Add support for editing column comments on Iceberg tables

[findinpath]

Description

Enable the Trino users to execute commands like the following:

COMMENT ON COLUMN iceberg_table.some_column IS 'A textual description of the purpose of some_column'

Relevant connector test: io.trino.testing.AbstractTestDistributedQueries#testCommentColumn

Is this change a fix, improvement, new feature, refactoring, or other?

This change is a new feature.

Is this a change to the core query engine, a connector, client library, or the SPI interfaces? (be specific)

This change affect only the Iceberg connector.

How would you describe this change to a non-technical end user or system administrator?

This PR adds the ability to edit comments for Iceberg table columns.

Related issues, pull requests, and links

PRs depending on this change: #11072

Documentation

(x) No documentation is needed.
( ) Sufficient documentation is included in this PR.
( ) Documentation PR is available with #prnumber.
( ) Documentation issue #issuenumber is filed, and can be handled later.

Release notes

( ) No release notes entries required.
(x) Release notes entries required with the following suggested text:

# Iceberg
* Add support for editing column comments

[alexjo2144]

Do we need to update the comment both in the metastore and via the Iceberg updateColumnDoc?

If we don't need the metastore's comment set we can move this code up to IcebergMetadata and make it catalog agnostic.

[findinpath]

I inspired myself in the implementation from the updateTableComment method which does also talk to the metastore.

[findepi]

I think we should remove both, as it leads to inconsistent state if the icebergTable.updateSchema().updateColumnDoc fails.

let's reconsider with a followup

[findepi]

I think we should remove both, as it leads to inconsistent state if the icebergTable.updateSchema().updateColumnDoc fails.

let's reconsider with a followup

[findepi]

As a follow-up can you please add tests for CREATE TABLE with column comment?

see

trino/testing/trino-testing/src/main/java/io/trino/testing/AbstractTestDistributedQueries.java

Lines 410 to 413 in dbc25ac

	// TODO: comment set when creating a table
	// assertUpdate("CREATE TABLE " + tableName + "(a integer COMMENT 'new column comment')");
	// assertThat(getColumnComment(tableName, "a")).isEqualTo("new column comment");
	// assertUpdate("DROP TABLE " + tableName);

[findinpath]

Created #11161 follow-up issue for ditching metastore updates for COMMENT on Iceberg table/column.

[mosabua]

Do we need to document this in the Iceberg connector SQL support section or somewhere? If not .. I dont see any other docs for this.

[findinpath]

@mosabua there is a link towards Schema and table management document within the https://trino.io/docs/current/connector/iceberg.html#sql-support section.
The COMMENT statement works same as for the other connectors now. https://trino.io/docs/current/sql/comment.html

I think that in this case (the current change just added a minor missing functionality for the Iceberg connector) there is no need for extra documentation. If there is a need to enrich the docs I can gladly take care of it.

[mosabua]

Thanks for checking that out. I agree @findinpath .. we are good ;-)