Source Posgres: [CDC] allow null values for columns

[yurii-bidiuk]

What

Fixes #8557

How

Added 'null' values to shema building.
Before schema for column looked like { "type": "string" }
Now: { "type": [ "string", null ] }

Recommended reading order

1. x.java
2. y.python

🚨 User Impact 🚨

There is no user impact

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[yurii-bidiuk]

/test connector=connectors/source-postgres

🕑 connectors/source-postgres https://github.com/airbytehq/airbyte/actions/runs/2371412185
✅ connectors/source-postgres https://github.com/airbytehq/airbyte/actions/runs/2371412185
No Python unittests run

[alexandertsukanov]

LGTM

[alexandr-shegeda]

LGTM. we can proceed with publishing and merging without airbyte review

[yurii-bidiuk]

/publish connector=connectors/source-postgres

🕑 connectors/source-postgres https://github.com/airbytehq/airbyte/actions/runs/2379210312
❌ Failed to publish connectors/source-postgres
❌ Couldn't auto-bump version for connectors/source-postgres

[grishick]

If I understand the changes correctly, this will make all Date, Text, and Money fields nullable (optional). I don't think that's the correct change though, because it will also allow non-nullable columns to be NULLs. Could we use RelationalColumn::isOptional to detect if a column is nullable?

[yurii-bidiuk]

/test connector=connectors/source-postgres

🕑 connectors/source-postgres https://github.com/airbytehq/airbyte/actions/runs/2382689650
✅ connectors/source-postgres https://github.com/airbytehq/airbyte/actions/runs/2382689650
No Python unittests run

Build Passed

Test summary info:

All Passed

[yurii-bidiuk]

@grishick
I tested these changes and it doesn't break any logic now. If I add optional only for nullable fields it will produce #8557. The reason is that delete event produces a message with all fields set as null [1, null, null, null] and if some of these fields has NOT NULL constrain, we will get #8557

[grishick]

@grishick I tested these changes and it doesn't break any logic now. If I add optional only for nullable fields it will produce #8557. The reason is that delete event produces a message with all fields set as null [1, null, null, null] and if some of these fields has NOT NULL constrain, we will get #8557

OK. Thank you for explaining that. For posterity, please add a comment in the code explaining why it is important to keep all fields NULL-able for CDC.

[grishick]

/publish connector=connectors/source-postgres run-tests=false

🕑 connectors/source-postgres https://github.com/airbytehq/airbyte/actions/runs/2397842913
🚀 Successfully published connectors/source-postgres
🚀 Auto-bumped version for connectors/source-postgres
✅ connectors/source-postgres https://github.com/airbytehq/airbyte/actions/runs/2397842913

[grishick]

I reran the build and tests locally to make sure they pass.

[yurii-bidiuk]

@grishick thank you for helping with this issue