// This has already been inspected and rejected
if (context.getRejectedJoinOps().contains(joinOp)) {
return false;
}
QBJoinTree joinCtx = pGraphContext.getJoinContext().get(joinOp);
if (joinCtx == null) {
return false;
}
Class<? extends BigTableSelectorForAutoSMJ> bigTableMatcherClass = null;
try {
bigTableMatcherClass =
(Class<? extends BigTableSelectorForAutoSMJ>)
(Class.forName(HiveConf.getVar(pGraphContext.getConf(),
HiveConf.ConfVars.HIVE_AUTO_SORTMERGE_JOIN_BIGTABLE_SELECTOR)));
} catch (ClassNotFoundException e) {
throw new SemanticException(e.getMessage());
}
BigTableSelectorForAutoSMJ bigTableMatcher =
(BigTableSelectorForAutoSMJ) ReflectionUtils.newInstance(bigTableMatcherClass, null);
JoinDesc joinDesc = joinOp.getConf();
JoinCondDesc[] joinCondns = joinDesc.getConds();
Set<Integer> joinCandidates = MapJoinProcessor.getBigTableCandidates(joinCondns);
if (joinCandidates.isEmpty()) {
// This is a full outer join. This can never be a map-join
// of any type. So return false.
return false;
}
int bigTablePosition =
bigTableMatcher.getBigTablePosition(pGraphContext, joinOp, joinCandidates);
if (bigTablePosition < 0) {
// contains aliases from sub-query
return false;
}
context.setBigTablePosition(bigTablePosition);
String joinAlias =
bigTablePosition == 0 ?
joinCtx.getLeftAlias() : joinCtx.getRightAliases()[bigTablePosition - 1];
joinAlias = QB.getAppendedAliasFromId(joinCtx.getId(), joinAlias);
Map<Byte, List<ExprNodeDesc>> keyExprMap = new HashMap<Byte, List<ExprNodeDesc>>();
List<Operator<? extends OperatorDesc>> parentOps = joinOp.getParentOperators();
// get the join keys from parent ReduceSink operators
for (Operator<? extends OperatorDesc> parentOp : parentOps) {
ReduceSinkDesc rsconf = ((ReduceSinkOperator)parentOp).getConf();
Byte tag = (byte) rsconf.getTag();
List<ExprNodeDesc> keys = rsconf.getKeyCols();
keyExprMap.put(tag, keys);
}
context.setKeyExprMap(keyExprMap);
// Make a deep copy of the aliases so that they are not changed in the context
String[] joinSrcs = joinCtx.getBaseSrc();
String[] srcs = new String[joinSrcs.length];
for (int srcPos = 0; srcPos < joinSrcs.length; srcPos++) {
joinSrcs[srcPos] = QB.getAppendedAliasFromId(joinCtx.getId(), joinSrcs[srcPos]);
srcs[srcPos] = new String(joinSrcs[srcPos]);
}
// Given a candidate map-join, can this join be converted.
// The candidate map-join was derived from the pluggable sort merge join big