Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/574#discussion_r77741606
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/expr/fn/FunctionImplementationRegistry.java
---
@@ -138,18 +171,25 @@ private String functionReplacement(FunctionCall
functionCall) {
/**
* Find the Drill function implementation that matches the name, arg
types and return type.
- * @param name
- * @param argTypes
- * @param returnType
- * @return
+ * If exact function implementation was not found and in case if Dynamic
UDF Support is enabled
+ * loads all missing remote functions and tries to find Drill
implementation one more time.
*/
public DrillFuncHolder findExactMatchingDrillFunction(String name,
List<MajorType> argTypes, MajorType returnType) {
+ return findExactMatchingDrillFunction(name, argTypes, returnType,
true);
+ }
+
+ private DrillFuncHolder findExactMatchingDrillFunction(String name,
List<MajorType> argTypes, MajorType returnType, boolean retry) {
for (DrillFuncHolder h : drillFuncRegistry.getMethods(name)) {
if (h.matches(returnType, argTypes)) {
return h;
}
}
+ if (retry && optionManager != null &&
optionManager.getOption(ExecConstants.DYNAMIC_UDF_SUPPORT_ENABLED).bool_val) {
+ if (loadRemoteFunctions()) {
--- End diff --
Race condition. Two fragments each call into this method to find functions.
Both don't find the function. Both will get the remote functions simutaneously.
Should there be some synchronization so that the remote checks are either
serialized, or we limit the number of resyncs per unit time?
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