Support Iceberg OPTIMIZE with WHERE casting timestamp_tz column to a date

[findepi]

Follow-up to #12795

Among other things, that PR added support for

-- regardless of session zone
ALTER TABLR iceberg_table EXECUTE optimize WHERE c_timestamp_tz > with_timezone(a_date_constant, 'UTC');

-- only when session zone is UTC
ALTER TABLR iceberg_table EXECUTE optimize WHERE c_timestamp_tz > a_date_constant

This PR adds support for

-- regardless of session zone
ALTER TABLR iceberg_table EXECUTE optimize WHERE CAST(c_timestamp_tz AS date) > a_date_constant

Further enhances #7905
Fixes #12362

[losipiuk]

For future: I wonder if we can communicate a constraint on a type from connector to engine so standard optimizer can handle that.

[findepi]

Yes, we could do that as part of io.trino.spi.connector.ColumnMetadata.

Or, we could use a dedicate type: #2273
A type may be better because this limitation -- storing point in time only, without time zone -- isn't really specific to Iceberg.

[findepi]

cc @martint

[findepi]

cc @martint

[findepi]

(just rebased to resolve a conflict with #12911)

[erichwang]

@findepi Just a quick question:

-- regardless of session zone
ALTER TABLR iceberg_table EXECUTE optimize WHERE CAST(c_timestamp_tz AS date) > a_date_constant

This wouldn't work for Iceberg time partitions since c_timestamp_tz could be in any time zone right? I thought we had discussed making it look like:

-- regardless of session zone
ALTER TABLR iceberg_table EXECUTE optimize WHERE CAST(c_timestamp_tz AT TIME ZONE 'UTC' AS date) > a_date_constant

To force the same timezone?

Side note: that being said, it looks like if we just do with_timezone(a_date_constant, 'UTC') in our query, that might already get us what we need, making this change more of a nice to have.

[findepi]

Just a quick question:

-- regardless of session zone
ALTER TABLR iceberg_table EXECUTE optimize WHERE CAST(c_timestamp_tz AS date) > a_date_constant

This wouldn't work for Iceberg time partitions since c_timestamp_tz could be in any time zone right?

in Iceberg, timestamp with time zone values are all in UTC. Iceberg stores point in time, but not the time zone.

Side note: that being said, it looks like if we just do with_timezone(a_date_constant, 'UTC') in our query, that might already get us what we need, making this change more of a nice to have.

Yep, this is already supported, but may be less intuitive to users.
CAST(c_timestamp_tz AS date) > a_date_constant looks simpler than
c_timestamp_tz > with_timezone(a_date_constant, 'UTC')

fortunately, it's or, not xor. People can choose whichever they prefer.

[colebow]

I think we should document this so users know how to leverage this...

[erichwang]

Yes, definitely prefer CAST(c_timestamp_tz AS date) > a_date_constant if possible. That's how I normally think about it.