Tried PostgreSQL with GCC-Profile guided optimization(PGO) and it is working with the HammerDB benchmark environment. Similarly, we tried PostgreSQL with Clang(12.0V) -Profile guided optimization(PGO) and it is not working and observed an error
"warning: default.profraw: Failed to uncompress data (zlib)
error: No profiles could be merged"
Reference bug #: 17200
Are there any plans to fix this issue in upcoming releases? Otherwise, could you please provide us a workaround/patch for this issue?
The following bug has been logged on the website:
Bug reference: 17200
Logged by: hpc researcher
Email address: hpcresearch.mspk@gmail.com
PostgreSQL version: 13.3
Operating system: RHEL8.4
Description:
I followed the below steps on Profile Guide Optimization with Clang
Environment.
And benchmark environment used HammedDB.
1.Build command:
------------
$ CC=clang CXX=clang++ ../configure --prefix=<path-to-install> CFLAGS='-O3
-fprofile-instr-generate' CXXFLAGS='-O3 -std=c++14 -stdlib=libc++
-fprofile-instr-generate'
2.Run HammerDB client(tpcc-schmea + test run(vu's).
3. default.profraw created in PostgreSQL(<path-to-install>)
4. convert the “raw” profile format by clang.(the merge
command:llvm-profdata tool)
5. llvm-profdata merge -output=code.profdata code- default.profraw
warning: default.profraw: Failed to uncompress data (zlib)
error: No profiles could be merged.(step5)
Ref:
https://clang.llvm.org/docs/UsersManual.html#profiling-with-instrumentation