@Override
public Object process(
Node nd, Stack<Node> stack, NodeProcessorCtx procCtx, Object... nodeOutputs)
throws SemanticException {
// If the reduce sink has not been introduced due to bucketing/sorting, ignore it
FileSinkOperator fsOp = (FileSinkOperator) nd;
ReduceSinkOperator rsOp =
(ReduceSinkOperator) fsOp.getParentOperators().get(0).getParentOperators().get(0);
List<ReduceSinkOperator> rsOps =
pGraphContext.getReduceSinkOperatorsAddedByEnforceBucketingSorting();
// nothing to do
if ((rsOps != null) && (!rsOps.contains(rsOp))) {
return null;
}
// Don't do this optimization with updates or deletes
if (pGraphContext.getContext().getAcidOperation() == AcidUtils.Operation.UPDATE
|| pGraphContext.getContext().getAcidOperation() == AcidUtils.Operation.DELETE) {
return null;
}
if (stack.get(0) instanceof TableScanOperator) {
TableScanOperator tso = ((TableScanOperator) stack.get(0));
if (SemanticAnalyzer.isAcidTable(tso.getConf().getTableMetadata())) {
/*ACID tables have complex directory layout and require merging of delta files
* on read thus we should not try to read bucket files directly*/
return null;
}
}
// Support for dynamic partitions can be added later
if (fsOp.getConf().getDynPartCtx() != null) {
return null;
}
// No conversion is possible for the reduce keys
for (ExprNodeDesc keyCol : rsOp.getConf().getKeyCols()) {
if (!(keyCol instanceof ExprNodeColumnDesc)) {
return null;
}
}
Table destTable = fsOp.getConf().getTable();
if (destTable == null) {
return null;
}
int numBucketsDestination = destTable.getNumBuckets();
// Get the positions for sorted and bucketed columns
// For sorted columns, also get the order (ascending/descending) - that should
// also match for this to be converted to a map-only job.
// Get the positions for sorted and bucketed columns
// For sorted columns, also get the order (ascending/descending) - that should
// also match for this to be converted to a map-only job.
List<Integer> bucketPositions =
getBucketPositions(destTable.getBucketCols(), destTable.getCols());
ObjectPair<List<Integer>, List<Integer>> sortOrderPositions =
getSortPositionsOrder(destTable.getSortCols(), destTable.getCols());
List<Integer> sortPositions = sortOrderPositions.getFirst();
List<Integer> sortOrder = sortOrderPositions.getSecond();
boolean useBucketSortPositions = true;
// Only selects and filters are allowed
Operator<? extends OperatorDesc> op = rsOp;
// TableScan will also be followed by a Select Operator. Find the expressions for the
// bucketed/sorted columns for the destination table
List<ExprNodeColumnDesc> sourceTableBucketCols = new ArrayList<ExprNodeColumnDesc>();
List<ExprNodeColumnDesc> sourceTableSortCols = new ArrayList<ExprNodeColumnDesc>();
op = op.getParentOperators().get(0);
while (true) {
if (!(op instanceof TableScanOperator)
&& !(op instanceof FilterOperator)
&& !(op instanceof SelectOperator)
&& !(op instanceof SMBMapJoinOperator)) {
return null;
}
if (op instanceof SMBMapJoinOperator) {
// Bucketing and sorting keys should exactly match
if (!(bucketPositions.equals(sortPositions))) {
return null;
}
SMBMapJoinOperator smbOp = (SMBMapJoinOperator) op;
SMBJoinDesc smbJoinDesc = smbOp.getConf();
int posBigTable = smbJoinDesc.getPosBigTable();
// join keys dont match the bucketing keys
List<ExprNodeDesc> keysBigTable = smbJoinDesc.getKeys().get((byte) posBigTable);
if (keysBigTable.size() != bucketPositions.size()) {
return null;
}
if (!validateSMBJoinKeys(
smbJoinDesc, sourceTableBucketCols, sourceTableSortCols, sortOrder)) {
return null;
}
sourceTableBucketCols.clear();
sourceTableSortCols.clear();
useBucketSortPositions = false;
for (ExprNodeDesc keyBigTable : keysBigTable) {
if (!(keyBigTable instanceof ExprNodeColumnDesc)) {
return null;
}
sourceTableBucketCols.add((ExprNodeColumnDesc) keyBigTable);
sourceTableSortCols.add((ExprNodeColumnDesc) keyBigTable);
}
// since it is a sort-merge join, only follow the big table
op = op.getParentOperators().get(posBigTable);
} else {
// nothing to be done for filters - the output schema does not change.
if (op instanceof TableScanOperator) {
assert !useBucketSortPositions;
TableScanOperator ts = (TableScanOperator) op;
Table srcTable = ts.getConf().getTableMetadata();
// Find the positions of the bucketed columns in the table corresponding
// to the select list.
