fix(connectors): unify extract_column_value into single free function

[atharvalade]

Which issue does this PR close?

Closes #3172

Rationale

Bug fixes or new type support added to one copy of extract_column_value silently won't apply to the other, causing divergence between sequential and parallel code paths.

What changed?

The Postgres source connector had extract_column_value as a method on PostgresSource (&self), making it impossible to call from static/parallel contexts without duplicating the function. Any future parallel/chunked path would need its own copy.

Converted it to a single free function callable from any context. Added missing DATE (via chrono::NaiveDate) and BPCHAR type handling that the parallel copy on the benchmark branch had but this version lacked.

Local Execution

• Passed
• Pre-commit hooks ran

AI Usage

1. Opus 4.6
2. exploration and implementation guidance
3. Verified via cargo check, clippy -D warnings, fmt --check, all 19 unit tests passing, CI lint scripts passing
4. Yes, all code can be explained

[codecov]

Codecov Report

❌ Patch coverage is 38.61386% with 62 lines in your changes missing coverage. Please review.
✅ Project coverage is 49.02%. Comparing base (a68fe1d) to head (830adf6).

Files with missing lines	Patch %	Lines
core/connectors/sources/postgres_source/src/lib.rs	38.61%	55 Missing and 7 partials ⚠️

❌ Your patch check has failed because the patch coverage (38.61%) is below the target coverage (50.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@              Coverage Diff              @@
##             master    #3199       +/-   ##
=============================================
- Coverage     74.17%   49.02%   -25.15%     
  Complexity      943      943               
=============================================
  Files          1237     1233        -4     
  Lines        112607    97283    -15324     
  Branches      89167    74183    -14984     
=============================================
- Hits          83521    47691    -35830     
- Misses        26294    47068    +20774     
+ Partials       2792     2524      -268     

Components	Coverage Δ
Rust Core	42.21% <38.61%> (-33.09%)	⬇️
Java SDK	58.44% <ø> (ø)
C# SDK	69.47% <ø> (-1.18%)	⬇️
Python SDK	81.43% <ø> (ø)
Node SDK	91.44% <ø> (-0.10%)	⬇️
Go SDK	39.80% <ø> (-0.11%)	⬇️

Files with missing lines	Coverage Δ
core/connectors/sources/postgres_source/src/lib.rs	67.76% <38.61%> (-0.15%)	⬇️

... and 394 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[lukaszzborek]

@atharvalade
In issue is Postgres source connector has two nearly identical functions and to remove one. But i don't see second one.
I'm jus asking for clarification, if i don't see something

Also remeber about #3196 where you also add Date

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs.

If you need a review, please ensure CI is green and the PR is rebased on the latest master. Don't hesitate to ping the maintainers - either @core on Discord or by mentioning them directly here on the PR.

Thank you for your contribution!

[hubcio]

/author

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs.

If you need a review, please ensure CI is green and the PR is rebased on the latest master. Don't hesitate to ping the maintainers - either @core on Discord or by mentioning them directly here on the PR.

Thank you for your contribution!

[atharvalade]

@atharvalade In issue is Postgres source connector has two nearly identical functions and to remove one. But i don't see second one. I'm jus asking for clarification, if i don't see something

Also remeber about #3196 where you also add Date

Good catch, the second copy (extract_column_value_static) lives on the feat/pg-to-iceberg-benchmark branch (not yet merged to master), where the parallel/chunked polling paths were added. This PR preemptively converts the method to a free function so that when those paths land, they can call the same function instead of duplicating it. I'll drop the DATE addition here since #3196 already covers it, and rebase on latest master.

[atharvalade]

/ready

[atharvalade]

/ready