TODO: Fix pagesHashStrategy to allow specifying channels for comparison, it currently
// requires us to rearrange the right side blocks in consecutive channel order
Page preGroupedPage = rearrangePage(page, preGroupedChannels);
if (pagesIndex.getPositionCount() == 0
|| pagesIndex.positionEqualsRow(
preGroupedPartitionHashStrategy, 0, 0, preGroupedPage.getBlocks())) {
// Find the position where the pre-grouped columns change
int groupEnd = findGroupEnd(preGroupedPage, preGroupedPartitionHashStrategy, 0);
// Add the section of the page that contains values for the current group
pagesIndex.addPage(page.getRegion(0, groupEnd));
if (page.getPositionCount() - groupEnd > 0) {
// Save the remaining page, which may contain multiple partitions
return page.getRegion(groupEnd, page.getPositionCount() - groupEnd);
} else {
// Page fully consumed
return null;
}
} else {
// We had previous results buffered, but the new page starts with new group values
return page;
}
}
// Assumes input grouped on relevant pagesHashStrategy columns
private static int findGroupEnd(
Page page, PagesHashStrategy pagesHashStrategy, int startPosition) {
checkArgument(page.getPositionCount() > 0, "Must have at least one position");
checkPositionIndex(startPosition, page.getPositionCount(), "startPosition out of bounds");
// Short circuit if the whole page has the same value
if (pagesHashStrategy.rowEqualsRow(
startPosition, page.getBlocks(), page.getPositionCount() - 1, page.getBlocks())) {
return page.getPositionCount();
}
// TODO: do position binary search
int endPosition = startPosition + 1;
while (endPosition < page.getPositionCount()
&& pagesHashStrategy.rowEqualsRow(
endPosition - 1, page.getBlocks(), endPosition, page.getBlocks())) {
endPosition++;
}
return endPosition;
}
@SuppressWarnings("NumericCastThatLosesPrecision")
@Override
public int getBucket(Page page, int position) {
long hash = 0;
for (Block block : page.getBlocks()) {
long value = BIGINT.getLong(block, position);
hash = (hash * 31) + XxHash64.hash(value);
}
int value = (int) (hash & Integer.MAX_VALUE);
return value % bucketCount;
}
@Override
public void addInput(Page page) {
requireNonNull(page, "page is null");
checkState(!finishing, "Operator is finishing");
checkState(channelSet != null, "Set has not been built yet");
checkState(outputPage == null, "Operator still has pending output");
// create the block builder for the new boolean column
// we know the exact size required for the block
BlockBuilder blockBuilder = BOOLEAN.createFixedSizeBlockBuilder(page.getPositionCount());
Page probeJoinPage = new Page(page.getBlock(probeJoinChannel));
// update hashing strategy to use probe cursor
for (int position = 0; position < page.getPositionCount(); position++) {
if (probeJoinPage.getBlock(0).isNull(position)) {
throw new PrestoException(
NOT_SUPPORTED,
"NULL values are not allowed on the probe side of SemiJoin operator. See the query plan for details.");
} else {
boolean contains = channelSet.contains(position, probeJoinPage);
if (!contains && channelSet.containsNull()) {
blockBuilder.appendNull();
} else {
BOOLEAN.writeBoolean(blockBuilder, contains);
}
}
}
// add the new boolean column to the page
Block[] sourceBlocks = page.getBlocks();
Block[] outputBlocks =
new Block[sourceBlocks.length + 1]; // +1 for the single boolean output channel
System.arraycopy(sourceBlocks, 0, outputBlocks, 0, sourceBlocks.length);
outputBlocks[sourceBlocks.length] = blockBuilder.build();
outputPage = new Page(outputBlocks);
}