Michael Ho has posted comments on this change.

Change subject: IMPALA-3674: Lazy materialization of LLVM module bitcode.
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Patch Set 4:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/3220/4/be/src/codegen/llvm-codegen.cc
File be/src/codegen/llvm-codegen.cc:

Line 249:   bool error = Linker::linkModules(*module_, std::move(new_module));
> I don't think it works reliably if either module is lazily loaded from what
Would you mind sharing with me offline the problem you ran into ?We may need to 
materialize the source module by calling MaterializeFunctionAndCallee() on each 
of the function of the source module so we pull in dependency from the 
destination module (i.e. the module loaded from memory in the existing code).

In the worst case, we may need to eagerly validate both the destination and 
source modules when LinkModule() is called. That will still get us the benefit 
in the common case where we don't need to load modules from external UDFs' 
implementation.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I6ed7862fc5e86005ecea83fa2ceb489e737d66b2
Gerrit-PatchSet: 4
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Michael Ho <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Michael Ho <[email protected]>
Gerrit-Reviewer: Mostafa Mokhtar <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
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