Increasing max size of Mongo BSON Objects results in Boost library compile error - mongodb

Question

I need to increase the max size of BSON objects in Mongo. Since the BSON object size is not directly configurable, I've attempted to do this by changing the constant in the source and recompiling.
The problem is that any attempt to change const int BSONObjMaxUserSize = 16 * 1024 * 1024; to anything other than 16 in this file causes a crash when the boost library goes to compile.
Leaving BSONObjMaxUserSize as 16 compiles perfectly, but changing it to anything else fails. I've tried numerous options (8,32, even 7 for good measure.)
I'm experiencing this in version 2.6.6 stable.
In file included from src/third_party/boost/boost/type_traits/type_with_alignment.hpp:19:0,
from src/third_party/boost/boost/smart_ptr/make_shared.hpp:17,
from src/third_party/boost/boost/make_shared.hpp:15,
from src/third_party/boost/boost/smart_ptr.hpp:28,
from src/mongo/pch.h:50,
from src/mongo/db/dur_commitjob.cpp:31:
src/third_party/boost/boost/static_assert.hpp:124:85: error: invalid application of 'sizeof' to incomplete type 'boost::STATIC_ASSERTION_FAILURE<false>'
sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >)>\
^
src/mongo/db/dur_commitjob.cpp:147:9: note: in expansion of macro 'BOOST_STATIC_ASSERT'
BOOST_STATIC_ASSERT( sizeof(void*)==4 || UncommittedBytesLimit > BSONObjMaxInternalSize * 6 );
^
src/third_party/boost/boost/static_assert.hpp:124:86: error: template argument 1 is invalid
sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >)>\
^
src/mongo/db/dur_commitjob.cpp:147:9: note: in expansion of macro 'BOOST_STATIC_ASSERT'
BOOST_STATIC_ASSERT( sizeof(void*)==4 || UncommittedBytesLimit > BSONObjMaxInternalSize * 6 );
^
src/mongo/db/dur_commitjob.cpp:147:102: error: invalid type in declaration before ';' token
BOOST_STATIC_ASSERT( sizeof(void*)==4 || UncommittedBytesLimit > BSONObjMaxInternalSize * 6 );
^
In file included from src/third_party/boost/boost/filesystem/v3/path_traits.hpp:23:0,
from src/third_party/boost/boost/filesystem/v3/path.hpp:25,
from src/third_party/boost/boost/filesystem/path.hpp:31,
from src/mongo/util/paths.h:21,
from src/mongo/db/storage/durable_mapped_file.h:35,
from src/mongo/db/dur.h:34,
from src/mongo/db/dur_commitjob.h:34,
from src/mongo/db/dur_commitjob.cpp:33:
src/third_party/boost/boost/system/error_code.hpp:214:36: error: 'boost::system::posix_category' defined but not used [-Werror=unused-variable]
static const error_category & posix_category = generic_category();
^
src/third_party/boost/boost/system/error_code.hpp:215:36: error: 'boost::system::errno_ecat' defined but not used [-Werror=unused-variable]
static const error_category & errno_ecat = generic_category();
^
src/third_party/boost/boost/system/error_code.hpp:216:36: error: 'boost::system::native_ecat' defined but not used [-Werror=unused-variable]
static const error_category & native_ecat = system_category();
^
cc1plus: all warnings being treated as errors
scons: *** [build/linux2/normal/mongo/db/dur_commitjob.o] Error 1
scons: building terminated because of errors.

Answer 1

It's not been a problem here:
cloned 0ae940b456ceafc3a0d47 from github
changed builder.h:
diff --git a/src/mongo/bson/util/builder.h b/src/mongo/bson/util/builder.h
index ae31074..8e34aee 100644
--- a/src/mongo/bson/util/builder.h
+++ b/src/mongo/bson/util/builder.h
## -63,7 +63,7 ## namespace mongo {
update $push (append) operation
various db.eval() type operations
*/
- const int BSONObjMaxUserSize = 16 * 1024 * 1024;
+ const int BSONObjMaxUserSize = 24 * 1024 * 1024;
/*
Sometimes we need objects slightly larger - an object in the replication local.oplog
Compiles cleanly with scons -j 8. Here's my system information:
OS version
/tmp/mongo$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.1 LTS
Release: 14.04
Codename: trusty
kernel version
/tmp/mongo$ uname -a
Linux desktop 3.13.0-37-generic #64-Ubuntu SMP Mon Sep 22 21:28:38 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
gcc version
/tmp/mongo$ gcc -v
Using built-in specs.
COLLECT_GCC=/usr/bin/gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.2-19ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
boost version
/tmp/mongo$ dpkg --status libboost-all-dev
Package: libboost-all-dev
Status: install ok installed
Priority: optional
Section: libdevel
Installed-Size: 26
Maintainer: Ubuntu Developers <ubuntu-devel-discuss#lists.ubuntu.com>
Architecture: amd64
Source: boost-defaults
Version: 1.54.0.1ubuntu1