[294] Optimise PostgresMetadataFetcher

[suddendust]

Description

I observed that querying information_schema for table metadata was much slower than querying pg_catalog for the same. See the following logs:

With information_schema:

2026-03-26 06:45:10.459 [pool-5-thread-3] INFO  o.h.c.d.p.PostgresLazyilyLoadedSchemaRegistry - {entityId=7a44307e-b93b-37a9-b53d-75fc07c713c3, entityType=API, requestId=b, shadowEventId=6bae0afe-6774-4cf5-b314-359ff396bb27, tenantId=3e761879-c77b-4d8f-a075-62ff28e8fa8c, writeType=CREATE_OR_REPLACE} Successfully loaded schema for table: entities_api_shadow, columns: 133, durationMs: 39

With pg_catalog:

2026-03-26 06:45:10.459 [pool-5-thread-3] INFO  o.h.c.d.p.PostgresLazyilyLoadedSchemaRegistry - {entityId=7a44307e-b93b-37a9-b53d-75fc07c713c3, entityType=API, requestId=b, shadowEventId=6bae0afe-6774-4cf5-b314-359ff396bb27, tenantId=3e761879-c77b-4d8f-a075-62ff28e8fa8c, writeType=CREATE_OR_REPLACE} Successfully loaded schema for table: entities_api_shadow, columns: 133, durationMs: 39

This is ~ 26x faster.

Testing

Tested both version in an sandbox env.

Checklist:

• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• Any dependent changes have been merged and published in downstream modules

Documentation

https://dba.stackexchange.com/questions/302587/what-is-faster-pg-catalog-or-information-schema

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 55.96%. Comparing base (f25bebd) to head (ebbb1c3).

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HEAD has 1 upload less than BASE

Flag	BASE (f25bebd)	HEAD (ebbb1c3)
integration	1	0

Additional details and impacted files

@@              Coverage Diff              @@
##               main     #283       +/-   ##
=============================================
- Coverage     81.63%   55.96%   -25.68%     
+ Complexity     1549     1548        -1     
=============================================
  Files           242      242               
  Lines          7450     7442        -8     
  Branches        720      719        -1     
=============================================
- Hits           6082     4165     -1917     
- Misses          916     2855     +1939     
+ Partials        452      422       -30     

Flag	Coverage Δ
integration	?
unit	55.96% <100.00%> (-0.03%)	⬇️

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