Slow Gatsby build on multicore VM vs MacBook

[vnugent]

I have a large gatsby site with 20K mdx files.

• Node: 16.11.0
• Gatsby: ^3.14.2 => 3.14.3
• PARALLEL_QUERY_RUNNING=true
• LMDB_STORE=true.

info Total nodes: 84446, SitePage nodes: 20208
success Building static HTML for pages - 45.545s - 20208/20208 443.70/s

On my 2018 Macbook the build usually takes 12 minutes. The fan comes on and the laptop gets warm. However, on a 4CPU, 8G Ubuntu VM, it takes over 40 minutes and only 1 CPU is doing the work (see top output). I have also set/unset GATSBY_CPU_COUNT=4 and GATSBY_EXPERIMENTAL_QUERY_CONCURRENCY=2,4,16,32 to no avail.

top - 08:07:42 up 24 min,  2 users,  load average: 1.00, 0.93, 0.67
Tasks: 138 total,   2 running, 136 sleeping,   0 stopped,   0 zombie
%Cpu0  :  1.7 us,  0.0 sy,  0.0 ni, 98.3 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
%Cpu1  : 99.0 us,  0.7 sy,  0.0 ni,  0.3 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st <----  Gatsby
%Cpu2  :  1.0 us,  0.3 sy,  0.0 ni, 98.7 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
%Cpu3  :  1.7 us,  0.0 sy,  0.0 ni, 98.3 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :   7952.7 total,   2980.4 free,   1968.9 used,   3003.4 buff/cache
MiB Swap:      0.0 total,      0.0 free,      0.0 used.   5682.6 avail Mem

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
   3306 build-u+  20   0 3585192   1.4g  89324 R 102.0  18.1   2:27.79 node
   3388 build-u+  20   0   12096   3876   3340 R   0.3   0.0   0:00.17 top
      1 root      20   0  164504  10788   7788 S   0.0   0.1   0:01.42 systemd
...

build log

info The following flags are active:
- PRESERVE_FILE_DOWNLOAD_CACHE · (Umbrella Issue
(https://gatsby.dev/cache-clearing-feedback)) · Don't delete the downloaded
files cache when changing gatsby-node.js & gatsby-config.js files.
- PARALLEL_SOURCING · EXPERIMENTAL · (Umbrella Issue
(https://gatsby.dev/parallel-sourcing-feedback)) · Run all source plugins at the
 same time instead of serially. For sites with multiple source plugins, this can
 speedup sourcing and transforming considerably.
- LMDB_STORE · EXPERIMENTAL · (Umbrella Issue
(https://gatsby.dev/lmdb-feedback)) · Store nodes in a persistent embedded
database (vs in-memory). Lowers peak memory usage. Requires Node v14.10 or
above.
- PARALLEL_QUERY_RUNNING · EXPERIMENTAL · (Umbrella Issue
(https://gatsby.dev/pqr-feedback)) · Parallelize running page queries in order
to better saturate all available cores. Improves time it takes to run queries
during gatsby build. Requires Node v14.10 or above.


ESC[2KESC[1AESC[2KESC[Gsuccess open and validate gatsby-configs, load plugins - 1.110s

ESC[2KESC[1AESC[2KESC[Gsuccess onPreInit - 0.006s

ESC[2KESC[1AESC[2KESC[Gsuccess initialize cache - 0.087s

ESC[2KESC[1AESC[2KESC[Gsuccess copy gatsby files - 0.054s

ESC[2KESC[1AESC[2KESC[Gsuccess Compiling Gatsby Functions - 0.276s

ESC[2KESC[1AESC[2KESC[Gsuccess onPreBootstrap - 0.291s

ESC[2KESC[1AESC[2KESC[Gsuccess createSchemaCustomization - 0.032s

<it's doing something here for a long time>