CDM cache warming issues one record-count query per concept on Snowflake, Spark and BigQuery (getConceptsForBatch.sql relies on integer division)

Aperta
  • Qualcosa non va?
#2,588 0 commenti 0 reazioni 0 assegnatari Vedi su GitHub

I maintainer di solito rispondono entro 1 giorno

@DG47 ci sta già lavorando.

Dal 10/11/2026.

  • #2589 di @DG47 — aperta

Valutazione

Difficoltà
3/5
Tempo stimato
1-2 giorni
Idoneità per principianti
66/100
Tipo di issue
Bug
Chiarezza
Specificata chiaramente
Stato di attività
Attiva
Stack tecnologico
java, spark, sql
Ambito
backend, databases

Direzione di ricerca

Start with getConceptsForBatch.sql and trace its use from CDMCacheService.warm into cacheRecordsBatch; the issue identifies the integer division expression that causes one group per concept on some platforms. Check how SqlRender handles the query for Snowflake, Spark/Databricks, and BigQuery, then verify warming batches concepts into ranges of 100,000 and reduces the number of getBatchConceptRecordCount queries.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Descrizione

Expected behavior

When the CDM record count cache is warmed for a source (CDMCacheService.warm), getConceptsForBatch.sql should split achilles_result_concept_count into ranges of 100,000 concepts (@batch_size), so that the warming job runs a handful of getBatchConceptRecordCount queries per source regardless of the database platform.

Actual behavior

The range id is computed as

select concept_id, ordinal / @batch_size as group_id
FROM (select concept_id, row_number() over (order by concept_id) as ordinal
      FROM @resultTableQualifier.achilles_result_concept_count c) Q

and the outer query groups by group_id. This only yields whole ranges where / on two integers is integer division (PostgreSQL, SQL Server, Redshift). SqlRender does not rewrite the expression for any dialect, so:

  • Snowflake: ordinal / 100000 is a NUMBER with six decimals (1 / 100000 = 0.000010), distinct for every ordinal.
  • Spark / Databricks: the quotient is a DOUBLE (1.0E-5), distinct for every ordinal.
  • BigQuery: / on INT64 returns FLOAT64, distinct for every ordinal.

So on those platforms every concept is its own group, the query returns one min_concept = max_concept row per concept, and cacheRecordsBatch runs one getBatchConceptRecordCount query per row of achilles_result_concept_count (typically several hundred thousand round trips). The warming job for such a source takes hours to days instead of minutes and in practice never completes.

Steps to reproduce behavior
  1. Configure a Snowflake, Databricks/Spark or BigQuery source with a results daimon whose schema contains achilles_result_concept_count (for example 300,000 rows) and is_cache_enabled = true.
  2. Start WebAPI (or call GET /cdmresults/clearCache to trigger warming) and watch the query history on the database.
  3. Observe select group_id, min(concept_id) ..., max(concept_id) ... group by group_id returning as many rows as the table has concepts, followed by one select cc.concept_id, record_count, descendant_record_count ... WHERE cc.concept_id >= ? and cc.concept_id <= ? per concept.

Directly on the platform:

-- Snowflake
select 1 / 100000;      -- 0.000010
-- Spark
select 1 / 100000;      -- 1.0E-5
-- BigQuery
select 1 / 100000;      -- 1.0E-5
-- PostgreSQL / SQL Server
select 1 / 100000;      -- 0
Environment
  • WebAPI master @ 89de588 (also present in 2.15.x; the query dates from the Data Sources caching work in #1993)
  • SqlRender 1.19.1
Lingua principale
Java
Stelle
153
Fork
186
Merge medio
2g 19h
PR unite (30g)
19

Preparare l'ambiente

  • Include un Dockerfile o un file Docker Compose
  • Nessun modello di pull request
  • Nessuna guida per i contributori

Come iniziare

  1. Leggi tutta la issue e poi la guida ai contributi del progetto.
  2. Commenta sulla issue per dire che te ne occupi tu — evita che due persone facciano lo stesso lavoro.
  3. Fai un fork del repository e lavora su un branch.
  4. Apri una pull request che faccia riferimento al numero della issue.

Altre issue di OHDSI/WebAPI

Tutte le issue di OHDSI/WebAPI

Issue simili

Altre issue su Java

Ricevi le nuove issue nella tua casella

Un breve riepilogo di issue GitHub adatte ai principianti.