~/talk

Make Your Data FABulous

Talkat Crunch Conference 2019 · 2019-10-17..10-18· [databases, distributed-systems]
slides:none on file

Introduces the FAB theory (must choose two of Fast, Accurate, Big) and shows concrete Elasticsearch tradeoffs: term aggregations undercount when shard-level top-k truncation returns 60 vs expected 64 and can be fixed by raising shard_size (default ~size1.5+10) at the cost of work; unique-count uses HyperLogLog++ with a precision default 3000 (cap 40000) — 800 precision yields ~6% error, ~80KB gives ~1% error; relevance (BM25/TF‑IDF) skews across shards and is corrected with DFS query_then_fetch* or by using one shard.

AI-written summary · about

  1. 0:00Start
  2. 1:38CAP Theorem
  3. 4:03Misconceptions Partition Tolerance is not a choice in a distributed system
  4. 7:00Robinson Crusoe
  5. 8:06dev/null breaks CAP: effect of write are always consistent, it's always available, and all replicas are consistent even during partitions.
  6. 9:12Mark Harwood
  7. 9:59Accurate Exact instead of approximate results
  8. 10:19Big Parallelization needed to handle the data
  9. 11:40Shard Unit of scale
  10. 19:30(Sub) Results Per Shard
  11. 20:49How Many? Results per shard Results for aggregation
  12. 24:09Cardinality Aggregation
  13. 30:56precision_threshold Default 3,000 Maximum 40,000
  14. 32:42Precompute Hashes? Client or mapper-murmura plugin
  15. 33:09It Depends large / high-cardinality fields low cardinality / numeric fields
  16. 33:44Improvement? "New cardinality estimation algorithms for HyperLogLog sketches"
  17. 35:12Term Frequency / Inverse Document Frequency (TF/IDF)
  18. 38:31DFS Query Then Fetch Distributed Frequency Search
  19. 40:41Single Shard Default in 7.0
  20. 43:01Conclusion
~/search
type to search 6,249 conferences, 138,987 speakers and 185,172 talks
~/help
cmdctrl k
search every conference, speaker and series
/
focus the filter search
h
home
c
conferences
s
speakers
e
series
t
light / dark — the status bar button does the same
?
this help
esc
close this, then clear every filter — or just the search, while you are typing in it

Ignored while you are typing. Pages without a filter rail have no search to focus.