// Consider the following scenario:
// T1(key, value1, value2) bucketed/sorted by key into 2 buckets
// T2(dummy, key, value1, value2) bucketed/sorted by key into 2 buckets
// A query like: insert overwrite table T2 select 1, key, value1, value2 from T1
// should be optimized.
// Start with the destination: T2, bucketed/sorted position is [1]
// At the source T1, the column corresponding to that position is [key], which
// maps to column [0] of T1, which is also bucketed/sorted into the same
// number of buckets
List<Integer> newBucketPositions = new ArrayList<Integer>();
for (int pos = 0; pos < bucketPositions.size(); pos++) {
ExprNodeColumnDesc col = sourceTableBucketCols.get(pos);
String colName = col.getColumn();
int bucketPos = findColumnPosition(srcTable.getCols(), colName);
if (bucketPos < 0) {
return null;
}
newBucketPositions.add(bucketPos);
}
// Find the positions/order of the sorted columns in the table corresponding
// to the select list.
List<Integer> newSortPositions = new ArrayList<Integer>();
for (int pos = 0; pos < sortPositions.size(); pos++) {
ExprNodeColumnDesc col = sourceTableSortCols.get(pos);
String colName = col.getColumn();
int sortPos = findColumnPosition(srcTable.getCols(), colName);
if (sortPos < 0) {
return null;
}
newSortPositions.add(sortPos);
}
if (srcTable.isPartitioned()) {
PrunedPartitionList prunedParts =
pGraphContext.getPrunedPartitions(srcTable.getTableName(), ts);
List<Partition> partitions = prunedParts.getNotDeniedPartns();
// Support for dynamic partitions can be added later
// The following is not optimized:
// insert overwrite table T1(ds='1', hr) select key, value, hr from T2 where ds = '1';
// where T1 and T2 are bucketed by the same keys and partitioned by ds. hr
if ((partitions == null) || (partitions.isEmpty()) || (partitions.size() > 1)) {
return null;
}
for (Partition partition : partitions) {
if (!checkPartition(
partition,
newBucketPositions,
newSortPositions,
sortOrder,
numBucketsDestination)) {
return null;
}
}
removeReduceSink(
rsOp, (TableScanOperator) op, fsOp, partitions.get(0).getSortedPaths());
return null;
} else {
if (!checkTable(
srcTable,
newBucketPositions,
newSortPositions,
sortOrder,
numBucketsDestination)) {
return null;
}
removeReduceSink(rsOp, (TableScanOperator) op, fsOp, srcTable.getSortedPaths());
return null;
}
}
// None of the operators is changing the positions
else if (op instanceof SelectOperator) {
SelectOperator selectOp = (SelectOperator) op;
SelectDesc selectDesc = selectOp.getConf();
// Iterate backwards, from the destination table to the top of the tree
// Based on the output column names, get the new columns.
if (!useBucketSortPositions) {
bucketPositions.clear();
sortPositions.clear();
List<String> outputColumnNames = selectDesc.getOutputColumnNames();
for (ExprNodeColumnDesc col : sourceTableBucketCols) {
String colName = col.getColumn();
int colPos = outputColumnNames.indexOf(colName);
if (colPos < 0) {
return null;
}
bucketPositions.add(colPos);
}
for (ExprNodeColumnDesc col : sourceTableSortCols) {
String colName = col.getColumn();
int colPos = outputColumnNames.indexOf(colName);
if (colPos < 0) {
return null;
}
sortPositions.add(colPos);
}
}
// There may be multiple selects - chose the one closest to the table
sourceTableBucketCols.clear();
sourceTableSortCols.clear();
// Only columns can be selected for both sorted and bucketed positions
for (int pos : bucketPositions) {
ExprNodeDesc selectColList = selectDesc.getColList().get(pos);
if (!(selectColList instanceof ExprNodeColumnDesc)) {
return null;
}
sourceTableBucketCols.add((ExprNodeColumnDesc) selectColList);
}
for (int pos : sortPositions) {
ExprNodeDesc selectColList = selectDesc.getColList().get(pos);
if (!(selectColList instanceof ExprNodeColumnDesc)) {
return null;
}
sourceTableSortCols.add((ExprNodeColumnDesc) selectColList);
}
useBucketSortPositions = false;
}
op = op.getParentOperators().get(0);
}
}
}
// The output columns for the destination table should match with the join keys
// This is to handle queries of the form:
// insert overwrite table T3
// select T1.key, T1.key2, UDF(T1.value, T2.value)
// from T1 join T2 on T1.key = T2.key and T1.key2 = T2.key2
// where T1, T2 and T3 are bucketized/sorted on key and key2
// Assuming T1 is the table on which the mapper is run, the following is true:
// . The number of buckets for T1 and T3 should be same
// . The bucketing/sorting columns for T1, T2 and T3 should be same
// . The sort order of T1 should match with the sort order for T3.
