Extrem long compile times for large schema files and failing validation

[ste-lam]

Used version of blaze: ce2165f

Blaze is extrem slow on debug builds! Release builds are also not fast when compiling larger schema files like:

• https://hl7.org/fhir/R4/fhir.schema.json

Additionally it also fails to validate a valid json file like the following:

• https://gemspec.gematik.de/ig/fhir/epa-medication/1.3.0/Parameters-example-epa-op-provide-dispensation-erp-input-parameters-2.json

Used code for testing:
example_blaze.cpp

compile_commands.json for release build

compile_commands.json for debug build

[jviotti]

Hey @ste-lam ,

That sounds very strange. Can you try this out with https://github.com/sourcemeta/jsonschema? That is a C++ CLI tool built around Blaze. On my system, the fhir.schema.json takes ~7 seconds to compile, which his not ultra fast, but not super slow either, taking into consideration the vast amount of static analysis it performs.

$ jsonschema version
14.7.1

$ time jsonschema compile fhir.schema.json > /dev/null
jsonschema compile fhir.schema.json > /dev/null  7.24s user 0.08s system 99% cpu 7.330 total

And then validating your example instance against it with the CLI works just fine, without any errors:

$ jsonschema validate fhir.schema.json Parameters-example-epa-op-provide-dispensation-erp-input-parameters-2.json -v
ok: /Users/jviotti/Downloads/Parameters-example-epa-op-provide-dispensation-erp-input-parameters-2.json
  matches /Users/jviotti/Downloads/fhir.schema.json

Could it be there is something off with your compiler? What system is this on? Does the CLI fail for you, or is equally slow? You can also study how the CLI integrates Blaze, though is almost the same as you are doing:

• https://github.com/sourcemeta/jsonschema/blob/main/src/command_compile.cc
• https://github.com/sourcemeta/jsonschema/blob/main/src/command_validate.cc

[ste-lam]

hi,
with the cli-tool (commit 1988b2bbc5c53b5c2b3791ea445a3ab41dd92b55) the validation works fine

maybe the compiled_schema helps why the validation fails with blaze
compiled_schema.json

[ste-lam]

validation speed with the cli-tool does not differ much, so that should be negligible.
However, the performance difference between the debug and release build is suprisingly huge, way more then what would one expect normally.

[jviotti]

However, the performance difference between the debug and release build is suprisingly huge, way more then what would one expect normally.

This might be for a few reasons: debug builds have tons of assertions in various of the libraries just to help catch issues early. Also our release builds do fat LTO and various other tricks to speed things up. Maybe that's the reason for the imbalance!

maybe the compiled_schema helps why the validation fails with blaze
compiled_schema.json

The validate command lets you pass a compiled template in JSON format using the --template option. Did you try that? Does it also fail? I'm not sure how the output of the template could be different for you on a native Blaze build vs in the CLI. What OS and compiler are you using?

[ste-lam]

validating with --template also works fine:

$ jsonschema validate ./schema.json ./test.json -v --template ./compiled_schema.json
Parsing pre-compiled schema template: ./compiled_schema.json
ok: ./test.json
  matches ./schema.json

so, it seems like compiling the schema is not the problem.
Do i miss an obvious step?

tested compilers: clang-18, clang-20, gcc-13

clang-18:

$ /usr/lib/llvm-18/bin/clang++ -v
Ubuntu clang version 18.1.8 (++20240731025043+3b5b5c1ec4a3-1~exp1~20240731145144.92)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm-18/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/12
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/13
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/13
Candidate multilib: .;@m64
Selected multilib: .;@m64

clang-20:

$ /usr/lib/llvm-20/bin/clang++ -v
Ubuntu clang version 20.1.8 (++20250804090239+87f0227cb601-1~exp1~20250804210352.139)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm-20/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/12
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/13
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/13
Candidate multilib: .;@m64
Selected multilib: .;@m64

gcc-13

$ g++-13 -v
Using built-in specs.
COLLECT_GCC=g++-13
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/13/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 13.3.0-6ubuntu2~24.04.1' --with-bugurl=file:///usr/share/doc/gcc-13/README.Bugs --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2 --prefix=/usr --with-gcc-major-version-only --program-suffix=-13 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/libexec --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-libstdcxx-backtrace --enable-gnu-unique-object --disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib --enable-libphobos-checking=release --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch --disable-werror --enable-cet --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none=/build/gcc-13-EldibY/gcc-13-13.3.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-13-EldibY/gcc-13-13.3.0/debian/tmp-gcn/usr --enable-offload-defaulted --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-build-config=bootstrap-lto-lean --enable-link-serialization=2
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.3.0 (Ubuntu 13.3.0-6ubuntu2~24.04.1) 

[ste-lam]

i found the obvious part:

i used

const sourcemeta::core::JSON instance{instance_str};

but it should be

const auto instance{sourcemeta::core::parse_json(instance_str)};

[jviotti]

Ah, right! With the first way, you were parsing the entire document as just a JSON string with those contents. Glad to hear you figured it out! Let me know if you face any other issues!