Horton

Re: Virtual generated columns

Peter Eisentraut <peter@eisentraut.org>

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From: Peter Eisentraut <peter@eisentraut.org>
To: jian he <jian.universality@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>, Dean Rasheed <dean.a.rasheed@gmail.com>
Date: 2025-01-08T16:17:13Z
Lists: pgsql-hackers

Commits

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  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__.

On 04.12.24 05:55, jian he wrote:
> On Fri, Nov 29, 2024 at 6:13 PM Peter Eisentraut <peter@eisentraut.org> wrote:
>>
>> - Added support for virtual columns in trigger column lists.  (For that,
>> I renamed ExecInitStoredGenerated() to ExecInitGenerated(), which
>> handles the computation of ri_extraUpdatedCols.)
>>
> 
> why not duplicate some code from ExecInitStoredGenerated to
> ExecGetExtraUpdatedCols?

This answers itself: I'd rather not duplicate code.  I don't see that as 
an improvement.

> * now the expression is that something initiated for the virtual
> generated column. which may not be necessary for virtual columns.
> let's make ResultRelInfo->ri_GeneratedExprsI,
> ResultRelInfo->ri_GeneratedExprsU be NULL for virtual columns.
> 
> currently it may look like this:
> (gdb) p resultRelInfo->ri_GeneratedExprsU
> $20 = (ExprState **) 0x34f9638
> (gdb) p resultRelInfo->ri_GeneratedExprsU[0]
> $21 = (ExprState *) 0x0
> (gdb) p resultRelInfo->ri_GeneratedExprsU[1]
> $22 = (ExprState *) 0x0
> (gdb) p resultRelInfo->ri_GeneratedExprsU[2]
> $23 = (ExprState *) 0x40

I have fixed that in v11.

> * ExecInitStoredGenerated main used in ExecComputeStoredGenerated.
> * we also need to slightly change ExecInitGenerated's comments.

also fixed

> * in InitResultRelInfo, do we need explicit set ri_Generated_valid to false?

Doesn't seem necessary.  The struct is initialized to zero at the beginning.