// . If T1 is partitioned, only a single partition of T1 can be selected.
// . The select list should contain with (T1.key, T1.key2) or (T2.key, T2.key2)
// . After the join, only selects and filters are allowed.
private boolean validateSMBJoinKeys(
SMBJoinDesc smbJoinDesc,
List<ExprNodeColumnDesc> sourceTableBucketCols,
List<ExprNodeColumnDesc> sourceTableSortCols,
List<Integer> sortOrder) {
// The sort-merge join creates the output sorted and bucketized by the same columns.
// This can be relaxed in the future if there is a requirement.
if (!sourceTableBucketCols.equals(sourceTableSortCols)) {
return false;
}
// Get the total number of columns selected, and for each output column, store the
// base table it points to. For
// insert overwrite table T3
// select T1.key, T1.key2, UDF(T1.value, T2.value)
// from T1 join T2 on T1.key = T2.key and T1.key2 = T2.key2
// the following arrays are created
// [0, 0, 0, 1] --> [T1, T1, T1, T2] (table mapping)
// [0, 1, 2, 0] --> [T1.0, T1.1, T1.2, T2.0] (table columns mapping)
Byte[] tagOrder = smbJoinDesc.getTagOrder();
Map<Byte, List<Integer>> retainList = smbJoinDesc.getRetainList();
int totalNumberColumns = 0;
for (Byte tag : tagOrder) {
totalNumberColumns += retainList.get(tag).size();
}
byte[] columnTableMappings = new byte[totalNumberColumns];
int[] columnNumberMappings = new int[totalNumberColumns];
int currentColumnPosition = 0;
for (Byte tag : tagOrder) {
for (int pos = 0; pos < retainList.get(tag).size(); pos++) {
columnTableMappings[currentColumnPosition] = tag;
columnNumberMappings[currentColumnPosition] = pos;
currentColumnPosition++;
}
}
// All output columns used for bucketing/sorting of the destination table should
// belong to the same input table
// insert overwrite table T3
// select T1.key, T2.key2, UDF(T1.value, T2.value)
// from T1 join T2 on T1.key = T2.key and T1.key2 = T2.key2
// is not optimized, whereas the insert is optimized if the select list is either changed to
// (T1.key, T1.key2, UDF(T1.value, T2.value)) or (T2.key, T2.key2, UDF(T1.value, T2.value))
// Get the input table and make sure the keys match
List<String> outputColumnNames = smbJoinDesc.getOutputColumnNames();
byte tableTag = -1;
int[] columnNumbersExprList = new int[sourceTableBucketCols.size()];
int currentColPosition = 0;
for (ExprNodeColumnDesc bucketCol : sourceTableBucketCols) {
String colName = bucketCol.getColumn();
int colNumber = outputColumnNames.indexOf(colName);
if (colNumber < 0) {
return false;
}
if (tableTag < 0) {
tableTag = columnTableMappings[colNumber];
} else if (tableTag != columnTableMappings[colNumber]) {
return false;
}
columnNumbersExprList[currentColPosition++] = columnNumberMappings[colNumber];
}
List<ExprNodeDesc> allExprs = smbJoinDesc.getExprs().get(tableTag);
List<ExprNodeDesc> keysSelectedTable = smbJoinDesc.getKeys().get(tableTag);
currentColPosition = 0;
for (ExprNodeDesc keySelectedTable : keysSelectedTable) {
if (!(keySelectedTable instanceof ExprNodeColumnDesc)) {
return false;
}
if (!allExprs.get(columnNumbersExprList[currentColPosition++]).isSame(keySelectedTable)) {
return false;
}
}
return true;
}