Re: Virtual generated columns
Peter Eisentraut <peter@eisentraut.org>
Commits
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the thread's linked commits as JSON, with link sources.
API reference →
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Expand virtual generated columns for ALTER COLUMN TYPE
- 5069fef1cfae 18.0 landed
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Eliminate code duplication in replace_rte_variables callbacks
- 363a6e8c6fcf 18.0 landed
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Expand virtual generated columns in the planner
- 1e4351af329f 18.0 landed
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Virtual generated columns
- 83ea6c54025b 18.0 landed
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Additional tests for stored generated columns
- 41084409f635 18.0 landed
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Improve generated_stored test
- 44b61efb7928 18.0 landed
- 86749ea3b766 18.0 landed
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Fix handling of CREATE DOMAIN with GENERATED constraint syntax
- 84a67725cd11 18.0 landed
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Add pg_constraint rows for not-null constraints
- 14e87ffa5c54 18.0 cited
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Put generated_stored test objects in a schema
- 894be11adfa6 18.0 landed
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Rename regress test generated to generated_stored
- b9ed4969250d 18.0 landed
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Small code simplification
- 7ff9afbbd1df 18.0 landed
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Remove useless code
- e26d313bad92 18.0 landed
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Remove useless initializations
- da2aeba8f533 18.0 landed
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doc: Clarify that pg_attrdef also stores generation expressions
- da486d360103 18.0 landed
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Clean out column-level pg_init_privs entries when dropping tables.
- 76618097a6c0 17.0 cited
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Re-implement the ereport() macro using __VA_ARGS__.
- e3a87b4991cc 13.0 cited
On 29.04.24 20:54, Corey Huinker wrote: > -- generation expression must be immutable > -CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision > GENERATED ALWAYS AS (random()) STORED); > +CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision > GENERATED ALWAYS AS (random()) VIRTUAL); > > Does a VIRTUAL generated column have to be immutable? I can see where > the STORED one has to be, but consider the following: > > CREATE TABLE foo ( > created_at timestamptz DEFAULT CURRENT_TIMESTAMP, > row_age interval GENERATED ALWAYS AS CURRENT_TIMESTAMP - created_at > ); I have been hesitant about this, but I'm now leaning toward that we could allow this. > -- can't have generated column that is a child of normal column > CREATE TABLE gtest_normal (a int, b int); > -CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS > (a * 2) STORED) INHERITS (gtest_normal); -- error > +CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS > (a * 2) VIRTUAL) INHERITS (gtest_normal); -- error > > This is the barrier to the partitioning reorganization scheme I > described above. Is there any hard rule why a child table couldn't have > a generated column matching the parent's regular column? I can see where > it might prevent indexing that column on the parent table, but is there > some other dealbreaker or is this just a "it doesn't work yet" situation? We had a quite a difficult time getting the inheritance business of stored generated columns working correctly. I'm sticking to the well-trodden path here. We can possibly expand this if someone wants to work out the details. > One last thing to keep in mind is that there are two special case > expressions in the spec: > > GENERATED ALWAYS AS ROW START > GENERATED ALWAYS AS ROW END > > and we'll need to be able to fit those into the catalog. I'll start > another thread for that unless you prefer I keep it here. I think this is a separate feature.