Horton

Re: Virtual generated columns

Peter Eisentraut <peter@eisentraut.org>

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From: Peter Eisentraut <peter@eisentraut.org>
To: pgsql-hackers <pgsql-hackers@postgresql.org>
Cc: jian he <jian.universality@gmail.com>, Dean Rasheed <dean.a.rasheed@gmail.com>
Date: 2025-01-14T13:37:49Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Expand virtual generated columns for ALTER COLUMN TYPE

  2. Eliminate code duplication in replace_rte_variables callbacks

  3. Expand virtual generated columns in the planner

  4. Virtual generated columns

  5. Additional tests for stored generated columns

  6. Improve generated_stored test

  7. Fix handling of CREATE DOMAIN with GENERATED constraint syntax

  8. Add pg_constraint rows for not-null constraints

  9. Put generated_stored test objects in a schema

  10. Rename regress test generated to generated_stored

  11. Small code simplification

  12. Remove useless code

  13. Remove useless initializations

  14. doc: Clarify that pg_attrdef also stores generation expressions

  15. Clean out column-level pg_init_privs entries when dropping tables.

  16. Re-implement the ereport() macro using __VA_ARGS__.

Attachments

On 13.01.25 19:15, Dean Rasheed wrote:
> On Wed, 8 Jan 2025 at 16:14, Peter Eisentraut <peter@eisentraut.org> wrote:
>>
>> Here is a new patch version
> 
> In expand_generated_columns_in_expr():
> 
> +       RangeTblEntry *rte;
> +
> +       rte = makeNode(RangeTblEntry);
> +       rte->relid = RelationGetRelid(rel);
> +
> +       node = expand_generated_columns_internal(node, rel, rt_index, rte);
> 
> This dummy RTE is a bit too minimal.
> 
> I think it should explicitly set rte->rtekind to RTE_RELATION, even
> though that's technically not necessary since RTE_RELATION is zero.
> 
> In addition, it needs to set rte->eref, because expandRTE() (called
> from ReplaceVarsFromTargetList()) needs that when expanding whole-row
> variables. Here's a simple reproducer which crashes:
> 
> CREATE TABLE foo (a int, b int GENERATED ALWAYS AS (a*2) VIRTUAL);
> ALTER TABLE foo ADD CONSTRAINT foo_check CHECK (foo IS NOT NULL);

Thanks, fixed.  Here is a new patch with that fixed and also a few 
tweaks suggested by Jian.

I've also added a patch that addresses logical replication.  It 
basically adds back some of the prohibitions against including generated 
columns in publications that have been lifted, but this time only for 
virtual generated columns, and amends the documentation.  It doesn't 
rename the publication option "publish_generated_columns", but maybe 
that should be done.