fix(ebean-dao): re-warm schema cache at end of ensureSchemaUpToDate (#618 regression)

[NatalliaUlashchick]

Summary

#615 pre-warmed SharedSchemaCache at the end of EbeanLocalAccess.ensureSchemaUpToDate(). #618 moved that pre-warm into the constructor (so it also runs for deploys that gate ensureSchemaUpToDate() off and migrate schema as a separate job) — but it removed the post-evolution re-warm.

For consumers that build their schema in-JVM at boot (i.e. that call ensureSchemaUpToDate() — e.g. integration tests / dev deploys with skipSchemaUpdate=false), the constructor pre-warm now runs before the schema-evolution DDL. It caches an empty/incomplete view that is pinned for the cache TTL, so columnExists()/indexExists() report missing columns/indexes, EbeanLocalAccess.batchGetUnion drops the aspect from its query, and reads silently return nothing.

Fix: restore the pre-warm at the end of ensureSchemaUpToDate() (after the evolution DDL is applied), while keeping #618's constructor pre-warm. The re-warm overwrites the stale entry with the complete, post-migration schema. It runs only where ensureSchemaUpToDate() is called (in-JVM schema build, skipSchemaUpdate=false); deploys that gate it off (prod) are unaffected — there the constructor pre-warm already sees the complete schema. Effectively recovers #615/0.6.183 behavior for that path without giving up #618's prod cold-start win.

Testing Done

• Added EbeanLocalAccessTest.testEnsureSchemaUpToDateReWarmsSharedSchemaCache: constructs an access (constructor pre-warm), adds a column after construction, then asserts ensureSchemaUpToDate() re-warms the shared cache. Fails on the pre-fix behavior (verified — 2 failures across both nonDollarVirtualColumnsEnabled factory variants); passes with the fix.
• All ensureSchemaUpToDate-exercising test classes pass: EbeanLocalAccessTest, InstrumentedEbeanLocalAccessTest, FlywaySchemaEvolutionManagerTest, FlywaySchemaEvolutionManagerTestWithoutServiceIdentifier.
• AIM to verify end-to-end on ai-metadata-gms against a build with this change.

Checklist

• The PR conforms to DataHub's Contributing Guideline (Commit Message Format)
• Links to related issues — regression from perf(ebean-dao): move SharedSchemaCache pre-warm to constructor #618; restores perf(ebean-dao): share schema metadata cache per database to fix cold-start P99 spikes #615 behavior; alternative to fix(ebean-dao): do not cache empty schema loads (SharedSchemaCache poisoning, #618 regression) #625
• Docs related to the changes have been added/updated (if applicable) — n/a

🤖 Generated with Claude Code

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.91%. Comparing base (e528785) to head (84de99a).

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #627      +/-   ##
============================================
+ Coverage     66.86%   66.91%   +0.05%     
- Complexity     1886     1887       +1     
============================================
  Files           148      148              
  Lines          7274     7276       +2     
  Branches        881      881              
============================================
+ Hits           4864     4869       +5     
+ Misses         2025     2022       -3     
  Partials        385      385              

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