Unable to build due to outdated dependencies

[musahaydar]

I am unable to build pmse with Python 3.8 due to outdated dependencies. pgenheaders.h was removed in Python 3.8, and the typed-ast package no longer supports Python 3.8+.

[KFilipek]

Hey, sorry for my late response.
Generally for old version of MongoDB they used Python2 which is no longer maintained.
Anyway, Ubuntu 21.04 still have packages for compatibility purposed and I successfully built this project using following commands:

# installing python2 and pip2
curl https://bootstrap.pypa.io/pip/2.7/get-pip.py --output get-pip.py
sudo python2 get-pip.py
pip2 --version

# clone repos
cd ~
git clone https://github.com/mongodb/mongo
git clone https://github.com/pmem/pmse
git clone https://github.com/pmem/pmdk

<BUILD HERE PMDK lib>

# set correct version of MongoDB for PMSE
git checkout r3.5.13 -b r3.5.13

# install dependencies
cd mongo
sudo apt install scons
pip2 install -r buildscripts/requirements.txt
mkdir -p src/mongo/db/modules/
ln -sf ~/pmse src/mongo/db/modules/pmse
python2 buildscripts/scons.py LIBPATH=~/pmdk/ -j $(nproc --all) core --disable-warnings-as-errors --dbg=off --opt=on

I'm waiting for your response if it helps you, then I will update Readme.
Best regards,
Krzysztof Filipek

[musahaydar]

This seems to build, but mongo fails to run, with the error exception in initAndListen: Location18656: Cannot start server with an unknown storage engine: pmse, terminating.

[KFilipek]

Hey,
It looks like you don't compile MongoDB with the PMSE.
Typical mistake is wrong path with symbolic link to pmse source directory.
You should see in your log this 2 marked lines at the bottom:

Checking whether backtrace_symbols is declared... (cached) yes
Checking whether backtrace_symbols_fd is declared... (cached) yes
Checking for C library pcap... (cached) no
Checking for C library wpcap... (cached) no
Checking if std::atomic<int64_t> works... (cached) yes
Checking if std::atomic<uint64_t> works... (cached) yes
Checking if std::atomic<int32_t> works... (cached) yes
Checking if std::atomic<uint32_t> works... (cached) yes
Checking for extended alignment 64 for concurrency types... (cached) yes
Checking for mongoc_get_major_version() in C library mongoc-1.0... (cached) no
configuring module: pmse
Configuring pmse storage engine module

Then it should works:

kfilipek@kfilipek-desktop:~/Development/work/mongo$ ./mongod --storageEngine=pmse --dbpath=/tmp/
2021-10-20T15:41:55.613+0200 I CONTROL  [initandlisten] MongoDB starting : pid=219389 port=27017 dbpath=/tmp/ 64-bit host=kfilipek-desktop
2021-10-20T15:41:55.613+0200 I CONTROL  [initandlisten] db version v3.5.13
2021-10-20T15:41:55.613+0200 I CONTROL  [initandlisten] git version: 52bbaa007cd84631d6da811d9a05b59f2dfad4f3
2021-10-20T15:41:55.613+0200 I CONTROL  [initandlisten] allocator: tcmalloc
2021-10-20T15:41:55.613+0200 I CONTROL  [initandlisten] modules: pmse 
2021-10-20T15:41:55.613+0200 I CONTROL  [initandlisten] build environment:
2021-10-20T15:41:55.613+0200 I CONTROL  [initandlisten]     distarch: x86_64
2021-10-20T15:41:55.613+0200 I CONTROL  [initandlisten]     target_arch: x86_64
2021-10-20T15:41:55.613+0200 I CONTROL  [initandlisten] options: { storage: { dbPath: "/tmp/", engine: "pmse" } }
2021-10-20T15:41:55.613+0200 I STORAGE  [initandlisten] /tmp/
2021-10-20T15:41:55.721+0200 I STORAGE  [initandlisten] Engine pool created
2021-10-20T15:41:55.767+0200 I STORAGE  [initandlisten] ns: _mdb_catalog
2021-10-20T15:41:55.767+0200 I STORAGE  [initandlisten] /tmp/_mdb_catalog

Make sure that you have proper link in mongo directory:

ls -alh src/mongo/db/modules/pmse
cd src/mongo/db/modules/pmse
ls -l

You should have files from PMSE:

build.py  build.pyc  LICENSE  README.md  run-jstests.py  SConscript  src  tests  utils