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Test hardware-based performance optimizations for WDQS import
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Per today's Search Platform triage meeting, I'm creating this ticket to specifically test hardware optimizations that could speed up the import process. This is in contrast to T336443 , where we are trying to figure out why a data reload is so much slower for our newest R450 chassis.


  • Look into possible hardware optimizations
  • Determine good benchmarking test
  • Enable optimizations one-at-a-time and capture results

Event Timeline

I/O testing: We'll test I/O wdqs1014 (R440) and wdqs1021 (R450) using fio. This Wikitech page might be useful

  • Data-reload (blackbox) testing:
    • Performance governors (powersave vs performance)
      • Powersave: wdqs1022 's data reload (powersave) took 25d, 13h
      • Performance governor: in progress on wdq1024

Hey @bking

I did some experiments a few years back (2021)
You can find my writeup from back then
This was mainly trying different Java and Blazegraph options to see how things changed the behaviour while loading data, but I also tried a bunch of different GCP hardware including different disk setups.

Thanks @Addshore , this is a wealth of great info!

Your observation

CPU clock speed makes a big difference with the first 10 batches of RDF taking 2 hours less on a c2-standard-8 3.1-3.8 Ghz machine instead of a n1-standard-8 2.2-3.7 Ghz machine. This was a reduction from 6 hours to 4 hours.

Seems to line up with the observations from T336443 . Will get a data-reload started on wdqs1024 and report back.

Gehel triaged this task as Low priority.Tue, Nov 28, 1:48 PM
Gehel edited projects, added Data-Platform-SRE; removed Epic, Wikidata-Query-Service, Wikidata.

@dr0ptp4kt mentioned that it's possible to limit the scope of a data reload. Specifically, it's possible to execute this against a single munged file instead of completing a whole reload. My guess is this can be done fairly easily with the current loadData script . Tagging this for further discussion.

^^ last comment was meant for T336443 , apologies for repeating the earlier comment.