Add replica identity check

[kvch]

Description

This PR adds a new replication check for making sure replicate identity is configured correctly for replicating updates and deletes.

Example output

Correct settings

$ pgstream check --replication -c pg2pg.yaml
✔ wal_level
✔ wal2json
✔ replication_slot_headroom
✔ replication_role_attr
✔ replica_identity
ran 5 checks

Incorrect settings

$ pgstream check --replication -c pg2pg.yaml
✔ wal_level
✔ wal2json
✔ replication_slot_headroom
✔ replication_role_attr
✘ replica_identity: "myschema"."table1": REPLICA IDENTITY=default but no PRIMARY KEY; UPDATE/DELETE WAL events will be skipped — add a PRIMARY KEY, set REPLICA IDENTITY FULL, or REPLICA IDENTITY USING INDEX <unique non-partial NOT-NULL index>
✘ replica_identity: "myschema"."table2": REPLICA IDENTITY=default but no PRIMARY KEY; UPDATE/DELETE WAL events will be skipped — add a PRIMARY KEY, set REPLICA IDENTITY FULL, or REPLICA IDENTITY USING INDEX <unique non-partial NOT-NULL index>
✘ replica_identity: "myschema"."table3": REPLICA IDENTITY=default but no PRIMARY KEY; UPDATE/DELETE WAL events will be skipped — add a PRIMARY KEY, set REPLICA IDENTITY FULL, or REPLICA IDENTITY USING INDEX <unique non-partial NOT-NULL index>
✘ replica_identity: "moreschema"."table1": REPLICA IDENTITY=default but no PRIMARY KEY; UPDATE/DELETE WAL events will be skipped — add a PRIMARY KEY, set REPLICA IDENTITY FULL, or REPLICA IDENTITY USING INDEX <unique non-partial NOT-NULL index>
ran 5 checks

Related Issue(s)

• Related to Add pgstream check command for pre-migration sanity checks #897

Type of Change

Please select the relevant option(s):

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update
• 🔧 Refactoring (no functional changes)
• ⚡ Performance improvement
• 🧪 Test coverage improvement
• 🔨 Build/CI changes
• 🧹 Code cleanup

Testing

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed
• All existing tests pass

Checklist

• Code follows project style guidelines
• Self-review completed
• Code is well-commented
• Documentation updated where necessary

Additional Notes

[kvch]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved the merge conflicts in this PR in commit c961994.

[kvch]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved the merge conflicts in commit 72efce2.

[github-actions]

Merging this branch will decrease overall coverage

Impacted Packages	Coverage Δ	🤖
github.com/xataio/pgstream/pkg/stream/preflight	46.24% (-2.35%)	👎

---

Coverage by file

Changed files (no unit tests)

Changed File	Coverage Δ	Total	Covered	Missed	🤖
github.com/xataio/pgstream/pkg/stream/preflight/builder.go	47.22% (ø)	36	17	19
github.com/xataio/pgstream/pkg/stream/preflight/replica_identity.go	35.48% (+35.48%)	31 (+31)	11 (+11)	20 (+20)	🌟

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.

Changed unit test files

• github.com/xataio/pgstream/pkg/stream/preflight/replica_identity_test.go