Github user amansinha100 commented on a diff in the pull request:
https://github.com/apache/drill/pull/397#discussion_r54688304
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/expr/fn/DrillFunctionRegistry.java
---
@@ -92,38 +94,110 @@ public DrillFunctionRegistry(ScanResult classpathScan)
{
}
public int size(){
- return methods.size();
+ return registeredFunctions.size();
}
/** Returns functions with given name. Function name is case
insensitive. */
public List<DrillFuncHolder> getMethods(String name) {
- return this.methods.get(name.toLowerCase());
+ return this.registeredFunctions.get(name.toLowerCase());
+ }
+
+ public Collection<DrillFuncHolder> getAllMethods() {
+ return
Collections.unmodifiableCollection(registeredFunctions.values());
}
public void register(DrillOperatorTable operatorTable) {
- SqlOperator op;
- for (Entry<String, Collection<DrillFuncHolder>> function :
methods.asMap().entrySet()) {
- Set<Integer> argCounts = Sets.newHashSet();
- String name = function.getKey().toUpperCase();
+ for (Entry<String, Collection<DrillFuncHolder>> function :
registeredFunctions.asMap().entrySet()) {
+ final ArrayListMultimap<Pair<Integer, Integer>, DrillFuncHolder>
functions = ArrayListMultimap.create();
+ final ArrayListMultimap<Integer, DrillFuncHolder> aggregateFunctions
= ArrayListMultimap.create();
+ final String name = function.getKey().toUpperCase();
+ boolean isDeterministic = true;
for (DrillFuncHolder func : function.getValue()) {
- if (argCounts.add(func.getParamCount())) {
- if (func.isAggregating()) {
- op = new DrillSqlAggOperator(name, func.getParamCount());
- } else {
- boolean isDeterministic;
- // prevent Drill from folding constant functions with types
that cannot be materialized
- // into literals
- if
(DrillConstExecutor.NON_REDUCIBLE_TYPES.contains(func.getReturnType().getMinorType()))
{
- isDeterministic = false;
- } else {
- isDeterministic = func.isDeterministic();
- }
- op = new DrillSqlOperator(name, func.getParamCount(),
func.getReturnType(), isDeterministic);
- }
- operatorTable.add(function.getKey(), op);
+ final int paramCount = func.getParamCount();
+ if(func.isAggregating()) {
+ aggregateFunctions.put(paramCount, func);
+ } else {
+ final Pair<Integer, Integer> argNumerRange =
getArgNumerRange(name, func);
+ functions.put(argNumerRange, func);
}
+
+ if(!func.isDeterministic()) {
+ isDeterministic = false;
+ }
+ }
+ for (Entry<Pair<Integer, Integer>, Collection<DrillFuncHolder>>
entry : functions.asMap().entrySet()) {
+ final DrillSqlOperator drillSqlOperator;
+ final Pair<Integer, Integer> range = entry.getKey();
+ final int max = range.getRight();
+ final int min = range.getLeft();
+ drillSqlOperator = new DrillSqlOperator(
+ name,
+ Lists.newArrayList(entry.getValue()),
+ min,
+ max,
+ isDeterministic);
+ operatorTable.add(name, drillSqlOperator);
+ }
+ for (Entry<Integer, Collection<DrillFuncHolder>> entry :
aggregateFunctions.asMap().entrySet()) {
+ operatorTable.add(name, new DrillSqlAggOperator(name,
Lists.newArrayList(entry.getValue()), entry.getKey()));
}
}
+
+ registerCalcitePlaceHolderFunction(operatorTable);
+ }
+
+ /**
+ * These {@link DrillSqlOperator} merely act as a placeholder so that
Calcite
+ * allows convert_to(), convert_from(), flatten(), date_part() functions
in SQL.
+ */
+ private void registerCalcitePlaceHolderFunction(DrillOperatorTable
operatorTable) {
+ final String convert_to = "CONVERT_TO";
--- End diff --
There ought to be a more declarative way to populate the operator table
with these types of functions. Here you have listed 4 such functions but what
if there are a lot more ? You should only need to call operatorTable.add(arg1,
arg2) once inside a loop and pass in different values of arg1, arg2 based on a
statically populated structure.
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