Release 13.0 Improve handling of unsupported collation-encoding combinations

[m3hm3t]

Queries using incompatible collations and encodings, such as da_DK.utf8 with SQL_ASCII, result in errors like:

ERROR: collation "da_DK.utf8" for encoding "SQL_ASCII" does not exist
ERROR: collation "pg_c_utf8" for encoding "SQL_ASCII" does not exist

Steps to Reproduce:
Execute a query specifying an unsupported collation:
CREATE TABLE test_table (id INT COLLATE "da_DK.utf8");

Expected Behavior:
Distributed query validation may catch unsupported configurations and provide actionable error messages.

Suggested Solution:

• Validate collation-encoding compatibility during table creation.
• Enhance error messages to provide actionable guidance.

Severity:
Not a blocker:
SQL_ASCII is rarely used in modern databases. It is considered outdated and is generally not recommended for new applications.

[m3hm3t]

This problem with da_DK.utf8 also occurs in the release-12.1 tests.

[m3hm3t]

release-13 test:
Update sqlancer-test-pipelines_2.yml · m3hm3t/citus-13.0@7d7bef7

to compare release-12.1 test:
Update sqlancer-test-pipelines_2.yml · m3hm3t/citus-13.0@7d7bef7

[onurctirtir]

Same here, as long as we get the same error message as what we would get for Postgres tables, I'd not say that this is a Citus issue.

[m3hm3t]

Same here, as long as we get the same error message as what we would get for Postgres tables, I'd not say that this is a Citus issue.

My conclusion as well that this is not a Citus-specific issue but a PostgreSQL limitation.

[onurctirtir]

I think we can close the issue then.